Cockroach Microbiome Disrupts Indoor Environmental Microbial Ecology with Potential Public Health Implications

Cockroaches pose a significant global public health concern. However, besides the well-recognized cockroach-induced allergy, the potential impact of the cockroach microbiome on human health through various means is not yet fully elucidated. This study aimed to clarify the health impacts of cockroaches by investigating the microbial interactions among cockroaches, the indoor environment, and humans. We simultaneously collected cockroach, indoor environment (indoor air and floor dust), and human (exhaled breath condensate and skin) samples from residential areas in five cities representing distinct climate zones in China. The 16S rDNA sequencing results revealed that cockroaches harbor diverse bacterial populations that vary across different cities. The prevalence of potential pathogenic bacteria (PPB) in cockroaches ranged from 1.1% to 58.9%, with dominant resistance genes conferring resistance to tetracycline, macrolide, and beta-lactam. The relationships between the cockroach microbiome and the associated environmental and human microbiomes were explored by using fast expectation-maximization microbial source tracking (FEAST). The potential contribution of cockroach bacteria to the floor dust-borne microbiome and indoor airborne microbiome was estimated to be 5.6% and 1.3%, respectively. Similarly, the potential contribution of cockroach PPB to the floor dust-borne microbiome and indoor airborne microbiome was calculated to be 4.0% and 1.2%, respectively. In residences with cockroach infestations, the contribution of other sources to the indoor environment was slightly increased. Collectively, the role of cockroaches in the transmission of microorganisms, particularly pathogenic bacteria and antibiotic resistance genes, cannot be overlooked.