Cefepime is not Inferior to carbapenems in the treatment of Enterobacter BSIs
By Stan Deresinski, MD, FACP, FIDSA
Clinical Professor of Medicine, Stanford University, Hospital Epidemiologist, Editor of Infectious Disease Alert
A retrospective analysis indicates that cefepime is effective in the treatment of patients with bacteremia due to Enterobacter species.
Siedner MJ, et al. Cefepime vs other antibacterial agents for the treatment of Enterobacter species bacteremia. Clin Infect Dis 2014;58:1554-63.
Treatment of patients with Enterobacter bacteremia with 3rd generation cephalosporins has been associated with the emergence of resistance during therapy. Enterobacter is among the Enterobacteriaceae that carry a chromosomal ampC gene. The product of this gene is a cephalosporinase capable of hydrolyzing most 3rd generation cephalosporins. While this gene is inducible, stably derepressed mutants occur at a frequency of approximately 10-7 and may be selected by exposure to a 3rd generation cephalosporin. As a consequence, some have suggested that a carbapenem is preferred for treatment of Enterobacter bacteremia.
Cefepime (which has been called a 4th generation cephalosporin), is more stable to ampC, than are 3rd generation cephalosporins, raising the possibility that it may be an effective and safe agent for the treatment of serious infections due to Enterobacter.
Seidner and colleagues retrospectively examined the efficacy of treatment of bacteremia due to Enterobacter species with either cefepime or a carbapenem in 368 patients at 2 Boston hospitals.
Of the 271 who had repeat blood cultures within one day of the initial positive, only 29 (11%) had a positive result ("persistent bacteremia"). Among patients who received monotherapy, this was observed in 4 of 16 (25%) who received a carbapenem (imipenem or meropenem) and in 0 of 36 (P<0.01) given cefepime. Most patients, however, received more than one antibiotic and when the entire group was considered, no individual antibiotic was independently associated with persistence of bacteremia or with mortality.
COMMENTARY
The results here are consistent with a smaller retrospective study that also demonstrated the efficacy of cefepime in the treatment of a variety of infections (bloodstream, pulmonary, intra-abdominal) due to ampC-producing Enterobacter, Citrobacter and Serratia.1
While there are a number of potentially confounding factors in the study by Siedner et al, especially that most patients received more than one antibiotic, the evidence supports the notion that cefepime is not inferior to carbapenems in the treatment of Enterobacter infection.
Reference
- Tamma PD, et al. The use of cefepime for treating ampC beta-lactamase-producing Enterobacteriaceae. Clin Infect Dis 2013;57:781-8.
