Prevalence of Opportunistic Pathogens and Diversity of Microbial Communities in the Water System of a Pulmonary Hospital.

Objective: Our objective was to investigate the occurrence of opportunistic pathogens and characterize the bacterial community structures in the water system of a pulmonary hospital.

Methods: The water samples were collected from automatic and manual faucets in the consulting room, treatment room, dressing room, respiratory ward, and other non-medical rooms in three buildings of the hospital. Quantitative polymerase chain reaction was used to quantify the load of several waterborne opportunistic pathogens and related microorganisms, including spp., spp., and . Illumina sequencing targeting 16S rRNA genes was performed to profile bacterial communities.

Results: The occurrence rates of spp., spp., and were 100%, 100%, and 76%, respectively in all samples. Higher occurrence rates of were observed in the outpatient service building (building 1, 91.7%) and respiration department and wards (building 2, 80%) than in the office building (building 3), where no was found. were more abundant in automatic faucets (average 2.21 × 10 gene copies/L) than in manual faucets (average 1.03 × 10 gene copies/mL) ( < 0.01). , , , , , and were the dominant bacterial phyla. Disinfectant residuals, nitrate, and temperature were found to be the key environmental factors driving microbial community structure shifts in water systems.

Conclusion: This study revealed a high level of colonization of water faucets by opportunistic pathogens and provided insight into the characteristics of microbial communities in a hospital water system and approaches to reduce risks of microbial contamination.