The ubiquity of microbes, their manifold activities and pervasive influence on the health of all life, local environments and the planet, necessitate an understanding of relevant microbial processes for informed, evidence‐based decision‐making at all levels of society – i.e. Microbiology Literacy. While teaching microbiology topics in school is key to this objective, a strategic program to expose children directly and personally to natural and managed microbial processes, and the results of their actions, through carefully planned class excursions to local venues, can be instrumental in bringing microbes to life for children. In outlining some of the options for microbiology excursions, providing suggestions for discussion topics, and considering their educational value, we strive to extend the vistas of current class excursions and to: (i) inspire teachers and school managers to incorporate more microbiology excursions into curricula; (ii) encourage microbiologists to support school excursions and generally get involved in bringing microbes to life for children; (iii) urge leaders of organisations (biopharma, food industries, universities, etc.) to give school outreach activities a more prominent place in their mission portfolios, and (iv) convey to policy makers the benefits of providing schools with funds, materials and flexibility for educational endeavours beyond the classroom.
The ubiquity of microbes, their manifold activities and pervasive influence on the health of all life, local environments and the planet, necessitate an understanding of relevant microbial processes for informed, evidence‐based decision‐making at all levels of society. These range from the individual (e.g. relating to diet, hygiene, vaccination, pet ownership, choice of domestic cleaning products) through to governments and international organizations (e.g. provision of clean water, managing climate change, food security, monitoring and controlling the spread of pathogens and antibiotic resistance) (Timmis et al. , 2019). Microbial products and activities are pivotal to remedying major societal problems (e.g. by degrading toxic pollutants and waste, attaining increased crop yields, producing biodegradable plastics, ensuring the supply of new medicines, including antibiotics, and providing sustainable fuels), and so are key to policy decisions aimed at achieving Sustainable Development Goals (see editorial by Timmis et al. , 2017a, and papers in the associated Special Issue of Microbial Biotechnology), including the provision of opportunities for entrepreneurship, economic growth and employment generation (Timmis et al. , 2017b). Microbes provide life‐supporting services to the humans, other animals and plants that they inhabit, and constitute Earth’s life‐support system by driving biogeochemical cycles. Consequently, microbiology is an exceptionally dynamic research field, with major discoveries being made at frantic speed. New understanding thereby acquired constitutes an increasingly reliable foundation that can aid decision‐making at all levels, but, in order to connect understanding and decision‐making, the attainment of microbiology literacy in society is needed.
At the heart of the advancement of microbiology literacy is the education and inspiration of children, who typically have a voracious appetite for knowledge and are readily stimulated by the dynamism and excitement of the topic. Realization of the existence of their own microbiomes, and the intimacy of the relationships children have with their microbial friends, will captivate them, stimulate their natural curiosity and fire their imagination and passion.
However, there exists a major impediment to teaching children about microbes, namely their microscopic size, which prevents them being portrayed by the teacher and noticed in the environment when children are out and about (exceptions include fungal fruiting bodies, lichens, eutrophic waters and biofilms). Microbes are thus essentially abstract entities that are not apparent as being majority partners of the communities in which we live, and responsible for the many processes occurring in and around us. It is paramount that we enable children to conjure up mental images of microbes, in order to establish and appreciate the links between natural and human‐managed microbial processes, on the one hand, and the underlying microbes and their activities, on the other hand.
Young children’s emotional attachment to ‘cute’ animals and teddy bears is predicated on their being visible and in most cases touchable/cuddlable. Of course, mushrooms, as macroscopic manifestations of microbial subunits, are generally more recognizable, with mushroom‐mimicking decorative objects and furniture being ubiquitous in children’s play areas (Fig. 1), but this is the exception.
And, as we have stated (Timmis et al. , 2019), it is essential for microbes to ‘transit from abstraction to pictorial perception and substance, and take up their rightful position in the human psyche. Visual aids will thus take centre stage …. and the exploding arena of microbial art will stimulate the imagination….As microbes transit from the abstract and take form, they will become real; children will have their favourites! Cuddly teddy bears and woolly sheep will be joined by steamy Methano, wily Wolbo and prickly Diatoma, who all have their individual (anthropocentric) characters assigned by agile toy manufacturers’. Real but invisible microbes become visible, cuddlable toys with names. They may even become characters in storybooks and TV cartoons, with goodies and baddies drawn from the real microbial world.
While toys and artwork will bring microbes to life and give them form for younger children, and in some cases inform about individual microbial functions, natural and managed microbial activities will remain essentially abstract. In order to remedy this deficit, it is crucial to expose children to tangible, readily comprehended examples of important microbial activities. Time‐honoured mechanisms for this are class experiments and organized class outings/excursions, which allow children to personally experience and investigate objects and processes in their natural settings. Class excursions are a particularly enjoyable means of creating links between microbes and their activities, of making microbial activities tangible and of immersing children in microbiology.
By introducing children to workplaces, operational plants or field sites, excursions can demonstrate the integrated nature of topics and bring reality to learning, thereby stimulating natural curiosity (see Knapp, 1996; Behrendt and Franklin, 2014), which may be especially pronounced in those who do not thrive in the traditional classroom (Ofsted, 2008). Microbiology excursions may reap extra benefits when taking place in natural surroundings, for which there is growing evidence of improved learning, as well as encouragement to develop a sense of responsibility for environmental stewardship (Ballantyne and Packer, 2002; Kuo et al. , 2019). Introducing children to microbiology beyond the classroom via organized events also provides a bridge to, and enriches, their informal learning from everyday environments and activities (Bell et al. , 2009), such as watching television (e.g. images of the sea: remembering microbes make up 65% of marine biomass; Bar‐On et al. , 2018), going for a walk (e.g. noticing the diversity of the lichens on walls and roofs) and visiting the shops (e.g. yeast made that baguette!) or a museum (e.g. the dark patches on that old document might be fungal growth).
Class excursions are not only educational and fun events for children and teachers alike, but also invaluable introductions to future professional options, which can lead to career orientation, summer jobs, internships and contacts. They also provide a different educational environment and expose pupils to new “teachers” with a diversity of personalities and teaching styles, which can be enriching.
Bringing microbes to life through class excursions can strongly stimulate children’s imagination and emotions by teachers exposing some of the more exceptional or extraordinary features of microbes and their manifestations, such as: being the first forms of life to evolve on, inhabit and populate, the Earth (and likely the last); their ability to grow in extreme environments (hot springs, ice, deep subsurface and inside salt crystals; Fig. 2) and the question of whether they may exist on other planets (and, indeed, whether life on Earth could have been ‘seeded’ from such microbe‐populated planets – panspermia?); the ubiquity and tenacity of microbes and the fact that they follow us into space, on our bodies and space craft; microbes contributing to about half the oxygen we breathe, driving evolution of ‘higher organisms’ – the Eukaryotes – and thus humans (e.g. via mitochondria and chloroplasts); their presence in and on humans in vast numbers, roughly equal to the number of human cells (and influencing our well‐being); inherent beauty (e.g. Thiomargarita namibiensis, one of the largest known Bacteria; Schulz 2002); unusual adaptations (e.g. Magnetospirillum magneticum that contains nanomagnets to navigate using Earth's geomagnetic field; Chen et al. , 2010); and other enigmatic forms (e.g. flat, square archaeal species, Haloquadratum walsbyi; Fig. 2).
With this Editorial, we strive to promote class excursions in practical microbiology and, to both facilitate this end and encourage teachers to consider available options, provide a non‐exhaustive list of possible excursions and microbial processes or products to explore. Local knowledge, along with an understanding of the role of microbiology in the processes listed below, is obviously key to identifying the most stimulating school trips and activities. We also provide some suggestions on the preparation of excursions, to maximize enjoyment and information acquisition by the class, and optimize class–venue interactions.
During the preparation of this Editorial, SARS‐CoV‐2 started to make its own global excursion into and through the human population with devastating consequences, causing many thousands of deaths in the process. Obviously, social distancing measures put in place to slow the spread of the virus make school excursions at the time of writing undesirable and, in most countries, impossible (perhaps making this the most untimely of editorials!). Nevertheless, the pandemic will pass, leaving children with many questions about how pathogens are transmitted across species and from person to person, how transmission can be reduced or interrupted, why infected people are affected to different extents, and how disease can be prevented or treated. It is certain that the COVID‐19 pandemic will have a major impact on children, from many different angles, and create a generation of youngsters who are much more aware of, and curious about, microbiology. It is therefore more important than ever to harness this curiosity by providing opportunities to get a balanced view of the microbial world.
The suggestions given below for class excursions are sorted for convenience into seven categories (Fig. 3), but many activities and associated discussion topics will be applicable across multiple headings. Moreover, identifying associations between categories should be encouraged.
