With the flu season here it’s a good time to review CA-MRSA, particularly CA-MRSA pneumonia. Emergency Medicine News has a blurb on CA-MRSA pneumonia which references this review in Emergency Medicine Clinics of North America.
Here are a few points of interest from both articles:
CA-MRSA does not represent the old MRSA (HA-MRSA) having escaped to the community. It has distinct microbiologic, clinical and epidemiologic characteristics.
Risk factors for CA-MRSA pneumonia are colonization, prior infection including skin and soft tissue, exposure and recent influenza or influenza like illness (respiratory epithelium damage from antecedent viral infection facilitates bacterial attachment). CA-MRSA should be considered in any case of severe pneumonia.
The PVL toxin imparts unique pathogenicity.
In the initial antibiotic selection for pneumonia, the IDSA/ATS guidelines say that if CA-MRSA is suspected add vancomycin or linezolid. The Emergency Medicine Clinics article, however, suggests that linezolid is preferred if CA-MRSA pneumonia is suspected. It also points out that both linezolid and clindamycin decrease toxin production, and suggests that if vancomycin is used, clindamycin should be added for life threatening infections.
The Clinics article contains a wealth of information on infection control including the limited indications and regimens for decolonization.