Be alert for severe cases of community-acquired pneumonia that might be caused by methicillin-resistant Staphylococcus aureus, the Centers for Disease Control and Prevention advised.
Although uncommon, community-acquired pneumonia (CAP) can be caused by methicillin-resistant S. aureus (MRSA). Such cases often affect young, otherwise healthy individuals and can be rapidly fatal. MRSA should be suspected in patients with severe pneumonia, especially during the influenza season, and in those with cavitary infiltrates. The index of suspicion for MRSA CAP should be particularly increased in those who have a history of MRSA skin infection or who have had close contact with MRSA-infected individuals, the CDC said (MMWR 2007;56:325–9).
During December 2006 to January 2007, 10 cases of severe MRSA CAP were reported to the CDC from Louisiana and Georgia. Patient ages ranged from 4 months to 48 years; eight were younger than 30 years. Five were female and five male. Six of the 10 patients died, including 4 children aged 8–14 years.
One patient had a history of chronic hepatitis C and hypertension, and two were current smokers. Four had documentation of recent MRSA skin and soft-tissue infection or were living with someone who did. In all 10 cases, influenzalike illness had been diagnosed prior to or concurrent with CAP. Six patients had laboratory-confirmed influenza. Of six for whom vaccination status was available, none had received influenza vaccine for the 2006–2007 season. Radiologic information, available for all 10 patients, showed unilobar infiltrates in 3 and multilobar infiltrates in 7. In three patients, MRSA was isolated from sputum only.
Particularly notable was the short period between any respiratory symptom onset and either death or recovery of MRSA from the patient: Respiratory symptoms began a median of 3 days (range 2–6 days) before collection of specimens that grew MRSA. Of the six patients who died, the median period from onset to death was 3.5 days (range 2–25 days); four of the six died within 4 days of symptom onset.
These short durations suggest that the influenza virus and the MRSA infections probably occurred concomitantly, the CDC noted.