Detection of Yersinia pestis over time in seeded bottled water samples by cultivation on heart infusion agar

The viable persistence of Yersinia pestis seeded in bottled spring water was evaluated by performing 2 studies that involved inoculating a total of 21 different test strains into individual 500 mL reservoirs. Approximately 2 x 104 CFU/mL of Y. pestis was inoculated into each reservoir and held for sampling at 26 degrees C +/- 1 degrees C. In study No. 2, 9 strains (Harbin, Nepal, UNH 1A, UNH 1B, ZE94, CO92, PB6, PB6 DP, and Pexu) could no longer be recovered using a plate count assay between 79 and 138 days post-seeding; other strains (K25 lcr, O19 Ca-6, and K25 pst) could no longer be recovered between 112 and 160 days post seeding. The data generated in this study demonstrate that certain strains of Y. pestis can remain viable in bottled water for extended periods of time.