Ethambutol resistance as determined by broth dilution method correlates better than sequencing results with embB mutations in multidrug-resistant Mycobacterium tuberculosis isolates

J Clin Microbiol. 2014 Feb;52(2):638-41. doi: 10.1128/JCM.02713-13. Epub 2013 Nov 27.

Abstract

We evaluated the correlation of phenotypic ethambutol (EMB) susceptibility as determined by two drug susceptibility methods with embB mutations in multidrug-resistant (MDR) Mycobacterium tuberculosis strains. The concordance rate for EMB resistance between broth dilution method and sequencing results (83.6%) was significantly higher than between the proportion method and sequencing results (61.7%) (P = 0.004). Of the embB mutants, 75.4% (46/61) possessed a mutation at embB306. Our results demonstrated that ethambutol resistance determined by broth dilution method reveals better correlation with embB mutations than the proportion method in MDR isolates.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antitubercular Agents / pharmacology*
  • Drug Resistance, Multiple, Bacterial*
  • Ethambutol / pharmacology*
  • Genotyping Techniques / methods
  • Humans
  • Microbial Sensitivity Tests / methods
  • Mutation, Missense
  • Mycobacterium tuberculosis / drug effects*
  • Mycobacterium tuberculosis / genetics*
  • Mycobacterium tuberculosis / isolation & purification
  • Pentosyltransferases / genetics*
  • Sequence Analysis, DNA
  • Tuberculosis, Multidrug-Resistant / microbiology*

Substances

  • Antitubercular Agents
  • Ethambutol
  • EmbB protein, Mycobacterium tuberculosis
  • Pentosyltransferases