An adequate supply of good‐quality food is essential for human health, and ‘End hunger, achieve food security’ is a key UN Sustainable Development Goal (Willett et al. , 2019). Furthermore, food and drink contribute to human culture, civilization and joie de vivre. And, not entirely irrelevant for this discourse, food is a topic of passionate interest for most children. For many foods, microbes play a pivotal role in their manufacture, enhancement of nutritional value, preservation, and potential spoilage or transmission of food‐borne disease. And, in turn, our diet greatly influences our microbiome, with consequences for our health (Kolodziejczyk et al. , 2019). Thus, there is the critical food–microbes–health nexus to explore and the personal decisions that result from it. Then, there is a growing awareness of the link between food choice and global crises like climate change, the livestock–greenhouse gas production–global warming nexus, leading to decisions about changes in behaviour, such as reducing meat consumption. Children are of course engaged, sometimes passionately, in the global warming debate, and some are leading efforts for policy changes. Many of them are aware of the food–climate connection and so are motivated to learn about food, the contributions of microbes in the food industry, interactions between food and the gut microbiome and their ecophysiological health consequences.
Fermented foods were probably the first processed foods. They proved to be a key element of human development and expansion, owing to their capacity to preserve cereal grains, legumes, vegetables, milk and meat, often improving nutritional value and providing food year‐round. Out of necessity, and no doubt an element of chance, grew a plethora of fermented foods and drinks, with a diversity of fascinating flavours, textures, colours and smells that became part of the cultural heritage of a society or region. Cheese is a particularly instructive example, with its enormous range of variations and combining historical (cheese manufacture is thought to have originated at least 7500 years ago), cultural, culinary (there are many ways of using cheese in food preparation) and olfactory aspects. Fermented foods can readily be used in school teaching, to understand not only the underlying microbiology, but also their importance in diet and human culture, and the key issues of food preservation and safety.
Visits to local markets, food stores and food companies will allow children to explore a wide range of products (in addition to fermented foods) and ingredients that derive from microbes or their processes, including microbes as food (fungal Quorn, cyanobacterial Spirulina ), diverse microbial metabolites (Kallscheuer, 2018) that are added to food (amino acids, vitamins, extracellular polysaccharides, acetic acid and citric acid) and enzymes (Raveendran et al. , 2018) (Fig. 4). In addition to the organizations listed below, universities and research centres with specialists in food microbiology (see Section 5) could be visited or contacted to request advice about food manufacturers in the local area.
During a visit to a food store, children can be challenged to identify the microbial contribution to the food’s production process and its ingredients (Fig. 4). For example, peering at the fresh/frozen pizza offering provides considerable opportunity to explore microbial involvement in the production of this favourite food (yeast in the rising of the dough base, lactic acid bacteria in cheese production and salami ripening, sliced mushrooms and microbial fermentation of olives). The issue of sourcing food more locally and rejuvenation of the traditional preservation methods of fermentation, which add nutritional value and limit food waste (Campbell‐Platt, 1994; Brüssow, 2007; Katz, 2012; Tamang et al. , 2016; El Sheikha, 2018; Willett et al. , 2019), are fascinating topics to explore with children. Specifically, they can be asked to identify various means, in addition to fermentation, of reducing microbial spoilage (i.e. pickling with vinegar, adding sugar or salt, drying, freezing, refrigerating, vacuum packing and canning) and to discuss how they work. This exercise can be followed up at school with relatively simple experiments to test student‐led hypotheses about the methods that best preserve the food while maintaining its nutritional value. A wonderful way to learn about microbial fermentation, along with aspects of culture and food safety, is to make fermented food in the classroom, ideally accompanied by creating hypotheses and designing experiments to test them, e.g. testing what happens if the starter culture is not added (Meléndez, 2019; Verran et al. , 2019).
While sugar may serve to preserve certain foods, it is all too often added in excess to attract consumers, impacting on health in many ways, e.g. tooth decay, obesity and diabetes. In particular, controversy surrounds the use of high‐fructose corn syrup (HFCS), a sweetener commonly added to processed foods and manufactured by a multistage process driven by microbial enzymes (Crabb and Shetty, 1999). Discussions can consider the Cold War as a spur for the development of HFCS in the United States due to reduced sugar cane supplies; the types of enzymes involved and why/how some are sourced from extremophiles (particularly thermophiles); and, since fructose intolerance/malabsorption is relatively common, issues of intestinal discomfort, the gut microbiome and food choice.
The carbon footprint associated with food, particularly meat production, has led to renewed discussions about alternative food sources, including microbe‐based food, feed and supplements. The thought of eating microbes may initially be viewed with trepidation by many children, until they discover those microbes and microbial products that they may be consuming already, such as mushrooms and those in yoghurt, cheese, salt, fermented foods, yeast extract, Quorn or Spirulina. Students should be encouraged to consider which microbes may be safe to eat, what biopolymers microbes are made of, and whether they could satisfy animal nutritional requirements. The economics and energy requirements associated with cultivating microbes should be a prime consideration, which may lead to discussions about the diversity of microbial metabolic processes and their capacity to grow using cheap feedstocks. In this respect, the possible use of autotrophic, aerobic, hydrogen‐oxidizing bacteria to generate protein as a food supplement provides and informative case study (Sillman et al. , 2019).
Agriculture uses vast swathes of land, provides jobs and livelihoods for many millions of people and, together with aquaculture, produces most of the food needed for the survival and growth of the world’s human population, our working animals and companion pets, as well as renewable materials for direct use (e.g. for clothing or construction) or conversion to useful chemicals or energy. Food production via aquaculture is increasing rapidly, now supplying more than half of the world’s fish and shellfish for human consumption (FAO, 2016). But, the need to feed a growing human population requires further enhancement of output, through sustainable intensification of agriculture and aquaculture (i.e. increased food production with reduced environmental impact; Godfray and Garnett, 2014; Cavicchioli et al. , 2019). Increasing food production in the face of relentless reduction in the available area and quality of agricultural land – the soil crisis – is a mounting challenge. Decision‐making in agricultural policy and practice is a difficult, complex and sometimes contentious undertaking, due to, for example competition between food and renewable production, as well as agricultural practices and global warming‐related extreme weather events causing loss of soils and agricultural acreage. Then, there is the conflict between high yield and sustainability, for example: the use of growth promoters and antibiotics in livestock leading to pollution and the spread of antibiotic resistance; fertilizer run‐off resulting in eutrophication of lakes, rivers and inshore seas; and pesticides polluting soils and water bodies, including those which supply our drinking water, with consequences for non‐target insects (e.g. pollinators and ecosystem engineers) and other animals including humans, plants and microbes.
Plant and animal microbiomes contribute enormously to the health of their hosts and hence to the yields of crop plants and food animals in agriculture and aquaculture (Mueller and Sachs 2015; Martin et al. , 2017; Trivedi et al. , 2017). Furthermore, agricultural soils need diverse and active microbial communities to maintain soil structure, outcompete pathogens, increase nutrient availability, provide resistance to stress and generally promote plant growth (Reid and Greene, 2013; McNear, 2013; Lee et al. , 2020). Similarly, diverse microbial communities are required to maintain healthy water bodies used for aquaculture (Dittmann et al. , 2017).
Despite their crucial influence on animal and plant productivity, microbial contributions are usually lacking from considerations of agriculture and aquaculture policy and practice, and the resulting decisions, so the base of available evidence of such decisions is incomplete and hence flawed. Microbiology literacy acquired through childhood education is essential for development of evidence‐based policies and decisions in agriculture and aquaculture relating to feeding world citizens, conserving productive soils, reducing environmental pollution and eutrophication and minimizing oxygen depletion of waters and its resulting lethal consequences for aquatic wildlife and thus sustainability. Therefore, excursions to agriculture, horticulture or aquaculture operations can be both fascinating for children to personally experience the origins of the food that appears on their plates, and important for increasing awareness of global grand challenges and their microbiology components.
Below, we outline some of the ways in which microbes influence the environment and food production, which can be explored by contacting the relevant landowners to arrange visits to farms (arable, livestock, shellfish and fish), forests and horticultural centres. Many universities, agencies and research centres (see Section 5) may be visited to obtain a more intimate understanding of the underlying microbiology. There are also industries that supply the agriculture and aquaculture sectors, providing microbial cultures that are added to soils to promote the health and growth of plants (biofertilizers), and to aquaculture waters as probiotics or to recycle excess nutrients from faeces and dead organisms (Martínez‐Córdova et al. , 2015). Finally, school or community farms provide an excellent way for children to become more invested in soils, plants, animals, including (shell)fish, and their microbiomes. Where space and cost are at a premium, edible fungi can be grown by inoculating bags of compost with spores. This can also serve as the basis of an agricultural experiment, for example by testing the effect of moisture and temperature on the rate of fruiting body formation.
