EVALUATION OF DIFFERENT PHENOTYPIC METHODS TO DETECT ESBL AND MBL PRODUCTION IN Escherichia coli AND Klebsiella SPECIES WITH DETECTION OF NDM-1 BY MOLECULAR METHOD

M. KUMAR¹*, R. DUTTA², S. SAXENA³, S. SINGHAL^4
1Department of Microbiology, Lady Hardinge Medical College, New Delhi - 110 001, India.
²Department of Microbiology, Lady Hardinge Medical College, New Delhi - 110 001, India.
³Department of Microbiology, Lady Hardinge Medical College, New Delhi - 110 001, India.
⁴Group Leader, Infectious Diseases, Biology Department, Daiichi Sankyo India Pharma Private Limited, Gurgaon - 122 015, Haryana, India.
* Corresponding Author : drmanu_05@rediffmail.com

Received : 20-02-2015     Accepted : 30-03-2015     Published : 09-04-2015
Volume : 7     Issue : 1       Pages : 598 - 603
Int J Microbiol Res 7.1 (2015):598-603

Keywords : Extended-spectrum β-lactamases, metallo-β-lactamases, New Delhi metallo-β-lactamase-1
Academic Editor : Neetu Shree, Dr Mohamed Abdelalim Ali
Conflict of Interest : None declared

Introduction: Gram negative bacteria are becoming increasingly resistant to antibiotics due to the production of ESBL and MBL. Microbiology laboratories must be prepared to screen for ESBL and MBL producing isolates by a low cost, convenient and sensitive procedure. Objectives: To detect ESBL and MBL production in Escherichia coli and Klebsiella species by using three different phenotypic methods and NDM-1 detection by PCR. Materials and Methods: ESBL production was detected using double disc synergy test (DDST), ESBL Etest and ESBL detection kits. For detecting MBL production, combined disk test, Modified Hodge test (MHT) and MBL Etest were used. MIC was determined by agar dilution, microbroth dilution and NDM-1 production by PCR. Results: Among Esch. coli, ESBL production was observed in 81.2%, 80.0%, 76.8% and 75.2% of 250 isolates by ESBL detection kit, DDST, Etest for ceftazidime and cefotaxime respectively. MBL production was observed in 12.5% of 40 isolates by MHT and 10% by both combined disk test and Etest. Among Klebsiella, ESBL production was observed in 63.3%, 62.2% and 61.0% of 267 isolates by Etest, ESBL detection kit and DDST. MBL production was observed in 35.1% of 97 isolates by MHT and 21.6% by both the combined disk test and Etest. 1 Esch. coli and 8 Klebsiella spp. were strongly positive, 1 each of Esch. coli and Klebsiella spp. was weakly positive, and 1 Esch. coli and 6 Klebsiella spp. were negative for NDM-1 production. Conclusion: Etest was best for detecting ESBL and MBL production among Gram negative bacteria.