The human gut harbors thousands and thousands of microbes, primarily bacteria, which have positive and opposed health effects. A recent Environmental Research journal paper evaluated how indoor microbiomes and metabolites affect the human gut microbiota.

Study: Impact of environmental characteristics on kid’s gut microbiota – A pilot study in assessing the role of indoor microbiome and metabolites. Image Credit: CI Photos / Shutterstock

Background

Gut bacterial dysbiosis has been related to the incidence of many diseases, akin to colorectal cancer, inflammatory skin diseases, and chronic kidney disease. Several indexes, akin to the Shannon index, Simpson index, Gut Microbiome Health Index (GMHI), and Faith’s PD, have been developed to look at gut health by measuring microbial diversity and abundance.

Several studies have indicated that the encircling environment and a person’s lifestyle significantly influence gut microbiota. Interestingly, it has been noted that children exposed to pets have an altered abundance of gut microbiota taxa, and people exposed to accommodate dust and soil have shown elevated gut microbial diversity. Individuals residing near green areas have enhanced α-diversity of the human gut. In contrast, those living in areas with high levels of air pollution are at a high risk of gut microbial dysbiosis, which impacts metabolic health.

Previous studies have indicated an association between indoor microbiome and microbial metabolites with chronic diseases (e.g., rhinitis, asthma, sick-building syndrome, and dermatitis). Common indoor microbiota, akin to Collinsella, Aspergillus subversicolor, and Cutibacterium have been linked with the incidence of many chronic diseases. Nevertheless, not all indoor microbes have negative effects. As an example, the presence of Lactobacillus iners, Prevotella and Dolosigranulum within the indoor environment is negatively related to the incidence of rhinitis. As well as, some indoor microbiome (e.g., Clostridium difficile) also modulates human gut microbiota.

Weight loss program plays a vital role in gut microbial population and abundance. A weight loss program wealthy in fiber favors useful bacteria, while a high-fat weight loss program enhances the extent of harmful bacteria, which promotes gut inflammation and alters intestinal permeability. More research is required to understand the impact of indoor microbiomes and metabolites on gut microbiota composition and variety.

Concerning the Study

This pilot study assessed the impact of indoor microbiome and metabolites on the human gut microbiota. A complete of 56 children between the age of three and 10, were recruited on this study. Electronic questionnaires were used to gather health information and relevant environmental characteristics. A distance-weighted method was used to estimate the annual outdoor air pollutants.

Fecal samples were obtained from the participants, and dirt samples were collected using a sterile sampler. DNA was extracted from the dust samples and was analyzed using a culture-independent shotgun metagenomic sequencing technique. As well as, liquid chromatography-mass spectrometry (LC-MS) was used for the chemical profiling of the dust samples.

The associations between environmental microbial and non-microbial characteristics and the variety/composition of the gut microbiota were investigated using PERMANOVA and regression models. As well as, the effect of environmental characteristics on GMHI was also examined.

Study Findings

The kids recruited on this study were randomly chosen from twelve out of sixteen districts in Shanghai, China. The study cohort consisted of 38% boys and 62% girls. Greater than half of the cohort had siblings, and around 59% of youngsters had pets or indoor plants during their early childhood. Twenty-one children resided in an area of heavy traffic. Some children had began kindergarten. Around 16% of youngsters were exposed to environmental tobacco smoking during their early childhood. 

A complete of 6,247 microbes were characterised from the indoor dust samples. Nearly all of microbes belonged to classes Bacilli, Gammaproteobacteria, and Actinobacteria, followed by Bacteroidia, Flavobacteria, Alphaproteobacteria, Betaproteobacteria, Clostridia, and Tissierellia. Among the most abundantly found microbial species are Cutibacterium acnes, Staphylococcus aureus, Staphylococcus epidermidis, and Micrococcus luteus. 

Facultative pathogens, akin to Pseudomonas aeruginosa, Mycobacterium tuberculosis, and Klebsiella pneumoniae, were also detected. Virulence aspects (VFs) and antimicrobial resistance genes (ARGs) were determined using molecular sequencing techniques. VFs were predominantly derived from facultative pathogens.

A complete of 1,442 metabolites and chemicals were characterised via the second stage of mass spectrometry (MS2). Metabolites, akin to primarily lipids (e.g., fatty acyl, flavonoid, and steroid derivatives), xenobiotics, amino acids, carbohydrates, cofactors, and vitamins, were identified during chemical profiling.

A complete of 318 bacteria were characterised from gut samples that belong to phyla Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes. Kid’s gut was enriched with Flavonifractor plautii, Oscillibacter, and Faecalibacterium. The age of youngsters and the time once they began kindergarten had a major impact on gut microbial composition. As well as, residing near heavy traffic also influenced gut microbial composition.

Amongst dietary characteristics, the frequency of drinking soft drinks substantially impacted gut microbial composition. The abundance of indoor metabolites and chemicals didn’t have any impact on the general gut microbial composition.

Conclusions

The authors claim this study to be the primary to look at the association between indoor microbiome/metabolites and gut microbiota. This study highlighted how indoor microbe exposure influences the human gut microbiota.