Numerous learning opportunities arise from investigating microbes in agriculture. For example, root nodules on legumes are visible manifestations of invisible microbes mediating an exceptionally important activity, namely nitrogen fixation by symbiotic Bacteria that provide plants with nitrogen in a form that can be used, e.g., for the production of proteins, thereby facilitating plant growth (Fig. 5). Similarly, observations of fungal hyphae in close association with plant roots may serve to introduce the roles of mycorrhizal fungi. Teacher‐guided discovery by children of root nodules and plant‐associated fungi can elicit discussions about plant–microbe symbioses in the rhizosphere – the intimate microbiome interface between the plant root and its soil medium – where crucial microbially driven physiological processes unfold that determine the availability of: a) nutrients, like nitrogen and phosphorus, essential to plant growth, b) hormones that stimulate plant growth, and c) pathogen inhibitors that suppress microbes causing root disease. Root microbiomes have also been shown to protect plants against drought, extreme temperatures and other stresses.
Visits to farms and garden centres can be linked to education about land use and soil as a resource, the ‘soil crisis’ (Koch et al. , 2013), and the beneficial roles of microbes in forming/maintaining healthy and productive soil. For example, in addition to contributing to soil formation by rock weathering (Napieralski et al. , 2019) and soil fertility, some soil microbes ‘glue’ together soil particles and reduce soil loss by wind and rain, and others degrade pollutants, including agricultural pesticides. The processing of crops grown as sources of renewable energy or chemical production often involves microbial activities, on‐site or off‐site, which can be discussed. The concept of the circular economy can be introduced and issues explored, such as spreading of animal waste on agricultural soils and the potential to unintentionally spread antibiotic‐resistant microbes and pathogens that may also infect humans (Berendonk et al. , 2015). Plant diseases caused by rusts, blights, wilts, galls, and their visible manifestations, on crop and non‐crop plants, can be stimuli for discussions about the causes of disease and different means of prevention or treatment, as well as their role in contributing to famine and influencing human history. A visible infestation of crops by aphids can be used to introduce the topic of the insect’s dependence (and vice versa) on its endosymbiotic Bacteria, Buchnera species, and more broadly, it can serve to introduce the topic of microbial control agents in agriculture, such as the insect‐killing bacterium Bacillus thuringiensis (Bt), used primarily to kill larvae of Lepidoptera (Bravo et al. , 2011; Engel and Moran, 2013). Cattle farmers can explain the problem of bovine tuberculosis, which can lead to microbiology‐informed debate about disease transmission and the pros and cons of badger culling.
And, not to forget, soils are a major repository of microbial diversity and hence the major source of microbiome diversity maintenance (in humans and other life forms), which is crucial for the health of most species in the biosphere (‘Let them eat dirt’; Finlay and Arrieta, 2016), which is also an interesting topic for children to explore.
A visit to a marine or freshwater aquaculture facility, quite apart from the interest in seeing the process of fish/mollusc/crustacean rearing, and the different developmental stages, provides an excellent platform to explore food webs (e.g. phytoplankton (and their associated beneficial heterotrophic microbes) – zooplankton – fish) and thus the interconnectedness of life, as well as the problems of the use of growth promoters and nutrient/faecal pollution that can lead to eutrophication and oxygen limitation of water bodies.
Microbes are central to the environmental and industrial biotechnology sectors, which contribute a burgeoning array of products and processes for sustainable economic growth (Timmis et al. , 2017). These range from municipal wastewater treatment plants to biotechnology start‐ups, and include long‐running chemical giants that have switched to using biological processes. These enterprises can be identified through local knowledge, directories, internet searches, asking school children and colleagues where family members work and contacting local universities and research centres.
Societal responsibility necessitates that everyone learns what happens to the wastes we produce, so that we transit from an out‐of‐sight, out‐of‐mind mentality when we flush the toilet or empty rubbish into the dustbin, to an awareness of the processes, needs and costs of what is thereby actioned. An excursion to a wastewater treatment plant/recycling facility can provide a particularly interesting and wide‐ranging microbiological experience, and almost every town has one (Fig. 6). Water companies are often accommodating to visits, and they may have specialized outreach professionals/microbiologists available. The olfactory component ensures a memorable visit, and the change in smell while progressing through the treatment plant demonstrates that the underpinning microbiological processes are working. Wastewater treatment eliminates much of the waste we produce and channel into the wastewater disposal system. It also removes a major fraction of the pathogens present in wastewater and thereby enormously reduces disease transmission and our infection burden. Currently, wastewater treatment focuses not only on waste destruction but increasingly on recovery of resources (notably the macronutrients nitrogen and phosphorus, but potentially gold and other precious metals), the recuperation of energy in the form of methane gas from anaerobic digesters and the creation of added‐value products like biopolymers, and hence plays a central role in a number of facets of the circular economy and societal development. Industrial wastewater treatment plants can additionally demonstrate the destruction of wastes, such as polluting chemicals, produced by commercial operations.
Diverse topics of microbiology in action can be addressed during a visit to a wastewater treatment plant, depending on the age group and interests of the students and teachers, such as floc formation/biofilms, nutrient cycling, the water cycle, aerobic versus anaerobic processes, pathogens, antimicrobial resistance, anaerobic digestion and the formation of biogas and digestate (Fig. 6). A close look at trickling filter beds can reveal a zoo of micro‐ and macro‐organisms contributing to the wastewater treatment process, leading to discussions about food webs. Protozoa and microbial metazoa grazing on Bacteria and Archaea make for good viewing under the microscope. Even without a microscope, children can see chironomid midge larvae which feed on the microbial biofilms, thereby keeping them continually growing and optimally active, as well as preventing the filters from becoming clogged. At landfill sites, children can explore microbial aspects of: the sources of the smell and how microbes can also be used to remove smelly volatile compounds, differential rates of degradation of different materials, biodegradable plastics, pollution from leachate and microbial remediation, coastal erosion and the impact of landfill waste entering the sea, generation and harnessing of methane from landfill. And, since sites for landfill compete with other uses, like agriculture and housing, the need to reduce landfill expansion and the key issues of separation, recycling, resource recovery and microbial involvement in these provide discussion topics for lifestyle decision‐making, which should encourage future generations to value and conserve resources.
When visiting petroleum companies or their field operations, or those organizations providing services to the petroleum industry, children can be taught about the role of microbes in cleaning up oils spills, including gasoline released from leaking storage tanks at petrol stations, as well as a range of other microbially driven processes, such as: in‐situ depletion of sulfide in oil reservoirs by encouraging nitrate‐reducing microbes, biodesulfurization of crude oil and coal, microbially enhanced oil recovery and prevention of microbially induced corrosion of metal structures. The impact of fossil fuel industries on climate and the extent to which petroleum‐based fuels and other products should still have a place in society are pertinent topics for discussion. However, when considering alternative energy and chemical sources, e.g. when visiting bioethanol or other biofuel plants, in addition to learning about the underlying biological process, the sources of the feedstock should be considered and the environmental and societal cost of its production deliberated, i.e. the fuel‐versus‐food debate. Then, the children can consider why it is preferable to produce sugar (as precursors for some biofuels) from alternative sources, particularly waste lignocellulosic material (e.g. waste paper, straw), followed by discussion of the types of microbes that degrade lignin and cellulose, where they can be found and how to harness their activities.
Children, for reasons of inter alia immunological naivety, overly hygienic upbringing in their early years, and classroom confinement, are particularly susceptible to infections. The physical and mental suffering caused by microbial disease affects children considerably, not least because of school absences and the stress of catch‐up, and frequently motivates them to want to learn more about, and sometimes to choose a career in, microbiology or medicine. Poorly evidenced propaganda about supposed negative effects of vaccination has led to the re‐emergence of some well‐contained, or almost eliminated, microbial diseases (e.g. measles and polio). Outbreaks of pathogens causing diseases characterized by high mortality rates (e.g. Ebola virus) or high infectivity enabling epidemic or pandemic spread (e.g. SARS‐CoV‐2 causing COVID‐19) occur regularly. Crucially, the global increase in antimicrobial resistance in previously treatable pathogens means that many infections have now become life‐threatening (Timmis et al. , 2019) and are predicted to become a major cause of global morbidity and mortality in the future.
On the other hand, there are exciting advances linking the human microbiome with well‐being, which promise to lead to new paradigms for diagnosis, prevention and therapy of both physical and mental health conditions originating from microbiome perturbations. The, by now, classical example of perturbed microbiota restoration – the successful use of faecal microbiota transplants to treat recurrent or refractory Clostridium difficile infections promoted by antibiotic therapy – is encouraging the assessment of similar interventions for other conditions (Mullish et al. , 2018). And bacteriophage therapy, another ecological strategy to deal with bacterial infections, is making a comeback (Brüssow, 2017; Gordillo Altamirano and Barr, 2019; Fig. 7).
Some of the obvious and interesting places to learn about the medical sector may not be practical for school excursions, especially for younger children, e.g. hospitals to learn about hygiene procedures in surgical and intensive care units and the importance of immunosuppression, and primary healthcare clinics to discover diagnostic procedures, what clinical samples reveal, and what tests will be carried out. However, others, especially teaching hospitals, may have educational facilities that can accommodate class excursions, and some primary healthcare clinics may also be amenable to organized visits, so it is worth enquiring. Health clinics and hospitals can be associated with physical and/or emotional discomfort, causing some children to view them with apprehension, so visits in a learning capacity can be very useful to establish familiarity and create a more positive, balanced perception.
