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The evolution of community MRSA in Australia – lessons for Europe?

Abstract number: 1133_194

Riley T.V., Coombs G.W., O'Brien F., Pearman J.W., Christiansen K., Grubb W.B.

In the early 1980s, epidemic MRSA (EMRSA) appeared on the east coast of Australia. EMRSA were multiply resistant and they became endemic in many large hospitals throughout Australia, except Western Australia (WA). A statewide screening and control policy was implemented in WA following an outbreak of EMRSA in a Perth hospital after the admission of an interstate patient in 1982. This involved screening all patients admitted to hospitals from interstate or overseas and all new staff that had worked outside WA in the previous 12 months. Following screening, patients infected or colonized with MRSA were isolated and treated, while infected or colonized staff were prohibited from contact with patients until the organism was eradicated. In WA, MRSA infection or colonization has been a notifiable condition since 1985. The WA Department of Health electronically flags cases of MRSA, allowing carriers to be identified and isolated on admission to any WA public hospital. In the late 1980s, non-multi-resistant community MRSA emerged in the north of WA. MRSA isolated from patients living in the remote Kimberley region were phenotypically and genotypically different to EMRSA and became known as WAMRSA. During the 1990s, WAMRSA spread to most regions of WA and, by 1997, a significant number of cases of infection and colonization were occurring in the Perth metropolitan area and other Australian states. WAMRSA have the community-associated SCCmec types IV and V that lack transposons, integrated plasmids and other antibiotic resistance genes. Since the screening and control policy was introduced, all MRSA clinical isolates, and those isolated through screening, have been sent to a reference laboratory where their identity was confirmed by standard procedures (mec/nuc PCR), complete antibiotic susceptibility was determined and the isolates typed, using initially PFGE and now MLST. In the 1990s, a different community MRSA was isolated in eastern Australia, frequently from people of Pacific Island decent. These were subsequently identified as ‘Western Samoan Phage Pattern’ strains, first described in New Zealand, and they can produce PVL. Most Australian community MRSA do not produce PVL, apart from the ‘Queensland’ clone. Although most Australian community MRSA do not spread when introduced into a hospital environment, some do have the capacity to cause outbreaks. Identifying the reasons for this and ways of identifying outbreak strains remains a challenge for us all.

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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