The human microbiome is a collection of different groups of microorganisms including-bacteria, archaea, eukaryotes, fungi as well as viruses.¹ The term microbiome includes these different organisms and their genes or genomes in association with the host ecosystem. The human microbiome is a collective term for all the microbiomes present in different anatomical areas including eye, ear, nose, hair follicles, gut, respiratory tract, urogenital tract, reproductive organs² (Figure 1). Each anatomical niche harbors its unique microbiome regulated by physiological factors like pH, temperature, oxygen and nutrient availability, moisture, host immune factors. These microbiomes are established early in life and are shaped and influenced by mode of birth, feeding, use of antibiotics, diet, disease and other environmental factors. The human microbiome includes commensals, symbiotic, and opportunistic pathogens living on as well inside the human body.³ Their coexistence may also provide certain benefits. For example, the human gut microbiome consists of many symbiotic bacteria which ferment dietary fibres to short chain fatty acids which are required for growth of colonocytes and modulate the immune responses.³ The opportunistic pathogens, present in less numbers in the human microbiome lead to disease conditions, for example disruption of gut microflora due to use of antibiotics can lead to Clostridioides difficile infection.⁴ The entire microbiome plays a significant role in maintaining the overall health of the human host.

The relevance of the human microbiome has increased manifold since the Human Microbiome Project was launched by the U.S. National Institutes of Health (NIH) in 2007 as it plays a crucial role in human health and disease resistance.⁵ It acts as an extensive reference database of the human microbiome in health, offering a starting point for understanding how it contributes to normal human physiology and how it varies in diseased conditions.^6,7 The commensal microbes of the human body regulate various mechanisms and physiological processes of the human host including immune response, digestion and respiration. Any alteration in the composition of microbiota found in healthy individuals or microbial dysbiosis can lead to disease states or disorders. This dysbiosis also plays an important role in the spread of AMR or antimicrobial resistance. This further escalates the growing burden of infectious diseases, especially in developing countries like India. The excessive or inappropriate use of antibiotics leads to dysbiosis or alteration of the microbiome. Under antibiotic pressure, the number of drug-resistant microbes increases, which leads to the problem of AMR. Further, the antimicrobial resistance genes (ARGs) can also be transferred to other organisms via HGT or horizontal gene transfer, leading to high prevalence of resistant microbes in the altered microbiome due to antibiotic-induced dysbiosis. The gut microbiota acts as a large reservoir of such resistant strains (‘resistome’).^8-11 The cross talks of microbes (bacteria, fungi, viruses) and human hosts are essential for the normal functioning of the body. This communication is hampered by changes in human microbiota composition and can lead to pathological conditions of different body organs. The understanding obtained from changes in the microbiome between healthy individuals and patients suffering from a particular disease also opens up new avenues of treatment strategies. For example, microbiome wide association studies (MWAS) compare the microbiomes of healthy individuals and patients to find out specific features like microbial taxa that are statistically associated or linked with disease states. This enables the identification of biomarkers associated with specific diseases so that precise therapeutic interventions can be provided to the patients as early as possible. Similarly, with such microbiome related studies, an early detection of colonization of Streptococcus in the nasal cavity can indicate the risk of asthma.¹² In this manner, custom-fit treatment options can be worked out for many important diseases like asthma.

The study of the human microbiome includes both culture-based and non-culture-based techniques. The former technique provides an approximation of microbial communities in a given sample, while the latter is more specific and has the potential to accurately identify the microbial populations using advanced tools like 16S/18S/ITS gene sequencing, metagenome sequencing, immunoassays, etc. Usually, a combination of both traditional culture-based and non-culture-based methods is applied to unravel the members of the microbiome of specific tissue samples. Often, inconsistencies in the microbial data composition or microbial diversity in different microbiomes like that of ear or eye have been reported possibly due to insufficient sample size or sequencing approach, and varied diagnostic criteria.¹³ Despite these constraints, dysbiosis in the microbiome of a specific organ is studied from the perspective that it is either the cause or consequence of any pathological state or disorder. Therapeutic solutions rely on development of diagnostic tools and techniques to detect changes in the associated microbiome. Thus, understanding the human microbiome becomes important right at the stage where the microbial world is introduced to the students. In this respect, we have discussed important human microbiomes of ear, eye, nose, hair, and gut microbiomes followed by simple classroom exercises that can help promote microbiome literacy among school students. Figure 2 illustrates the role of microbiome literacy¹⁴ in the field of education and research with a specific focus on India.

An attempt is also made to bring out the existing gaps in the NCERT-CBSE Science textbooks related to microbiomes which can be easily filled by discussing and integrating microbiomes in our class discussions. It also becomes relevant to include these discussions as India’s National Education Policy (NEP) 2020 aims to transform the country’s education system by emphasizing interdisciplinary learning, critical thinking, and scientific literacy.¹⁵ With a focus on STEM education and research, the policy framework can provide a foundation for incorporating microbiome-related topics. A comparative analysis of education systems in India and other countries offer insights into best practices and areas for improvement. Incorporating microbiome concepts into biology, health, and environmental education can foster a deeper understanding of the human microbiome and its impact on health and disease.¹⁶ Encouraging research in microbiome science can help India stay at the forefront of this rapidly evolving field. Incorporating microbiome education into India’s education system will promote scientific literacy, critical thinking, and interdisciplinary learning. By exploring global best practices and comparative perspectives, India can develop effective microbiome education initiatives that align with its education policy and research goals. Also, this work is an attempt to raise awareness among academicians and curriculum framework makers to include and integrate microbiome education in the existing science textbooks and curriculum. The rapidly evolving field of microbiome science has potential consequences for human health, disease, and the environment. The Table 1 provides a comparative overview¹⁷ of microbiome education, research, and significant initiatives in South-East Asian countries, India and other countries.

