An assessment of potential public health risk associated with the extended survival of indicator and pathogenic bacteria in freshwater lake sediments

Abstract

a b s t r a c tMicrocosm studies were performed to evaluate the survival of Escherichia coli, Salmonella paratyphi and Vibrio parahaemolyticus in water and sediment collected from the freshwater region of Vembanad Lake (9 35 • N 76 25• E) along the south west coast of India. All three test microorganisms showed significantly (p < 0.01) higher survival in sediment compared to overlying water. The survival in different sediment types with different particle size and organic carbon content revealed that sediment with small particle size and high organic carbon content could enhance their extended survival (p < 0.05). The results indicate that sediments of the Lake could act as a reservoir of pathogenic bacteria and exhibit a potential health hazard from possible resuspension and subsequent ingestion during recreational activities. Therefore, the assessment of bacterial concentration in freshwater Lake sediments used for contact and non contact recreation has of considerable significance for the proper assessment of microbial pollution of the overlying water, and for the management and protection of related health risk at specific recreational sites. Besides, assessment of the bacterial concentration in sediments can be used as a relatively stable indicator of long term mean bacterial concentration in the water column above.

Salmonella in surface and drinking water: Occurrence and water-mediated transmission

“…In contrast to what has been previously described in other studies (Mezrioui, Baleux, & Trousselier, 1995;Rhodes & Karton, 1988;Winfield & Groisman, 2003), E. coli cells showed a better survival capacity when compared to S. Typhimurium under all tested conditions. In another microcosm study by the same research group, an enhanced survival capacity of Salmonella in lake sediment with respect to the overlaying water was observed (Chandran et al, 2011). According to these results, the lake sediment offered some sort of protection for this enteric pathogen and, thus, potentially act as a reservoir of Salmonella.…”

“…They are usually present in large numbers in raw sewage (10 3 -10 4 CFU/L) and can still be present in wastewater effluent after advanced secondary treatment including coagulation, filtration and disinfection (Maier, Pepper, & Gerba, 2000;Wéry, Lhoutellier, Ducray, Delgenès, & Godon, 2008). Soil and sediment were also found to harbor salmonellae (Abdel-Monem & Dowidar, 1990;Gorski et al, 2011;Tobias & Heinemeyer, 1994) and sediment particles are believed to function as a micro ecological niche enhancing salmonellae survival in lakes (Chandran et al, 2011). In the aquatic environment this pathogen has been repeatedly detected in various types of natural waters such as rivers, lakes, coastal waters, estuarine as well as contaminated ground water (Haley, Cole, & Lipp, 2009;Levantesi et al, 2010;Martinez-Urtaza, Liebana, Garcia-Migura, Perez-Piñeiro, & Saco, 2004;Polo et al, 1999;Wilkes et al, 2009).…”

Predicting Salmonella Populations from Biological, Chemical, and Physical Indicators in Florida Surface Waters

“…Contradictory results have been reported as to the efficacy of index or indicator organisms in predicting the presence and/or prevalence of human pathogens, such as Salmonella, in surface waters (16)(17)(18)(19). While any specific pathogen may not be present in the sample being tested, the presence of index microorganisms is meant to suggest that pathogens have a reasonable likelihood of being present (1).…”

High prevalence of multiple-antibiotic-resistant (MAR) Escherichia coli in river bed sediments of the Apies River, South Africa

“…A loopful of the media was collected and streaked on eosin methylene blue (EMB) agar (Merck, South Africa) (Chandran et al 2011). The plates were incubated at 37°C for 24 h. Single colonies with characteristic green metallic sheen were picked using sterilised toothpicks and transferred into test tubes containing 5 mL tryptone water (Merck, South Africa).…”