Clinical outcomes following treatment of Enterobacter species pneumonia with piperacillin/tazobactam compared to cefepime or ertapenem

Background: Enterobacter spp. are a common cause of nosocomial pneumonia and treatment can be complicated by AmpC resistance. Carbapenems are the treatment of choice; however, alternatives are needed. Cefepime has been shown to be non-inferior to carbapenems. There are limited data to support the use of piperacillin/tazobactam. The objective of this study was to determine if piperacillin/tazobactam is non-inferior to cefepime or ertapenem for Enterobacter pneumonia treatment. Objectives: To compare the rate of clinical cure in patients with Enterobacter pneumonia receiving definitive treatment with piperacillin/tazobactam, cefepime, or ertapenem. Secondary outcomes included hospital mortality, infection-related length of stay, duration of mechanical ventilation, recurrent pneumonia, and resistance. Methods: Retrospective, single-center study. Results: Of 114 patients included, 59 received definitive treatment with piperacillin/tazobactam and 55 received cefepime or ertapenem. There was no difference in the proportion of patients who achieved clinical cure in the piperacillin/tazobactam group compared to the cefepime or ertapenem group (76.3% vs. 87.3%, P = 0.13). Treatment group was not associated with clinical cure when controlling for confounders in multivariable logistic regression (adjusted odds ratio [OR] 0.59, 95% confidence interval [CI] 0.15-2.37). The rate of recurrent pneumonia was 11.4% in the piperacillin/tazobactam group and 6.7% in the cefepime or ertapenem group (P = 0.48). Other secondary outcomes did not differ between the groups. Conclusions: In this retrospective study of patients with Enterobacter pneumonia, clinical cure with piperacillin/tazobactam was comparable to that with cefepime or ertapenem; however, a prospective trial with a larger population is needed to determine if definitive treatment with piperacillin/tazobactam is non-inferior to definitive treatment with cefepime or ertapenem.