Clonal analysis and toxin gene carriage of meticillin-resistant Staphylococcus aureus isolated from three hospitals in western Greece

Abstract number: R2342

Drougka E., Foka A., Chini V., Levidiotou S., Michalakopoulou K., Vamvakopoulou S., Christodoulidi I., Anastassiou E.D., Spiliopoulou I.

Objectives: Meticillin-resistant Staphylococcus aureus (MRSA) is associated with an increasing number of both community and hospital-associated infections (CA/ HA-MRSA). The aim of this study was to identify clonal types correlated with the presence of genes encoding TSST-1 (tst) and Panton-Valentine leukocidin (lukS and lukF, PVL) among MRSA collected in three hospitals receiving patients from Western Greece.

Methods: In total 692 S. aureus isolates were characterised by conventional methods, followed by the determination of oxacillin MIC by the Etest. PBP2a production was investigated by a Latex agglutination test (bioMerieux). The presence of mecA, tst, lukSPV and lukFPV genes (encoding PVL) and agr groups were defined by PCRs. Clonal types were identified by PFGE of chromosomal DNA SmaI digests and named by their PFGE/agr types. CA-MRSA were isolated from patients without any predisposing risk factors.

Results: A total of 315 MRSA (mecA-positive) were isolated from different patients during one-year period, including 114 (36.2%) strains from children. The great majority (228, 72.4%) was CA-MRSA while 87 strains (27.6%) were HA-MRSA, derived mainly from the department of Orthopaedics. The PFGE analysis revealed 11 PFGE types (named A, B, C, E, G, F, J, K, L, M and N) common among the hospitals. Clonal and PCR analysis are shown at Table 1. Among the HA-MRSA four new clones were identified (J/3, L/2, M/3 and N/1) which were PVL and tst-negative. Among CA-MRSA clone C/3 carrying PVL genes predominated.

Conclusions: In Greece we are encountering an increasing rate of S. aureus infections, mainly due to the spread of CA-MRSA producing PVL. The identification of new clones in the participating hospitals reinforces the aspect of the continuous MRSA evolution.

Table l. Clones and toxin genes among MRSA isolated during one-year period

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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