Details

Autor(en) / Beteiligte

• Pierce, Virginia M
• Simner, Patricia J
• Lonsway, David R
• Roe-Carpenter, Darcie E
• Johnson, J Kristie
• Brasso, William B
• Bobenchik, April M
• Lockett, Zabrina C
• Charnot-Katsikas, Angella
• Ferraro, Mary Jane
• Thomson, Jr, Richard B
• Jenkins, Stephen G
• Limbago, Brandi M
• Das, Sanchita
• Ledeboer, Nathan A.

Titel

Modified Carbapenem Inactivation Method for Phenotypic Detection of Carbapenemase Production among Enterobacteriaceae

Ist Teil von

• Journal of clinical microbiology, 2017-08, Vol.55 (8), p.2321-2333

Ort / Verlag

United States: American Society for Microbiology

Erscheinungsjahr

2017

Quelle

MEDLINE

Beschreibungen/Notizen

• The ability of clinical microbiology laboratories to reliably detect carbapenemase-producing carbapenem-resistant (CP-CRE) is an important element of the effort to prevent and contain the spread of these pathogens and an integral part of antimicrobial stewardship. All existing methods have limitations. A new, straightforward, inexpensive, and specific phenotypic method for the detection of carbapenemase production, the carbapenem inactivation method (CIM), was recently described. Here we describe a two-stage evaluation of a modified carbapenem inactivation method (mCIM), in which tryptic soy broth was substituted for water during the inactivation step and the length of this incubation was extended. A validation study was performed in a single clinical laboratory to determine the accuracy of the mCIM, followed by a nine-laboratory study to verify the reproducibility of these results and define the zone size cutoff that best discriminated between CP-CRE and members of the family that do not produce carbapenemases. Bacterial isolates previously characterized through whole-genome sequencing or targeted PCR as to the presence or absence of carbapenemase genes were tested for carbapenemase production using the mCIM; isolates with Ambler class A, B, and D carbapenemases, non-CP-CRE isolates, and carbapenem-susceptible isolates were included. The sensitivity of the mCIM observed in the validation study was 99% (95% confidence interval [95% CI], 93% to 100%), and the specificity was 100% (95% CI, 82% to 100%). In the second stage of the study, the range of sensitivities observed across nine laboratories was 93% to 100%, with a mean of 97%; the range of specificities was 97% to 100%, with a mean of 99%. The mCIM was easy to perform and interpret for , with results in less than 24 h and excellent reproducibility across laboratories.