Colonization of Biofilms in a Freshwater Stream by Escherichia Coli and Bacteroides
Detection of fecal contamination of freshwater streams has traditionally been assessed by fecal coliforms and Escherichia coli, but new research methods have allowed for the use of the anaerobic, enteric bacterium Bacteroides for molecular marker fecal detection. However, a confirmation of the presence of E. coli and Bacteroides in media other than the water column, such as biofilms, has received little attention. Water samples and biofilms from one area of Wilson's Creek were assessed for total coliforms, E. coli, and Bacteroides. A biofilm collection device was constructed with removable glass slides for biofilm growth and analysis. Water column and biofilm samples were collected every two weeks for analysis. Physical parameters such as water temperature, pH, dissolved oxygen, and flow rate were determined for each sampling event. The water column and biofilm samples were assessed for total coliforms and E. coli utilizing an IDEXX Colilert-18 test, and presence of Bacteroides was determined utilizing a PCR assay on DNA extracted from water and biofilm samples. E. coli was present in all water and biofilm samples collected with no significant correlation between the two. Bacteroides was also found to be present in water and biofilm samples.
biofilm, Bacteroides, Escherichia coli, fecal, freshwater, Biology
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