Persistence of Yersinia pestis in tap water microcosm.

This study investigates the long-term persistence of Yersinia pestis in tap water microcosms at 25°C and examines its proteomic landscape and ability to cause lethal infection in a mouse model during persistence, assessing its potential risk for waterborne transmission. Five Y. pestis strains representing different biovars and molecular profiles were studied by seeding tap water microcosms with different bacterial concentrations. All strains remained viable for approximately 120 days in High-Concentration Microcosms (HCM) and 60 days in Low-Concentration Microcosms (LCM). Mass spectrometry analysis revealed that 1,825 proteins (~72%) remained expressed in tap water for over 100 days, with 113 and 43 proteins showing differential expression at 60 and 100 days in HCM, respectively, suggesting adaptive shifts to the aquatic environment. Stress-response proteins (CspA1, CspA2, HspQ) and regulatory proteins (LysR, GntR) appeared to support survival, while virulence-associated proteins (YopE, YopB, ail, adhesins) were also expressed. Notably, mice inoculated with water from day 90 HCM succumbed to infection, underscoring the pathogen’s ability to retain infectivity even in unfavourable conditions. These findings highlight the resilience of Y. pestis in water, its prolonged survival while maintaining virulence, and the potential risks of waterborne transmission, emphasizing the need for effective mitigation strategies against biothreat agents.