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Ten-year of community-acquired methicillin-resistant Staphylococcus aureus ST80-IV clone in Denmark

Abstract number: 1134_02_376

Larsen A.R., Goering R.V., Pallesen L.V., Skov R.

Objectives:

To determine the epidemiology in Denmark of the pandemic European CA-MRSA clone ST80-IV with respect to subtypes, dissemination, acquisition and types of infection.

Methods:

All methicillin resistant Staphylococcus aureus (MRSA) isolated in Denmark between 1999–2003 were referred to and stored at the Staphylococcus Laboratory, Statens Serum Institut (N = 617). The isolates were characterized by macro-restriction (SmaI) analysis using PFGE, SCCmec typing, dru sequence typing, antibiotic susceptibility testing and PCR amplification of the Panton Valentine Leukocidin gene (pvl). Clinical and epidemiological information from all patients were obtained from discharge summaries and registered.

Results:

Between 1999 and 2003, the MRSA ST80-IV clone accounted for 28% (172/617) of the total number of MRSA in Denmark and 30% (146/490) of Infections due to ST80-IV had primarily community onset (122/146) and thereby ST80-IV accounted for 67% of all community onset MRSA in the period. More than 80% of the ST80-IV infections were skin and soft tissue infections. By comparing the antibiogram of ST80-IV (streptomycin-, kanamycin-, tetra-cycline- and fusidic acid -resistant and gentamicin sensitive) with the isolates stored in our S. aureus bacteraemia collection, we traced the ST80-IV clone back to 1993. Before 1999 one to five ST80-IV isolates were encountered pr. year, which increased to 25, 26, 50, 26 and 45 isolates in the years after. By PFGE, the ST80-IV isolates exhibited nine different patterns (A1–9), of which 60% were type A1. Nine Type A1 isolates, isolated 1993–2003 were subjected to dru typing, which has earlier enabled separation of PFGE clones into subtypes. This was however not possible for the ST80-IV isolates.

Conclusions:

ST80-IV isolates cause a large proportion of the MRSA infections in Denmark and in particular among the infections with a community onset. The success of ST80-IV as an infective clone outside the hospital environment may in part be due to its small SCCmec type IV and its ability to cause skin and soft tissue infections probably associated with the expression of PVL. The dru sequence typing could not subdivide the major type of ST80-IV found in Denmark pointing out the strict clonality of this clone, which may indicate that it is a very well adapted pathogen.

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Subject:
Location: Oxford, UK
Presentation type:
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