Effectiveness and tolerability of low dose clindamycin for treatment of prosthetic joint infections, a retrospective cohort study

BACKGROUND: Clindamycin is a potential drug for treating prosthetic joint infections, but pharmacokinetic monitoring shows that coadministration with rifampicin significantly reduces clindamycin concentrations. This study aimed to describe the real-world effectiveness and tolerability of clindamycin given alone or in combination with rifampicin or other antibiotics for treatment of PJI. METHODS: This single-centre, retrospective cohort study, included patients treated for PJI from 2010 to 2022. PJI was defined according to a modified version of the 2011 Musculoskeletal Infection Society (MSIS) definition that was used clinically during the study period. Patients treated with a clindamycin-based therapy (used when first-line drugs were unsuitable) were included. Data were extracted manually from electronic records. Cure required no clinical or microbiological signs of recurrence of the same bacteria after 24 months of follow-up. Factors affecting treatment outcome were assessed using logistic regression analyses. RESULTS: The two-year treatment success after clindamycin monotherapy (n = 46) and combination therapy (n = 62) at a typical dose of 300 mg three times daily was 82% (95% confidence interval [CI] 75-90%, n = 89/108). Two-year clindamycin treatment success following DAIR (n = 46), one stage exchange (n = 23) and two stage exchange (n = 32) were 72% (95% CI 58-85%), 91% (95% CI 79-100) and 94% (95% CI 85-100), respectively. Overall treatment success was 80% (95% CI 67-93%, n = 40) for patients receiving clindamycin/rifampicin. Staphylococcus aureus was independently associated with lower treatment success in a multivariable logistic regression OR 0.17 CI (0.05-0.64, p = 0.008). Side-effects were more frequent in patients receiving clindamycin + rifampicin (39%) compared to clindamycin monotherapy (10%) p = 0.002). CONCLUSIONS: Clindamycin (300 mg three times daily), administered as monotherapy or in combination with other antibiotics including rifampicin, appeared to be an effective and well-tolerated treatment for PJI. However, these regimens may be less effective in infections caused by S. aureus.