Some diagnostic laboratories may be amenable to school visits, and public health agencies often have outreach divisions, and may also allow/encourage visits. Academic centres, learned societies and museums all provide opportunities to learn about the role of microbes in health and disease, and health workers often visit schools to talk about microbiological topics, such as sexually transmitted diseases. Opportunities offered by healthcare‐system outreach programmes, and by the availability of enthusiastic health professionals for outreach activities, can significantly enhance the educational benefits of health‐centric excursions and in‐school follow‐ups.
Some organizations for health‐related microbiology‐centric excursions are given below:
In order to ensure a balanced narrative, before discussing pathogens and disease, it is helpful to remind students of the ways in which microbes promote health or reduce risk of disease, such as: microbiome steering of immune‐system development in infants, microbiome inhibition of pathogen colonization and reproduction on body surfaces, biotechnological use of microbes and microbial products to create vaccines and therapies, destruction of pathogens by microbial activities in wastewater treatment, preservation of food by fermentation, enhancement of crop yield and degradation of pollutants.
Children enjoy learning about disease and benefit from clear, contextualized images of the relevant causative pathogens under discussion, in terms of their size (e.g. relative to something that the particular age group would recognize), type (e.g. Bacteria, viruses and protozoa) and source/reservoirs of infection. Epidemiological games (e.g. Centre for Disease Control’s Solve the Outbreak), incorporating elements of forensic detective work, provide an illuminating way to illustrate how disease can spread.
Opportunities to relate infection dangers to everyday life should be embraced. For instance, discussion of modes of transmission and their prevention is particularly interesting to young children who play outside and have pet animals, and may usefully include transmission by biting insect vectors. Examples include Borrelia burgdorferi, a bacterial species that causes Lyme disease and is transmitted by ticks residing in grass, and Plasmodium, a protozoal genus with several species that cause malaria, which is transmitted by mosquitoes. Zoonoses – the transmission of infectious agents from reservoir animals to humans – also include Borrelia, whose primary hosts are mammals, and Salmonella serovars, which infect chickens and may be transmitted to us in our food if we do not observe good hygiene and properly cook the meat. And, particularly topical is the genetic evolution of animal pathogens, like HIV, as well as SARS, MERS and other coronaviruses, to become human pathogens (Cui et al. , 2019; Brüssow, 2020). All of these topics enable the teacher to discuss relevant practices to help restrict the spread of pathogens, such as washing hands before handling food or eating and after going to the toilet, environmental management (e.g. water treatment for cholera), avoidance (e.g. avoiding physical contacts, like handshaking/hugging, social distancing and quarantining during epidemics like that caused by coronavirus), protection (e.g. spraying with mosquito repellent for malaria and using condoms for sexually transmitted diseases), vaccination and treatments (e.g. whether or not to use antibiotics). These issues can lead to discussion of broader topics, including One Health (see WHO web pages) – public health strategies based on the integrated nature of human, animal and environmental health – which targets the key health‐relevant components in this interactive network. In this context, an important issue for discussion is the spread of antibiotic resistance through the use of antibiotics in farming and aquaculture. Moreover, such personally relevant, and sometimes frightening, issues provide an opportunity to consider the dissemination of misinformation via the internet and thus the importance of the scientific method, ethics and communicating research.
Diagnostic and public‐health laboratories can introduce children to the different levels of pathogenicity and infectivity of pathogens, and thus containment needed for safe handling, as well as the different means of detection, typing and quantification (Fig. 7). Older children can be introduced to the application of molecular methods for detection of pathogens, e.g. using the polymerase chain reaction (PCR), the underpinning of which was the discovery of the thermophilic bacterium, Thermus aquaticus, from colourful thermal springs in Yellowstone National Park, which was the source of thermostable DNA polymerase that made PCR feasible. Visits to pharmaceutical companies will focus on the development and manufacture of therapeutic drugs, e.g. for microbial diseases, and the process of drug discovery. Inspiration for many pharmaceuticals is often drawn from nature, and it will help children to value microbes if they recognize that they are the source of much of that inspiration or the products themselves. So, it is useful to make connections with everyday sensations, such as the smell of soil after rain caused by geosmin‐producing Streptomyces species, which are the source of a range of antibiotics and other pharmaceuticals. A natural development to this discussion would be to consider the role that such secondary metabolites play in nature.
Many schools are in visiting distance of an academic research centre, where children can experience the cutting edge of discovery by a variety of means listed below. Within academia, outreach activities are generally encouraged, and specific outreach days are often hosted. Sound advice to specialists on communicating science to children and the general public is provided by many learned societies and a variety of publications (e.g. Bowater and Yeoman, 2012; Westenberg, 2016; Illingworth and Prokop, 2017). Academic centres have an advantage over many commercial or industrial settings in that they are likely to have laboratories that can accommodate demonstrations, hands‐on experiments and bioinformatics. They can also be a good source of contacts to relevant industry, e.g. via their technology/science parks and research connections. In addition, visits to an academic centre can often facilitate choices of study topics and create contacts helpful for future tertiary education and internships.
Involving children directly in research activities, for example through joining microbiologists undertaking fieldwork, provides first‐hand experience of what being a microbiologist is like. As an example of one exercise organized by the Danish Technical University and supported by industrial sponsors, school children collected samples to isolate lactic acid bacteria and made headline news with the discovery of 10 new species. Such activities, and larger‐scale citizen‐science or mass‐experiment projects, give direct experience of the scientific method, including hypothesis setting, experimental design and problem solving. Importantly, this will promote enthusiasm for microbiological research, and the principles learned can be applied to tackle complex problems encountered in later life.
Schools can be involved in a range of citizen‐science activities, many of which do not require a visit to a nearby academic centre, as instructions and materials may be provided or otherwise easily obtained. The ‘Small World Initiative’, developed at Yale University as a citizen‐science programme in which students isolate microbes from their local environment and identify antibiotics produced by them, has grown into a wider research programme (Davis et al. , 2017). It has also been adapted in several other countries, e.g. to encourage the involvement of school children and include aspects of service learning (Valderrama et al. , 2018), i.e. combining learning objectives with community service (Webb, 2017). Another example of service learning is provided by Rutgers University graduate students, who run a mobile laboratory, from which, among other activities, they introduce school children to the spread of microbial infections (Irizarry‐Barreto et al. , 2018). DTU Bioengineering also has an effective model, whereby students run an organization named the Biotech Academy, which provides outreach and teaching in schools.
The long‐running initiative called ‘Discover the Microbes Within! The Wolbachia Project’ enables students to see what it is like to be a scientist by participating in research. It is premised on the facts that arthropods represent about 85% of all animal species, and the bacterial endosymbionts, Wolbachia spp., occur in at least 40% of all arthropod species. Therefore, immersion microbiology in this symbiotic world is accessible to all students and classrooms across the world. This project allows a wide selection of arthropods and habitats to be investigated and involves children in the search for Wolbachia symbionts and their bacteriophages.
Learned societies, charities and foundations fund and host events, and support and mobilize scientists, with the remit of engaging schools and the public in science. Teachers and pupils can take advantage of these events by being members themselves and/or subscribing to the relevant mailing lists. Nearly all academic centres, and/or the departments within them, have personnel responsible for outreach activities, who can provide information about what they can offer from among the following:
Points to discuss will depend on the research area presented and can be guided by the microbiology expert, and/or ideas should be available on the relevant websites. For example, the ‘Big Compost Experiment’ invites the public to select bioplastic packaging and test their biodegradation, which encourages learning about the chemistry and (micro)biology of different types of bioplastics as well as the composting process (Fig. 8). The discussion could readily be extended to include the wider issue of plastic pollution as outlined in the next section.
An advantage of field excursions is that they can take place in accessible local environments, including urban sites and the school grounds, thereby reducing cost, limiting disruption to timetabled classes and allowing repeat visits (Howarth and Slingsby, 2004). And, although the individual microbial agents underlying the activity to be experienced cannot be seen with the naked eye, clusters/networks of cells, biofilms and slimes may be visible, and the activities themselves can be experienced by the senses, visually, and in some cases, by touch, smell, taste (for known foods!) or sound (see the Discussion).
Children are thrilled to discover previously invisible animate beings and inanimate objects, and are captivated by new microscopic worlds in the samples they have taken. Thus, we stress the importance for each school to have at least one microscope. However, a child’s curiosity may dwindle on the walk from the field site to the classroom or in the queue for the microscope, which makes portable and affordable tools like the Foldscope extremely valuable for microbiological excursions. By assembling their personal, or team, Foldscope beforehand, children appreciate the technology behind the optical microscope. Moreover, the sense of ownership of their Foldscope, together with the ability to view their samples immediately, will enhance children’s enjoyment and sense of discovery. The mantra ‘small is beautiful’ translates into reality as invisible microbes are revealed, become tangible, enter the memory of the child, to be automatically recalled and linked to a relevant microbial habitat and/or activity. Then, sharing their achievements and experiences with the global Foldscope community is fun and reinforces the interest and reward of their studies: they become active members of a worldwide network of discovery of the microscopic unknown!
