Vancomycin-resistant enterococci remain rare in New Zealand

Abstract

Vancomycin resistance in Enterococcus faecalis and E. faecium (VREF) has been closely monitored in New Zealand (NZ) following the emergence of VREF in other countries. Diagnostic laboratories are requested to submit all probable isolates of VREF for reference testing, which includes confirmation of antimicrobial susceptibility, van gene PCR, and pulsed-field gel electrophoresis (PFGE) typing. A total of 17 VREF isolates from 15 patients were confirmed between 1996, when the first isolate was identified, and 2002. Two different strains of VREF were isolated from each of two patients. The 15 patients were from several areas throughout NZ. E. faecalis with the vanA genotype was most common, being isolated from 12 patients. Of the three PFGE patterns identified among the vanA-positive E. faecalis isolates, one pattern was predominant (11 of 13 isolates). VbnB-positive E. faecalis was isolated from one patient and vanA-positive E. faecium were isolated from the remaining two patients. Available data indicate that at least one third of the VREF isolated were clinically significant and the majority of patients had one or more risk factors for VREF. Only two patients were colonised or infected with VREF resistant to amoxicillin. These data indicate that VREF are rare in NZ, and the predominance of one strain of vanA-positive E. faecalis suggests a widespread environmental reservoir of the strain.