Molecular characterization of glycopeptide-resistant enterococci from hospitals of the picardy region (france)

Abstract

We studied 138 glycopeptide-resistant enterococci (GRE) strains, consisting of 131 glycopeptide-resistant Enterococcus faecium (GREfm) and 7 glycopeptide-resistant Enterococcus faecalis (GREfs). The GREfm strains were resistant to penicillin, ampicillin, vancomycin, and teicoplanin, while the GREfs strains were only resistant to vancomycin and teicoplanin. The van A gene was the only glycopeptide determinant present in all GRE isolates investigated. Genes coding for Hyl and Hyl+ Esp were detected in 39 (29.8%) and 92 (70.2%) of the 131 GREfm isolates, respectively. Three of the 7 GREfs were positive for gelE+asa 1 genes, 3 for gel E gene, and 1 for asa 1 gene. The genetic relationship between the 138 GRE was analyzed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). GREfm isolates were clustered in a single genogroup (pulsotype A), and GREfs were clustered in six genogroups (pulsotypes B-G). Among the isolates investigated by MLST, only 18 PCR products were sequenced (12 E. faecium and 6 E. faecalis), and 9 sequence types (STs) were identified.

Figure 1

PFGE dendrogram with the corresponding MLST sequence types of the GRE isolates, digested with SmaI. Strains were clustered by the unweighted pair-group method with arithmetic mean (UPGMA). Each row represents a unique PFGE type with its unique PFGE pattern. The corresponding MLST sequence type (ST) is shown with the corresponding strains. Molecular weight: (MW). Bacteriophage λ-ladder is given in kbp (48.5 kb–485.0 kb) *PFGE type A (PA) isolates 3, 4, 6–8, 10–13–24, 27, 29–32, 34, 36, 37, 39–43, 45, 46, 49–53, 55–60, 63–101, 103–115, 117–138. (+): positive.