Staphylococcus aureus Skin and Soft Tissue Infection Recurrence Rates in Outpatients: A Retrospective Database Study at 3 US Medical Centers.

Background: Staphylococcus aureus skin and soft tissue infections (SA-SSTIs) are common in healthcare and community settings, and recurrences occur at variable frequency, even after successful initial treatment. Knowing the exact burden and timing of recurrent disease is critical to planning and evaluating interventions to prevent recurrent SSTIs.

Methods: In this retrospective study, SSTI cases in patients aged ≥18 years at 3 US medical centers (Columbia, Chicago, Vanderbilt) between 2006 and 2016 were analyzed according to a biennial cohort design. Index SSTIs (with or without key comorbidities), either microbiologically confirmed to be SA-SSTI or not microbiologically tested (NMT-SSTI), were recorded within 1 calendar year and followed up for 12 months for recurrent infections. The number of index cases, proportion of index cases with ≥1 recurrence(s), time to first recurrence, and number of recurrences were collected for both SA-SSTI and NMT-SSTI events.

Results: In the most recent cohorts, 4755 SSTI cases were reported at Columbia, 2873 at Chicago, and 6433 at Vanderbilt. Of these, 452, 153, and 354 cases were confirmed to be due to S. aureus. Most cases were reported in patients without key comorbidities. Across centers, 16.4%-19.0% (SA-SSTI) and 11.0%-19.2% (NMT-SSTI) of index cases had ≥1 recurrence(s). In patients without key comorbidities, more than 60% of index SSTIs with recurrences had only 1 recurrence, half of which occurred in the first 3 months following primary infection.

Conclusions: SA-SSTI recurrences are common among healthy adults and occur in at least 1 in 6 individuals during the 1 year following the primary event.