Phenotypic and molecular characterization of the carbapenem resistant Klebsiella pneumoniae and Escherichia coli causing blood stream infections

Archa, Sharma (2015) Phenotypic and molecular characterization of the carbapenem resistant Klebsiella pneumoniae and Escherichia coli causing blood stream infections. Masters thesis, Christian Medical College, Vellore.

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Abstract

OBJECTIVES: Phenotypic and molecular characterization of the carbapenemase producing Klebsiella pneumoniae and Escherichia coli causing blood stream infections by 1. Phenotypic differentiation of carbapenemase and non-carbapenemase mediated mechanisms by the CarbaNP test. 2. Molecular characterization of the isolates for blaNDM, blaKPC, blaOXA48 like, blaIMP, blaVIM genesby multiplex-PCR. 3. To sequence a proportion of the positive isolates to determine the enzyme variants. METHODS: During the study period 122 consecutive non- duplicate carbapenem resistant Klebsiella pneumoniae and Escherichia coli isolates causing blood stream infection were included in the study. The isolates were identified by cultural and biochemical characteristics. Carbapenemresistance was tested by imipenem and meropenem disk diffusion testing. CarbaNP test was done for the detection of carbapenemase production. Molecular characterization of the carbapenem resistant isolates was performed using amultiplex-PCR forblaNDM, blaKPC, blaOXA48 like, blaIMPand blaVIM genes. 20 random isolates positiveforblaOXA48 like and 7 isolates positive forblaNDM genes were sequenced to identify the enzyme variants. RESULTS: Of the 122 isolates 97% were positive for carbapenemase production by CarbaNP test. blaNDM was found to be the predominant gene seen in 40% of the isolates. This was followed by blaOXA48like gene in 39%. 12% of the strains showed co-existence of both blaNDM and blaOXA48likegenes. None of the isolates showed blaVIM, blaKPCand blaIMPgenes. All the 20 (100%) of the blaOXA48 like genes were found to be blaOXA181 a variant of the blaOXA48 like gene. The 7 blaNDM gene positives were found to be theblaNDM 1 variant.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Klebsiella pneumoniae ; Escherichia coli ; Carbapenem ; resistance ; India.
Subjects: MEDICAL > Microbiology
Depositing User: Punitha K
Date Deposited: 23 May 2018 03:31
Last Modified: 27 May 2018 07:16
URI: http://repository-tnmgrmu.ac.in/id/eprint/8045

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