Indian Journal of Microbiology Research


Detection of co-existence of β-lactamases in Gram negative bacteria using disc potentiation tests


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Author Details: Vijaya Shivanna, Achut Rao

Volume : 4

Issue : 1

Online ISSN : 2394-5478

Print ISSN : 2394-546X

Article First Page : 64

Article End Page : 67


Abstract

Background: The extended spectrum β-lactamases(ESBLs), AmpCβ-lactamases and metalloβ-lactamases (MBLs), have emerged worldwide as a cause of antimicrobial resistance in Gram negative bacteria (GNB). So the present study was conducted to detect all three β-lactamases in GNB using disc potentiation tests.
Materials and Methods: A total of 200 Gram negative clinical isolates from a tertiary care centre were identified and antibiotic susceptibility testing was done according to Clinical and Laboratory Standards Institute (CLSI) guidelines. The screening and phenotypic confirmatory test recommended by CLSI were carried out for ESBL detection. Detection of AmpCβ-lactamase was done by phenyl boronic acid test. MBL were detected using EDTA disc potentiation test.
Result: Of a total of 200 Gram negative isolates, pure ESBL were seen in 50(25%) isolates and pure AmpC were seen in 35(17.5%) isolates. ESBL and AmpC co-existed in 38(19%) isolates. AmpC and MBL co-occurred in a single isolate.
Conclusion: we recommend the phenotypic tests using various inhibitors for the detection of β-lactamases.

Keywords:
β-lactamases, Extended spectrum β-lactamases (ESBLs), AmpCβ-lactamases, Metalloβ-lactamases (MBLs), Co-existence.