Antibiotic resistance profile of Enterococcus faecium and Enterococcus faecalis isolated from broiler cloacal samples


Abstract: The present study was performed to isolate and identify Enterococcus spp. from broiler cloacal samples to species level, to determine their resistance patterns to various antibiotics, and to detect vancomycin resistance genes. Cloacal samples of broilers collected from slaughterhouses were inoculated in Slanetz and Bartley agars with and without vancomycin (6 μg/mL). Antibiotic resistance/susceptibility testing of the isolated and identified enterococci was performed by using the disk diffusion test. Multiplex PCR was used to identify the species and to detect vancomycin resistance genes. The majority of the isolated enterococci was Enterococcus faecium (60.43%, n = 142) and Enterococcus faecalis (33.62%, n = 79). E. casseliflavus and E. gallinarum were identified from 8 (3.42%) and 6 (2.56%) isolates, respectively. It was found that 88.9% of the enterococci were resistant to tetracycline and 83.4% of them were resistant to erythromycin. As a result, none of the strains isolated from cloacal samples of broilers carried the vanA and vanB genes. It was observed that 54.9% of E. faecium isolates and 78.4% of E. faecalis isolates were multidrug resistant (resistant to 3 or more antibiotic groups). The lack of vancomycin-resistant Enterococcus among the enterococci isolates was important for public health.

Keywords: Antibiotic resistance, broiler, Enterococcus faecalis, Enterococcus faecium, vanA

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