[Antimicrobial susceptibility and molecular typing of Enterococcus faecium isolated from humans, chickens and...

Comparative studies on antimicrobial susceptibility patterns and molecular typing of Enterococcus isolates of different origins provides valuable information concerning the epidemiology of enterococcal infections. We analyzed clinical isolates and we surveyed faecal samples of humans (hospitalised patients and healthy volunteers), faecal samples of poultry and environmental samples. A total of 68 E. faecium isolates were obtained: 43 from humans, 5 from poultry and 20 from water. We compared the antibiotic resistance patterns and pulsed field gel electrophoresis (PFGE) profiles of these strains.We used polymerase chain reaction (PCR) to examine them for the presence of 8 aminoglycoside resistance genes. Differences among percentages of antimicrobial resistance between clinical and non clinical isolates were found. All enterococci were susceptible to vancomycin and teicoplanin. Four aminoglycoside resistance genes were detected, most frequently ant(6)-Ia and aph(3')-IIIa. Presence of isolates resistant to gentamicin but negative for all genes tested suggest that additional resistance genes may exist. VRE are still rare inside and outside hospitals in Gran Canaria (Spain). The high frequency of ampicillin resistance among clinical enterococci and the fact that several isolates share the same PFGE type were isolated from different wards of our hospital suggest that ampicillin-resistant E. faecium are endemic in our Hospital.