Medical News Stories
The Use of Cefepime for Treating AmpC β-Lactamase-Producing Enterobacteriaceae
Study Question: Can cefepime be used effectively to treat invasive infections caused by AmpC β-lactamase-producing organisms?
Study Description: This study prospectively identified patients over a 1-year period who had bloodstream infections, pneumonia, or intra-abdominal infections caused by Enterobacter spp, Serratia marcescens, or Citrobacter spp that produced AmpC β-lactamases. Based on the treating physician’s decision, patients received either cefepime or meropenem as empiric therapy, and had to continue for another 72 hours as definitive therapy to qualify for study inclusion. Thirty-day all-cause mortality from the day of first positive culture was the primary outcome.
Results: There were 399 patients who met eligibility criteria; 96 of those had cultures with confirmed AmpC β-lactamase-producing organisms. Thirty-two matched pairs were identified via propensity score matching for analysis. A difference in history of a multidrug-resistant gram-negative organism remained after matching. There were 10 deaths among patients who received cefepime and 11 deaths among patients who received meropenem, a non-significant difference. In the matched pair analysis, after adjusting for prior multi-drug-resistant gram-negative organisms, there was no difference in 30-day mortality between patients who received cefepime or meropenem. Length of stay was not statistically different between groups in a doubly robust model. Sixteen patients had a positive culture, growing the same species, after the initial positive culture. Only one cefepime-treated patient had a second positive culture that had become resistant to cefepime.
Conclusion(s): Cefepime may be an effective option for treatment of invasive infections caused by AmpC β-lactamase-producing organisms.
Perspective: Infections caused by AmpC β-lactamase-producing organisms are a significant cause of morbidity and mortality, and treatment options are limited. Widespread use of carbapenems to treat these infections has the potential to add to the problem of multidrug-resistant gram-negative organisms, so the possibility of cefepime as a treatment option is promising. This study found no difference in mortality or length of stay between patients who received cefepime or meropenem. The study was not randomized or blinded, and baseline characteristics between the groups were different, although matched pairs were analyzed to account for these differences. Although limited by a small sample size and single center, the results of this study pave the way for larger, prospective trials.