Molecular study of methicillin-resistant Staphylococcus aureus bacteraemia in a tertiary care hospital

Abstract number: 1734_40

Platsouka E., Kraniotaki E., Belesiotou E., Argyropoulou A., Perivolioti E., Paniara O.

Objectives: Bacteraemia is a serious complication in hospitalised patients and nosocomial Staphylococcus aureus bacteraemia, in particular with methicillin resistant S. aureus (MRSA) is a major problem with treatment difficulties. A molecular analysis of representative MRSA blood isolates of patients was carried out in a Greek tertiary care hospital.

Methods: Between March 2004 and October 2006 a total of 232 S. aureus blood isolates were collected, one isolate per patient. Blood bottles were incubated in BACTEC-NR 9240 automatic system according to standard recommendations. They were identified by standard methods and MICs were determined by the broth microdilution method, according to CLSI guidelines. Molecular typing was performed by using PFGE technique, with digestion of genomic DNAs from the staphylococcal isolates by the restriction endonuclease SmaI.

Results: Of 232 S. aureus blood isolates, 158 in Medical wards, 36 in Surgical wards and 38 in ICUs, 121 (52.15%) were MRSA and 111 (47.85%) MSSA. The distribution of MRSA bacteraemia in the hospital was: Medical wards 67 (42.40%), Surgical wards 23 (63.89%), ICUs 31 (81.58%). The resulting restriction endonuclease digestion patterns showed four different genotypes with several common bands suggesting a common epidemiologic background, according to Tenover criteria (Tenover et al., 1995).

Conclusion: The incidence of MRSA bacteraemia is higher in ICUs than in the medical and surgical wards. MRSA isolates in ICU patients seems to belong to a common clone. Other typing techniques apart from PFGE, will be performed in order to characterise completely the MRSA clones in our hospital, since the presenting results are preliminary.

Session Details

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