Table (1): Microbiome education across the Globe: Initiatives and Insights

The rationale of the present study is to identify the knowledge gaps about microbiome research in the biology NCERT textbooks, which are commonly studied by school students and is recommended by UGC (University Grants Commission) for school curriculum. However, limited or exclusion of contemporary topics of resistome; microbiome dysbiosis and emergence of AMR; host-microbe interactions with the holistic concept of human microbiome; disease pathogenesis and molecular diagnostics limit the microbiome literacy at school level. Hence it becomes important to assess current status of microbiome literacy in India and compare across the globe, followed by pedagogical interventions like simple classroom exercises which can be implemented to address the emerging educational and public health needs.²⁰ This will in turn emphasize the growing importance of microbiome ecology to AMR and One-Health priorities.²¹

Study design and methodology
The present study used qualitative descriptive curriculum analysis. The main objective was to find core themes or topics pertaining to microbes and microbiology which can be further augmented with recent research findings about the human microbiome. This will ensure the promotion of microbiome literacy at the school level education and better understanding of human diseases and diagnostics. The primary data sources included the school curriculum biology NCERT textbooks, peer reviewed studies and reports on microbiome research, curriculum frameworks and education policies related to microbiome studies in different countries like USA, China, Europe, South East Asia and India. The data sources were retrieved from official government websites, university or research institutes and literature databases like PubMed, Scopus, Web of Science. The inclusion criteria were curriculum documents of class 9 to 12 and latest published research papers and review articles in microbiome research. The exclusion criteria included non-official documents, blogs or opinion sources. The methodology flow included firstly, thorough screening of the existing school curriculum and biology textbooks to identify the knowledge gaps to be filled by topics in microbiome research using inclusion and exclusion criteria. After the gaps were identified, we then focused on topics which can be easily extended or elaborated with microbiome studies in classroom settings. In order to effectively communicate the concept of microbiome within the microbiology framework, we have discussed some simple classroom exercises and use of online tools/databases which can be used by students and educators. All these strategic pedagogical measures will help in integration of microbiome literacy at the school level.

Microbiome literacy and its relevance
Microbial colonies are present throughout our food ecosystems; from cultivation and harvesting to processing and packaging. Understanding these microbiomes is essential to address growing societal challenges related to food consumption and climate change. Microorganisms play important roles in ecosystems by impacting soil quality and plant development while also contributing to food production and nutrient circulation systems essential for sustainability, in agriculture where they can influence both crop productivity and resistance to pests and diseases. In the context of climate change, microbiomes are involved in carbon and nitrogen cycling, which impact greenhouse gas emissions. By studying and harnessing microbiomes, more sustainable agricultural practices can be developed, improving food security, and mitigating some effects of climate change.²² The application of new technologies developed from such correlations will hugely impact public health and geopolitics. Consequently, it becomes crucial to introduce and empower students to the benefits and potential applications of microbiomes through scientific communications.

India faces a complex public health challenge, simultaneously combating a high prevalence of infectious diseases and a rising tide of non-communicable, lifestyle-related disorders. In this context, the human microbiome assumes particular significance. Traditional Indian dietary practices, characterized by their abundance of fermented foods and a rich variety of plant-based ingredients, inherently foster a diverse and robust microbial ecosystem, which may offer crucial insights into both disease susceptibility and resilience. Yet, the rapid modernization, urbanization, and shift towards processed foods, coupled with widespread antibiotic use, threaten to disrupt this delicate balance, contributing to the rise of chronic conditions. It is within this context that the urgent need for microbiome literacy in the Indian curriculum emerges as a vital public health and educational imperative.

Currently, the average Indian citizen possesses a limited understanding of the microbiome, which needs to be changed, especially amongst the students. Microorganisms are often predominantly associated with disease-causing “germs”, leading to a fear-based perception rather than an appreciation for their beneficial roles. By educating students about the microbiome, we can promote informed health choices, antibiotic awareness, and a prepared future workforce. A pedagogical approach that emphasizes interdisciplinary learning, hands-on activities, and real-world applications can help nurture a microbiome-literate society that values microbiome health and makes informed decisions about their health.

To enable informed decision-making, citizens need to be educated in microbiome literacy at school education.²³ The stubborn ESKAPE pathogens, named as per the first letter of the genera, viz., Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter sp., known to antimicrobial resistance (AMR) and prioritized by WHO can be prevented by following simple hygiene practices.^24,25 These follow a global surveillance system to track their spread and genetic changes. Health literacy advocated by WHO considers public health as a social determinant of inequities and economic growth.²⁶

Despite the immense importance and biotechnological advancements for their application, a negative perception prevails of microbes as disease-causing agents.²⁷ The challenges of the COVID-19 outbreak have led to germophobia in the general public though on the other hand, a post-pandemic rise in general hygiene, and awareness programs is also seen.²⁸ The negative prejudice is also supported by the increasing reports of hospital-acquired infections,²⁹ antibiotic and multidrug resistance variants,³⁰ mistrust of vaccines,³¹ and the ever-expected threat of several infectious diseases and possible pandemics.³² Hence, microbial as well as microbiome literacy programs are essential for developing an understanding as well as their appreciation (Table 2). Globally to educate and promote microbiome and microbial literacy, several science pedagogies have been developed for school children. These can be initiated as classroom discussions, excursions, video clips and followed up by assignments and activities first at family and friends and later at community level. Chen, 2021 have designed a video game “Tiny Biome Tales” to educate about the impact of health behaviour and practices on the human microbiome.³³ Education activities designed by Rabelo-Fernandez and Rios-Velazquez (2021) based on a combination of talks, assignments, projects, and assessments showed an increase of more than 40% of microbiome concepts.³⁴

Table (2): Relevance for microbial-microbiome literacy in schools

So far, gut microbiomes have been the focus for popularizing microbiome literacy majorly through social channels and press releases,⁴² but there is an emergent need for holistic inclusion of other microbiomes. To widen the unbiased understanding, proactive communications are required. This will ensure increased trust and acceptance of scientific advancements; improve community health; bring transparency in policy processes; and inspire and involve people in health development programs.^43,44 School education is an appropriate medium to prevent misinterpretation of findings; understand risks and hazards; and encourage and influence public perception.^45,46 Subsequent sections of the present article present a brief discussion of important human microbiomes and the association of dysbiosis or disequilibrium of these microbiomes with pathogenic states or diseases. This can be useful in providing scientific insights about the important human microbiomes, particularly regarding human health.

