[Enterococcus spp. colonized in the gastrointestinal tract of patients in hemato-oncology and intensive care units and their resistance profiles to vancomycin].

The aim of this study was to identify the Enterococcus spp. and to determine their vancomycin-resistance profiles, in the samples collected from the patients who were described as risky groups for vancomycin-resistant enterococcal (VRE) colonization, in scope of a survey study carried out in our hospital for the first time. Rectal swab samples were taken once in a month from a total of 180 patients who were hospitalized in the Surgery and Intensive Care Units, adult Oncology-Hematology and Pediatric Oncology Units between March-December 2006. The samples were cultivated onto bile-esculine agar media, and Miniapi system (bioMerieux, France) was used for the identification at species-level (Rapid ID 32 Strep kit, bioMerieux, France) and for the detection of antimicrobial susceptibilities (ATB Enterococcus kit, bioMerieux, France). MIC levels have been determined by the use of vancomycin E-test (AB Biodisk, Sweden) strips in brain-heart infusion agar (Merck, France). According to the culture results, 126 of the patients (70%) have been found to be colonized with Enterococcus spp. The most frequently isolated species were as follows respectively; E. faecium (42%), E. faecalis (31%), E. avium (12%), E. gallinarum (8%) and E. casseliflavus, (5.6%). Four of the E. faecium strains (3.2%) were found resistant to vancomycin by both automated antibiotic susceptibility test system and E-test (MIC >256 mg/ml). Vancomycin-resistant strains have been identified as being VanA genotypes by polymerase chain reaction. Beta-lactamase production has not been detected in any one of the strains with the use of nitrocephin (Remel, U.S.A.) disk. As a result the colonization rates of enterococcal species and VRE were found as 70% and 3.2%, respectively in our patients. Infections with VRE have not been detected in colonized patients during the follow-up period. In conclusion, in order to detect and prevent the spread of VRE, surveillance cultures should be regularly performed from hospitalized patients, in collaboration with educational studies for hospital personel, controlling the use of vancomycin and cephalosporins and cooperation between microbiology laboratories and inpatient clinics.