Methicillin-resistantStaphylococcus aureusClones, Western Australia

Geoffrey W Coombs,Warren B Grubb,Julie C Pearson,Keryn J Christiansen,Ronan J Murray,Frances G O'Brien

doi:10.3201/eid1202.050454

Abstract

Community-associated methicillin-resistant Staphylococcus aureus (MRSA) was first reported in Western Australia in the early 1990s from indigenous peoples living in remote areas. Although a statewide policy of screening all hospital patients and staff who have lived outside the state for MRSA has prevented the establishment of multidrug-resistant epidemic MRSA, the policy has not prevented SCCmec type IV and type V MRSA clones from becoming established. Of the 4,099 MRSA isolates analyzed (referred to the Gram-positive Bacteria Typing and Research Unit) from July 2003 to December 2004, 77.5% were community-associated MRSA (CA-MRSA). Using multilocus sequence/staphylococcal chromosome cassette mec typing, 22 CA-MRSA clones were characterized. Of these isolates, 55.5% were resistant to >1 non-beta-lactam antimicrobial drug. Five Panton-Valentine leukocidin (PVL)-positive CA-MRSA clones were identified. The emergence of multidrug-resistant CA-MRSA clones and the detection of PVL toxin genes in clones previously reported as PVL negative is a major public health concern.

Highlights

Community-associated methicillin-resistant Staphylococcus aureus (MRSA) was first reported in Western Australia in the early 1990s from indigenous peoples living in remote areas
This study describes the different epidemic and CAMRSA clones isolated in Western Australia (WA) and establishes their genetic relatedness
The results presented here demonstrate that this is the case for CA-Methicillin-resistant S. aureus (MRSA) isolated within a single state of Australia (WA)

Summary

Introduction

Community-associated methicillin-resistant Staphylococcus aureus (MRSA) was first reported in Western Australia in the early 1990s from indigenous peoples living in remote areas. In the early 1990s, nonmultidrug-resistant MRSA (nmMRSA) were observed in WA, initially from indigenous people in remote communities [7] but subsequently in Perth, the state capital Australian states, and studies in Queensland and New South Wales showed a strong association between community-acquired infection with nmMRSA and Polynesian ethnicity. Isolates causing these infections were indistinguishable by phage typing and pulsed-field gel electrophoresis from those previously reported in New Zealand [9,10]. A second strain (WAMRSA-7 or Qld MRSA) has been associated with community-acquired infections in Caucasians in Queensland [11]

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Discussion

Conclusion