Severe coinfection with seasonal influenza A (H3N2) virus and Staphylococcus aureus--Maryland, February-March 2012.

On March 5, 2012, the Maryland Department of Health and Mental Hygiene (DHMH) and the Calvert County Health Department were notified of three deaths following respiratory illness among members of a Maryland family. One family member (patient A) experienced upper-respiratory symptoms and died unexpectedly at home. Two others (patients B and C) sought medical care for fever, shortness of breath, and cough productive of bloody sputum and died during their hospitalizations. All three family members had confirmed infection with seasonal influenza A (H3N2) virus. Patients B and C had confirmed coinfection with methicillin-resistant Staphylococcus aureus (MRSA), which manifested in both patients as MRSA pneumonia and bacteremia. DHMH and the Calvert County Health Department, in collaboration with the District of Columbia Department of Health, local hospitals, and CDC, conducted an investigation to determine the cause of the illnesses and identify additional related cases. Three additional family members with influenza were identified, two of whom were confirmed to have influenza A (H3N2) and required hospitalization, but neither was coinfected with MRSA, and both recovered. Influenza vaccination remains the best method for preventing complications from influenza; when influenza infection is suspected, treatment with influenza antiviral agents is recommended in certain cases. In addition, when high clinical suspicion for serious S. aureus coinfection exists, empiric coverage with antibiotics, including those with activity against methicillin-resistant strains, should be instituted.