Wednesday, November 15, 2006 - 2:30 PM
237-4
Random Amplified Polymorphic DNA Analysis and Genotypic Analysis of Verotoxin-Producing Escherichia coli from North Alabama Watersheds.
Protecting surface water quality in the face of a burgeoning human population has become a major challenge for many states. One of the many concerns regarding water quality is to minimize the concentration of pathogens in water and thereby minimize the risk of waterborne disease to humans or to animals.Fifty-four water samples collected from local watersheds in North Alabama were analyzed for VTEC strains using modified tryptic soy broth with novobiocin as a pre-enrichment broth and Cefixime-Tellurite Sorbitol MacConkey agar (CT-SMAC) as a selective media. The isolates were characterized serologically with O157 and H7 antisera, and Shiga-toxin (stx-1 and stx-2) genes with PCR assay. A total of 300 isolates were obtained, of which 30 (10%) were O157:H7, 135 (45%) O157: non H7 and 135 (45%) non O157:H7. Of the 30 O157:H7 positive isolates, 18 (60%) isolates gave positive PCR for VT genes and these VT positive isolates were further analyzed by random amplified polymorphic DNA (RAPD) analysis using five decamer universal primer pairs and compared with geographical water shed profiles. Five isolates from each watershed group (Flint River, Madison Creek , and Red Creek) were subjected to RAPD and dendrograms was generated. Data indicated that 75% of the strains from Flint River had similar profiles in comparison to Madison creek (30%) and red creek strains (25%). Overall, Flint River watershed exhibited less number of polymorphic bands (5) compared to Madison creek (12) and Red creek (15). This study indicates that DNA fingerprinting when used in combination with genotypic and serological testing maybe a valuable epidemiological tool for tracking waterborne outbreaks.
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