Antibiotic resistance profiles and integrons in Enterobacteriaceae from the riverside of Evros-Ardas with respect to chemical and waste pollution*

Objective: The aim of this study was to evaluate the presence of Enterobacteriaceae in different locations of the Evros-Ardas river ecosystem at the borderline of Greece-Turkey. Materials and methods: Usual filter methods were applied for the collection of water samples from the riverside subjected to waste and/or borderline polluted stream. Sampling was accomplished during 3 months, from January to March. A total of 150 strains were isolated and identified by API Me´rieux. The antibiotic resistance profiles were performed according to CLSI; phylogeny analysis was performed by RAPD (random amplification polymorphic DNA analysis); integron class I, II and III were detected by PCR amplification of integrases I and II by using degenerated primers. The detection of the classes of integrons was performed after RsaI digestion of the PCR products and agarose gel electrophoresis. The antibiotic gene cassettes were also generated by PCR. Results : In all, 90% of the isolates were usual environmental strains without antibiotic resistance. Resistance to ampicilllin, amoxicillin, and/or ampicillin/sulbactam and several cephalosporins was detected in 12 strains. Resistance to tetracycline and chloramphenicol was observed in two isolates; resistance to nalidixic acid and to fluoroquinolones was detected in three strains. Finally, resistance to sulfamethoxazole and trimethoprim was observed in four isolates. Integron class I was detected in four isolates and class II in two of them. Several profiles were identified by RAPD and some unique types. Conclusion : It has been shown that plasmids containing b-lactamase, tetracycline and chloramphenicol genes as well as integron class I and II contribute to the pathogenic profiles of the isolates of the region. According to our results four locations represented environmental niches of pathogenic and antibiotic-resistant Enterobacteriaceae, namely the locations Ardas, Elaia bridge, Rizia and Kastanies and Evros Nea Vissa. Further investigation must be undertaken to control the microbial pollution of the riverside in Evros. Key words: antibiotic resistance, Enterobacteriaceae, integron, pollution