A Proteomic View on Persistence of Yersinia pestis in Tap Water Microcosm

This study presents a proteomic perspective on the long-term persistence and adaptive mechanisms of Yersinia pestis in tap water microcosms at 25°C. Multiple strains representing different biovars were seeded into tap water at high (10⁸ CFU/mL) or low (10⁵ CFU/mL) concentrations. The strains were found to remain viable for 60-120 days. Nano-liquid chromatography coupled with tandem mass spectrometry (nLC-MS/MS) was used to carry out the proteomic profiling of Y. pestis in the tap water microcosms. When compared with pure Y. pestis culture, a substantial number of proteins (~ 72%) continued to express during long term persistence in tap water over time, yet many were found to be differentially expressed. STRING analysis revealed that the differentially expressed proteins included those involved in trans-membrane transport e.g. ABC transporters, sugar and arginine transporters likely supporting nutrient acquisition in nutrient-limited milieu. In addition, proteins related to stress response such as cold-shock proteins (CspA1, CspA2) were also identified, suggesting probable mechanisms for coping with environmental stress. Interestingly, quorum sensing-related regulators, attachment related proteins including Ail & adhesins, and components of the T3SS and T6SS systems were also detected, which may have facilitated the intercellular communication and surface attachment. The infectivity potential was evaluated by mouse challenge assay, and it was found that animals inoculated intraperitoneally with the day 90 sample succumbed to infection. These findings highlight the ability of Y. pestis to persist in tap water while maintaining virulence, underscoring the need for effective decontamination strategies to reduce potential waterborne transmission risks.