Open AccessEmergence and Characterization of Community-Associated Methicillin-Resistant Staphyloccocus aureus Infections in Denmark, 1999 to 2006
Author(s) -
Anders Rhod Larsen,
Marc Stegger,
S. Böcher,
Marit Sørum,
Dominique Monnet,
Robert Skov
Publication year - 2009
Publication title -
journal of clinical microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.349
H-Index - 255
eISSN - 1070-633X
pISSN - 0095-1137
DOI - 10.1128/jcm.01557-08
Subject(s) - staphylococcus aureus , epidemiology , microbiology and biotechnology , typing , methicillin resistant staphylococcus aureus , staphylococcal infections , danish , antibiotics , medicine , leukocidin , molecular epidemiology , clinical microbiology , antibiotic resistance , transmission (telecommunications) , veterinary medicine , biology , bacteria , genotype , linguistics , philosophy , genetics , biochemistry , electrical engineering , engineering , gene
The epidemiology of methicillin-resistantStaphylococcus aureus (MRSA) infections has changed worldwide. From being strictly nosocomial, MRSA is now frequently found as a community-associated (CA) pathogen. Denmark has been a low-prevalence country for MRSA since the mid-1970s but has in recent years experienced an increasing number of CA-MRSA cases. The aim of this study was to describe the emergence of CA-MRSA infections in Denmark. All Danish MRSA specimens and corresponding clinical data from 1999 to 2006 were investigated. Isolates were analyzed by antibiotic resistance and molecular typing and were assigned to clonal complexes (CC). Clinical data were extracted from discharge summaries and general practitioners' notes, from which assessments of community association were made for all infected cases. CA-MRSA cases constituted 29.4% of all MRSA infections (n = 1,790) and an increasing proportion of the annual numbers of MRSA infections during the study period. CA-MRSA was associated with a young age, skin and soft tissue infections, and non-Danish origin. Transmission between household members was frequently reported. Molecular typing showed >60 circulating clones, where 89.4% of the isolates belonged to five CC (CC80, CC8, CC30, CC5, and CC22), 81.2% carried staphylococcal cassette chromosomemec IV, and 163/244 (69.4%) were positive for Panton-Valentine leukocidin. Clinical and microbiological characteristics indicated that import of MRSA occurs frequently. Resistance to ≥3 antibiotic classes was observed for 48.8% of the isolates. The emergence of CA-MRSA in Denmark was caused by diverse strains, both well-known and new CA-MRSA strains. The results suggest multiple introductions of MRSA as an important source for CA-MRSA infections in Denmark.