Annals of Clinical Microbiology, The official Journal of the Korean Society of Clinical Microbiology

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pISSN 2288-0585 eISSN 2288-6850

Strategies for Interpretive Standards of β-Lactams Susceptibility Testing and Identification of Extended-Spectrum β-Lactamases and Carbapenemases in Enterobacteriaceae

Review article

Annals of Clinical Microbiology (Ann Clin Microbiol) 2013 September, Volume 16, Issue 3, pages 111-119.

https://doi.org/10.5145/ACM.2013.16.3.111

Strategies for Interpretive Standards of β-Lactams Susceptibility Testing and Identification of Extended-Spectrum β-Lactamases and Carbapenemases in Enterobacteriaceae

Yeon-Joon Park1, Wonkeun Song2
Department of Laboratory Medicine, 1College of Medicine, The Catholic University of Korea, Seoul, 2Hallym University College of Medicine, Chuncheon, Korea

Abstract

The Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) have recently revised the susceptibility interpretive criteria of oxyimino-β-lactams and carbapenems for Enterobacteriaceae. According to the new criteria, susceptibility testing results are sufficient to detect extended-spectrum β-lactamases (ESBLs) and carbapenemases; it is not necessary to perform ESBL or carbapenemase detection tests for therapeutic purposes. Thus, it has been recommended that these related tests be performed only for infection control. These changes in the susceptibility guidelines are supported by some clinical cases and the results of pharmacodynamic and animal studies. However, differences still exist between the breakpoints established by the CLSI and EUCAST with regard to some oxyimino-β-lactam and carbapenem antibiotics, in particular, the breakpoints for ceftazidime and cefepime established by the CLSI are higher than those established by the EUCAST. Also, similar numbers of successful and unsuccessful cases have been reported regarding the use of cephalosporins or carbapenems in treating infections caused by low-minimal inhibitory concentration (MIC) ESBL-producers or low-MIC carbapenemase-producers. Finally, routine susceptibility test methods are not as accurate as research-purpose test methods, showing differences in MICs ranging approximately from 1 to 8 μg/mL. In conclusion, it is strategically prudent to continue to perform ESBL and carbapenemase detection tests and to avoid the use of the corresponding antimicrobial agents for the treatment of ESBL- or carbapenemase-producing bacterial infections. (Ann Clin Microbiol 2013;16:111-119)

Keywords

β-Lactams, Carbapenemase, Enterobacteriaceae, Extended-spectrum β-lactamases, Microbial sensitivity tests