In some situations, it may be possible for teachers to incorporate simple field experiments into excursions, involving observations and perturbations, with or without simple measuring devices. This has the virtue of extending class experiments to field experiments and revealing the essential link between the two in obtaining a realistic picture of microbial functioning and contribution to environmental processes.
A wide range of microbial manifestations is explored in the wonderful book ‘A Field Guide to Bacteria’ (Dyer, 2003) and the excellent website ‘Exploring the Invisible’. A few ideas out of hundreds of possibilities are presented here.
Microbes and their activities are often more obvious than we realize, and the urban environment with its building stones/materials, wooden structures, monuments and cemeteries provides opportunities to explore the roles of microbes in everyday life as architects of both construction and decay (see ‘This is Microgeography’ website and Fig. 9 for example). Microbial builders include species used to repair monuments by facilitating calcium carbonate cement formation (Gao et al. , 2019). It has also been proposed that the extracellular polymeric substances (polysaccharide‐rich slime) produced by microbes degrading cellulose serve as a binder in the construction of mud buildings (Vissac et al. , 2017). No surface is free of microbes, and microbial colonies may be visible on buildings, headstones, monuments and rocks in the form of melanized fungi, green algae, multicoloured lichens and microbially formed minerals (manganese and iron oxides, and calcium oxalate) on stone, mortar, plaster or stucco (Gadd, 2017; Fig. 9). Such biofilms, crusts and patinas may lead to deterioration (e.g. via acid‐producing Bacteria, Archaea and fungi) or protection (e.g. by hydrophobic biofilms keeping out water) (Gadd, 2017). Thus, everyday stone objects provide the basis for visualizing microbes, their interactions and the effects of their various activities.
Fossilized calcium carbonate shells of eukaryotic microbes (especially coccolithophores and foraminifera) are the main component of chalk, which serves as a building material (e.g. parts of Westminster Abbey in London) and is still used for writing on blackboards in many classrooms across the world. Children are fascinated when they realize that such everyday objects, the rock beneath their feet and iconic natural formations, such as the White Cliffs of Dover (Fig. 10), are the remnants of microbes that bloomed in the oceans. The rock dolostone is a widely used building material, with examples including York Minster (UK) and the Western Wall in Jerusalem. Unlike chalk, the shells derive from larger, multicellular organisms, but microbes, specifically anaerobic sulfate‐reducing bacteria in marine sediments, are understood to be responsible for much of the formation of dolostone’s main mineral, dolomite (CaMg(CO3)2) (Krause et al. , 2012). Many other remnants or signs of microbial activity appear in the rock record, such as microbialites and banded iron formations (Fig. 10).
Two diverse and distinct eukaryotic groups, fungi with their hyphal networks and fruiting bodies (Fig. 11), and slime moulds with their massive multinucleate cells and fruiting bodies (Fig. 12), provide a fascinating visual and often beautiful portrayal of the microbial world. Important information about the state of world’s fungi is provided by Willis (2018) and Kew Gardens – Protecting precious fungi web page, while Glime (2019) provides well‐illustrated information about slime moulds.
Fungi are attractive to children given that they are often morphologically distinctive, and the basidiomycete fruiting bodies are steeped in folklore; for example the insecticidal, hallucinogenic, home for elves, Amanita muscaria (fly agaric) and fairy rings formed by numerous fungal species. Fruiting bodies are also fascinating because they are dynamic, changing form and often colour and odour as they age. They can sometimes be seen releasing vast numbers of spores (e.g. puffballs). Fungal hyphal networks can be seen with the naked eye by looking at mouldy bread, degrading wood and beneath forest litter. Likewise, fungal rhizomorphs, such as those from Armillaria mellea (honey fungus), can be identified in the field. The beauty of ephemeral fruiting bodies, along with the extent and longevity of many fungal mycelia (the largest organisms are fungi: the honey fungus mycelium can extend over several kilometres), fascinate children and can stimulate discussion about fungal life cycles, chemical defence and signalling (and link to production of antimicrobials), positive and negative interactions with plants and roles in biodegradation.
Microbes are all around us, and local universities, wildlife organizations, amateur enthusiasts and field centres/councils are frequently eager to offer advice and tours/activities. Here, we list a range of environments where microbiology can be seen in action.
While exploring the built environment with children, it is pertinent to ask them: why wooden structures decay more rapidly than those made of stone, why they need more protection from microbes, and why wooden window frames and fascias have largely been replaced with plastic. The role of cellulolytic and ligninolytic microbes in deterioration should naturally follow from these questions (Fig. 14). Thereafter, the plastic problem is likely to be a topic of discussion, with questions such as: why are most plastics resistant to biodegradation, what are the global problems caused by non‐/slowly biodegradable plastics, from where can we get biodegradable plastics (microbes, plants, crustaceans, etc.)? These questions may provoke students to design experiments to test the biodegradability of different polymers (Fig. 8) and thereby lead them to establish cultures to grow polymer‐degrading microbes.
If age‐appropriate, the eternal cycle of life and death, and the involvement of microbes in it, can be discussed during a history trip to a local cemetery. This may usefully lead into a discussion of cremation, carbon footprints of different means of disposing of our earthly remains (including composting), the issue of mercury fillings of teeth and the deposition of mercury downwind of crematoria, mercury resistance in microbes and the application of mercury‐resistant microbes in the detoxification of mercury‐polluted waste streams (von Canstein et al. , 1999).
It is valuable to combine different field activities to obtain a more complete and integrated understanding of a system’s ecology, providing opportunities to consider food webs, nutrient cycling, etc. (Barberán et al. , 2016). When investigating a rock pool, in addition to using a magnifier to view zooplankton, a microscope can make microbes visible and initiate a discussion about their abundance and importance in diverse ecosystem processes, pointing out that every cubic millimetre (the size of a poppy seed) houses approximately 10,000 viruses (Suttle, 2007), 600 Bacteria (including 150 cyanobacteria), nine microalgae, six Archaea (Karner et al. , 2001) and on average less than one protozoan (Zubkov et al. , 2007). Then, if you were able to sample 100 m below the seawater surface, the relative contribution of Archaea would increase greatly, in some locations occurring in the same abundance as Bacteria (Karner et al. , 2001).
Freshwater lakes are generally transparent due to relatively low concentrations of the macronutrients, nitrogen and phosphorous, limiting the growth and abundance of phototrophic microbes. But, with a seasonal, or sporadic, input of nutrients (e.g. run‐off from agricultural land), the water body may turn a deep, turbid green colour owing to dense blooms of phototrophic microbes, such as cyanobacteria or eukaryotic microalgae, a process known as eutrophication (Chislock et al. , 2013). As microalgae die, aerobic heterotrophic microbes consume their organic remains leading to the depletion of oxygen, which may result in the death of oxygen‐dependent aquatic animals, including fish. Moreover, some microalgae produce toxins that poison animals that live in the lake (Fig. 15) and, when this happens, children are prohibited from swimming or fishing in the lake. Having the flexibility for the class to go out and inspect such a bloom, especially when it is making the local news, can provide multiple educational benefits. Not only will such an excursion stimulate a discussion about the underlying microbiological processes, it should also lead to an exploration of the link between our food requirements, farming practices and their environmental effects. Moreover, interested families are likely to question their children/siblings about their visit, and thus continue the learning process for the student and their family.
A core role of most museums is to support school visits, though in many cases they have the ‘visible’, rather than the ‘invisible’, on show. However, those with artefacts, ancient or recent, are almost always confronted with issues of conservation, including the mitigation of microbe‐mediated deterioration. Thus, a visit to such museums may be combined with exposure to microbially based conservation programmes. Moreover, there are museums and exhibitions specifically dedicated to microbes and their activities, reflecting the public’s fascination with microbes, and museums’ remit to promote and contribute to Sustainable Development Goals (McGhie, 2019; Fig. 16). Then, there are zoos, aquariums and botanical gardens, some of which may have expertise in microbial infections, biological control methods and microbiomes; fungi are sometimes showcased in botanical gardens (e.g. Kew Gardens in London; Willis, 2018), while slime moulds have recently been introduced into the collection of the Parc Zoologique de Paris. Visits to livery stables, animal sanctuaries or dog/cat homes may provide a more local and cost‐effective means of combining children’s typical love of animals and learning about the microbial contribution to health and disease. However, for such excursions the expertise in microbiology will most probably have to come from the teacher or an outside recruit.
