Modified Carba NP Test: Simple and rapid method to differentiate KPC- and MBL-producing Klebsiella species

J Clin Lab Anal. 2018 Sep;32(7):e22448. doi: 10.1002/jcla.22448. Epub 2018 Mar 30.

Abstract

Background: The aim of this study was to evaluate the modified Carba NP test to differentiate KPC (Klebsiella pneumoniae carbapenemase)- and MBL (metallo-β-lactamase)-producing Klebsiella species.

Methods: A total of 508 non-duplicate clinical isolates of Klebsiella spp. were processed by modified Carba NP and combined disc tests which were further confirmed by conventional polymerase chain reaction (PCR), a gold standard method for statistical analysis.

Results: Modified Carba NP test demonstrated 91.7% sensitivity, 100% specificity, 100% positive predictive value (PPV) and 99.8% negative predictive value (NPV) for KPC and 96.7%, 100%, 100%, and 99.5% for MBL detection, respectively.

Conclusion: The performance of modified Carba NP test was significantly better than combined disc test, fulfilling the requirement of simple and rapid test for clinical applications.

Keywords: KPC; MBL; Klebsiella species; carbapenemase; modified Carba NP.

MeSH terms

  • Bacterial Proteins / genetics*
  • Klebsiella / classification*
  • Klebsiella / drug effects
  • Klebsiella / enzymology*
  • Klebsiella / genetics
  • Molecular Typing / methods*
  • Polymerase Chain Reaction
  • Sensitivity and Specificity
  • beta-Lactam Resistance / genetics*
  • beta-Lactamases / genetics*

Substances

  • Bacterial Proteins
  • beta-Lactamases
  • carbapenemase