Know your microbiome
Many recent studies have reported the importance of the human microbiome in improvement of health and disease diagnosis.^47,48 Thus, it becomes imperative to understand key anatomical microbiomes of the human host in order to promote microbiome literacy, which will enable the students to appreciate the role of microbiome in human health and disease states. So, in this section, we have discussed six modules on hair follicle, ocular, oral, nasal, ear and gut microbiomes including their brief introduction followed by the microbial diversity and composition in both healthy and diseases states.

Hair follicle microbiome
Hair follicle (HF), as the name suggests is a pouch or tube-like structure present in the outermost layer of skin or epidermis. The root of the hair follicle is formed by cells and blood vessels. They are responsible for the growth, color, and texture of hair. The hair follicles also provide epithelial stem cells for the repair of wounds. They also play a vital role in thermoregulation, tactile sensation, and protection against harmful ultraviolet (UV) radiation.⁴⁹ There are more than five million human HFs that regulate hair growth throughout our life span.⁵⁰ Hair follicles have been regarded as one of the human body’s anatomic sites of immune privilege (IP). The understanding of follicular microbiomes is important in the treatment of pathological states like folliculitis, acne vulgaris, alopecia areata, hidradenitis suppurativa, and cicatricial alopecias.^51,52

The HF microbiome primarily consists of a large number of actinobacteria, which are also found abundantly in the skin microbiome.^53-55 The actinobacteria of HF microbiome majorly belong to members of the genus Propionibacteria and Corynebacteria. The other bacterial groups include Firmicutes, with a predominance of Staphylococci and Streptococci, and Proteobacteria including Pseudomonades, Acinetobacter spp., and Moraxella spp.^56,57 The distal epithelium of HF consists of biofilms of Cutibacterium acnes.⁵⁸ While C. acnes and S. epidermidis are the most common bacteria in the scalp microbiota of healthy subjects,⁵⁹ there are a few more bacterial members that dwell in a healthy HF. Different eukaryotic DNA viruses, including Adeno-associated virus 2 (AAV2) and human papillomaviruses (HPVs), mainly beta-papilloma viruses⁵⁷ are also found to populate a healthy HF. These viruses can also turn into opportunistic pathogens in immunocompromised individuals and trigger latent skin infections. It has been shown that these viruses can latch on to the base membrane under immunocompromised conditions and overgrow the scalp and face skin with epithelial hyperplasia and wart-like protrusions.^60,61 The HF constitutes a small niche in which the follicle-bacteria-epithelium: tripartite interactions play a crucial role in maintaining skin health.^62,63 From the available metagenomic data of HFs, it has been reported that non-viral size fractions of the HF microbiota comprise mainly of bacteria and viruses infecting bacteria have also been reported. The presence of bacteriophages (viruses that infect bacteria) suggests their plausible role as an important regulator of microbial diversity by modifying bacterial populations under homeostatic, as well as unhealthy conditions of the host.^64,65

In addition, the HFs are also heavily populated by fungi, particularly lipophilic species belonging to the Malassezia genus, including M. restricta and M. globosa.⁶⁶ The incidence of both species increases and decreases, respectively in dandruff and patients with seborrheic dermatitis.^67,68 While tinea capitis is a fungal infection of scalp hair, an increase in the number of dermatophytes like Trichophyton spp. and Microsporum spp. has also been found.⁶⁹ The increase in the number of dermatophytes produced a decrease in the number of Malassezia, and it is suggested that dermatophytes regulate the density of Malassezia spp.⁷⁰ The HF microbiome also harbours small arachnids or commensal mite species, D. brevis and D. folliculorum that inhabit the pilosebaceous unit of facial skin from the very beginning of their life after birth.⁷¹

Changes in HF microbiome and scalp or hair-related diseases
The microbiota of HF may get out of order in hair-related disease states or disorders like bacterial or fungal folliculitis, tinea capitis, syphilitic alopecia, and herpes simplex or herpes zoster-associated folliculitis^72-78 (Figure 3). The imbalanced state of the HF microbiome is associated with pathological states like acne.⁷⁹ Dagnelie M-A, 2019 reported a decrease in Staphylococci and Enterococci and an increase in the density of P. acnes in healthy controls compared to acne patients.⁸⁰ However, Kelhala H-L, 2018 reported the opposite finding with an abundance of Staphylococci and Enterococci and a decrease in P. acnes.⁸¹ A similar microbial profile is also observed in another inflammatory disease of HF-Alopecia areata, which is commonly known as spot baldness or patchy hair loss. An increased abundance of P. acnes has been found in androgenetic alopecia.⁸²

Hidradenitis suppurativa (HS), commonly referred to as acne inversa in which patients develop painful lumps or cysts in armpits, groin and breast areas. The studies have shown that such patients show a high number of bacterial members of genus Staphylococcus aureus and anaerobes belonging to the genus Porphyromonas and Peptoniphilus.^83,84 However, the proportion of P. acnes reduces in this inflammatory disease of HFs.^56,85,86 The rise of S. aureus is also seen in Folliculitis decalvans (FD), a scalp disease.⁸⁷ These bacterial species may also cause the release of antimicrobial peptides (AMPs) in large amounts to elicit an inflammatory response. Haemophilus and anaerobic pathogens including Prevotella spp., Anaerococcus spp. and Mobiluncus spp. are also present in HS lesions. M. restricta and M. globosa populations also increased similar to other features of HF microbiome dysbiosis in alopecic areas of the vertex.⁸⁸

