Methicillin-resistant Staphylococcus aureus in the Australian community: an evolving epidemic

Graeme R. Nimmo*, Geoffrey W. Coombs, Julie C. Pearson, Francis G. O'Brien, Keryn J. Christiansen, John D. Turnidge, Iain B. Gosbell, Peter Collignon, Mary Louise McLaws, Joan Faoagali, Narelle George, Jacqueline Harper, Jacqueline Schooneveldt, Susan Bradbury, Sue Tiley, Tom Gottlieb, Glenn Funnell, Clarence Fernandes, Richard Benn, Barbara YanHelen Ziochos, Alison Vickery, David Mitchell, Sam Ryder, James Branley, Denis Spelman, Clare Franklin, Sue Garland, Gena Gonis, Mary Jo Waters, Linda Joyce, Peter Ward, John Andrew, Alistair McGregor, Rob Peterson, Jan Bell, Irene Lim, Rachael Pratt, Hendrik Pruul, Leigh Mulgrave, David McGechie, Graham Francis, Gary Lurn, Miriam Paul, Jenny Robson, P. C. Lee, Sue Benson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

95 Citations (Scopus)

Abstract

Objective: To describe antimicrobial resistance and molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) isolated in community settings in Australia. Design and setting: Survey of S. aureus isolates collected prospectively Australia-wide between July 2004 and February 2005; results were compared with those of similar surveys conducted in 2000 and 2002. Main outcome measures: Up to 100 consecutive, unique clinical isolates of S. aureus from outpatient settings were collected at each of 22 teaching hospital and five private laboratories from cities in all Australian states and territories. They were characterised by antimicrobial susceptibilities (by agar dilution methods), coagulase gene typing, pulsed-field gel electrophoresis, multilocus sequence typing, SCCmec typing and polymerase chain reaction tests for Panton-Valentine leukocidin (PVL) gene. Results: 2652 S. aureus isolates were collected, of which 395 (14.9%) were MRSA. The number of community-associated MRSA (CA-MRSA) isolates rose from 4.7% (118/2498) of S. aureus isolates in 2000 to 7.3% (194/2652) in 2004 (P=0.001). Of the three major CA-MRSA strains, WA-1 constituted 45/257 (18%) of MRSA in 2000 and 64/395 (16%) in 2004 (P=0.89), while the Queensland (QLD) strain increased from 13/257 (5%) to 58/395 (15%) (P=0.0004), and the south-west Pacific (SWP) strain decreased from 33/257 (13%) to 26/395 (7%) (P=0.01). PVL genes were detected in 90/195 (46%) of CA-MRSA strains, including 5/64 (8%) of WA-1, 56/58 (97%) of QLD, and 25/26 (96%) of SWP strains. Among health care-associated MRSA strains, all AUS-2 and AUS-3 isolates were multidrug-resistant, and UK EMRSA-15 isolates were resistant to ciprofloxacin and erythromycin (50%) or to ciprofloxacin alone (44%). Almost all (98%) of CA-MRSA strains were non-multiresistant. Conclusions: Community-onset MRSA continues to spread throughout Australia. The hypervirulence determinant PVL is often found in two of the most common CA-MRSA strains. The rapid changes in prevalence emphasise the importance of ongoing surveillance.

Original languageEnglish
Pages (from-to)384-388
Number of pages5
JournalMedical Journal of Australia
Volume184
Issue number8
Publication statusPublished - 17 Apr 2006
Externally publishedYes

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