IOWA CITY, IA – Co-infection with Staphylococcus aureus and influenza more than quadruples the risk of death compared to those without influenza, according to a new study.

The article published recently in the national Centers for Disease Control and Prevention’s Emerging Infectious Diseases journal was based on an analysis of 195 respiratory infection patients who had positive cultures and who were hospitalized in two hospitals in Iowa and Maryland during 2003–2009.

Background information in the article notes that Staphylococcus aureus is a common cause of respiratory infections, including pneumonia and can lead to necrotizing pneumonia and death.

Study authors from the University of Iowa and Iowa City VA Healthcare System point out that influenza complicated by S. aureus co-infection can progress rapidly to death within a week of symptom onset.

The retrospective cohort study included pediatric and adult patients admitted to the University of Iowa Hospitals and Clinics or to the University of Maryland Medical Center during the study period. The patients were majority male (59%) with a median age of 42.

Of the 195 patients, 32 (16%) had positive influenza test results, making them more likely to receive quinolones (odds ratio [OR] 3.30) than were patients whose influenza tests were negative.

Results indicate that, of the 32 influenza-positive patients, nine (28%) died; five of them had MRSA.

“In conclusion, among patients whose respiratory cultures grew S. aureus, patients with influenza were significantly more likely to die than were patients whose influenza tests were negative,” study authors write. “Interventions that increase influenza vaccination rates among patients at high risk for S. aureus respiratory infections may prevent both co-infection and death.”

  1. McDanel JS, Perencevich EN, Storm J, Diekema DJ, Herwaldt L, Johnson JK,
    Winokur PL, Schweizer ML. Increased Mortality Rates Associated with
    Staphylococcus aureus and Influenza Co-infection, Maryland and Iowa, USA(1).
    Emerg Infect Dis. 2016 Jul;22(7):1253-6. doi: 10.3201/eid2207.151319. PubMed
    PMID: 27315549; PubMed Central PMCID: PMC4918165.