This Article Full Text Full Text (PDF) Other Versions of this Article: AAC.01083-07v1 52/3/995    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Choi, S.-H. Articles by Kim, Y. S. Search for Related Content PubMed PubMed Citation Articles by Choi, S.-H. Articles by Kim, Y. S.

 Previous Article  |  Next Article 

Antimicrobial Agents and Chemotherapy, March 2008, p. 995-1000, Vol. 52, No. 3
0066-4804/08/$08.00+0     doi:10.1128/AAC.01083-07
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Emergence of Antibiotic Resistance during Therapy for Infections Caused by Enterobacteriaceae Producing AmpC β-Lactamase: Implications for Antibiotic Use

Division of Infectious Diseases,¹ Department of Laboratory Medicine, Asan Medical Center, University of Ulsan College of Medicine,² Center for Antimicrobial Resistance and Microbial Genetics, University of Ulsan, Seoul, Republic of Korea³

Received 17 August 2007/ Returned for modification 21 September 2007/ Accepted 10 December 2007

Enterobacter spp., Serratia marcescens, Citrobacter freundii, and Morganella morganii are characterized by chromosomally encoded AmpC β-lactamases and possess the ability to develop resistance upon exposure to broad-spectrum cephalosporins. To determine the incidences of the emergence of resistance during antimicrobial therapy for infections caused by these organisms and the effect of the emergence of resistance on patient outcomes, all patients who were admitted to the Asan Medical Center (Seoul, Republic of Korea) from January 2005 to June 2006 and whose clinical specimens yielded Enterobacter spp., S. marcescens, C. freundii, or M. morganii were monitored prospectively. The main end point was the emergence of resistance during antimicrobial therapy. A total of 732 patients with infections were included for analysis. The overall incidence of the emergence of antimicrobial resistance during antimicrobial therapy was 1.9% (14/732). Resistance to broad-spectrum cephalosporins, cefepime, extended-spectrum penicillin, carbapenem, fluoroquinolones, and aminoglycosides emerged during treatment in 5.0% (11/218), 0% (0/20), 2.0% (2/100), 0% (0/226), 0% (0/153), and 1.1% (1/89) of patients, respectively. The emergence of resistance to broad-spectrum cephalosporins occurred more often in Enterobacter spp. (8.3%, 10/121) than in C. freundii (2.6%, 1/39), S. marcescens (0%, 0/37), or M. morganii (0%, 0/21). Biliary tract infection associated with malignant bile duct invasion was significantly associated with the emergence of resistance to broad-spectrum cephalosporins (P = 0.024 at a significance level of 0.042, by use of the Bonferroni correction). Only 1 of the 14 patients whose isolates developed resistance during antimicrobial therapy died. The emergence of resistance was more frequently associated with broad-spectrum cephalosporins than with the other antimicrobial agents tested, especially in Enterobacter spp. However, the emergence of resistance was associated with a low risk of mortality.

Published ahead of print on 17 December 2007.

This article has been cited by other articles:

• McPherson, C., Gal, P., Ransom, J L. (2008). Treatment of Citrobacter koseri Infection with Ciprofloxacin and Cefotaxime in a Preterm Infant. The Annals of Pharmacotherapy 42: 1134-1138 [Abstract] [Full Text]