Rapid and low-cost colorimetric method using 2,3,5-triphenyltetrazolium chloride for detection of multidrug-resistant Mycobacterium tuberculosis

J Med Microbiol. 2006 Dec;55(Pt 12):1657-1659. doi: 10.1099/jmm.0.46442-0.

Abstract

A rapid and inexpensive method for the detection of drug resistance in Mycobacterium tuberculosis is essential for the effective control of tuberculosis. The aim of this study was to evaluate a colorimetric method using 2,3,5-triphenyltetrazolium chloride (TTC) for antibiotic susceptibility testing of M. tuberculosis isolates. Eleven multidrug-resistant (MDR) isolates of M. tuberculosis and 12 isolates which were susceptible to rifampicin (RIF) and isoniazid (INH) were used. The test was performed with a critical concentration of 0.2 microg ml(-1) for INH and 2.0 microg ml(-1) for RIF in 7H9GC broth with 0.625 microg TTC ml(-1). Each isolate was inoculated under these conditions and inspected daily for colour changes; the results were obtained after a mean of 4.9 days. The sensitivity and specificity of this method were 100 % and 92 %, respectively, for both antibiotics. Considering the speed, technical ease and cost-effectiveness of this method, the TTC assay is a good alternative method for drug susceptibility testing of M. tuberculosis isolates.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibiotics, Antitubercular / pharmacology*
  • Bacteriological Techniques / methods*
  • Drug Resistance, Multiple, Bacterial*
  • Humans
  • Isoniazid / pharmacology*
  • Microbial Sensitivity Tests / methods*
  • Mycobacterium tuberculosis / drug effects*
  • Rifampin / pharmacology*
  • Sensitivity and Specificity
  • Tetrazolium Salts
  • Tuberculosis / microbiology*

Substances

  • Antibiotics, Antitubercular
  • Tetrazolium Salts
  • triphenyltetrazolium
  • Isoniazid
  • Rifampin