Antibiotic Susceptibility of Shiga Toxin Producing E. coli O157:H7 Isolated from Different Water Sources

Abstract

Nowadays the extensive use of antibiotics for the treatment of humans and warm blooded animals has influenced the frequency and spread of antibiotic resistant E. coli O157:H7 in different aqueous sources. Thus, the main aim of this study was to evaluate the antibiotic susceptibilities of E. coli O157:H7 isolated from different water sources and establish a correlation between the presence of virulence genes of E. coli O157:H7 with the resistance to six antibiotic groups (amoxicillin, cefixime, ciprofloxacin, tetracycline, clarithromycin and streptomycin) extensively used in Egypt. To achieve this aim 44 suspect E. coli O157:H7 isolates were confirmed by biochemical tests and were characterized for six virulence genes: fliC, stx1, stx2, eae, rfbE and hlyA using multiplex PCR. All E. coli O157:H7 isolates carrying three (stx2, eae and rfbE) or more virulence genes were resistant to amoxicillin and 77% were resistant to clarithomycin. In conclusion, it appears that the environmental E. coli O157:H7 strains develop strategies for antibiotic resistance more than reference strains.