Community-associated methicillin-resistant Staphylococcus aureus : Continuing to evolve

In the 2003 issue of The Canadian Journal of Infectious Diseases, the emergence of methicillin-resistant Staphylococcus aureus (MRSA) as a community-acquired pathogen in Canada was reviewed (1). This followed reports of severe, invasive community-acquired MRSA (CA-MRSA) infections in children in Minnesota and North Dakota (USA), and recognition of its role as a pathogen in several Canadian outbreaks. The emergence of CA-MRSA as a pathogen of epidemiological significance in Canada prompted a meeting in 2005 sponsored by the Public Health Agency of Canada, the Ontario Ministry of Health and Long-Term Care and the Canadian Committee on Antibiotic Resistance, that made recommendations for its prevention and management; it was published in the Journal in 2006 (2). Since then, research has produced evidence that supports previous findings, challenges others and introduces new ones. Of particular interest is the appearance of CA-MRSA as a nosocomial pathogen, and the potential for its genetic intermingling with its hospital-acquired counterpart (HA-MRSA).