Emergence of worldwide epidemic clones of vancomycin-resistant Enterococcus faecium in a Northern Spain hospital
Abstract number: 1733_179
Romo M., Tomita H., Ike Y., Martínez-Martínez L., Francia M.
Objectives: Vancomycin-resistant enterococcal outbreaks are unusual in Spain. However, between October 2002 and April 2004, 31 clinical isolates of VanA E. faecium were reported in our hospital. These isolates showed high-level resistance to ampicillin, erythromycin, ciprofloxacin and aminoglycosides. Preliminary PFGE typing indicated the presence of two different patterns. The objective of this study was to determine the genetic lineages from which our isolates were derived along with the conjugative elements involved in the vancomycin resistance dissemination in our institution.
Methods:E. faecium isolates were genotyped by MultiLocus Sequence Typing (MLST). The clonal relationship between the isolates was analysed by the allelic profiles of the sequence types (STs) through the web site (http://www.mlst.net). Southern Hybridisation methods using a digoxigenin-based nonradioisotope system (Boehringer GmbH, Mannheim, Germany) and standard protocols were performed to determine the presence of pMG1-like plasmids.
Results: Among the 31 E. faecium isolates, two STs were identified, ST132 (representing 85% of the isolates) and ST18 (15%), being coincidental with the two PFGE patterns previously shown. Analysis of the allelic profile of the STs suggested all the isolates be assigned to clonal complex 17, with each ST being a double locus variant of ST17, a well-known world wide epidemic strain. ST132 strains were shown to harbour the highly conjugative pMG1-like plasmids, frequently found in vancomycin resistant E. faecium clinical isolates in Japan and USA. pMG1 was absent from ST18 isolates.
Conclusions: Our data suggested the outbreak occurred in our hospital was caused by two hospital adapted multi-resistant E. faecium clones forming part of the major circulating epidemic lineage in the world. pMG1-like plasmids appear to be involved in the vancomycin dissemination, at least in our predominant clone.
|Session name:||European Society of Clinical Microbiology and Infectious Diseases|
|Location:||ICC, Munich, Germany|
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