Efficacy of cefoperazone/sulbactam for ESBL-producing Escherichia coli and Klebsiella pneumoniae bacteraemia and the factors associated with poor outcomes

Objective We aimed to assess the efficacy of cefoperazone/sulbactam (CPZ/SUL) in extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales infections and identify factors influencing outcomes.Methods This retrospective multicentre study was conducted in Taiwan (January 2015 to December 2020) and examined the efficacy of CPZ/SUL treatment in ESBL-producing Enterobacterales bacteraemia. The minimum inhibitory concentrations (MICs) were determined using agar dilution; ESBL/AmpC genes were detected using polymerase chain reaction. The primary outcome was clinical success, whereas the secondary outcome was 30-day mortality. Clinical success was defined as the complete resolution of clinical signs and symptoms of K. pneumoniae or E. coli infection, with no evidence of persistent or recurrent bacteraemia. The factors influencing outcomes were identified using a multivariate analysis.Results CPZ/SUL demonstrated a clinical success rate of 82.7% (91/110) in treating ESBL-producing Enterobacterales bacteraemia, with a 30-day mortality rate of 9.1% (10/110). Among 110 ESBL-producing isolates, a high clinical success rate was observed at an MIC of <= 32/32 mg/L. Multivariate analysis revealed that a Charlson comorbidity index (CCI) of >= 6 was associated with lower clinical success [odds ratio (OR): 5.80, 95% confidence interval (CI): 1.15-29.14, P = 0.033]. High Sequential Organ Failure Assessment scores (>= 6) were significantly associated with increased 30-day mortality (OR: 14.34, 95% CI: 1.45-141.82, P = 0.023).Discussion CPZ/SUL demonstrated a clinical success rate of 82.7% (91/110) in treating ESBL-producing Enterobacterales bacteraemia. Treatment success was evident when the CPZ and SUL MIC was <= 32/32 mg/L. Comorbidities (CCI >= 6) were associated with lower clinical success, while disease severity (Sequential Organ Failure Assessment score >= 6) correlated with higher mortality.