Changes in the scalp microbiome have also been observed in Seborrheic dermatitis, commonly known as dandruff, which is an inflammatory skin condition found in sebaceous areas. This pathological condition is found in its mild form as Dandruff on the scalp in which Cutibacterium spp. decreases while there is an increase in Staphylococcus spp.^68,89 Some studies have reported that in cases of Dandruff, the number of Malassezia bacteria double as compared to normal levels^90,91 but Soares et al. 2016 found no such difference in healthy controls.⁹² Also, M. restricta and S. aureus are found predominantly in scalp swabs taken from patients suffering from scalp psoriasis.^93,94 Interestingly, alterations in gut microbiome with a decreased abundance of actinobacteria have been found to contribute to scalp psoriasis. This finding has highlighted the role of the ‘gut-skin’ skin axis in psoriasis.^94,95 So, understanding of HF microbiome is becoming important in clinical dermatology and is opening new avenues for the management and control of hair-related diseases.^96,97

Ocular microbiome
Ocular microbiome refers to all kinds of microbes including commensals as well as pathogenic microorganisms present in the eye. The interface between the eye and the area including cornea, conjunctiva, tear film, and eyelids comprises the ‘ocular’ surface. The maximum number of microbes have been recovered from the conjunctiva and eyelid while the lower abundance of microbial diversity has been found in tears.⁹⁸ Different species of gram-positive bacteria like Staphylococcus, Streptococcus, Propionibacterium, Diphtheroid, and Micrococcus have been found commonly in the ocular surface with Staphylococcus among the most abundant of all bacteria.^99,100 The composition of the ‘core ocular microbiome’ has been reported by many researchers with differences in the bacterial members of different genera.^101-104 Recently, Suzuki, reported that Propionibacterium was the most prevalent bacterial species on the ocular surface in the young subjects while Corynebacterium or Neisseriaceae was found in the elderly subjects.¹⁰⁵

Changes in ocular microbiome and eye diseases
The ocular microbiota can be shaped or changed by many variables like environmental factors, age, gender and endogenous host factors, and personal habits-like wearing contact lenses or some disease states, infection or use of antibiotics, etc.¹⁰⁶ Altered ocular surface microbiota is linked with diseases such as meibomian gland dysfunction or dry eye syndrome and some autoimmune diseases like Behcet’s disease (BD), rheumatoid arthritis, and Sjogren’s syndrome and other diseases like diabetes, high cholesterol, and triglycerides, conjunctivitis.^107-115 For some diseases like uveitis, characterized by acute or chronic intraocular inflammation of infectious or non-infectious origin, the linkage between intestinal and ocular microbiota was reported by Horai et al., using the spontaneous uveitis mouse model.¹¹⁶ Also, gut and oral microbiota are found to be associated with glaucoma.¹¹⁷ However, further investigations are required to validate these findings and to further elaborate the cross-talks of gut or oral microbiota with ocular microbiome. These will also help in the treatment of ocular diseases using intra-ocular commensal organisms.¹¹⁸

The oral microbiome
The oral cavity serves as a habitat for a plethora of microbial species, ranking second only to the gastrointestinal system in microbial diversity.¹¹⁹ These microorganisms are dispersed throughout both hard and soft tissues, encompassing the surfaces of teeth and the oral mucosa.¹²⁰

Healthy oral cavities inhabit bacterial genera, including Gram-positive bacteria namely, Abiotrophia, Peptostreptococcus, Streptococcus, Stomatococcus, Actinomyces, Bifidobacterium, Corynebacterium, Eubacterium, Lactobacillus, Propionibacterium, Pseudoramibacter, Rothia, as well as Gram-negative bacteria like Moraxella, Neisseria, Veillonella, Hemophilus, Campylobacter, Capnocytophaga, Leptotrichia, Desulfobacter, Desulfovibrio, Eikenella, Fusobacterium, Prevotella, Selemonas, Simonsiella, Treponema, Wolinella.^119,121 Beyond bacteria, the oral cavity hosts diverse protozoans predominantly Entamoeba gingivalis and Trichomonas tenax, and fungal genera like Candida, Cladosporium, Aureobasidium, Saccharomycetales, Aspergillus, Fusarium, and Cryptococcus.¹²²

Changes in oral microbiome and diseases
Oral lesions have been linked to the DNA viral families Herpesviridae, Papillomaviridae, and Poxviridae. Oral cavity infections can also be caused by RNA viruses, such as enteroviruses and paramyxoviruses. Various herpesviruses, including herpes simplex virus (HSV) and cytomegalovirus (CMV), can be found in the oral cavity.^123,124 Streptococcus mutans is known for its role in causing dental caries (cavities) by producing acids that contribute to tooth decay.¹²⁵ Porphyromonas gingivalis is associated with periodontitis, a severe form of gum disease.¹²⁶

Nasal microbiome
The nasal cavity harbors many commensal bacteria which protect us from pathogenic microbes. Chronic rhinosinusitis (CRS) has been associated with alterations in the microbiota, it is known that CRS patients may experience qualitative and quantitative shifts in microbes in the nasal cavity.^127,128 In patients with chronic rhinosinusitis without nasal polyps, the middle meatus predominantly contained Streptococcus, Haemophilus, and Fusobacterium species, whereas those with nasal polyps had an increased presence of Staphylococcus, Alloiococcus, and Corynebacterium species.¹²⁹

