Does home microbial environment affect our health?

Did you know that children spend most of their time indoors, surrounded by millions of invisible microorganisms? While many people associate indoor environments with safety, emerging scientific evidence suggests that the bacteria living in household dust may significantly influence children’s respiratory health. Research suggests that indoor bacteria can either protect against or contribute to allergic diseases such as asthma.

Modern lifestyles mean that people spend nearly 90% of their time indoors, making household microbial exposure an important determinant of health. However, some queries still arise like:

• Which household factors most strongly influence the indoor microbiome?
• Does the bacterial composition differ between homes of asthmatic and healthy children?
• Can household habits be modified to promote healthier microbial environments?

To answer these questions, researchers from institute for institute for Anthropological Research and university of Rijeka, Croatia conducted one of the first comprehensive indoor microbiome studies and investigated how environmental factors shape the bacterial communities found in bed dust and whether these microbial differences are associated with childhood asthma.

What our Home’s Microbiome tells us?

Dust samples were collected from the 90 beds from households with children aged 5–18 years, along with diagnosed cases of asthma in 59 children, while 31 children were taken as healthy control. Instead of analyzing airborne microbes alone, focus was concentrated on bed dust, as it is an ideal source because children spend many hours sleeping and are continuously exposed to microorganisms present in bedding.

Advanced DNA Sequencing

Bacterial communities were identified from extracted microbial DNA from each dust sample. Sequencing using Illumina MiSeq platform for 16S rRNA gene generated:

• Over 6.1 million sequencing reads
• More than 16,000 Amplicon Sequence Variants (ASVs)
• Identification of bacteria across 36 different bacterial phyla

Further, sophisticated bioinformatics software including QIIME2, DADA2, and R statistical packages enabled researchers to accurately profile bacterial diversity and compare microbial communities across households.

Study outcomes revealed that the overall balance of bacterial species (β-diversity) differed between households with asthmatic children and those without asthma and are associated with respiratory health.

Certain bacterial genera including Enhydrobacter, Micrococcus, and Paracoccusshowed statistically significant differences between the two groups.

Environmental Factors Examined

Environmental variables were also analysed such as:

• Urban vs. suburban living
• House versus apartment
• Presence of pets
• Furniture dusting frequency
• Mattress vacuuming frequency

These variables when statistically compared with bacterial diversity and asthma status to identify meaningful relationships. There are significant microbial differences among suburban homes, urban built environment and urban homes surrounded by green spaces. Nearby vegetation, urbanization, and surrounding ecosystems contribute to the bacterial communities that eventually enter homes.

Housing Type Influences Microbial Diversity

Whether children live in a house or an apartment also affects bacterial diversity.

Although dominant bacterial groups remains relatively stable, several less abundant bacterial taxa varies according to housing type, demonstrating that building characteristics can shape indoor microbial exposure.

Pets Contribute to a Richer Indoor Microbiome

Homes with dogs or cats shows measurable differences in bacterial composition compared to homes without pets. As found pet ownership significantly influenced bacterial diversity and is also associated with asthma-related microbial interactions. Some bacteria that are linked to pet ownership have also previously been associated with beneficial immune development.

Cleaning Habits Shape Indoor Bacteria

Cleaning practices greatly influence microbial diversity in homes. Dusting and vacuuming frequencies significantly influence bacterial community composition

While cleaning helps reduce dust accumulation, frequent cleaning may also reduce exposure to a broader range of microorganisms. These findings are discussed in relation to the hygiene hypothesis, which proposes that limited microbial exposure during childhood may contribute to increased allergy and asthma risk.