Household dust bacteria linked to flame retardants and PAHs in Czech homes

Household dust is more than a nuisance to be wiped away: it is a mixture of living microbes and chemical pollutants that occupants breathe in and touch every day. A new study published in Environmental Microbiome has mapped how these two components of indoor dust relate to one another in Czech homes, finding that certain bacterial genera consistently appear alongside higher concentrations of polycyclic aromatic hydrocarbons (PAHs), their oxygenated derivatives, and brominated flame retardants.

The researchers collected dust from 88 households, comprising 53 flats and 35 houses, and analyzed each sample for both its bacterial community and its chemical burden. Bacterial communities were characterized using 16S rRNA amplicon sequencing together with quantitative PCR, while the chemical analysis targeted 46 pollutants spanning eight classes: bisphenols, musks, organophosphate flame retardants, oxygenated PAHs, PAHs, polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and phthalate esters. This paired design allowed the team to test whether the abundance of particular bacterial groups tracked the levels of particular chemicals within the same homes.

The comparisons revealed clear patterns. Dust from houses contained higher concentrations of PAHs than dust from flats, and house dust also carried higher relative abundances of the genera Methylobacterium-Methylorubrum and Sphingomonas. The relative abundance of Methylobacterium-Methylorubrum correlated positively with that of Sphingomonas, as well as with concentrations of oxy-PAHs and PAHs. Additional relationships emerged between Sphingomonas and PBDEs, and between Lactococcus and PCBs. Beyond individual genera, the diversity of the bacterial community itself was tied to the chemical environment: concentrations of musks and PCBs correlated with bacteriome alpha-diversity. Together with window opening, house age, air-conditioning, temperature, garden access, and indoor smoking, these chemical factors explained 37 percent of the variability in alpha-diversity across the sampled households.

The authors point out that some strains within Methylobacterium-Methylorubrum and Sphingomonas have previously shown the ability to degrade organic compounds, which makes their association with PAHs, PAH derivatives, and PBDEs in dust particularly intriguing. However, the study’s authors are careful about the limits of what their data can show. Because the associations were measured at the level of bacterial genera, the design cannot determine the direction of causality, whether bacteria respond to the chemicals, the chemicals shape the bacteria, or both are driven by shared housing characteristics, and the findings carry no direct implications for human health outcomes. The team notes that further mechanistic studies at lower taxonomic levels will be needed to clarify these relationships. The article was published as an open-access paper on 1 October 2026 and is being shared early as a peer-reviewed, accepted manuscript that is citable under a permanent DOI, subject to final editorial edits.

Subject of Research: Associations between indoor dust bacterial communities and chemical pollutants in Czech households

Article Title: Associations between bacteriome and chemical pollutants in indoor dust from Czech households

Article References: Klvanova, E., Bohm, J., Marcinekova, P., Melymuk, L., Kukucka, P., Senk, P., Martinik, J., Pribylova, P., Jilkova, S. R., Andryskova, L., Klanova, J., & Borilova Linhartova, P. (2026). Associations between bacteriome and chemical pollutants in indoor dust from Czech households. Environmental Microbiome. https://doi.org/10.1186/s40793-026-00971-y

Image Credits: AI Generated

DOI: 10.1186/s40793-026-00971-y

Keywords: indoor dust, bacteriome, PAHs, PBDEs, PCBs, 16S rRNA sequencing, Czech households, chemical pollutants, alpha-diversity, indoor exposure, Environmental Microbiome, Sphingomonas