The school liaison officer in local museums, zoos, aquariums or botanical gardens should be able to advise on microbiological research, exhibits or activities that could form part of a school visit. Here, we highlight some microbiology‐focused museums and exhibitions. As the home of so many microbiological innovators, and some of the more unusual museums, it is unsurprising that the Netherlands hosts the world’s biggest museum dedicated to microbiology; the Micropia Museum in Amsterdam is a rarity among museums in focusing on microbiology in such an engaging and impactful way. Another can be found at the Instituto Butantan in Brazil. The Wellcome Trust Collection, London, UK, has for many years revealed to the public the role of microbes in human disease and health, and there is growing adoption of itinerant microbiological exhibits and activities in other museums, such as the BioArt and Bacteria exhibition, and the Bacterial World exhibition with its giant inflatable Escherichia coli (Fig. 16), the Microbiota exhibition at La Cité des Sciences in Paris, France, the Outbreak exhibition at the Smithsonian Museum of Science and the World in a Drop: photographic explorations of microbial life in Harvard Museum of Natural History, USA. The Eden Project (Cornwall, UK) has a focus on Invisible Worlds. The Bioluminescent Photograph Booth was a touring interactive exhibition using bacterial bioluminescence to enable ghostly images of the human subjects. An innovative, immersive exhibit at the Exploratorium Science Museum in San Francisco, USA, used the light‐sensitive behaviour of a Euglena species to give the impression that the eukaryotic microbe was dancing with visitors while in reality avoiding their shadow (Lam et al. , 2019). More unusually, microbial metagenomics data sets have been set to music (Larsen, 2016), and bubbles from fermentative microbes have been used to play relaxing tunes in an interactive exhibit called a Fermentophone (Fig. 16). Importantly, there are also museums associated with inspirational microbiologists, e.g. Beijerinck Museum in Delft (the Netherlands), Museum at the Robert Koch Institute in Berlin (Germany), Alexander Fleming’s Museum in London (UK) and Louis Pasteur’s house in Arbois (France).
Children tend to be aware of the value of higher organisms, such as honey bees as pollinators, and recognize the power and beauty of endangered sentinel species like Amur leopards. Older children also understand the wider value of biodiversity and its conservation. Thus, a visit to a zoo, aquarium, botanical garden or a museum provides an ideal opportunity to encourage debate about the contribution of microbes to the health and conservation efforts of animals (Bahrndorff et al. , 2016; Trevelline et al. , 2019) and plants (Berg and Raaijmakers, 2018). The difficulty in keeping some animals in zoos, such as three‐toed sloths, has been attributed to obtaining the right diet to support their specialized internal and external microbiomes (Dyer, 2003; Pauli et al. , 2014; Dill‐McFarland et al. , 2016; Fig. 17). Three‐toed sloths are fascinating from another microbiological standpoint: they carry around in cracks in their fur portable microbial ‘vegetable gardens’ which provide valuable nutrients on demand (Fig. 17). Flamingos in zoos may lose their pink pigmentation, as they are not feeding on their usual carotenoid‐rich cyanobacteria and microalgae (directly or indirectly), which impart the pink colouration in their natural habitat (Dyer, 2003).
Emblems for schools, towns, states, etc., can deliver powerful messages about issues of local importance and serve as sources of civic pride. New Jersey has antibiotic‐producing Streptomyces griseus as its state microbe, while Oregon, famous for its craft beer production, has Saccharomyces cerevisiae, so microbes have been adopted as important emblems. A microbiology excursion may thus be enhanced by asking children to think about which microbe deserves to be considered for their school, town or state emblem. Older children can be challenged to consider which microbe they would most want to conserve and why, e.g. because of its rarity, beauty or value to humans. This question is sure to evoke a response that can be explored further by discussing why we are innately less likely to want to conserve small organisms, yet why we should do so.
It will be informative to consider the consequences of microbial extinctions and how to conserve microbes; for example, by focusing on habitats, the habitats’ genetic resources or on cultured microbes (Cockell and Jones, 2009; Paul and Mormile, 2017). In the case of protecting or preserving habitats, which is of course key to protecting endangered species of plants and animals, children can/should be encouraged to develop a sense of pride in their local ecosystems as they start to learn about the microbes within. When considering preservation of microbial cultures, children can be introduced to the valuable roles played by Microbial Domain Biological Resource Centres (Antunes et al. , 2016), which can also make for an interesting excursion.
Finally, most zoos have ants, usually tropical leafcutter ants, which can elicit discussions about their interactions with microbes, notably the different ways that they farm fungi, and the role of associated antibiotic‐producing bacteria (Chomicki and Renner, 2017; Whitaker and Stolzmann, 2019). Children are particularly fascinated by interactions that induce weird behavioural changes in animals, for example the fungus Ophiocordyceps sp. that uses carpenter ants as a vehicle for reproduction and dispersal – creating so‐called zombie ants (Hughes et al. , 2011; Araújo and Hughes, 2019; Fig. 17). And, of course, this can trigger discussions about the varied behavioural effects that Wolbachia species have in diverse insect hosts (see Section 5).
Useful advice on running and evaluating activities, including site visits and field trips, is given by Behrendt and Franklin (2014) and the Council for Learning Outside the Classroom (LOtC). There is a large body of evidence to show that active learning promotes student performance (Freeman et al. , 2014). Therefore, in order to get maximal benefit from excursions, it is important for the host to develop age‐appropriate and engaging activities. When teaching microbiology to young children, the focus should be on discovery, the wonder and amazement of microbes, nurturing respect for microbes and understanding that they are members of the natural world like all other more familiar organisms. Then, children can be introduced to the roles that microbes play and services that they render, such as recycling and degrading. For older children, there can be more focus on global issues and the networking/integration of microbial processes.
The following points provide some general, and some microbiology‐specific, tips that may be helpful when preparing for an excursion.
While the novelty of excursions provides unparalleled learning benefits, they are clearly associated with a logistical and financial cost. Where the logistics are inhibitory, or funds are lacking for this purpose, alternatives are available. The most obvious strategy is to invite into the classroom a speaker working in a microbiological area. A former student, especially if charismatic, who can easily relate to the class and local circumstances, can be particularly valuable. Such external speakers should use pictures, videos, props and, where possible, replace/intercalate a talk with practical activities, as appropriate for the age group; for example, Couto (2017) provides an imaginative way to introduce biofilms to 4‐ to 6‐year‐old children, and Vrentas et al. (2011) take students on an imagined MicroSafari. Such hands‐on and interactive activities (and more, e.g. an insect’s head with Ophiocordyceps growing out of it (Fig. 17), smelly food (Fig. 4), settling activated sludge (Fig. 6) and making electricity from microbes and mud) are particularly memorable and can evoke long‐lasting interest in microbiology.
Speakers and teachers can use a plethora of resources, especially via the internet (e.g. Guarner and Niño, 2016), to draw students into the world of microbes. Some videos illustrate important concepts that would be much more difficult to convey by other means. For example, large‐scale experimental design and the clever use of time‐lapse imaging resulted in a very powerful demonstration of bacterial evolution in action by use of the Microbial Evolution and Growth Arena (MEGA) plate (Baym et al. , 2016). National and international microbiological societies, together with many academic centres, provide excellent resources on their websites, and, moreover, given the importance of microbes to all scientific disciplines, other learned societies and organizations, from astrobiology to zoology, have microbiology‐focused resources. For example, the International Ocean Discovery Program (IODP) has useful resources for educating children about the deep biosphere. Public Health England’s e‐Bug initiative provides excellent material for school children of different ages, including lesson plans on antimicrobial resistance, the value of which in improving understanding of the issue by children in India has been shown (Fernandes et al. , 2019).
Social media, together with other media outlets, feature microbiology news stories that can precipitate class debates on topical and/or controversial issues. Social media also provides a vehicle for teaching microbiology, using a range of approaches from informative cartoons to interactive courses (López‐Goñi et al. , 2016). Comics, with their visuals, narrative and metaphors, are an enjoyable way to learn about microbiology (Scavone et al. , 2019). There is a growing availability of games, such as Top Trump‐style games, like Comic Bacteria’s Micro‐Match and the Eden Project’s Invisible Worlds, as well as online games, such as those developed by Public Health England’s e‐Bug initiative (Farrell et al. , 2011), the Centre for Disease Control (Solve the Outbreak) and the American Museum of Natural History (Bacteria in the Cafeteria). Foldit is a citizen‐science game (aimed at older children and adults) that takes advantage of human pattern recognition and puzzle‐solving skills to determine protein structures (Cooper et al. , 2010). A current challenge is to design protein structures that would block the coronavirus spike protein’s interaction with host cells, as a step towards antiviral drug development. Reference to the use of microbiology in science fiction or popular culture can spark the interest of children, but should generally be considered as a starting point for discussion, e.g. what are the microbes in the pink salt lakes that are the subject of a ‘Go Jetters’ episode? However, the improbability of humans being infected with Ophiocordyceps sp. and turning into zombies, as imagined in the video game ‘The Last of Us’, may need reinforcing.
