Antibiotic courses of 8 days or less were not associated with increased treatment failure in studies of skin and soft-tissue infection and of male urinary tract infection.

The minimum therapy duration necessary for successful treatment of common infections remains unknown for many conditions. Two retrospective observational studies (Published in the Open Forum Infectious Disease 2019 June) have now addressed shorter versus longer duration of antibiotic therapy in specific populations.

Ihm and colleagues evaluated uncomplicated skin and skin structure infections (SSTIs) in 207 patients with obesity body-mass index ≥30, heart failure, or both. Participants were classified as having short (≤8 days) or long duration (>8 days) of antibiotic therapy for SSTIs. In a propensity score-matched subset of patients, significantly more patients receiving long-duration therapy had treatment failure than did patients receiving short-course therapy (29% vs.10%).

Germanos and colleagues evaluated 637 urinary tract infections (UTIs) in 573 men and classified participants as having received ≤7 days or >7 days of antibiotic therapy. Longer treatment duration was associated with increased recurrence in men without complicating factors.

The continued emergence of antibiotic resistance and increased recognition of adverse events highlights the reality that antibiotics are a precious resource but can have negative consequences. These two studies reinforce that appropriate treatment duration for many infectious diseases has not been rigorously studied. Usually, shorter therapy now has demonstrated successful results and should be adopted for these conditions.