• Vol. 35 No. 7, 479–486
  • 15 July 2006

Community-associated Methicillin-resistant Staphylococcus aureus: Overview and Local Situation



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Introduction: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has emerged worldwide. In contrast to healthcare-associated MRSA (HA-MRSA), CA-MRSA isolates are usually susceptible to multiple non-beta-lactam antibiotics and cause a distinct spectrum of infections in epidemiologically disparate populations – in particular, cutaneous abscesses, necrotising fasciitis and necrotising pneumonia. They arise from a broader genetic background, and possess differing virulence genes. We aim to describe the distribution of different molecular subtypes of CA-MRSA among various regions and discuss briefly the implications of CA-MRSA from a local perspective.

Methods: Literature review of articles on CA-MRSA, focusing mainly on reports where the genetic background of isolates had been analysed using multi-locus sequence typing (MLST). Singapore data were obtained from the local CA-MRSA database.

Results: MLST analysis demonstrated the presence of epidemic subtypes of CA-MRSA within most geographic areas. In parts of the United States, community MRSA infections currently exceed those caused by their methicillin-susceptible counterparts. In Singapore, CA-MRSA infections are increasing, predominantly as a result of the spread of ST30 clones.

Conclusion: Available evidence suggests that the emergence of MRSA from the community is not going to be a transient phenomenon. Local guidelines for dealing with this phenomenon at both therapeutic and preventive levels are needed prior to the potential development of a situation mirroring that of meso-endemic HA-MRSA in local hospitals or CA-MRSA epidemics in parts of USA.

The emergence and spread of methicillin-resistant Staphylococcus aureus (MRSA) isolates from the community that are distinct from their archetypal healthcare-associated counterparts (HA-MRSA) marked a critical evolutionary milestone for the organism. In less than 2 decades, particularly in the last 3 years, this initially sporadic phenomenon of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has become a global reality, leading to paradigm shifts in the perception and management of staphylococcal infections in countries where CA-MRSA has reached epidemic proportions.

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