Comparison of meropenem MICs and susceptibilities for carbapenemase-producing Klebsiella pneumoniae isolates by various testing methods. Academic Article uri icon

Overview

abstract

  • We describe the levels of agreement between broth microdilution, Etest, Vitek 2, Sensititre, and MicroScan methods to accurately define the meropenem MIC and categorical interpretation of susceptibility against carbapenemase-producing Klebsiella pneumoniae (KPC). A total of 46 clinical K. pneumoniae isolates with KPC genotypes, all modified Hodge test and bla(KPC) positive, collected from two hospitals in NY were included. Results obtained by each method were compared with those from broth microdilution (the reference method), and agreement was assessed based on MICs and Clinical Laboratory Standards Institute (CLSI) interpretative criteria using 2010 susceptibility breakpoints. Based on broth microdilution, 0%, 2.2%, and 97.8% of the KPC isolates were classified as susceptible, intermediate, and resistant to meropenem, respectively. Results from MicroScan demonstrated the most agreement with those from broth microdilution, with 95.6% agreement based on the MIC and 2.2% classified as minor errors, and no major or very major errors. Etest demonstrated 82.6% agreement with broth microdilution MICs, a very major error rate of 2.2%, and a minor error rate of 2.2%. Vitek 2 MIC agreement was 30.4%, with a 23.9% very major error rate and a 39.1% minor error rate. Sensititre demonstrated MIC agreement for 26.1% of isolates, with a 3% very major error rate and a 26.1% minor error rate. Application of FDA breakpoints had little effect on minor error rates but increased very major error rates to 58.7% for Vitek 2 and Sensititre. Meropenem MIC results and categorical interpretations for carbapenemase-producing K. pneumoniae differ by methodology. Confirmation of testing results is encouraged when an accurate MIC is required for antibiotic dosing optimization.

publication date

  • May 19, 2010

Research

keywords

  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Klebsiella pneumoniae
  • Microbial Sensitivity Tests
  • Thienamycins
  • beta-Lactamases

Identity

PubMed Central ID

  • PMC2897473

Scopus Document Identifier

  • 77954447800

Digital Object Identifier (DOI)

  • 10.1016/j.rmedc.2009.09.011

PubMed ID

  • 20484603

Additional Document Info

volume

  • 48

issue

  • 7