Cefepime versus carbapenem for treating complicated urinary tract infection caused by cefoxitin-nonsusceptible ESCPM organisms: a multicenter, real-world study.

Background: This investigation aimed to compare the efficacy of cefepime and carbapenem for complicated urinary tract infection (cUTI) caused by presumptive AmpC β-lactamase-producing Enterobacter spp., Serratia marcescens, Citrobacter freundii, Providencia spp., and Morganella morganii (ESCPM).

Methods: Data of 458 individuals with cUTI caused by cefoxitin-nonsusceptible [minimum inhibitory concentration (MIC) > 8 µg/mL] and cefepime-susceptible (MIC ≤ 2 µg/mL) ESCPM was acquired from four Chinese hospitals between 2010 and 2022 and were reviewed retrospectively.

Results: 125 and 333 patients received cefepime and carbapenems, respectively, as antimicrobial therapy. The 28-day treatment failure rate was 15.7% (72/458). The following factors were identified as independent predictors for 28-day therapy: age, cefepime MIC = 2 µg/mL, immunocompromised status, infection source control, appropriate empirical therapy, and days from illness onset to active therapy. In patients who required cefepime MIC ≤ 1 µg/mL, a multivariate logistic model indicated that cefepime was linked with a similar risk of 28-day treatment failure [odd ratio (OR) 1.791, 95% confidence interval (CI) 0.600-5.350, p = 0.296] compared with carbapenems after controlling these predictors. Compared with individuals with cefoxitin-nonsusceptible ESCPM, those with isolates of cefepime (MIC = 2 µg/mL) had an enhanced risk of 28-day treatment failure (OR = 2.579, 95% CI = 1.012-6.572, p = 0.047). A propensity score for treatment analysis validated this relationship.

Conclusions: The cefepime and carbapenem had comparable efficacy for treating cUTI caused by cefoxitin-nonsusceptible ESCPM organisms with cefepime MIC ≤ 1 µg/mL, whereas carbapenems are potentially more effective for isolates with cefepime MIC = 2 µg/mL.