|Year : 2015 | Volume
| Issue : 4 | Page : 603-606
Evaluation of Carba NP test for rapid detection of carbapenemase producing Enterobacteriaceae
S Mitra1, M Kazi1, M Panchal1, C Rodrigues1, A Shetty2
1 Hinduja National Hospital and Medical Research Centre, Mahim, Mumbai, Maharashtra, India
2 Department of Microbiology, Shri Parmanand Deepchand, Hinduja National Hospital and Medical Research Centre, Mahim, Mumbai, Maharashtra, India, India
|Date of Submission||09-Jun-2014|
|Date of Acceptance||20-Jan-2015|
|Date of Web Publication||16-Oct-2015|
Department of Microbiology, Shri Parmanand Deepchand, Hinduja National Hospital and Medical Research Centre, Mahim, Mumbai, Maharashtra, India
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Mitra S, Kazi M, Panchal M, Rodrigues C, Shetty A. Evaluation of Carba NP test for rapid detection of carbapenemase producing Enterobacteriaceae. Indian J Med Microbiol 2015;33:603-6
|How to cite this URL:|
Mitra S, Kazi M, Panchal M, Rodrigues C, Shetty A. Evaluation of Carba NP test for rapid detection of carbapenemase producing Enterobacteriaceae. Indian J Med Microbiol [serial online] 2015 [cited 2019 Dec 16];33:603-6. Available from: http://www.ijmm.org/text.asp?2015/33/4/603/167332
The increasing prevalence of carbepenem-resistant Enterobacteriaceae (CRE) has led to a serious healthcare concern worldwide. To identify carbepenem resistance, almost all of the laboratories still practice age-old disc-diffusion method to report antimicrobial susceptibility. But the current scenario requires rapid, simple and economical tests that provide results with decreased turn-around-time (TAT). In 2012, Nordmann et al., reported a novel, inexpensive and rapid biochemical test (CarbaNP) to identify carbapenemase-producing Enterobacteriaceae (CPE). The test is based on hydrolysis of imipenem by carbapenemases (if present), that is colorimetrically detected (red changes to yellow/orange). The test highlighted 100% sensitivity and specificity in comparison to molecular-based techniques. The performance of the test was further evaluated by Tijet et al., and found to have decreased sensitivity (80%). This prompted us to evaluate the test in our setting as it is rapid, inexpensive and can detect CPE with a shorter TAT. For this, 27 CPE harbouring and 6 carbapenem susceptible isolates were selected and molecularly characterized for the presence of blaNDM-1, blaKPC-2, blaOXA-48 [Figure 1]. Polymerase chain reaction (PCR) was performed on the bacterial isolates with previously published primers for NDM-1, KPC-2 and OXA-48 and was further confirmed by sequencing [Figure 2] and [Figure 3]. Of the 27 CPE harbouring strains, 12, 11 and 4 harboured blaOXA-48, blaNDM-1 and blaNDM-1 + OXA-48, respectively, as the mechanism of carbapenem resistance, whereas the remaining 6 were carbapenem susceptible.
Carba NP test was evaluated with two modifications: (a) Imipenem-cilastatin was employed instead of imipenem and (b) CelLytic B 2X buffer (Sigma) was used for bacterial lysis instead of B-PERII Bacterial Protein Extraction reagent (Thermo Scientific, Pierce), whereas other parameters remained unchanged. The test was positive for 66.66% (18/27) of the molecularly characterized CPE harbouring isolates and negative for 33.33% (9/27). Eighteen CPE isolates were Carba NP positive [55.55% (10/18) blaNDM-1, 22.22% (4/18) blaOXA-48 and 22.22% (4/18) blaNDM-1 + OXA-48], and nine were Carba NP negative [29.62% (8/27) blaOXA-48 and 3.7% (1/27) blaNDM-1]. The test had a poor performance in identifying blaOXA-48 carbapenemases. Similar results were obtained by Tijet et al., in detecting OXA-48 carbapenemases by Carba NP test. Identifying OXA-48/OXA-181 is essential as the strain has been found widespread among Indian subcontinent. In contrast to the results obtained by Nordmann et al., the test has shown high rates of false-negative (33.33%) in identifying CPE.
In conclusion, the test seems to be promising in identifying NDM-1 producers but performs poorly in detecting OXA-48 carbapenemases. Therefore, the test needs to be further evaluated with increased sample size, possibly by increasing the concentration of imipenem and the amount of bacteria.
| ~ Acknowledgements|| |
We thank the National Health and Education Society, P. D. Hinduja National Hospital and Medical Research Centre for their encouragement and support. We also thank the hospital staff of Department of Microbiology for their support and co-operation.
| ~ References|| |
Nordmann P, Poirel L, Dortet L. Rapid detection of carbapenemase producing Enterobacteriaceae
. Emerg Infect Dis 2012;18:1503-7.
Tijet N, Boyd D, Patel SN, Mulvey MR, Melano RG. Evaluation of the Carba NP test for rapid detection of carbapenemase-producing Enterobacteriaceae and pseudomonas aeruginosa. Antimicrob Agents Chemother 2013;57:4578-80.
Manchanda V, Rai S, Gupta S, Rautela RS, Chopra R, Rawat DS, et al
. Development of TaqMan real-time polymerase chain reaction for the detection of newly emerging form of carbapenem resistance gene in clinical isolates of Escherichia coli, Klebsiella pneumonia, and Acinetobacter baumannii
. Indian J Med Microbiol 2011;29:249-53.
Dallenne C, Da Costa A, Decré D, Favier C, Arlet G. Development of a set of multiplex PCR assays for the detection of genes encoding important beta-lactamases in Enterobacteriaceae. J Antimicob Chemother 2010;65:490-5.
Poirel L, Dortet L, Bernabeu S, Nordmann P. Genetic features of blaNDM-1-positive Enterobacteriaceae
. Antimicrob Agents Chemother 2011;55:5403-7.
[Figure 1], [Figure 2], [Figure 3]