Changes in nasal microbiome and diseases
In healthy individuals, the presence of Neisseria and Haemophilus in the anterior nares is abundant while it decreases in tissue infections.^130,131 Another study that noted differences between the nasal microbiomes of asthmatics and non-asthmatics, found members of the Proteobacteria and Bacteroidetes to be more often present in the microbiota of asthmatics.^132-134 For example, Prevotella buccalis and Gardnerella vaginalis were prominent in asthma patients,¹³⁵ and Sphingomonas and Halomonas were found to be less in number in bronchoalveolar lavage fluid as reported by Sverrild in 2017.¹³⁶ During older age, a shifted composition of the nasal microbiome was noted, including species from the genera Moraxella, Staphylococcus, Corynebacterium, Haemophilus, Fusobacterium, Prevotella, and Dolosigranulum in asthmatic children in a study by Perez-Losada, 2016.¹³⁷ Alterations in the nasal microbiome have also been associated with allergic rhinitis (AR), commonly known as hay fever. The swab samples of patients with AR showed enrichment of Propionibacterium and Corynebacterium, but Streptococcus were low in abundance.¹²⁹ This imbalance in the nasal microbiome dysbiosis may initiate inflammation that eventually leads to the development of neurodegenerative diseases. Increased nasopharyngeal microbe abundance has been identified in the brains of neurodegenerative patients. For example, a high load of C. pneumoniae and P. acnes bacteria was observed in the brain of Alzheimer’s patients.^138,139 Other studies indicated that certain strains of Corynebacterium diphtheriae were producing toxins that could also be linked to sporadic Alzheimer’s Disease incidence.^140,141

The synergistic relationship of different microbes also helps shape the nasal microbiome. For example, in patients infected with the influenza A virus, high abundance of Streptococcus (S. pneumoniae and S. aureus), Phyllobacterium, Moraxella, Staphylococcus, Corynebacterium, and Dolosigranulum has been identified in nasopharyngeal microbiota. Similarly, infections with adenovirus or rhinovirus have been associated with elevated levels of S. pneumoniae. Some microorganisms located in the upper respiratory tract (nose and pharynx) including species belonging to Streptococcus like S. pneumoniae cause pneumococcal infections taking the prevalence of these diseases with the age.^141,142 Furthermore, the combined effect of both the nasal and gut microbiota helps to shape the microbial community of mucosal areas, making it an area that can experience dysfunction when its microbiome is perturbed or into a state of dysbiosis.

Ear microbiome
The ear canal in humans is around 2.5 to 3 cm in length and is composed of two main sections: the distal cartilaginous canal and the proximal bony canal.¹⁴³ The histology of the distal canal is quite similar to the outer skin and consists of sebaceous and ceruminous glands and a large number of hair follicles.¹⁴⁴ The microbiota of healthy individuals is mainly dominated by bacterial members from two major groups- Firmicutes and Actinobacteria.¹⁴⁵ Among the bacterial members, Staphylococcus auricularis and Cutibacterium acnes, Corynebacterium otitidis are present in large numbers.¹⁴⁶

Changes in ear microbiome and ear diseases
The ecosystem of the ear is affected by the presence and absence of different bacteria. The changes in ear microbiota are seen in ear infections such as otitis media (OM) or middle ear infection and otitis externa (OE) or Swimmer’s Ear, in which Proteobacteria and Bacteroides have been detected in patients with otitis.¹⁴⁵ The increased abundance of Proteobacteria has also been detected in patients with Generalized anxiety disorder, thereby suggesting a microbiota-ear-brain interaction.¹⁴⁷

There are substantial differences in microbiome diversity and biomass between healthy and diseased ears. Studies indicate that the diseased otitis externa (OE) comprises fungal pathogens like ascomycetes (Candida sp. and Aspergillus sp.) and bacterial pathogens including Staphylococcus aureus, Staphylococcus haemolyticus, Klebsiella, Pseudomonas aeruginosa, and Cutibacterium acnes.^145,148 In people with otitis media (OM), the ears harbored an elevated number of fungal microorganisms like Candida parapsilosis and bacterial species such as Turicella otitidis, Alloiococcus otitidis, Staphylococcus auricularis, Moraxella catarrhalis, Haemophilus influenzae, Streptococcus pneumoniae, C. jeikeium, C. striatum, S. marcescens, Streptococcus agalactiae, and Achromobacter xylosoxidans.^149,150

Gut microbiome
Gut microbiome is home to a vast community of microorganisms, including bacteria, viruses, and fungi, all living in the digestive system. These tiny beings play a crucial role in keeping us healthy: by helping with digestion, supporting our immune system, and more.¹⁵¹ But when this delicate balance is disrupted, it can lead to a range of health problems.³

Compared to other body parts, the gut microbiome is incredibly diverse, with a unique mix of microorganisms in each healthy person. In healthy adults, the most common bacterial groups are Firmicutes, Bacteroidetes, Actinobacteria, Proteobacteria, Fusobacteria, and Verrucomicrobia.¹⁵² Within the Firmicutes group alone, there are over 200 different types, with Clostridium being the most common in the healthy gut.^153,154 Along with bacteria, the gut also contains viruses (like bacteriophages), fungi (such as Candida and Saccharomyces), and archaea.^155,156 These microorganisms interact in complex ways, affecting our health and how diseases develop.

Changes in the gut microbiome and dysbiosis
The interplay between the gut microbiota- comprising bacteria, fungi, and viruses- and the host’s immune system is a critical factor contributing to dysbiosis, which is linked to various diseases. When this microbiome balance is disturbed, a condition called dysbiosis can occur, it can cause various diseases. Chronic digestive conditions like Irritable Bowel Syndrome (IBS) and ulcerative colitis, are closely tied to changes in the gut microbiome.^157,158 Inflammatory Bowel Diseases, such as Crohn’s disease and IBD, are often associated with an increase in microorganisms like Candida and Streptococcus, as well as viruses like Caudovirales phages.^159,160 Research has shown that people with Crohn’s disease tend to have higher levels of C. albicans and Malassezia, but lower levels of Saccharomyces.¹⁵⁹

Changes in the gut’s viral population have also been linked to diseases like IBD, colorectal cancer, and other gastrointestinal disorders.^161,162 For example, repeated rotavirus infections have been associated with the development of celiac disease.¹⁶³ Gut viruses can influence bacterial behavior, affecting both viral infections and how viruses spread.¹⁶⁴ In terms of metabolic health, shifts in the gut microbiome have been connected to obesity and Type 2 Diabetes.^165,166 Numerous studies have also linked the onset of type 1 diabetes to alterations in the enteric virome, such as the development of early-life infection with DNA viruses from the Circoviridae family.¹⁶⁷ Additionally, obesity has also been associated with an imbalance in the ratio of Firmicutes to Bacteroidetes, with metabolically obese individuals often showing a microbiota composition skewed towards Firmicutes.^151,168 Additionally, gut viruses like rotaviruses and reoviruses have been implicated in the occurrence and progression of Type 2 Diabetes.^99,169

To conclude, Figure 4 illustrates the disequilibrium of the five human microbiomes as discussed above. As can be seen, the dysbiosis of microbiome can result in development of different diseases which can be included to signify the relevance of microbiome literacy in science education.

