Virginia Institute of Marine Science
Applied and Environmental Microbiology
Survival of Escherichia coli and Salmonella spp. in estuarine waters was compared over a variety of seasonal temperatures during in situ exposure in diffusion chambers. Sublethal stress was measured by both selective-versus-resuscitative enumeration procedures and an electrochemical detection method. E. coli and Salmonella spp. test suspensions, prepared to minimize sublethal injury, were exposed in a shallow tidal creek and at a site 7.1 km further downriver. Bacterial die-off and sublethal stress in filtered estuarine water were inversely related to water temperature. Salmonella spp. populations exhibited significantly less die-off and stress than did E. coli at water temperatures of <10°C. Although the most pronounced reductions (ca. 3 log units) in test bacteria occurred during seasonally warm temperatures in the presence of the autochthonous microbiota, 102 to 104 test cells per ml remained after 2 weeks of exposure to temperatures of >15°C. Reductions in test bacteria were associated with increases in the densities of microflagellates and plaque forming microorganisms. These studies demonstrated the survival potential of enteric bacteria in estuarine waters and showed that survival was a function of interacting biological and physical factors.
Rhodes, MW and Kator, HI, Survival Of Escherichia-Coli And Salmonella Spp In Estuarine Environments (1988). Applied and Environmental Microbiology, 54(12), 2902-2907.