Clinical comparison of ertapenem and cefepime for treatment of infections caused by AmpC beta-lactamase-producing Enterobacteriaceae

There are no comparative data evaluating outcomes of ertapenem treatment for infections with AmpC-producing Enterobacteriaceae. This retrospective matched case-control study was conducted between 2009 and 2012. Sixteen cases treated with ertapenem were matched 1:2 with 32 control cases treated with cefepime based on age, culture source, and hospital service. There were more cefepime-resistant organisms in the ertapenem group (cefepime resistance present in 44% of patients treated with ertapenem compared with 0% of control patients, p < 0.001). Ertapenem was used empirically in 25% of patients compared with 88% who received cefepime empirically (p < 0.001). Consequently, 56% of patients on ertapenem received inappropriate initial therapy compared with 9% of patients on cefepime (p < 0.001). No differences in clinical success were identified (69% for ertapenem vs 88% for cefepime, p = 0.138). Although a trend favoring cefepime could be suspected, it should be noted that no statistically significant difference in clinical success was detected despite the presence of more resistant organisms and delays in initiation of appropriate therapy among patients receiving ertapenem.