Molecular typing and antimicrobial susceptibility of vancomycin-resistant Enterococcus faecium in Brazil.

Abstract

To characterize vancomycin-resistant enterococci (VRE) isolates and to evaluate the mode of dissemination of this pathogen in Brazil. We collected 22 vancomycin-resistant Enterococcus faecium isolates from 6 medical centers in Sao Paulo, Brazil, and 1 isolate from a medical center in Curitiba, Brazil. All Brazilian hospitals that had identified vancomycin-resistant E. faecium up to the beginning of this study (late 1999) contributed isolates to the study. The isolates were susceptibility tested using the broth microdilution method and the E-test. The presence of vancomycin resistance genes (vanA, vanB, vanC1, vanC2-3, and vanD) was evaluated by polymerase chain reaction; molecular typing was performed by pulsed-field gel electrophoresis (PFGE). The vanA gene was demonstrated in all vancomycin-resistant E. faecium, except for 1 isolate. None of the vancomycin resistance genes cited above was detected in the isolate from Curitiba, which was the first vancomycin-resistant E. faecium described in Brazil. All isolates were resistant to ampicillin and teicoplanin. The main clone remains susceptible to doxycycline and chloramphenicol, but intermediate to quinupristin-dalfopristin. PFGE analysis demonstrated 7 major PFGE patterns. A unique PFGE pattern with 4 subtypes was detected in 17 isolates from 4 different hospitals. The results of our study indicate the occurrence of intra- and interhospital dissemination of VRE in Sao Paulo, Brazil.