Visiting speakers enable interaction of children with professional microbiologists, especially in standard classes rather than large assemblies. However, many more school children can be reached if more microbiologists prepare and share educational videos. The educational benefits could be enhanced by the involvement of production companies and teachers to assist with the aesthetic and content. Such online videos hand more control to the teachers, who can embed the video material into the curriculum at the most appropriate time, pause the video and discuss key points (or deal with discipline issues). The topic of such videos could include microbiology excursions and present a phenomenon around which the rest of the presentation pivots, e.g. how to get fuel from your faeces. Engagement of commercial enterprises in the production of visual aids will require financing from grant agencies and philanthropic sources, who are encouraged to dedicate resources for such purposes.
On the other hand, interaction with scientists can be achieved remotely, which is particularly valuable for isolated communities. Notable mechanisms for doing this are ‘I’m a scientist get me out of here’ and ‘Skype a scientist’. Both mechanisms give the opportunity to ask questions, better understand what being a scientist is like and learn that scientists come from all walks of life, thereby raising aspirations of children. The latter matches scientists with classrooms across the globe and could be used to integrate the scientist as a virtual participant into parts of a school field trip.
Some field locations are remote or difficult to access, in which case live feeds, e.g. via Facebook, can instil some of the excitement of the microbiological activity. For example, a highlight of a recent postgraduate training school on the Deep Hypersaline Biosphere (funded by the EU COST Action MedSalt) was a descent of over a kilometre into Boulby salt mine and Boulby Underground Laboratory (Fig. 18). The visit coincided with the Mine Analogue Research (MINAR) event at which tools were being tested in the salt mine’s ‘Mars Yard’ for future planetary exploration. Subterranean interviews and demonstrations were shared using live feeds to schools and colleges across the world, illustrating children’s intrinsic interest in astrobiological research (Cockell et al. , 2019). Oceanographic research institutes often film and make freely available, sometimes in real time, their research trips, including deep‐sea dives by submersibles (Fig. 18).
In future, more field expeditions into unusual microbial habitats should, where possible, be financed, planned and executed in such a way that an educational component can be accomplished, and the excitement and scientific achievements of the expedition shared with children of different ages. Virtual reality and augmented reality are now feasible, extra‐sensory options for schools, as simple viewers costing $5‐10 apiece, coupled with free virtual reality apps on smartphones, allow an immersive experience of expeditions, either ready‐made (e.g. from Google Expeditions) or home‐made (Minocha et al. 2018).
A basic knowledge of microbiology is an essential enabler of some of the new policy decisions that will be necessary to attain sustainable development of human societies and to reverse current unsustainable practices entrained by previous inadequately informed decisions, so it is imperative that society becomes microbiology‐literate (Timmis, et al , 2019). For society to attain microbiology literacy, relevant aspects of microbiology must become an essential component of basic education. Happily, the breadth, depth and excitement of microbiology, along with its dynamic research advances, and especially new discoveries about our microbiomes, make it a perfect topic for stimulating curious young minds. Microbes are pervasive in their influence on us and our environment, and the results of microbial activities are highly tangible for children – witness the number of products in shops that have a microbial origin or component. Almost certainly as a consequence, there is a considerable body of experience that testifies to the fact that exposure of children to microbiology can ignite a veritable passion for the subject. The primary goal of this Editorial is to promote class excursions as a powerful means of nurturing interest in microbes, through enabling children to experience and engage with the microbial world in a very individual, personal and intimate manner. However, other, equally important goals are: to engage teachers and stimulate them to consider the value of class excursions, to recognize and encourage those academics already involved in bringing microbiology to children in diverse settings, to induce others to participate in the introduction of microbiology in basic education, and to support schools in their endeavours (Redfern et al. , 2013). With this Editorial, we seek to motivate schools to expand their portfolio and frequency of excursions, and academic microbiology groups to share more ideas, resources and time to allow a wider audience – children and adults – to experience microbes and microbiologists in action.
The examples provided in this Editorial may be centred on microbiology, but none will be exclusively so, and nor should they. Excursions afford the opportunity to explore societal, cultural and civilizational issues, both global (e.g. feedstocks used in the processes discussed, and issues surrounding their trade, transport and carbon footprint) and local (e.g. regional pride in the products, local employment opportunities and environmental impact of the processes), all of which are key components of any geography syllabus. Indeed, excursions can demonstrate how integration of knowledge and understanding from a range of other disciplines are essential for successful businesses, drawing on: engineering, physics, mathematics (e.g. design and construction of fermenters for production and recovery of microbial products such as enzymes and amino acids, calculating/controlling hydrodynamics of water flow in wastewater treatment), chemistry (e.g. identifying flavour compounds in food microbiology), biology (e.g. human health, the mode of action of drugs, how enzymes work, molecular biology tools such as gene editing and the polymerase chain reaction, created through innovative microbiology research), economics (e.g. long‐term economic viability of companies and diversification, by turning waste into profitable material), history (e.g. the role of the industry in the growth and identity of the region; how microbial infections have contributed to past events, including the eradication of civilizations), social sciences and psychology (e.g. the nature and role of stakeholders in all sorts of issues, such as the use of growth promoters in food animal husbandry and impacts on drug resistance in pathogens, human behaviours in response to pandemics, societal and logistical challenges associated with testing for pathogens), technology (e.g. how key infrastructure, such as clean rooms and fermentation tanks, works and is controlled), art and design (e.g. how a product is marketed, degradation and restoration of art objects from ancient manuscripts to cinematographic film), and ethical issues (e.g. industrial carbon footprint, animal testing and welfare). Excursions should thus imbue children with a sense that the most rewarding jobs will require them to be adaptable and integrate ideas from a range of subjects.
The corollary of this is that microbiological understanding collaterally supports understanding in a range of other disciplines. Consequently, excursions that are not primarily designed to have a microbiology focus can still present the excitement of the invisible world of microbes to children, as exemplified in a number of the discussion topics associated with the suggested excursions.
Most importantly, and especially because microbiology excursions can incorporate multiple topics, they can expose/elevate awareness of local issues and global Grand Challenges, provide unique opportunities to explore and discuss them, instil a sense of community‐global responsibility and encourage participation in collective efforts that seek solutions.
It is well known that stimulating multiple senses enhances learning (Shams and Seitz, 2008), and excursions provide ideal situations in which microbes and their activities can be seen, touched, smelled, sometimes tasted, and occasionally heard. Visual manifestations of microbial agglomerations and their activities are of central importance in learning about microbiology, and many examples are scattered throughout this Editorial. But, there are more ways by which microbes and their activities can stimulate our senses, as outlined here.
The microbes within a school pond, for example, will only really come alive for children when they can see them at the single‐cell level under a microscope or stereomicroscope, i.e. when they can discover microbes’ relative sizes, cell division, motility and how they are eaten by protozoa and small invertebrates. Children usually love visual action – the more frenetic, the better – and there are few examples in nature with more frenetic action than the microbial goings‐on in pond water. Microscopic examination of glass slides left in a pond over time will enable children to observe microbial colonization and biofilm production, and thus explore ecological concepts such as succession, which is normally exemplified by larger organisms. It is also enjoyable and educational for children to observe microbial colonies of different forms, textures and colours growing on agar plates inoculated with samples they have taken during an excursion (Fig. 19).
Touching a slimy pebble from a pond or stream should initiate discussions about biofilms, including which microorganisms create them, what is the chemical nature of the slime, what benefits the slime provides for the microbes producing it and perhaps other microbes embedded in it. Any disgust exhibited by some children may be tempered (or perhaps enhanced) by pointing out that they will certainly have eaten microbial slime with considerable pleasure. For example, the texture of many varieties of ice cream is enhanced by xanthan gum, a high molecular weight polysaccharide produced by the bacterium Xanthomonas campestris. Children may then consider where else they find biofilms: trickling filters in wastewater treatment plants, air pollutant biofilters, snottites in caves (Macaldy et al., 2007), the bottoms of shower curtains, taps and unwashed sinks, the surfaces of drainpipes, teeth and catheters. The discussion could be extended to consider the ubiquity of biofilms, their benefits to the environment and health (e.g. the ‘second skins’ of plants and animals that protect against pathogens, biofilms in waste and pollution treatment) along with their harmful effects (e.g. steel corrosion, tooth decay, as well as housing pathogens and protecting them against antimicrobials and disinfectants).
