Risk factors for recurrence in patients with Staphylococcus aureus infections complicated by bacteremia

Recurrence is a common complication of Staphylococcus aureus infections. A shorter duration of antibiotic treatment for a S. aureus infection has been previously suggested as a possible risk factor for recurrence. We conducted a retrospective cohort study of patients with S. aureus infection complicated by bacteremia who survived their initial treatment (N = 397) at the VA Maryland Health Care System from 1995 to 2004 to determine if 2 weeks or less of antibiotic therapy is significantly associated with a higher rate of recurrence. Recurrence was defined as recurrence of infection because of S. aureus with the same susceptibility to methicillin within 1 year of treatment of the initial bacteremia. Seventeen percent of patients who survived their initial infection had a recurrence of infection. Mean duration of antibiotic therapy in those who recurred was longer than in those who did not recur (21 versus 18 days, P = .18). No evidence was found to support an association between a duration of therapy of 14 days or less and an increased risk for recurrence (RR, 0.68; 95% CI, 0.44-1.04). However, being HIV infected (OR, 4.59; 95% CI, 1.61-13.10), having diabetes (OR, 2.02; 95% CI, 1.13-3.61) and having an infection due to a methicillin-resistant S. aureus (MRSA) (OR, 2.11; 95% CI, 1.17-3.80) were independent risk factors for recurrence. In conclusion, 2 weeks or less of antibiotic therapy was not associated with an increased risk for recurrence. However, patients with diabetes or HIV infection and patients with MRSA infections are at an increased risk for recurrence and should be followed more closely.