OBJECTIVES: This prospective, multicentre, French observational study was set up to describe the conditions and outcomes of ceftolozane/tazobactam (TOL/TAZ) use in hospital settings.

METHODS: Adults who received at least one dose of TOL/TAZ were eligible for inclusion. Enrolled patients were treated according to standard of care and followed up until stop of TOL/TAZ. Prescription was either documented, following the results of the antibiogram, or empirical.

RESULTS:

A total of 260 patients were enrolled between October 2018 and December 2019. Mean age was 56.8 years, 67.3% were males, and 81% presented with multi-drug resistant bacteria at inclusion. TOL/TAZ prescription was documented for 68% (N=177) of patients. Most documented cases (77.4%) received other treatment lines prior to TOL/TAZ. Carbapenems (25.5%), cephalosporins (18.2%), and penicillins (16.1%) were the most frequently prescribed single treatments, immediately prior to TOL/TAZ. Inversely, 27.7% of empirical patients received prior treatment, mostly carbapenems (34.8%) as single line immediately prior to TOL/TAZ. Moreover, 40.7% and 67.5% of documented and empirical patients respectively received concomitant antibiotic lines. Most were initiated at the same time as TOL/TAZ (69.4% and 80.4% for documented vs empirical patients). In both groups, aminoglycosides, fluoroquinolones, and lipo/glycopeptides were the most frequently prescribed. Median duration of TOL/TAZ treatment was 16.1 days (1–115, N=176) vs 14.8 days (2–93, N=83) for documented vs empirical therapy. Reported reasons for TOL/TAZ discontinuation in documented vs empirical cases were: complete cure (63.8% vs 28.9%), partial cure (7.9% vs 41%), adaptation to microbiological results (11.3% vs 13.3%), death (4.0% vs 2.4%), treatment failure (2.8% vs 6%), adverse event (1.7% vs 3.6%), and other (8.5% vs 4.8%).

CONCLUSIONS: Treatment failures were low, irrespective of prescription type. Based on these results, TOL/TAZ can be considered an effective option for the treatment of complicated bacterial infections in healthcare settings.