Gaps in microbiome literacy: Present status and future in India
The present Indian school curriculum introduces students with microorganisms and their purpose; however, a more comprehensive understanding of microbiology in terms of complexity with a focus on human microbial communities, their interactions and intra-individual variations can also be included.^23,170 This information will help in understanding the overall impact of microbes on human health, disease susceptibility, immune development, effects of environmental factors (antibiotics and pollutants) on the human microbiota, cancer, neurological diseases, fetal development, childhood and growth. Discussions can further be extended to include the relationship between microorganisms and non-communicable diseases such as diabetes mellitus, obesity and mental illness. Integrating microbiome literacy into the existing Indian school curriculum requires careful, phased, age appropriate and progressive approach to raise awareness based on the diverse educational landscape.^{15,21,23,171,172} Primary School discussions can focus more on using captivating tales, illustrations, and easy exercises to introduce fundamental ideas of microbes, emphasizing the existence of “good germs” in our bodies and in traditional foods, with a balanced emphasis on hygiene and health.¹⁷³ While the Middle School exercises can describe in further detail about the various microbial communities, their function in digestion, and the influence of dietary choices with basic fermentation experiments (NEP 2020). The  Senior Secondary School students can learn more about the composition and roles of the human microbiome, how it relates to different illnesses, and how antibiotics work. At higher education and further research level, current studies on the microbiome and ethical issues can be discussed by providing the potential for research projects and real-world applications in biology, microbiology, biochemistry, nutrition, public health courses and incorporating current microbiome science. The undergraduate students can use computational biology tools for microbiome analysis.^174,175

A brief synopsis of applications of various microorganisms presented in the National Council of Educational Research and Training (NCERT) textbook of Science and Biology (https://ncert.nic.in/textbook.php?iesc1=0-12), which can be further extended to include microbiomes is presented below:

Microbiome in food production
In food production, the application of microorganisms extends beyond fermentation. Probiotics are healthy microorganisms embedded in fermented food products¹⁷⁶ while inulin, the synthetic polymer, is a non-digestible food that helps these good microorganisms to grow.^177,178 The presence and the amount of microbial diversity influence the safety, preservation and the nutritional value of food. Therefore, it is necessary to present details on the role of microbial populations in food flavoring and safety as well as food storage.¹⁷⁹ In addition, the textbook can include such aspects as the influence of probiotics and prebiotics on the gut microbiome through food, which nourishes the gut microbiome.

While the NCERT book describes the ways how fermentation is employed in some foods including curd, dosa, idli and cheese, it however does not take into account the potential contribution of the microbiome in food safety and preservation aspects.^180,181 In order to upgrade its content, the text book can include the importance of probiotic administration to obtain beneficial properties for the gut microbiota along with diet and dietary factors affecting gut microflora and their retention.

Microbiome in healthcare and medicine
The microorganisms are introduced as Friend and Foe in relation to the production of antibiotics in Indian science textbooks (NCERT Science – Class 8 Chapter 2: Microorganisms: Friend and Foe; NCERT Biology – Class 12, Chapter 10: Microbes in Human Welfare). These books discuss how microbes are used in household products, industrial products, biogas production, biocontrol agents and biofertilizers. However, it does not discuss the wider role of the human microbiome in maintaining sound physical and mental health. Teaching about microbiomes shall give students a broader understanding of how essentially microbes affect overall human health.⁵ The gut microbiome during digestion breaks down the carbohydrates, proteins and fats through various processes to essential nutrient elements which get absorbed to be used as building blocks for the human body and overall human health.¹⁸² The human microbiome helps in distinguishing between harmful bacteria and beneficial microorganisms to prevent autoimmune diseases. A balanced microbiome protects against pathogens causing infections and gastrointestinal disorders.¹⁸³ It is also important to understand that microbiome imbalance is associated with a variety of conditions, including inflammatory bowel disease, constipation, obesity, anxiety, depression and even mental illness.^184,185 Medical treatments like Fecal microbial transplantation (FMT) are used in which fecal matter from a healthy donor is transferred to the stomach of a patient with a variety of serious illnesses to revitalise the gut microbiome. FMT has shown efficacy in conditions such as Clostridium difficile infection and may hold promise for other related bacterial infections.¹⁸⁶ Thus, teaching microbiomes by different school programs shall help students understand the role played by microorganisms in maintaining a good physical and mental health.

Microbiome in sewage treatment
The NCERT textbook mentions heterotrophic microbes but does not discuss details about the diverse microbial communities involved (Class 12 biology textbook-Chapter 10, section 10.3: Microbes in Sewage Treatment). The biodiversity of wastewater organisms, including bacteria, archaea, and fungi, needs to be highlighted to better understand their specific role in breakdown of organic matter, pollutants and sewage.¹⁸⁷ Moreover, the curriculum should include information on emerging microbial technology, which uses bacteria to convert wastewater organic matter into electricity, like microbial fuel cells (MFCs) as well as bio-electrochemical systems for nutrient recovery.^188-191

Microbiome in environmental welfare
Environmental microbiomes comprise of soil microbes which contribute to nutrient cycling and plant health, while aquatic microbes play a role in water quality. Recent advances in microbial research, including metagenomics, have changed our understanding of microbe groups, opening the way for new applications in bioremediation and sustainable agriculture.^192-194 The concept of the environment microbiomes should be introduced in the textbook, emphasizing their important role of nutrient cycling, soil fertility, and litter decomposition.

