Antibiotic Stewardship in Treatment of Osteoarticular Infections Based on Local Epidemiology and Bacterial Growth Times.

Incubation for 14 days is recommended for the culture of microorganisms from osteoarticular infections (OAI), but there are no recommendations for postoperative antibiotic stewardship concerning empirical antimicrobial therapy (EAT), while prolonging broad-spectrum EAT results in adverse effects. The aim of this study was to describe the local OAI epidemiology with consideration of bacterial growth times to determine which antibiotic stewardship intervention should be implemented in cases of negative culture after 2 days of incubation. We performed a 1-year, single-center, noninterventional cohort study at the Pitié-Salpêtrière hospital OAI reference center. Samples were taken as part of the local standard of care protocol for adult patients who underwent surgery for OAI (native or device related) and received EAT (i.e., piperacillin-tazobactam plus daptomycin [PTD]) following surgery. The time to culture positivity was monitored daily. Overall, 147 patients were recruited, accounting for 151 episodes of OAI, including 112 device-related infections. Microbiological cultures were positive in 144 cases, including 42% polymicrobial infections. Overall, a definitive microbiological result was obtained within 48 h in 118 cases (78%) and within 5 days in 130 cases (86%). After 5 days, only Gram-positive bacteria were recovered, especially Cutibacterium acnes, Staphylococcus spp., and Streptococcus spp. Overall, 90% of culture-positive OAI were correctly treated with the locally established EAT. EAT guidance for OAI was in agreement with our local epidemiology. Our results supported antibiotic stewardship intervention consisting of stopping piperacillin-tazobactam treatment at day 5 in cases of negative culture. IMPORTANCE Osteoarticular infections (OAI) remain challenging to diagnose and to treat. One of the issues concerns postoperative empirical antimicrobial therapy (EAT), which is usually a combination of broad-spectrum antibiotics. This EAT is maintained up to 2 weeks, until the availability of the microbiological results (identification and drug susceptibility testing of the microorganisms responsible for the OAI). Our results provide new data that will help to improve OAI management, especially EAT. Indeed, we have shown that antibiotic stewardship intervention consisting of stopping the antibiotic targeting Gram-negative bacteria included in the EAT could be implemented in cases where culture is negative after 5 days of incubation. The benefits of such an antibiotic stewardship plan include improved patient outcomes, reduced adverse events (including Clostridioides difficile infection), improvement in rates of susceptibilities to targeted antibiotics, and optimization of resource utilization across the continuum of care.