

@article {9126,
	title = {{Survival, Physiological-Response, and Recovery of Enteric Bacteria Exposed To a Polar Marine-Environment}},
	journal = {Applied and Environmental Microbiology},
	volume = {60},
	number = {8},
	year = {1994},
	pages = {2977{\textendash}2984},
	abstract = {Survival, sublethal injury, and recoverability of Escherichia coli,{\$}\backslash{\$}nEnterococcus faecalis, Salmonella typhimurium, and Yersinia{\$}\backslash{\$}nentercolitica were investigated by using diffusion chambers over 54 to{\$}\backslash{\$}n56 days of in situ exposure to a polar marine environment (-1.8 degrees{\$}\backslash{\$}nC; salinity, 34.5 ppt) at McMurdo Station, Antarctica. Plate counts were{\$}\backslash{\$}nused to assess recoverability and injury, whereas direct viable counts{\$}\backslash{\$}n(DVCs) and 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) reduction were{\$}\backslash{\$}nutilized to determine substrate responsiveness and respiratory activity,{\$}\backslash{\$}nrespectively. T-90 values (times for 10 fold decreases in numbers of{\$}\backslash{\$}nrecoverable cells) on nonselective medium were ca. 216 to 259 h for E.{\$}\backslash{\$}ncoli, S. typhimurium, and Y. enterocolitica and 432 h for E. faecalis.{\$}\backslash{\$}nSublethal injury was greater in populations of indicator bacteria than{\$}\backslash{\$}nin pathogens. DVCs, CTC reduction, and plate counts indicated{\$}\backslash{\$}nprogressive increases in viable but nonculturable cells in E. coli, S.{\$}\backslash{\$}ntyphimurium, and Y. enterocolitica cultures throughout the 54-day{\$}\backslash{\$}nexposure. Forty-eight-day exposure off. coli, S. typhimurium, and Y.{\$}\backslash{\$}nenterocolitica resulted in decreased optimal incubation temperatures for{\$}\backslash{\$}ncolony formation and inability to form colonies at 37 degrees C. The{\$}\backslash{\$}ndetection of responsive E. coli, S. typhimurium and Y. enterocolitica by{\$}\backslash{\$}nthe DVC and CTC methods remained within 1{\{}{\%}{\}} of inoculum values during 54{\$}\backslash{\$}ndays of exposure, indicating some long-term persistence in the{\$}\backslash{\$}nviable-but-nonculturable state. Percentages of respiring E. coli and S.{\$}\backslash{\$}ntyphimurium increased significantly upon addition of nutrients at all{\$}\backslash{\$}ntemperatures tested, indicating that nutrient availability rather than{\$}\backslash{\$}ntemperature limited enteric bacterial activity in this very cold{\$}\backslash{\$}nenvironment. Large nutrient inputs to low-temperature marine{\$}\backslash{\$}nenvironments may thus allow for the long-term persistence of enteric{\$}\backslash{\$}nbacteria in a nonrecoverable state.},
	issn = {0099-2240},
	author = {Smith, J J and Howington, J P and McFeters, G A}
}
