Evaluation of the prevalence of insertion element IS16 in vancomycin-resistant enterococci strains of Enterococcus faecium isolated from transplantology patients from a Warsaw Hospital between 2010 and 2012.

The study included 79 vancomycin-resistant Enterococcus faecium (VRE) strains isolated from 33 patients after kidney (n = 19) or liver (n = 14) transplantation; these patients were hospitalized between 2010 and 2012. The strains were obtained from infected persons as well as from carriers. All examined strains were tested for the susceptibility to antimicrobials active against enterococci and for the presence of vanA and vanB genes as well as the presence of the insertion sequence IS16 considered as one of the markers of hospital-associated strains. All 79 VRE strains of E faecium possessed IS16 and the vanA (vanB-negative) determinant. All tested strains were resistant to at least three groups of drugs; therefore, they were recognized as multidrug resistant. All isolates were resistant to glycopeptides, ampicillin, and most were resistant to tetracyclines, macrolides, nitrofurans, and high concentrations of aminoglycosides. The presence of insertion element IS16 and multiple resistance determinants prove that strains colonizing or infecting solid organ recipients were typical nosocomial pathogens.