[Infections with Van B phenotype Enterococcus faecium and E. faecalis in patients with immune deficiency during the...

In this work, we have analyzed the second outbreak of VRE with the VanB phenotype to be identified in the country. The aim of this study was to characteristics of the types of resistance to glycopeptide antibiotic and to check the resistance patterns of these pathogens. A trial of monitoring the risk factors for colonization or infection with VRE as well as epidemiological investigation were undertaken. Genus identification of the isolates was performed according to the method of Facklam and Collins, and species were identified using the API 20 Strep test. MICs of different antimicrobial agents were determined by the E-test method. The isolates collected during the investigation demonstrated resistance to multiple antimicrobials, which is a common characteristic of VRE. Isolates were found to be uniformly resistant to penicillin, fluoroquinolones, tetracycline and to high concentrations of aminoglycosides. The only drugs with in vitro activity against the isolates were ampicillin (VRES), linezolid (VRES, VREM) and quinupristin-dalfopristin (VREM). Except for a single VREM isolate, they all revealed the typical VanB phenotype with resistance to vancomycin and susceptibility to teicoplanin. One of the VREM isolates turned out to be resistant to teicoplanin, which coincided with the use of this antibiotic in the patient's therapy. Its vanB gene variant differed by a single mutation from that found in other isolates; however, it also lacked a large part of the vanB gene claster, including the regulatory genes vanRB and -SB, and the vancomycin--inducible promoter PYB. Our studies have found an association between colonization or infection with VRE and the mean duration of hospital stay, previously administration of glycopeptide, cephalosporins and imipenem. These organisms were a common cause of monoethiological bloodstream infections.