Microbiome in agriculture
The synergy between soil microorganisms and plants is vital in determining the development, growth, resilience and overall health of crops against biotic and abiotic stress. It is important to revisit the basics and learn the cooperation of plants and soil microbiomes for sustainable agriculture practices.^195-198 Facilitating soil properties for nitrogen-fixing bacteria, phosphate-solubilizing microorganisms, etc., can help to increase crop yields as well as reduce the use of synthetic fertilizers that might be environmentally damaging.¹⁹⁹ Some microbial communities also improve nutrient availability, enhance resistance against diseases and help plants tolerate drought conditions in various crops. Microbial based strategies are being used to restore the health of soil by reintroducing microbial communities that have been depleted due to intensive farming.³⁸ As we expand our understanding of plants and soil microbes, these insights can lead to more efficient and environmentally friendly agricultural systems, meeting global challenges such as food security and environmental issues managing environmental pollution. The application of these microbial-driven approaches or plant microbiome research would align with wider initiatives (second green revolution) aimed at shifting towards sustainable agriculture.^200,201 Hence, inclusion of such concepts is equally important in science textbooks to highlight the importance of plant microbiomes.

Microbiome research and future applications
Future applications of microbial research could include advanced personalized medicine driven by microbiome data,²⁰² improving agricultural productivity through optimizing plant-microbial interactions and understanding plant microbiomes,²⁰³ and promoting environmental sustainability through microbial technology to reduce pollution for waste management.^204,205 Current research is already focusing on developing personalized treatments that consider an individual’s microbiome composition,²⁰⁶ offering more effective therapies for various diseases, including metabolic disorders and cancers.^206,207 This growing body of work lays the foundation for transformative advances in many areas and include techniques like fecal microbiota transplantation (FMT), engineered microbial consortia, probiotics and other microbiome-based therapies.^208,209

There are various pedagogical opportunities for enhancing microbiome education. Integrating real-world examples can make microbial concepts more relevant and interesting to students. To improve future editions of the textbook, various modifications can be made, for example, a separate section on role of human microbiome in health and medicine can be added in NCERT Class 12 Biology chapter “Microbes in Human Welfare”. A chapter devoted to the human microbiome should thoroughly discuss its diversity, function, and significance. Real-world case studies and models can illustrate the impact of microorganisms on human health and the environment. Incorporating recent research findings and emerging resources into microbiology research will keep the content relevant, while providing interactive and engaging features such as quizzes, visuals and graphical activities can enhance student engagement and understanding. By addressing these gaps and incorporating suggested improvements, future NCERT textbooks can provide students with a comprehensive understanding of microorganisms and microbiomes as well as their relevance in our daily lives.^21,210

Indian initiatives towards promoting microbial and microbiome literacy
Advancements over the past two decades in microscopy and sequencing techniques with algorithms and data analysis have generated huge database resources for applied research. Limitations still exist to classify and characterize the unculturable diversity. However, novel culture-free techniques have provided advanced ecological understandings of unknown phylogenies.^211,212 Considering the impact of microbes on our well-being and bioeconomy, a global school literacy program International Microbiology Literacy Initiative (IMiLI), has been launched.^23,210 The program aims to generate a teaching topic framework on various topics of microbial literacy for the school curriculum by integrating learning resources, experiments, and excursions.²¹³ In alignment with the global initiative to promote microbiome literacy, several Indian schools have implemented programs focused on community-relevant microbial activities. These initiatives aim to educate students about the impact of microorganisms on the environment and explore ways to harness their potential for environmental benefits (https://imili.org/concept). The Department of Biotechnology, Government of India promotes innovation through its “Microbial and Natural Science Programme”, which supports advanced biotech research in basic and translational studies. The program aims to promote knowledge and innovation in microbial and natural sciences, addressing key challenges in biotechnology. This program focuses on the use of basic research to understand interactions with their environment, and translate scientific discoveries into practical outcomes like development of eco-science tools, novel technologies and bioprocesses that boost economic growth, improve human health, and promote environmental sustainability (https://dbtindia.gov.in/ microbial-and-natural-sciences). The key areas include Terrestrial Ecology and Bioprocesses, the integration of Biotechnology with Indian Traditional Medicine, Marine-resource Technologies, and Post-Harvest and Food Processing Technologies. The aim is to promote environmentally friendly utilization of biological resources while gaining a comprehensive understanding of their mechanisms and ecological interactions. National-level microbial repositories, National Centre for Microbial Resource (NCMR, http://ncmr.nccs.res.in/ncmr/home) have been curated for bioprospecting purposes and biotechnological assessments. Several community outreach programs are conducted for researchers, the agriculture sector, and women empowerment (https://dbtindia.gov.in/publications). India’s National Biotechnology Development Strategy (NBDS) for 2021-2025 aims to foster a knowledge-driven bioeconomy through innovation and social responsibility. To achieve broader outreach, the strategy emphasizes integrating biotechnology resources and opportunities into school education, complementing existing undergraduate, postgraduate, and doctoral research programs. This integration will promote societal growth and career guidance among students. To realize this vision, the Department of Biotechnology will establish DNA Clubs, or Natural Resource Awareness clubs, in aspirational districts’ schools, catering to grades 6-10. These clubs will provide hands-on science education and training for teachers and students through practical instruction in basic science programs (https://dbtindia.gov.in/sites/default/files/NBDS_March%202021.pdf).

