Isolation of vancomycin-resistant Enterococcus faecium from Italian cheeses Original Research Article

Several industrial and artisan Italian cheeses were screened for the presence of vancomycin-resistant enterococci (VRE). One hundred and two strains, mostly belonging to the species Enterococcus faecium after species-specific PCR identification, were tested for antibiotic susceptibility by standard disc diffusion method and for resistance to vancomycin in liquid medium. About 25% of strains were resistant to both vancomycin and teicoplanin. PCR experiments showed that all resistant isolates harboured the vanA gene. Minimum inhibitory concentration (MIC) values of vancomycin for most of the vancomycin resistant E. faecium (VREF) ranged from 128 to 512 μg ml−1(high level resistance). PCR fingerprinting of VREF indicated that multiple isolation of the same strains did not occur. The importance of finding VRE in cheeses is discussed.