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Epidemiology of multiresistant Enterococcus faecalis and Enterococcus faecium collected during 2004 to 2006 in a Lisbon hospital

Abstract number: 1733_191

Pires R., Pereira M., Rodrigues P., Carvalho S., Ferreira T., Mato R.

Objectives: Determination of the prevalence, evolution of antimicrobial resistance, and clonality of high-level gentamicin (HLGR) and glycopeptide resistant (GR) E. faecalis (E.fl) and E. faecium (E.fm) recovered from infection products during 2004 to 2006 in a public community (350-beds) Lisbon hospital.

Methods: Microbial identification and antimicrobial susceptibility testing were performed using the VITEK 2 system. HLGR and GR E.fl and E.fm were confirmed by PCR detection of aac(6')-aph(2'') and vanA/B/C1/C2 genes and clones were assessed by SmaI-PFGE and carriage of the esp gene. Multiplex-PCR was used to detect the cylA, asaI, gelE and hyl virulence genes among GR isolates.

Results: A total of 403 isolates were recovered during 2004–2006. The prevalence of E.fl and other enterococcal species (E. durans, E. casseliflavus, E. avium by decreasing order of frequency) increased from 68 to 81% and from 0.6 to 6%, respectively, while E.fm decreased from 30 to 11%. HLGR-E.fl increased from 31 to 41% and resistance to ampicillin-Amp (4%), ciprofloxacin-Cip (40%), erythromycin-E (89%), and vancomycin-Va (1%) remained stable. Most (90%) of the E.fm were resistant to Amp, Cip and E, and resistance to Va decreased from 14 to 8%. HLGR-E.fm increased from 62 to 77%.

All HLGR isolates (n = 162) carried the aac(6')-aph(2'') genes. GR-E.fl (n = 3) and GR-E.fm (n = 5) were vanA-positive. HLGR-E.fl (n = 107) were of 27 PFGE patterns. PFGE-AO was prevalent (n = 53) and increased in prevalence during the study period (37.5% to 61.5%). esp-positive HLGR-E.fl increased from 25 to 82%, in parallel with the increment of esp-positive HLGR-E.fl PFGE-AO from 8 to 92%. PFGE-AO also included GR-E.fl isolates positive for cylA, asaI, gelE and one isolate was also esp-positive. HLGR-E.fm (n = 55) were of 11 PFGE types. Three major clones (PFGE-a, -o and -c) coexisted in 2004. PFGE-a decreased from 2005 (76%) to 2006 (20%) while PFGE-c emerged as dominant (50%). The esp gene increased from 68 to 90%. GR-E.fm were of PFGE-a, -o (two esp-positive isolates), -c and -d (all esp-negative, HLG susceptible). PFGE-o and -c isolates carried only gelE.

Conclusions: Enterococcal infections mainly by HLGR-E.fl and E.fm seem to be increasing. The prevalence of GR strains was lower that the published data. One major E.fl nosocomial clone is acquiring virulence traits over time. To our best knowledge this is the first molecular epidemiological study of enterococcal infections from a Portuguese hospital.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Subject:
Location: ICC, Munich, Germany
Presentation type:
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