A notable example of this initiative is the DBT-Foldscope Programme, which has successfully introduced an ultra-affordable paper microscope to over 400 schools nationwide. Through workshops and training, the program encourages research, scientific curiosity among students and educators, paving the way for future generations who are not only ‘microbial’ literates but also ‘microbiome’ literates (https://www.biotech.co.in/en/dbt-foldscope-programme). India’s 2017 National Health Policy (NHP) emphasized the importance of school health programs, aiming to integrate health and hygiene into the curriculum. The program expands reproductive and sexual health education to include nutrition, calorie consumption and psychological well-being. In addition, it recommends upgrading traditional medicine and yoga through the ministry of AYUSH (Ayurveda, Yoga & Naturopathy, Unani, Siddha, Homeopathy), as well as ensuring quality infrastructure development and building workforce capacity.²¹⁴ Introducing microbial and microbiome knowledge into classrooms aligns with these objectives by fostering a comprehensive understanding of health and wellness. By incorporating microbiome literacy, students can acquire essential skills for preventive and promotive healthcare, ultimately contributing to the establishment of a healthier society.

Integrating microbiology into the curriculum offers many benefits. First, it helps students understand the interactions between microbial communities and their impact on life, health, and the environment. Second, they gain a comprehensive view of how microbes impact health, food production, and sustainability. Additionally, a strong foundation in biology will enable students to choose their wellness skills appropriately. They will also be well-equipped for the future, ready to embrace the scientific and medical advances that result from ongoing microbiological research. Ultimately, this will empower students with the knowledge of how their microbial allies shape their health and future.^20,215-217 This “microbial compass” exemplifies how understanding our microbiome can serve as a guide for what students need to live healthier, more sustainable lives and have an even greater connection with the nature around them.

Suggested discussions and exercises to study microbiomes in the classroom
Human microbiome studies are often abstract, making it challenging for students to understand different microbial processes and their effects on the human body. The integration of visual aids such as detailed drawings, schematic diagrams, flowcharts and concept maps helps students to relate to the concepts of complex microbial interactions.^218,219 However, visualization alone is not sufficient for deep learning. Encouraging critical thinking through discussions (Figure 5) and exercises (Figure 6) fosters analytical reasoning and scientific inquiry, further strengthening the understanding of microbiomes.²²⁰ Educators can also plan lessons and experiments to help students appreciate various human microbiomes (Table 3). Following a thorough explanation of the fundamentals of microbiome concepts, the learning process can be improved by combining the concepts of microbial biology with chemistry, environmental sciences, and social sciences. This integrative approach will not only deepen content mastery but also cultivate the ability to apply microbial thinking to real-life challenges such as pandemics. Therefore, combining visual aids, critical inquiry, and interdisciplinary learning creates a dynamic, holistic educational model that empowers students to engage deeply with the microbial world.

Table (3): Suggested lessons and experiments to understand human microbiome

Importance of bioinformatics tools to study human microbiomes
Using bioinformatics tools at the undergraduate level can augment educational value, especially when dealing with complex topics like human microbiome.²²¹ The microbiome of humans harbors a variety of microorganisms. Bioinformatics tools allow students to explore real-world microbiome data, such as identifying which microbes are present in different parts of the body and what their roles are.^222,223 Therefore, they begin to understand how researchers make sense of the invisible microbial world. Instead of just reading about the microbiome in textbooks, students can see how microbiome data is collected, analyzed and turned into meaningful conclusions. For example, initiatives like the PUMAA project (Platform for Accessible Microbiome Analysis),²²⁴ Microbiomes for All initiative, supported by the American Society for Microbiology (ASM) help in promoting microbiome literacy to students in an easy, creative and interactive manner.²²⁵

Some simple web-based tools that can be easily used by teachers and students at the undergraduate and even at Senior Secondary level to gain critical insight and understanding about various aspects of the human microbiome.²²⁶ Here, we present a step-through approach for two such open access tools: HMDAD (Human microbe-disease association database)²²⁷ and AMADIS²²⁸: A Comprehensive Database for Association Between Microbiota and Disease for developing an understanding about human microbiome.

(A) Use of HMDAD (Human microbe–disease association database)
Procedure for Exercise 1

1. Go to the website- http://www.cuilab.cn/hmdad
2. Click on browse (given on the top row).
3. Two icons will appear- diseases and microbes.
4. Click on Diseases.
5. A list of diseases will be displayed.
6. Click on Cystic fibrosis.
7. It will display the number of microorganisms affected by the disease along with their status in the disease condition.

Based on the exercise above, it can be inferred that microbes-Burkholderia, Coxiellaceae, Lactobacillus, Lysobacter, Rickettsiales, Staphylococcus aureus, Stenotrophomonas maltophilia, Streptococcus mitis and Xanthomonas are associated with cystic fibrosis. While the incidence of all the other bacteria listed rises during cystic fibrosis, the prevalence of Streptococcus mitis alone decreases in the human body (Figures 7 and 8).

Procedure for Exercise 2

1. Go to the website- http://www.cuilab.cn/hmdad
2. Click on browse (given on the top row)
3. Two icons will appear- diseases and microbes.
4. Click on microbes.
5. A list of microbes will be displayed.
6. Click on Shigella.
7. It will display by which disease condition it is affected and its status in different disease conditions.

Based on the exercise above, it can be concluded that Shigella is linked to type 1 diabetes mellitus and that its prevalence rises in people with type 1 diabetes.

(B) Use of AMADIS: A Comprehensive Database for Association Between Microbiota and Disease
Procedure for Exercise 1:

1. Go to the website- https://gift2disease.net/GIFTED/network.jsp
2. Click on browse (given on the top row).
3. Five options will appear- Gut Microbiota, Diseases, Sample type, System and Mechanism
4. Click on Diseases.
5. A list of diseases will be displayed.
6. Click on Alzheimer’s Disease.
7. It will display the number of microorganisms affected by the disease along with other information such as sample type, omics, mechanisms, genes and more complete details to enrich your query results.

So, using this simple exercise, students will be able to visualize the microbial composition in a disease state like Alzheimer’s Disease. In the same way, this exercise can be used to explore microbes affected by diseases and their details during the disease (Figures 9, 10 and 11).

In addition to these tools, a list of other useful tools and databases to study microbiomes is given in Table 4. These tools have an easy user interface and can be easily accessed and used by educators and students in the classroom easily using desktops, laptops or even smartphones.

Table (4): List of databases and tools to study the human microbiome