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Prevalence of colonization with vancomycin-resistant and ampicillin-resistant Enterococcus faecium in a university hospital in northern Spain

Abstract number: P1014

Romo M., Goicoechea P., Calvo J., de la Cal M., Gozalo M., Alvarez M., Fariñas M.C., Martínez-Martínez L., Francia M.V.

Objectives: CC17 Enterococcus faecium has increasingly been reported as a nosocomial pathogen worldwide. We aimed to investigate vancomycin-resistant (VRE) and ampicillin-resistant (ARE) E. faecium intestinal colonization among inpatients at our hospital. Antibiotic susceptibility, clonal relationship and the presence of virulence determinants or mobile genetic elements were specifically determined.

Methods: From February to August 2009, 576 patients admitted to several units at our hospital (and without hospital stays during the previous year) were screened for VRE or ARE faecal carriage. Rectal swabs (collected on admission and weekly until the patients' discharge) were inoculated onto azide bile-esculin agar plates with ampicillin (16 mg/L) or vancomycin (6 mg/L) for 48 h. Identification and susceptibility testing were done with the Walk-Away System and confirmed by 16S DNA sequencing and E-test method, respectively. Clonal relatedness was assayed by PFGE and MLST. Specific virulence determinants and plasmid content were tested by PCR as previously described.

Results: On admission, 24 patients were colonized with ARE and 1 with VRE. 9 patients were ARE colonized after a hospital stay >48 h. The percentages of resistance of the 34 E. faecium isolates recovered were: ampicillin (97), ciprofloxacin (91), erythromycin (85), high-level resistance streptomycin (82), high-level resistance gentamicin (8), tetracycline (32), vancomycin (2), teicoplanin (2), chloramphenicol (26), linezolid (0), quinupristin/dalfopristin (29). The isolates were classified into 14 PFGE types, highlighting the presence of 1 major clone containing 15 isolates. MLST analysis displayed 9 known sequence types (STs), ST117, ST18, ST17, ST192, ST375, ST262, ST264, ST265, ST123 and 2 new STs. Most of the isolates belonged to CC17 (76%). The percentages of virulence genes were as follows: esp (55), hyl (17), acm (44) and entA (88). Isolates encoded a variety of plasmid modules, being pRE25, pEF1, pCIZ2, pAD1 and pEFNP1 the predominant ones.

Conclusions: 1 of every 25 patients was ARE colonized on admission at our hospital. As CC17 represents a clonal complex usually associated to hospital settings and rarely found in the community, CC17 carriage on admission might be associated with previous hospital stays. CC17 ARE intestinal persistence times might then be longer than 1year, facilitating dissemination of these strains. VRE was nearly absent among hospitalized patients at our hospital.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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