engleski

Antibiotic resistance pattern among the cheese related enterococci

The production of traditional food is gaining importance all over the world, both in terms of preservation of inheritance and as a key issue for the high-quality human nutrition. Traditional hard type Istrian cheese is one of the most important Croatian products with a long history of manufacturing. To evaluate the safety of Istrian cheese and to evaluate the application of enterococci as starter cultures in a production of Istrian cheese it is of prime importance to characterize its natural enterococcal community mainly in respect to the occurrence of antibiotic resistance pattern. Istrian cheese constitutes the reservoir of enterococci and consequently a potential reservoir of antibiotic resistance and virulance traits which could be transferred to humans in intestinal. If the resistance to commonly used antibiotics is present, the transfer to human pathogens cannot be excluded such producer should avoid the application of respective strains into the food chain. Therefore, the aim of this study was to investigate antibiotic susceptibility of enterococcal microora naturally present in raw milk, whey, curd and cheese samples during the ripening. To achieve these aim enterococci were isolated on selective agar medium (CATC) and proceeded to DNA extraction and molecular characterization based on genus- and species- specic PCR. The bacteria belonging to genus Enterococcus were grouped by RAPD PCR and representative of each RAPD group were analyzed for antibiotic susceptibility based on BBL disc diusion method and E- strips. The results from the disc test analysis preformed on 17 enterococcal representatives, identied all 17 representatives as being resistant to ampicillin, penicillin, tetracycline, amoxicillin/clavulanic acid and clindamycin, with 90%, 96% and 50% of the isolates being resistant to rifampin, ceftazidime or cefuroxime and erythromycin, respectively. Resistance to vancomycin was between 0.25-4 ug/ml.

antibiotic resistance; enterococci; Istrian cheese

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