Multidrug-resistant (MDR) Enterococcus faecalis and E. faecium are one of the leading causes of nosocomial infections for humans. The emergence of vancomycin-resistant enterococci (VRE) causes concern because this drug is often one the few therapeutic alternatives for treatment of multidrug-resistant (MDR) enterococcal infections. Although the widespread of MDR enterococci is driven also by the selective pressure produced by the use and overuse of drugs in both human and veterinary practice, the characterization of VRE strains of human nosocomial-acquired infections has been extensively reported while less attention has been given to the role of pets as reservoir of these pathogens. The aim of this study was to evaluate the prevalence and to study the characterization of antimicrobial-resistance of VRE from household dogs.
Antimicrobial susceptibility to vancomycin, high-level aminoglycosides and to other compounds of one hundred-seventy enterococci isolated from household dogs was determined by the disk diffusion method based on recommendations of the CLSI. The species confirmation and the antimicrobial-resistance genotypes of VRE were assessed by PCR assays as previously described.
VRE were detected in 84/170 isolates (49%). The 7% and 13% of VRE showed high-level resistances to gentamycin and streptomycin respectively. Most of these isolates were also classified as multidrug-resistant, showing a lack or reduced susceptibility to three or more antimicrobials of clinical relevance. The genotypic characterization has not been completed yet. However, preliminary data showed that 2.4% and 19% of the 84 vancomycin and penicillin-resistant isolates harboured the vanC1 and blaZ gene respectively. None of the isolates carried vanA and vanB genes.
These results suggests that dogs may play a role in the spreading of enterococci with last-line drug resistances to humans and stress the need of monitoring antimicrobial-resistance also in pets.