Antimicrobial prophylaxis with ampicillin/sulbactam versus cefazolin for orthopedic implant-related surgical site infections: A retrospective cohort study.

Background: Cefazolin is widely used for surgical prophylaxis in orthopedic implant surgeries. However, there is insufficient evidence of the superiority of cefazolin over other antibiotics, such as ampicillin/sulbactam (ABPC/SBT), in reducing surgical site infection (SSI). Moreover, concerns exist regarding the adverse events associated with these antimicrobial agents, such as Clostridioides difficile infection. This study aimed to evaluate the comparative effectiveness of ABPC/SBT versus cefazolin prophylaxis in reducing SSI and all-cause mortality rates and its safety regarding Clostridioides difficile infection in major orthopedic implant surgeries.

Methods: This retrospective cohort study used data from the Diagnosis Procedure Combination database in Japan. We included adult patients who underwent a major orthopedic implant surgery between July 2010 and March 2022. Patients underwent surgery with either cefazolin or ABPC/SBT prophylaxis. The primary outcome was in-hospital SSI, whereas the secondary outcomes were 90-day SSI, 1-year SSI, in-hospital all-cause mortality, and Clostridioides difficile infection. The outcomes were compared between the two groups using propensity-score overlap weighting.

Results: We identified 440,651 eligible patients, including 17,651 in the ABPC/SBT group and 423,000 in the cefazolin group. The propensity-score overlap weighting successfully balanced patient and institutional characteristics between the groups. No significant differences were observed in in-hospital SSI (risk difference, -0.02 %; 95 % confidence interval (CI), -0.13 to 0.10 %), 90-day SSI (risk difference, 0.00 %; 95 % CI, -0.13 to 0.14 %), 1-year SSI (risk difference, -0.02 %; 95 % CI, -0.17 to 0.13 %), or in-hospital mortality (risk difference, -0.01 %; 95 % CI, -0.05 to 0.04 %) between the groups. However, the ABPC/SBT group had a significantly lower Clostridioides difficile infection (risk difference, -0.02 %; 95 % CI, -0.03 to -0.01 %) than that of the cefazolin group.

Conclusions: ABPC/SBT may be comparable to cefazolin as an alternative therapy for preventing early SSIs in patients who undergo major orthopedic implant surgery, with a lower risk of Clostridioides difficile infection.