Simplified Protocol for Carba NP Test for Enhanced Detection of Carbapenemase Producers Directly from Bacterial Cultures

J Clin Microbiol. 2015 Dec;53(12):3908-11. doi: 10.1128/JCM.02032-15. Epub 2015 Sep 30.


We compared carbapenemase detection among 266 Gram-negative bacilli (161 carbapenemase producers) using the Carba NP tests issued by the CLSI (CNPt-CLSI) and a novel protocol (CNPt-direct) designed for carbapenemase detection direct from bacterial cultures (instead of bacterial extracts required by the CLSI tests). The specificities were comparable (100%), but the CNPt-direct was more sensitive (98% versus 84%). The CNPt-direct was easier to perform due to the direct use of colonies and offered a more robust detection of carbapenemase producers.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / analysis*
  • Bacteriological Techniques / methods*
  • Gram-Negative Bacteria / enzymology*
  • Gram-Negative Bacteria / isolation & purification*
  • Humans
  • Sensitivity and Specificity
  • beta-Lactamases / analysis*


  • Bacterial Proteins
  • beta-Lactamases
  • carbapenemase