title: Ertapenem susceptibility of extended spectrum beta-lactamase-producing organisms.
abstract: BACKGROUND
  Infections caused by multiply drug resistant organisms such as extended spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae are increasing. Carbapenems (imipenem and meropenem) are the antibiotics commonly used to treat these agents. There is limited clinical data regarding the efficacy of the newest carbapenem, ertapenem, against these organisms. Ertapenem susceptibility of ESBL-producing E. coli and K. pneumoniae clinical isolates were evaluated and compared to imipenem to determine if imipenem susceptibility could be used as a surrogate for ertapenem susceptibility.
  
  
  METHODS
  100 ESBL isolates (n = 34 E. coli and n = 66 K. pneumoniae) collected from 2005-2006 clinical specimens at WRAMC were identified and tested for susceptibility by Vitek Legacy [bioMerieux, Durham, NC]. Ertapenem susceptibility was performed via epsilometer test (E-test) [AB Biodisk, Solna, Sweden].
  
  
  RESULTS
  100% of ESBL isolates tested were susceptible to ertapenem. 100% of the same isolates were also susceptible to imipenem.
  
  
  CONCLUSIONS
  These results, based on 100% susceptibility, suggest that ertapenem may be an alternative to other carbapenems for the treatment of infections caused by ESBL-producing E. coli and K. pneumoniae. Clinical outcomes studies are needed to determine if ertapenem is effective for the treatment of infection caused by these organisms. However, due to lack of resistant isolates, we are unable to conclude whether imipenem susceptibility accurately predicts ertapenem susceptibility.
authors.affiliation: Walter Reed Army Medical Center, Washington, DC 20307, USA. rmody1917@aol.com
authors.forename: Rupal M
authors.initials: RM
authors.lastname: Mody
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Erwin
authors.forename: Amy M
authors.initials: AM
authors.lastname: Summers
authors.forename: Hector A
authors.initials: HA
authors.lastname: Carrero
authors.forename: Edward B
authors.initials: EB
authors.lastname: Selby
authors.forename: Allesa J
authors.initials: AJ
authors.lastname: Ewell
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Moran
mesh_terms: D000900:Anti-Bacterial Agents / Q000191:economics / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial; D000077727:Ertapenem; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology; D004927:Escherichia coli Infections / Q000382:microbiology; D006801:Humans; D015378:Imipenem / Q000191:economics / Q000494:pharmacology; D007710:Klebsiella Infections / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000201:enzymology; D008826:Microbial Sensitivity Tests; D008889:Military Personnel; D001618:beta-Lactamases / Q000096:biosynthesis*; D047090:beta-Lactams / Q000191:economics / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D047090:beta-Lactams; D015378:Imipenem; D001618:beta-Lactamases; D000077727:Ertapenem