Clinical Outcomes of Third-Generation Cephalosporins, Carbapenems, and Piperacillin-Tazobactam in the Treatment of AmpC- Associated Enterobacterales Species Sepsis

Background AmpC-producing Enterobacterales are associated with resistance to many β-lactam antibiotics, and the optimal treatment approach remains challenging. The primary aim is to describe real-world outcomes of hospitalised patients with AmpC-associated Enterobacterales infections treated with different antibiotics. Methods This was a retrospective cohort study, including hospitalised patients with confirmed infections based on clinical evaluation and laboratory confirmation caused by AmpC-producing Enterobacterales. Patients received definitive therapy using 3GCss, piperacillin-tazobactam, or carbapenems, based on final culture results showing full susceptibility to the administered antibiotics. Results Patients were categorised into 3GCs, piperacillin-tazobactam, and carbapenem treatment groups. Significant baseline differences were observed; the carbapenem group included patients with higher rates of shock (32.4%) and mechanical ventilation (26.5%), compared to lower rates in the 3GCs group (shock 7%, mechanical ventilation 17%). After adjustment for potential confounders, Clinical failure rates were 17% for the 3GCs group, 32% for the piperacillin-tazobactam group, and 41% for the carbapenem group. The 28-day mortality (7%) and overall mortality (12%) were lowest in the 3GC group, followed by the piperacillin-tazobactam group (14.7% 28-day mortality). Conclusion In this real-world cohort, mortality and clinical failure appeared lower among patients with AmpC-associated Enterobacterales infections who received third-generation cephalosporins or piperacillin-tazobactam compared with carbapenems. These findings suggest that third-generation cephalosporins and piperacillin-tazobactam might be reasonable options in selected, less critically ill patients, but larger prospective studies are needed to better define their role, as these results are exploratory.