The review by Loewen et al on community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is a solid reminder for general practitioners and the general medical community.1 The important contemporary concerns about CA-MRSA began more than a decade ago with the proliferation of strains that were capable of being modestly invasive and often produced deep soft-tissue infections such as boils.2 The clinical scenario now is much different, and although methicillin-resistant S aureus is, and will continue to be, a microbial hazard in both communities and institutions, we have seen a considerable decline in the absolute numbers of CA-MRSA infections. This noticeable reduction occurred early in this decade. There remain foci of endemicity, but the absolute number of such infections is markedly reduced.
The pandemic of CA-MRSA did, however, stir the medical community to action. There had been complacency, certainly in Canada, that the status quo would remain.3 As for any outbreak, careful attention to rational preventive measures would have had a role in maintaining control.4,5 Overcoming a “counterculture” in the medical populace was also a critical feature of controlling outbreaks.6,7
If one were to ascribe the reduction in CA-MRSA infection entirely to medical interventions, whether they be for infection control or treatment, it would be quite an honour. The valid postulate remains, however, that the wave of CA-MRSA infection was ready to happen, given historical patterns of community outbreaks of S aureus. Indeed, the genesis of hypervirulent clones with hyperendemicity and antibiotic pressure was inevitable and predictable.8 Both the microbiology and the dermatology communities recognized that abscess-causing S aureus commonly returns to the general populace in cycles.9 Methicillin resistance does not necessarily confer greater pathogenicity.9 Rather, the CA-MRSA outbreaks of the past decade likely combined the features of a cycling S aureus strain with enhanced virulence and the complicating trait of being methicillin resistant. Effectively, the reduction in the infectious cycle would be both a function of purposeful control and treatment efforts and the evolution of immunity in the population to those virulence factors. Future relapses of the same in cyclical fashion are also now quite predictable.
Footnotes
Competing interests
None declared
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