Community-onset invasive methicillin-resistant Staphylococcus aureus infections following hospital discharge

Background The majority of invasive methicillin-resistant Staphylococcus aureus (MRSA) infections in the United States are community-onset and occur in persons with recent health care exposure. Methods We performed a matched case-control study to identify risk factors for invasive MRSA infection among recently discharged patients. Cases had MRSA cultured from a normally sterile body site within 100 days following hospital discharge. Controls were matched on hospital, week of admission, and age. Results Among 77 cases, the most common types of invasive MRSA infection were bloodstream infection and osteomyelitis. Independent risk factors were a history of a MRSA-positive clinical culture from a superficial body site in the 12 months preceding the invasive infection (matched odds ratio [mOR], 23; 95% confidence interval [CI]: 3.7-142), hemodialysis (mOR, 21; 95% CI: 1.7-257), prior hospitalization length of stay >5 days (mOR, 4.5; 95% CI: 1.6-12), and male sex (mOR, 2.9; 95% CI: 1.1-7.9). Conclusion Risk factors for postdischarge invasive MRSA infections can be identified prior to discharge and remain with the patient after the hospitalization ends. Measures to prevent community-onset invasive MRSA infections might start in the hospital but should also be evaluated in postdischarge settings.