Bacterial Escherichia coli isolates were derived from waters of the Nowohucki Reservoir (Cracow, Poland) in summer and winter seasons. In total, 94 strains, identified as E. coli, were isolated from five sampling sites in the area of the reservoir. Based on the disk-diffusion tests, it was found that the tested isolates were predominantly resistant to ticarcillin and ampicillin. Numerous multi-drug resistant strains were detected, which however did not exhibit the ESBL phenotype. However, PCR approach allowed to detect ESBL-mechanism genes (CTX-M3, OXA, SHV, and TEM) in as much as 38 % of E. coli isolates. These results were coupled with significant molecular diversity of the E. coli strains revealed in BOXA1R-based rep-PCR technique.
Keywords: Antibiotic resistance; Disk-diffusion method; ESBL; Escherichia coli; PCR; Water.