title: Identification and differentiation of carbapenemases in Klebsiella pneumoniae: a phenotypic test evaluation study from jaipur, India.
abstract: BACKGROUND
  Carbapenem resistance is one of the major threats faced in antimicrobial treatment of infections caused by gram negative organisms. In recent years, carbapenem resistance has emerged in Klebsiella pneumoniae isolates due to acquisition of carbapenemases which belong to Ambler class A KPC type enzymes or to Ambler class B metallo-β-lactamases (MBL). Routine lab detection of carbapenemase producing K. pneumoniae isolates is crucial, both for a therapeutic management and an efficient infection control.
  
  
  METHODS
  A study was conducted on 60 carbapenem resistant Klebsiella pneumoniae strains which were isolated from various clinical samples over a period of one year (September 2010-August 2011), at a tertiary care hospital in Jaipur. Phenotypic confirmatory test was done by using discs of Meropenem alone and those with phenyl boronic acid (PBA) or Ethylenediaminetetraacetic acid (EDTA) or both, for detection of carbapenemase production and differentiation of KPC and MBL enzymes.
  
  
  RESULTS
  Of the 60 carbapenem resistant Klebsiella pneumoniae isolates, 53 (88.33%) were found to be MBL producers, 4(6.66%) were found to be MBL and KPC co-producers and the rest of the 3(5%) isolates were negative for both MBL and KPC production, as was seen by combined disc testing.
  
  
  CONCLUSIONS
  The combined disc test is a simple test which can be used for differentiation of carbapenemases and it can be easily incorporated in routine microbiology lab testing.
authors.affiliation: Senior Microbiologist, Department of Laboratory Medicine (SRL Ltd.), Fortis Escorts Hospital , Jaipur, Rajasthan, India .
authors.forename: Smita
authors.initials: S
authors.lastname: Sood
keywords: Carbapenem resistance; Carbapenemase inhibition tests; Enterobacteriaceae; Klebseilla pneumoniae; Modified hodge test