Antimicrobial resistance to cefotaxime and ertapenem in Enterobacteriaceae: the effects of altering clinical breakpoints

Authors

  • Po-Yu Liu Taichung Veterans General Hospital, Taichung, Taiwan
  • Zhi-Yuan Shi Taichung Veterans General Hospital, Taichung, Taiwan
  • Kwong-Chung Tung National Chung-Hsing University, Taichung, Taiwan
  • Ching-Lin Shyu National Chung-Hsing University, Taichung, Taiwan
  • Kun-Wei Chan National Chiayi University, Chiayi, Taiwan
  • Jai-Wen Liu Chung Shan Medical University Hospital, Taichung, Taiwan
  • Zong-Yen Wu National Chung-Hsing University, Taichung, Taiwan
  • Chih-Chuan Kao Dajia Lee's Hospital, Lee's Medical Corporation, Taichung, Taiwan
  • Yi-Ching Huang Taichung Veterans General Hospital, Taichung, Taiwan
  • Chin-Fu Lin Taichung Veterans General Hospital, Taichung, Taiwan

DOI:

https://doi.org/10.3855/jidc.3335

Keywords:

Drug Resistance, Enterobacteriaceae, microbial sensitivity tests, cefotaxime, ertapenem

Abstract

Introduction: The Clinical and Laboratory Standards Institute (CLSI) updated its antimicrobial susceptibility testing interpretation criteria for Enterobacteriaceae. This study assessed the effects of clinical breakpoint changes in the CLSI 2009 to 2012 guidelines on antibiotic susceptibility testing reports.

Methodology: In total, 2,076 non-duplicate clinical isolates of Enterobacteriaceae were analyzed. The disk diffusion method was used for susceptibility testing. The CLSI 2009-12 clinical breakpoints were applied to determine susceptibility of cefotaxime and ertapenem. Combined-disk testing was used for phenotypic confirmation of extended-spectrum beta–lactamase (ESBL) production.

Results: In total, Enterobacteriaceae resistance rates to cefotaxime increased from 13.1% using the CLSI 2009 guidelines to 23.6% with the CLSI 2010-12 guidelines, and the resistance rates to ertapenem were 0.4%, 1.0% and 0.8% with CLSI 2009, 2011 and 2012, respectively. Based on the 2010-12 CLSI criteria, all ESBL-producing Escherichia coli and Klebsiella pneumoniae were resistant to cefotaxime. Marked differences in susceptibility to ertapenem between the 2009 CLSI criteria and 2012-12 CLSI criteria were noted in ESBL-producing K. pneumoniae.

Conclusions: Breakpoints changes in the updated CLSI guidelines resulted in higher resistance rates to cefotaxime and ertapenem. In addition, the effects were different in individual Enterobacteriaceae species. As a result, clinicians may opt to use alternative antimicrobial agents. Upon implementation of the newer CLSI guidelines, laboratories should be aware of the possible consequences and closely monitor the effects.

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Published

2014-03-13

How to Cite

1.
Liu P-Y, Shi Z-Y, Tung K-C, Shyu C-L, Chan K-W, Liu J-W, Wu Z-Y, Kao C-C, Huang Y-C, Lin C-F (2014) Antimicrobial resistance to cefotaxime and ertapenem in Enterobacteriaceae: the effects of altering clinical breakpoints. J Infect Dev Ctries 8:289–296. doi: 10.3855/jidc.3335

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Section

Original Articles