Detection of Possible Pathogenicity of Antibiotic Resistant Escherichia coli Isolated from Urban Playa Lakes and the Feces of Canada Geese and Resident Waterfowl

Logan Adams


In a collaborative effort to study the effects of migratory and domestic waterfowl on the water quality of urban playa lakes, the Lubbock Christian University Natural and Physical Sciences departments have isolated Escherichia coli from playa lake water and the feces of migratory Canada geese and resident waterfowl. In previous studies, it was determined that forty isolated samples were resistant to at least one antibiotic. In this study, samples of the antibiotic resistant E. coli were further analyzed for the presence of Shiga-like toxin producing genes (stx1 and stx2) and the presence of enterohemolysin. Methods for determining the presence stx1 and stx2 include isolation of genomic DNA followed by Polymerase Chain Reaction. The PCR product was then sequenced using Beckman Coulter’s genomic services. Sequences produced from the shiga toxin primers were compared to known gene sequences, which allowed for positive identification of Shiga toxin-producing E. coli (STEC). Methods for determining the presence of enterohemolysin consist of growing isolates on tryptic soy agar medium supplemented with 5% sheep’s blood and, after incubation, observing the plates for hemolysis. E. coli producing Shiga-like toxin and enterohemolysin can cause various gastrointestinal complications including hemolytic uremic syndrome (HUS), acute renal failure, and end stage renal disease. If the isolated organisms contain the shiga toxin genes of stx1 or stx2 and/or enterohemolysin, then the E. coli present at Lubbock playa lakes is potentially pathogenic. Urban playa lakes are often used for recreational activity, and the presence of antibiotic resistant STEC would be of significant clinical importance.


Shiga toxin; E. coli; Enterohemolysin

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