Evaluation of CHROMagarTMmSuperCARBATM as a Phenotypic Test for Detection of Carbapenemase Producing OrganismsCorrespondence Address :
Dr. Rani Diana Sahni,
Department of Clinical Microbiology, 8th Floor, ASHA Building, Christian Medical College, Vellore, Tamil Nadu, India. E-mail: firstname.lastname@example.org
Introduction: Carbapenem resistance among Enterobacteriaceae continues to escalate. Carbapenemase encoding genes borne on plasmids leads to wide-spread transmission among Enterobacteriaceae. The accurate and rapid detection of Carbapenemase producing-Carbapenem resistant Enterobacteriaceae (CP-CRE) is imperative for patient management as well as for hospital infection control measures. We therefore evaluated the CHROMagar™mSuperCARBA™ (CMSCs) a phenotypic screening test for detection of CP-CRE.
Aim: To evaluate the performance of CMSCs as a phenotypic test for detection of carbapenemase producing organisms.
Materials and Methods: A total of 150 consecutive Carbapenem resistant Enterobacteriaceae (CRE) (E. coli n=81 and Klebsiella spp. n=69), isolated from consecutive hospitalised patients with significant bacteriuria, were subjected to CRE Multiplex PCR for the detection of blaKPC, blaNDM, blaVIM, blaOXA-48 like and blaIMP genes. Phenotypic detection of carbapenemase production was evaluated by the chromogenic medium CMSC, CarbaNP and Modified Hodge Test (MHT).
Results: The multiplex PCR detected carbapenemase encoding gene(s) in 108 isolates. The sensitivity of CMSC, CarbaNP test and MHT in detecting isolates carrying blaNDM and blaOXA48-like genes was 94.4%, 67.6%, 56.3% and 96%, 40.8%, 38.8% respectively. While overall sensitivity of CMSC, CarbaNP test and MHT for detection of CP-CRE was 85.3%, 46.6% and 40% respectively; with a negative likelihood ratio of 0.18, 0.55 and 0.64 respectively.
Conclusion: CMSC emerged as the most sensitive test for detection of isolates carrying blaNDM and blaOXA48-like genes, with an excellent negative likelihood ratio. In addition, it was found to be inexpensive and has the fastest turnaround time. It is a promising phenotypic test especially in geographic regions with wide spread resistance due to blaNDM and blaOXA48-like CP-CRE.
Carbapenem resistant enterobacteriaceae, Chromogenic medium, OXA-48-like
Anushree Ulhas Amladi, Thambu David Sudarsanam, Subramani Kandasamy, Nitin Kekre, Balaji Veeraraghavan, Rani Diana Sahni. EVALUATION OF CHROMAGARTMMSUPERCARBATM AS A PHENOTYPIC TEST FOR DETECTION OF CARBAPENEMASE PRODUCING ORGANISMS. Journal of Clinical and Diagnostic Research [serial online] 2019 September [cited: 2019 Aug 20 ]; 13:DC11-DC15. Available from
Date of Submission: Apr 15, 2019
Date of Peer Review: Jun 01, 2019
Date of Acceptance: Jun 28, 2019
Date of Publishing: Sep 01, 2019
FINANCIAL OR OTHER COMPETING INTERESTS: As declared above.
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