Community-associated meticillin-resistant Staphylococcus aureus in Finland: ten-year perspective

Abstract number: P1441

Salmenlinna S., Vuopio-Varkila J., Kardén-Lilja M., Kanerva M., Möttönen T., Virtanen M., Lyytikäinen O.

Objectives: During 1997–1999, one fifth of all Finnish meticillin-resistant Staphylococcus aureus (MRSA) isolates (n = 308) were obtained from persons without connection to hospitals, and three strain types (FIN-4, -11, -14) were associated with community acquisition. Thereafter, the number of MRSA isolates has remarkably increased and new strain types appeared. We estimated the proportion of community-associated MRSA (CA-MRSA) and compared the MRSA isolates obtained during 2004–2006 in persons with and without hospital contact in terms of strain type. The results were compared with those reported from years 1997–1999.

Methods: MRSA isolate was defined as community-associated if MRSA specimen was obtained outside hospital settings or within two days of hospital admission from a person who had not been hospitalised within two years before date of MRSA isolation. We analysed previous hospitalisations for all MRSA-positive persons during 2004–2006 (n = 3054) by using data from the National Hospital Discharge Register. The isolates were typed by pulsed field gel electrophoresis and tested for antimicrobial susceptibility. Selectively, multi locus sequence typing (MLST), spa typing, SCCmec determination, and Panton-Valentine leukocidin (PVL) gene detection were performed.

Results: Of the 4054 MRSA-positive persons, 4030 (99%) were included in the study; 570 (14%) had CA-MRSA. A total of 36 strain types were shared by leqslant R: less-than-or-eq, slant5 persons, and 109 sporadic strains were identified. Ten different strain types (FIN-4, -5, -11, -12, -15, -17, -19, -20, -25, -30) as well as sporadic strains were more likely to be found from persons without hospital contact. All 10 CA-MRSA strain types had SCCmec IV or V, representing 8 different MLST types and 9 spa types, and 4 were PLV-positive. Of the sporadic CA-MRSA strains, 16 were tested for PVL genes, and 3 were positive.

Conclusions: The proportion of CA-MRSA did not increase. However, the absolute number of CA-MRSA isolates rose five-fold. Two of the old CA-MRSA strain types persisted and several new emerged. Internationally recognised, PLV-positive CA-MRSA clones were also recognised in Finland.

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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