Enhanced detection of Carbapenemase-Producing Enterobacteriaceae by an optimized phenol red assay

Publication date: Available online 18 September 2017
Source:Diagnostic Microbiology and Infectious Disease
Author(s): Jeremy Surre, Isabelle Canard, Pierrot Bourne Branchu, Estelle Courbiere, Christine Franceschi, Sonia Chatellier, Alex van Belkum, Mahendrasingh Ramjeet
Screening for the detection of carbapenemase-producing bacteria still encounters issues related to workflow, limit of detection or qualitative interpretation. We developed a spectrophotometry-based version of the Carba NP phenol red assay (Nordmann et al., 2012) in a microtiter plate format, compatible with low bacterial cell counts. We were able to detect highly active carbapenemases such as KPC and IMP in 30min. A wider range of carbapenemases including OXA-48 were detected using higher inocula, still being competitive compared with currently available phenol red assays. Validation experiments of our test with a panel of 81 Enterobacteriaceae showed good performance with 93% of sensitivity and 92% of specificity. The compatibility of our routine-friendly protocol with automation offers great perspectives for high throughput screening in outbreak situations and/or in big laboratories.

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