Resumen

SALAS-VARGAS, Ana V. et al. Prevalencia e identificación genotípica de Enterococos Vancomicina resistentes en pacientes en un medio hospitalario. Acta méd. costarric [online]. 2004, vol.46, n.1, pp.19-26. ISSN 0001-6002.

Justification and Objectives: Enterococcus are Gram positive bacteria involved in community and nosocomial infections. There has been an increased interest in these bacteria because of their resistance to multiple antimicrobial drugs and their transposon-mediated resistance to glycopeptides. Colonization of patients with enterococci is a risk factor for septicemia. Our main objectives were identification of patients colonized by vancomycin resistant enterococci (VRE) in two tertiary care hospitals, analysis of the antibiotic sensitivity to vancomycin of the isolated bacteria, study of the risk factors to acquire these bacteria and study of the isolations with high resistance profile to the vancomycin with the purpose of identifying genetic determinants of resistance, were the objectives of this study. Patients and methods: this is a prospective, and experimental study conducted from may to august 2001. We studied 106 patients hospitalized in the Intensive Care Units (ICU) of the Hospital México and Hospital San Juan de Dios and also the Medical Emergency Ward of the latter. Rectal swaps were taken in order to isolate VRE and to study the minimal inhibitory concentrations of vancomycin. Strains isolates with higher MIC's were studied for genetic determinants Results: VRE colonization rates in gastrointestinal tract were 52%. Using the chi square test and logistic regression some factors were identified for gastrointestinal tract colonization, being service of origin before admission to ICU, days of stay in ICU and previous use of third generation cephalosporins the main ones. VRE with MIC µ512 mg/ml were demonstraded in 29.6% of the isolates, and in all of them (E.gallinarum, E.,faecium, E. casseliflavus, and E.hirae) the van A gen was found. All E. faecalis isolates showed vancomycin MIC£16 mg/ml. Conclusions: We found a high colonization rate of the gastrointestinal tract, higher than the reported prevalence in other studies in the medicalliterature. Few studies in world wide literature have identified the van A gene in non-pathogenic enterococci. The relevance of these findings is discussed.

Palabras clave : enterococos; enterococos vancomicina-resistentes; vancomicina; resistencia a antibióticos; antibióticos.