Multicenter exploration of microbial communities in hospital toilets reveals: antibiotic exposure in a nosocomial settings selects for coEnterococcus over commensal taxa.

Abstract

Background: Excessive antibiotic utilization in hospital settings catalyzes the emergence and dissemination of multidrug resistant (MDR) bacteria, with sanitary facilities serving as critical vectors for their propagation. This study investigated the impact of patient antibiotic exposure on microbial diversity in hospital sanitary facilities, as well as the emergence of uniform communities and prospering taxa under antibiotic pressure.

Methods: For this purpose a cross-sectional study was conducted between September 2022 and April 2023 from eight hospitals in seven cities across five countries, representing a diverse mix of tertiary care, military, oncological, psychiatric, and general teaching hospitals to analyze bacterial population differences in hospital toilets on wards with high versus minimal antibiotic administration using 16s rRNA amplicon sequencing.

Results: PCoA analysis with Bray-Curtis and unweighted UniFrac metrics revealed microbial clustering influenced by antibiotic exposure and geography. Among all taxa analyzed, Enterococcus showed the strongest and most consistent association with high-exposure environments, making it one of the most striking findings in our dataset.

Conclusion: Routine overuse of antimicrobial agents aimed at false patient safety promotes a high-risk environment in the sanitary facilities of respective wards. Hence, the issue of hospital acquired infections with MDR pathogens transcends mere pathogen spread, entailing significant changes to both environmental and microbial landscapes over time. The situation signals an emerging ecological problem within healthcare environments, and highlights the urgency for an integrated approach to antimicrobial stewardship. The low detection of key nosocomial Gram-negative genera likely reflects the focus on toilets rather than sinks or showers.