Clonal dissemination of VanA-type glycopeptide-resistant Enterococcus faecalis between hospitals of two cities located 100 km apart

Abstract

Nosocomial dissemination of glycopeptide-resistant enterococci represents a major problem in hospitals worldwide. In Brazil, the dissemination among hospitals in the city of São Paulo of polyclonal DNA profiles was previously described for vancomycin-resistant Enterococcus faecium. We describe here the dissemination of VanA phenotype E. faecalis between two hospitals located in different cities in the State of São Paulo. The index outbreak occurred in a tertiary care university hospital (HCUSP) in the city of São Paulo and three years later a cluster caused by the same strain was recognized in two patients hospitalized in a private tertiary care hospital (CMC) located 100 km away in the interior of the state. From May to July 1999, 10 strains of vancomycin-resistant E. faecalis were isolated from 10 patients hospitalized in the HCUSP. The DNA genotyping using pulsed-field gel electrophoresis (PFGE) showed that all isolates were originated from the same clone, suggesting nosocomial dissemination. From May to July 2002, three strains of vancomycin-resistant E. faecalis were isolated from two patients hospitalized in CMC and both patients were colonized by the vancomycin-resistant Enterococcus in skin lesions. All isolates from CMC and HCUSP were highly resistant to vancomycin and teicoplanin. The three strains from CMC had minimum inhibitory concentration >256 µg/ml for vancomycin, and 64 (CMC 1 and CMC 2) and 96 µg/ml (CMC 3) for teicoplanin, characterizing a profile of VanA resistance to glycopeptides. All strains had the presence of the transposon Tn1546 detected by PCR and were closely related when typed by PFGE. The dissemination of the E. faecalis VanA phenotype among hospitals located in different cities is of great concern because E. faecalis commonly colonizes the gastrointestinal tract of patients and healthy persons for periods varying from weeks to years, which, together with the persistence of vancomycin-resistant Enterococcus in hospital rooms after standard cleaning procedures, increases the risk of the dissemination and reservoir of the bacteria.

Genotypic characterization of hospitalEnterococcus faecalisstrains using multiple-locus variable-number tandem-repeat analysis

“…Similar results were obtained by others (Kuriyama et al. 2003; Moretti et al. 2004), showing the potential of enterococci to be transmitted within a hospital as well as between settings.…”

“…In epidemiological studies of enterococcal infections, several genotypic methods have been applied. Among these, DNA fingerprinting by pulsed-field gel electrophoresis (PFGE) is the most frequently used (Murray et al 1990;Moretti et al 2004).…”

Multilocus Sequence Typing of Hospital-Associated Enterococcus faecium from Brazil Reveals Their Unique Evolutionary History

“…The spread of genetically related enterococci has occurred within hospitals of São Paulo and Brasília 3,18,25 and, in addition, between hospitals located in different cities of the Federal District and the State of São Paulo. 12,19 The isolates belonging to clusters IV, V, and VI represent additional examples of interhospital spread of genetically related strains in Brazil. The ability of isolates from the clusters I-VI to persist within ICUs and spread between hospitals in Brazil suggest that they have adapted extremely well to the hospital environment.…”

Virulence factors in vancomycin-resistant and vancomycin - susceptible Enterococcus faecalis from Brazil

“…However, no other VanD strains have been reported in Brazil. On the other hand, a predominant clone of vancomycin-resistant E. faecalis (VREFS) VanA has recently been disseminating throughout hospitals in Sao Paulo and other cities (8,18,19). It was of interest to identify virulence factors and antibiotic resistance profiles among isolates of the disseminating clone and compare them with subsets of vancomycin-sensitive E. faecalis (VSEFS) from several sources in Brazil.…”