Indoor Microbiome and The Rising Asthma Prevalence

The prevalence of asthma has increased in the past few decades in most developed and developing countries. Large-scale, cross-sectional epidemiological studies have reported several factors associated with asthma prevalence and severity, including parental asthma, tobacco smoking, preterm delivery, virus infection, and air pollution. However, a puzzling problem is that the time trends in the prevalence of these risk factors cannot explain the rise in asthma. For example, the prevalence of smoking and clinical pneumonia have been decreasing globally in the past few decades. Recent progress in high-throughput sequencing technology has promoted the progress of microbiome research and established associations between human and indoor microbiomes, and many metabolic, cognitive, and immune diseases including asthma and allergies. In this review, the authors systematically summarise the current literature, standard practice, and analysis pipeline in the field of indoor microbiome and asthma. The strength and limitation of different analytical approaches are discussed, including the utilisation of relative and absolute abundance in the associated studies. The authors discuss new frameworks of integrated microbiome research from different ecological niches, functional profiling from multiomics data, and how these new insights can facilitate understanding of asthma mechanisms and even the development of new personalised treatment strategies for the rising asthma epidemic.

Early life home microbiome and hyperactivity/inattention in school-age children

This study evaluates the association between indoor microbial diversity early in life and hyperactivity/inattention symptoms in children at ages 10 and 15 years. A random sample enriched with subjects with hyperactivity/inattention at age 15 years was selected from the German LISA birth cohort. Bedroom floor dust was collected at age 3 months and 4 bacterial and fungal diversity measures [number of observed operational taxonomic units (OTUs), Chao1, Shannon and Simpson indices] were calculated from Illumina MiSeq sequencing data. Hyperactivity/inattention was based on the Strengths and Difficulties Questionnaire at ages 10 and 15 (cut-off ≥7). Adjusted associations between 4 diversity measures in tertiles and hyperactivity/inattention were investigated with weighted and survey logistic regression models. We included 226 individuals with information on microbial diversity and hyperactivity/inattention. Early life bacterial diversity was inversely associated with hyperactivity/inattention at age 10 [bacterial OTUs (medium vs low: aOR = 0.4, 95%CI = (0.2–0.8)) and Chao1 (medium vs low: 0.3 (0.1–0.5); high vs low: 0.3 (0.2–0.6)], whereas fungal diversity was directly associated [Chao1 (high vs low: 2.1 (1.1–4.0)), Shannon (medium vs low: 2.8 (1.3–5.8)), and Simpson (medium vs low: 4.7 (2.4–9.3))]. At age 15, only Shannon index was significantly associated with hyperactivity/inattention [bacteria (medium vs low: 2.3 (1.2–4.2); fungi (high vs low: 0.5 (0.3–0.9))]. In conclusion, early life exposure to microbial diversity may play a role in the psychobehavioural development. We observe heterogeneity in the direction of the associations encouraging further longitudinal studies to deepen our understanding of the characteristics of the microbial community underlying the observed associations.

Microbes in the built environment

The COVID-19 pandemic has encouraged scientists and the general population to think more than ever before about how we interact with microbes in our indoor spaces. Research investigating transmission of SARS-CoV-2 has advanced our knowledge significantly in the last two years. However, indoor and built environment microbiomes are extremely complex polymicrobial systems. We have barely scratched the surface in our understanding of the microbial inhabitants of our indoor and urban spaces. The Microbes in the Built Environment Collection showcases recent research in this important topic around the globe.

Our interface with the built environment: immunity and the indoor microbiota

The rise of urbanization and an increasingly indoor life-style has affected human interactions with our microbiota in unprecedented ways. We discuss how this lifestyle may influence immune development and function, and argue that it is time that we examined ways to manipulate the indoor environment to increase our exposure to a wider phylogeny of microorganisms. An important step is to continue to engage citizen scientists in the efforts to characterize our interactions with the diverse microbial environments that we inhabit.

Microbiota of the indoor environment: a meta-analysis

As modern humans, we spend the majority of our time in indoor environments. Consequently, environmental exposure to microorganisms has important implications for human health, and a better understanding of the ecological drivers and processes that impact indoor microbial assemblages will be key for expanding our knowledge of the built environment. In the present investigation, we combined recent studies examining the microbiota of the built environment in order to identify unifying community patterns and the relative importance of indoor environmental factors. Ultimately, the present meta-analysis focused on studies of bacteria and archaea due to the limited number of high-throughput fungal studies from the indoor environment. We combined 16S ribosomal RNA (rRNA) gene datasets from 16 surveys of indoor environments conducted worldwide, additionally including 7 other studies representing putative environmental sources of microbial taxa (outdoor air, soil, and the human body).

Your Tiny Roommates: Meet the Microbes Living in Your Home

Every home you’ve ever lived in has had a population in the billions—and in many cases, that’s a good thing

There’s no such thing as living alone. Never mind if you’re the only person in your house and have no dog, no cat, not even fish. You’ve still got at least several billion roommates—and so do we all. Some of them are harmless, some are actually helpful and some could, in the right concentration and the wrong circumstance, kill you. They are, of course, bacteria, fungi and viruses, and like it or not, they’re on you, around you and deeply within you.

Your Tiny Roommates: Meet the Microbes Living in Your Home

Every home you’ve ever lived in has had a population in the billions—and in many cases, that’s a good thing

There’s no such thing as living alone. Never mind if you’re the only person in your house and have no dog, no cat, not even fish. You’ve still got at least several billion roommates—and so do we all. Some of them are harmless, some are actually helpful and some could, in the right concentration and the wrong circumstance, kill you. They are, of course, bacteria, fungi and viruses, and like it or not, they’re on you, around you and deeply within you …

Thousands of microbes found in house dust

Introduction of Probiotic-Based Sanitation in the Emergency Ward of a Children’s Hospital During the COVID-19 Pandemic

Antimicrobial resistance (AMR) represents a major threat to public health, especially in the hospital environment, and the massive use of disinfectants to prevent COVID-19 transmission might intensify this risk, possibly leading to future AMR pandemics. However, the control of microbial contamination is crucial in hospitals, since hospital microbiomes can cause healthcare-associated infections (HAIs), which are particularly frequent and severe in pediatric wards due to children having high susceptibility.

Could we fight healthcare-associated infections and antimicrobial resistance with probiotic-based sanitation? Commentary

Healthcare-associated infections (HAI) affect every year about 4 million hospitalized patients in the EU, causing over 33 000 deaths as a direct consequence and over 1.1 billion € associated costs. Besides the persistent microbial contamination of the hospital environment, a major cause is the rampant antimicrobial resistance (AMR) of the HAI-associated pathogens. The hospital environment itself is in fact a reservoir of resistant pathogens, apparently not sufficiently controlled by conventional chemical-based sanitation. A recently published study, the SAN-ICA study, performed in Italy, suggests that the fight against AMR may involve probiotic-based sanitation approaches, as they might stably reduce AMR surface pathogens, finally reducing HAI incidence. Here we discuss the reported results and argue that their use may provide a novel approach which deserves exploration.