Introduction: Glycopeptide resistance in Enterococcus spp. is a clinical problem because of the rapid dissemination of these microorganisms, possible transfer of vancomycin resistance to more virulent pathogens, such as Staphylococcus aureus, and the limited therapeutic possibilities for the infections they cause. In this study, 10 strains of vancomycin-resistant Enterococcus faecium isolated from 10 different patients in our hospital during 2004 to 2005 were characterized.
Methods: PCR was used to analyze the gene implicated in glycopeptide resistance. Molecular analysis of clinical isolates was performed by pulsed-field gel electrophoresis (PFGE). The presence of genes previously associated with epidemicity/virulence (esp, hyl, asa1, gel, cyl) was also studied. Risk factors were determined in a case-control study.
Results: The most commonly detected gene was vanA. PFGE analysis revealed 5 different genotypes (A-E), with a predominance of genotype A (n=3) and B (n=3). The esp (surface protein) and hyl (hyaluronidase) genes were detected in all strains, with the exception of genotypes B and D. The purK1 allele, associated with clonal complex 17 was demonstrated in all strains.
Conclusion: Prior administration of cephalosporins, aminoglycosides and vancomycin alone or in combination was significantly associated with colonization/infection by vancomycin-resistant Enterococcus faecium.