Survival of Escherichia coli and Salmonella spp. in estuarine environments.
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 less than 10 degrees 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, 10(2) to 10(4) test cells per ml remained after 2 weeks of exposure to temperatures of greater than 15 degrees 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
M W
MW
Department of Biological and Fisheries Sciences, Virginia Institute of Marine Science, School of Marine Science, College of William and Mary, Gloucester Point 23062.
Kator
H
H
D004926:Escherichia coli / Q000302:isolation & purification*; D005618:Fresh Water; D012475:Salmonella / Q000302:isolation & purification*; D012621:Seasons; D013696:Temperature; D014865:Waste Disposal, Fluid; D014871:Water Microbiology