Clonal analysis of vancomycin-resistant Enterococcus faecium by MLVA and PFGE typing

Abstract number: P1666

Jagiello E., Kuch A., Sadowy E., Hryniewicz W.

Objective: The aim of the study was to reveal the clonal structure of a vancomycin-resistant E. faecium (VREM) population by MLVA and PFGE approaches and to compare these methods in an epidemiologic investigation.

Methods: This study was performed on 121 VREM isolates collected from several Polish hospitals in the National Medicines Institute in Warsaw between January 2006 and November 2007. The VREM were obtained from rectal swabs (n = 91), wound lesions (n = 7), blood (n = 13), urine (n = 8) and CSF (n = 2). PCR for van genes was performed for all isolates, followed by MLVA and PFGE (SmaI digest) typing.

Results: There were 35 vanA and 85 vanB genotypes detected among the isolates. In 2007 90% of isolates were vanA-positive, in contrast with 2006, when only 9.3% of isolates had the vanA genes.MLVA and PFGE resulted in 35 and 21 types of 119 and 117 typeable isolates, respectively. Comparable values of the discriminatory power, 0.6391 for MLVA and 0.6309 for PFGE, were observed. Among the determined MLVA types (MTs) 12 were new. MT159 was predominant in 2007, representing 77.9% isolates from that year. The most of 2007 isolates (74.7%) belonged to 15 subtypes of the PFGE type PT1, which comprised 92.5% of the MT159 isolates. Both MLVA and PFGE revealed greater genetic diversity among 2006 isolates (12 MTs and 22 PTs among 30 isolates) than among those from 2007 (11 MTs and 15 PTs among 91 isolates). No predominant MLVA or PFGE type was detected in 2006. The majority of isolates from 2006 and 2007 (>70% and >90% respectively) were classified into the CC17 clonal complex based on allele profiles determined by MLVA.

Conclusion: MLVA appeared to be comparably usefull to PFGE in the epidemiologic analysis of VREM. Both methods reflected highly concordant data concerning the level of genetic diversity among the investigated isolates.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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