Risk groups Children <2 years old Athletes (mainly contact-sport participants) Injection drug users Men who have sex with men Military personnel Inmates of correctional facilities, residential homes or shelters Vets, pet owners and pig farmers Patients with post-flu-like illness and/or severe pneumonia Patients with concurrent SSTI History of colonization or recent infection with CA-MRSA History of antibiotic consumption in the previous year, particularly quinolones or macrolides