Antibiotic resistance of enterococcal isolates in raw milk

Citak S., Yucel N., Mendi A.

JOURNAL OF FOOD PROCESSING AND PRESERVATION, vol.29, no.3-4, pp.183-195, 2005 (SCI-Expanded) identifier identifier


In the present study, 177 Enterococci isolated from 78 raw milk samples were identified by the API 20 Strep system and conventional biochemical tests. Enterococcus faecalis (54.2%) and E. faecium (29%) were the most frequently isolated species, followed by E. durans (6.2%), E. hirae/dispar (5.0%), E. gallinarum groups (3.0%), E. mundtii (2.2%) and E. raffinosus (0.5%). A disk-diffusion method was applied to assay in vitro activity of antibiotics against Enterococcal isolates obtained from raw milk. There was a high frequency of oxacillin, streptomycin and erythromycin (E) resistance in enterococcal isolates (95, 97 and 86%). Vancomycin (VA) and teicoplanin resistance was observed in 48 and 52% of E. faecalis isolates, respectively. The corresponding values were 26 and 33% for E. faecium. Resistance to VA was significantly associated to E, rifampin, gentamycin, ampicillin and ceftriaxone resistance. Implications and public health aspects of antibiotic resistance, especially VA-resistant Enterococci in food, are discussed.