Children have an acute awareness of smell, so exploration of microbial odours is a powerful way to relate microbes to sensory perception. In some cases, it could be interesting to ask children ‘what are smells and how do we detect them?’. Odours are volatile chemicals that are recognized by olfactory receptors in the nose (it has been suggested that we can distinguish up to one trillion different odours; Bushdid et al. , 2014). Volatiles are not only important for us to anticipate and appreciate a nice curry or react to unpleasant or dangerous situations, such as food that has gone bad or a gas leak, but are used by microbes to communicate among themselves and with other organisms, in order to orchestrate some joint action (Ryu et al. , 2003). To get children involved, it can be helpful to pose the question: ‘Can I smell microbes?’ and then to ask them to identify smells they are familiar with, perhaps categorized into nice and unpleasant odours, and then discuss which of these has a microbial origin. Body odours (also from pets) emanating from poo, flatulence, old sweat, smelly (‘cheesy’) feet (see comments on Propionibacter and Brevibacterium, below) and bad breath are all produced by microbes when they metabolize chemicals in the particular body sites they inhabit. Volatile chemicals produced by microbes from secreted oils in the axillae have been considered to have pheromone properties, and so the microbiome may act like an invisible puppet master in attracting mates. Volatiles in breath are currently being actively investigated as biomarkers of disease for non‐invasive diagnostic procedures.
Outside, we have the nice smells of rotting leaves on the ground in autumn and compost heaps all the year‐round and, of course, the smell of soil after rain, caused by geosmin‐producing Streptomyces species, to which we alluded above. The bad‐egg smell derived from stirring up the black mud at the bottom of a pond will likely evoke a memorable response from children. Here, it is informative to discover which microbes produce the smell (sulfate‐reducing bacteria), what is the chemical involved, how it may be created (for older children having done some chemistry), where the responsible microbes live and why they may be beneficial or harmful in different scenarios. This activity may be coupled with digging a small pit, in which the redox zonation in sediments may be seen in the form of microbially induced changes in the colour of iron minerals, from aerobic (rusty) to sulfate‐reducing/sulfidogenic (grey‐black) (Fig. 13). The evocative smell of the sea can serve as the basis for a discussion on biogenic volatile chemicals, primarily dimethylsulfide (DMS), which is produced by microbial breakdown of dimethylsulfoniopropionate, a multifunctional metabolite found in many marine microbes that can serve as an osmolyte, antioxidant and cryoprotectant. Discussions could then turn to the role of DMS in cloud condensation and potentially global cooling, and even how seabirds use DMS as a directional olfactory cue (Steinke et al. , 2011).
In the home, there are well‐known odours produced by microbes, including those coming from food, like cheese (see below), sauces obtained by fermentation, vinegar and pickles of all sorts, and fermented meats. The same smells can be experienced in restaurants and food stores. Shops and stalls selling fish may have the typical odour of fish that is not super fresh. This is trimethylamine, a pungent chemical produced by microbes living on/in the fish from trimethylamine oxide, a versatile chemical made by fish to protect against the protein‐destabilizing effect of urea, salinity and high pressure (Yancey, 2005). The flavours of food definitely provide an enjoyable way for children to learn about microbes. Cheeses, for example, derive from coagulated milk, yet they can taste and smell differently and have a range of textures and skins, reflecting the different microbes and processes used in their manufacture. The microbial communities that develop are a consequence of, inter alia, the microbial inoculum, the cheese ‘environment’, e.g. humidity, salinity, temperature and pH. The fungus, Penicillium roqueforti , grows in the cracks made in cheeses like Stilton (Fig. 3) and Roquefort, giving the distinctive earthy flavour and blue veins (Kindstedt, 2014). Microbial fermentation products give interesting flavours and textures, e.g. the bacterium Propionobacter sp. produces CO2 (the holes) and acetate/propionate in typical Swiss alpine cheeses – the same microbial genus also contributes to the unwashed smell in humans. Similarly, Brevibacterium linens that grows on the surface of some cheeses also grows under our toenails, producing a distinctive smell common to both. Thus, from cheese, the discussion can turn to the microbial origin of the human aroma and its influence in attracting a mate.
Sound is not a sense we commonly associate with microbes. However, the Fermentophone (Fig. 16) harnesses bubbles from colourful fermentations to create music. Bubbles can also be seen and sometimes heard to pop when escaping from the water column to the atmosphere. Children will often ask what causes the bubbles and the answer will depend on various factors including illumination. But, in a stagnant muddy pond it is likely that bubbles from the sediment are formed from methane, which can stimulate discussions about methane’s role as a greenhouse gas. Showing children videos of burning methane emanating from a pond is highly recommended, with the common outcome of conversations turning to personal methane production and its egress, thus providing a link between the individual and their microbiome, specifically in this case their archaeome (Fig. 13).
Measuring the temperature of a school compost pile over time provides another means of sensing microbial activity that can feed discussions about energetics, decay and microbial interactions with other species, such as compost worms, which may be considered to be environmental engineers, and their all‐important gut microbes which carry out many of the compost digestive processes (Medina‐Sauza et al. , 2019). Children could use a thermometer to accurately record changes in temperature or simply use touch to sense microbial activity by feeling the warmth of a metal rod inserted into the compost heap. There are other tools to detect microbial activity; for example the MudWatt (Magical Microbes; Jude and Jude, 2015) provides a cheap yet very effective device to observe metal‐reducing microbes in sediments/soils making electricity and generating light.
For all excursions, learning can be reinforced in the classroom with follow‐up activities: designing posters, presenting news reports, building models and other artwork and including agar art, which involves developing images using microbes inoculated onto agar plates (Charkoudian et al. , 2010; Adkins et al. , 2018; Fig. 20). The significance of a visit to a bakery, for example, would be enhanced by investigating gas production (using balloons) and pH change (using indicators) in yeast cultures back in the classroom. After exploring microbial contributions to foods in shops, manufacturing facilities or research laboratories, it is fun and instructive for children to make their own fermented foods, such as tempeh (Fig. 21). Samples transported back to the class can become the subject of observation/investigation/experimentation. These activities are facilitated by tools like the Foldscope (Cybulski et al. , 2014), together with a range of open‐source technology and products, such as centrifuges (Bhamla et al. , 2017) and nephelometers (Wijnen et al. , 2014). Samples of sea salt, salted fish or salt‐rich fermented food can be enriched in medium to grow extreme halophiles, such as Halobacterium salinarum, which is readily cultivated, safe to work with and is a striking red colour (Baxter et al. , 2012; DasSarma et al. , 2016; Fig. 2). Winogradsky columns provide another relatively simple means of exploring the different ways in which microbes obtain energy, their interactions, succession and niche partitioning, using mud and water from local environments (Anderson and Hairston, 1999; Fig. 13). The Microbiology in Schools Advisory Committee (MISAC), which has been established for 50 years, provides outstanding and wide‐ranging educational resources, many of which have been adopted worldwide, for those keen to teach microbiology in schools. Obviously, any classwork involving the cultivation of microbes should be carried out according to Good Microbiological Laboratory Practice (see the online guide by the Microbiology Society).
There is an urgent need for society to acquire literacy in microbiology, and the education and inspiration of children lie at the heart of this endeavour. Pivotal to this are actions that will enable children to ‘see’ invisible microbes, by experiencing their activities and consequences of such activities. Here, we have discussed the importance of class excursions to experience and explore microbes in action, provided a range of examples, and have suggested some organizational issues that may be helpful for obtaining maximum benefit from such excursions. To advance the goal of initiating class excursions in microbiology, we make the following recommendations:
TJM acknowledges support from the following UKRI grants: STFC ‘Trace gas bio‐signatures: implications for NOMAD’ ST/S001425/1) and NERC ‘FUSED – Functionality of Urban Soils supporting Ecosystem service Delivery’ (NE/S005560/1). We are very grateful to the following for providing suggestions and images: Margaret Adams, Geof Adams, Selwa Alsam, Judith Armitage, Emese Bartha, Ricardo Cavicchioli, Scott Chimileski, James Chong, Joseph Christie‐Oleza, Graeme Churchard, Martha Clokie, Mike Dyall‐Smith, Martha Endika, Alessandra Marcon Gasperini, Immanuel Giel, Charlotte Gruender, Myriam de Haan, Natalie Hicks, Tanja A. Hofmann, Mike Jetten, Bo Barker Jørgensen, Stefan Hyman, Patrick Jung, Z. Ceren Karahan, Roberto Kolter, Philippe Laissue, Sang Yup Lee, Miika Leppänen, Andrea Lohberger, Derek R. Lovley, Etienne Low‐Décarie, Naresh Magan, Margaret McFall‐Ngai, Mairi McGenity, Carmen Michán, Corrado Nai, Victor Parro, Sean Paling, Ángeles Prieto Fernández, James I. Prosser, Juan Luis Ramos Martín, Martin Rejzek. Peter Paolo Rivera, Eliora Ron, Joshua Rosenstock, Angela Sessitsch, Alex Shakspeare, Paul Shields, Andriy Sibirny, Nicky Slee, Cindy J. Smith, J. Cameron Thrash, Andreas Thywißen, Jezz Timms, Graham J.C. Underwood, Joanna Urban, Toungporn Uttarotai, Aurélie Villedieu, Dave Whitinger, Polona Zalar, the American Society for Microbiology and entrants for the Agar Art competition, Great Salt Lake Institute, MARUM – Center for Marine Environmental Sciences, NASA, University of Georgia. TJM and KT are even more grateful to their families for tolerating the long periods of absence while creating this Editorial.