Introduction
Methicillin-resistant Staphylococcus aureus is one of most important problems in infection control and it can be found in almost all geographic areas (1). A significant increase of CA-WAMRSA has been reported between 1998 and 2002 (2). Recently, Pantone-Valentine Leukocidine (PVL) positive MRSA clones has emerged as a cause of both hospital-acquired and community-acquired infections in Western Australia (3). The aim of this study was to examine the epidemiology of CA-MRSA clones in Western Australia in the past 10 years (2003-2013).
Methods
A systematic review was performed to identify eligible articles. The MEDLINE database from 2002 to 2013 was collected by combining words of “clones”, “MRSA”, “epidemiology” and “Western Australia”. Only articles reporting MRSA strains epidemiology in Western Australia were included.
Results
In the past 10 years, 9 studies were conducted to analyse the clones of CA-MRSA circulating in WA with total 15.512 isolates. Among these isolates, there were 10 predominant clones of CA-MRSA circulating in WA: WA MRSA-1 (32,82%), Queensland (22,67 %), WA MRSA-2 (22,67 %), WA MRSA-3 (9,86 %), WSPP MRSA (4,81%), WA MRSA-121 (1,85 %), USA300 (1,64%), Taiwan CA-MRSA (0,72%), Bengal Bay (0,61 %) and WA MRSA-62 (0,49 %). The percentages of PVL positive CA-MRSA clones such as Queensland (Qld) clone has been increasing significantly (R2=0,67) from 2,38 % in 2002 to 25,69% in 2013. In contrast, the percentages of two major PVL negative clones, WA MRSA-1 and WA MRSA 2, have been decreasing nearly by half from 52,38 % to 27,71 % and 30,95 % to 16,59 % respectively in the last 11 years.
Discussion
WA MRSA-1 clones remains the predominant CA MRSA clones isolated in WA. Generally, WA MRSA clones were not carry the gene encoding Panton–Valentine leukocidin (PVL). PVL is a toxin that capable to create polymeric pores in leukocyte membran (4). In conclusion, PVL positive clones have been introduced in WA from other states and overseas in the last eleven years. Due to the virulance factor of PVL toxin, the emergence of PVL positive CA-MRSA should be considered as public health concerns.