International Journal of Current Microbiology and Applied Sciences (IJCMAS)
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Original Research Articles                      Volume : 5, Issue:4, April, 2016

PRINT ISSN : 2319-7692
Online ISSN : 2319-7706
Issues : 12 per year
Publisher : Excellent Publishers
Email : /
Editor-in-chief: Dr.M.Prakash
Index Copernicus ICV 2018: 95.39
NAAS RATING 2020: 5.38

Int.J.Curr.Microbiol.App.Sci.2016.5(4): 133-139

Detection of Inducible and Non-inducible (constitutive) AmpC β-lactamase-producing Gram-Negative Bacteria among Family Enterobacteriaceae by Two Phenotypic Methods-Disk Antagonism Test (DAT) and AmpC disk Test at a Tertiary Care Hospital, Himachal Pradesh, India
A. K. Ashok*, S. C. Jaryal, K. Thakur, A. Sood, P. K. Gupta, and S. Thakur
Department of Microbiology, Dr. Rajendra Prasad Govt. Medical College Kangra at Tanda, Himachal Pradesh, India
*Corresponding author

Gram-negative bacilli particularly among family Enterobacteriaceae produce AmpC β-lactamases which are often responsible for multidrug resistance. Their detection is problematic in routine as there are no Clinical Laboratory Standards Institute (CLSI) or other approved criteria for screening and detection of AmpC β-lactamases. So, it is a matter of great concern. Also only some studies have shown a few phenotypic methods which are comparatively easy and cheap. There has not been done such study in our state Himachal Pradesh. So it was decided to perform such types of studies at our institute. Aims & Objectives: To detect inducible and non-inducible (constitutive) AmpC β-lactamases by Disk Antagonism Test (DAT) and AmpC Disk methods. Material and Methods: Out of total 9105 clinical samples received in the Department of Microbiology for culture and sensitivity, 1200 samples were identified by colony morphology, Gram staining and Biochemical reactions as belonging to family Enterobacteriaceae. These samples were isolated from urine, pus, blood, and others. These isolates were screened by cefoxitin disk test. Those organisms sensitive to cefoxitin disc test were subjected to Disk antagonism test (DAT) & those resistant to it were subjected to AmpC disk test. Results: Of the 1200 isolates 575 were cefoxitin sensitive and 625 were cefoxitin resistant. Of 625 cefoxitin-resistant isolates, 48 (4.0%) isolates were found to be positive for AmpC β−lactamase production by the phenotypic method AmpC disc test. Out of 575 cefoxitin sensitive strains, 28(4.87%) revealed the presence of inducible AmpC β−lactamase by Disk antagonism test. Conclusions: The test DAT to know inducible AmpC β-lactamase and AmpC disk test to know plasmid-mediated AmpC β-lactamase is simple, less time consuming as well as cost effective and has a reliable approach.

Keywords: AmpC β-lactamase, cefoxitin screening, cefoxitin sensitive, cefoxitin resistant, Disk ntagonism test, AmpC disk test.

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How to cite this article:

Ashok, A.K., S.C. Jaryal, K. Thakur, A. Sood, P.K. Gupta, Thakur, S. 2016.  Detection of Inducible and Non-inducible (constitutive) AmpC β-lactamase–producing Gram-Negative Bacteria among Family Enterobacteriaceae by Two Phenotypic Methods-Disk AntagonismInt.J.Curr.Microbiol.App.Sci. 5(4): 133-139. doi:
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