title: Competitive Survival of Escherichia coli, Vibrio cholerae, Salmonella typhimurium and Shigella dysenteriae in Riverbed Sediments.
abstract: Studies on the survival of bacterial enteric pathogens in riverbed sediments have mostly focused on individual organisms. Reports on the competitive survival of these pathogens in riverbed sediments under the same experimental setup are limited. We investigated the survival of Escherichia coli, Salmonella enterica ser. Typhimurium, Vibrio cholerae and Shigella dysenteriae in riverbed sediments of the Apies River. Experiments were performed in flow chambers containing three sediment types and connected to aquarium pumps immersed in river water to maintain continuous water circulation. Each chamber was inoculated with ~107CFU/mL (final concentration) of each microorganism and kept at 4, 20 and 30 °C. Chambers were sampled on days 0, 1, 2, 7, 14 and 28. At 4 °C, only E. coli and S. typhimurium survived throughout the 28 experimental days. V. cholerae had the shortest survival time at this temperature and was not detected in any of the sediment chambers 24 h after inoculation. S. dysenteriae only survived until day 7. At an increased temperature of 20 °C, only S. dysenteriae was not detected on day 28 of the experiment. At 30 °C, V. cholerae and Salmonella survived longer (28 days) than E. coli (14 days) and S. dysenteriae (4 days). Vibrio cholerae was shown to have the highest T90values (32 days) in all sediment types at 20 and 30 °C. We conclude that the sediments of the Apies River present a favourable environment for the survival of indicator and pathogenic bacteria depending on the prevailing temperature.
authors.affiliation: Department of Environmental, Water and Earth Science, Tshwane University of Technology, Arcadia Campus, 175 Nelson Mandela Drive, Pretoria, 0001, South Africa. lutherkinga@yahoo.fr.
authors.forename: Akebe Luther King
authors.initials: AL
authors.lastname: Abia
authors.affiliation: Natural Resources and the Environment, CSIR, PO Box 395, Pretoria, 0001, South Africa.
authors.forename: Eunice
authors.initials: E
authors.lastname: Ubomba-Jaswa
authors.affiliation: Department of Environmental, Water and Earth Science, Tshwane University of Technology, Arcadia Campus, 175 Nelson Mandela Drive, Pretoria, 0001, South Africa. mombamnb@tut.ac.za.
authors.forename: Maggy Ndombo Benteke
authors.initials: MN
authors.lastname: Momba
mesh_terms: D004926:Escherichia coli / Q000302:isolation & purification*; D019015:Geologic Sediments / Q000382:microbiology*; D045483:Rivers / Q000382:microbiology*; D012486:Salmonella typhimurium / Q000302:isolation & purification*; D012762:Shigella dysenteriae / Q000302:isolation & purification*; D013696:Temperature; D014734:Vibrio cholerae / Q000302:isolation & purification*; D014871:Water Microbiology; D014876:Water Pollution
keywords: Competitive survival; Escherichia coli; Microbial pathogens; Riverbed sediments; Salmonella; Shigella