Is oral antibiotic therapy as effective as intravenous treatment in bacterial osteomyelitis? A real-life experience.

Osteomyelitis is a relatively understudied disease with no standardized and evidence-based approach to treatment. We aimed to evaluate a cohort of patients with osteomyelitis, comparing the outcomes between intravenous (IV) and oral treatment. We performed an observational retrospective study on osteomyelitis cases in adult patients seen for care between 2017 and 2019. We collected information on patient characteristics, microbiological etiology, infection treatment, and outcome. In addition, we divided osteomyelitis cases by antibiotic regimens [oral (OTG) vs. intravenous±oral (ITG)] and therapy durations to evaluate outcomes differences. A total of 235 episodes of osteomyelitis were evaluated, with a higher prevalence in male gender. Staphylococci, especially S. aureus, were the most common strains. Out of the 235 evaluated episodes, we selected 142 cases. Of these, 75 were treated with OTG and 67 with ITG. Gram-positive bacteria were the most frequent aetiological agents, with 81 isolates (61.8%). Full recovery was observed in 79 (55.6%) cases; of these, 36 (53.7%) were in the ITG and 43 (57.3%) in the OTG (p = 0.666). At the logistic regression, a polymicrobial infection [OR 4.16 (95%CI 1.28-13.4), p = 0.017] and a less than six weeks treatment duration [OR 4.24 (95%CI 1.38-5.43) p = 0.004] were significantly associated with a higher risk of treatment failure. Our study suggests that oral treatment efficacy is comparable to ITG therapy for osteomyelitis, confirming the most recent evidence suggesting that oral therapy is non-inferior to intravenous therapy to treat osteomyelitis.