title: Rapid colorimetric pyrazinamide susceptibility testing of Mycobacterium tuberculosis.
abstract: METHODS
  Colorimetric methods for detecting drug resistance in Mycobacterium tuberculosis are very attractive, as they are cheap, easy to use and require no costly apparatus. Although the current colorimetric methods have been used for other drugs, such as rifampicin and isoniazid, few of the colorimetric methods have been reported to have been used in performing drug susceptibility testing (DST) against pyrazinamide (PZA).
  
  
  OBJECTIVE
  To develop a rapid and reliable colorimetric method for PZA DST using a monotetrazolium redox dye, 5-cyano-2,3-ditolyl tetrazolium chloride (CTC), as indicator of viability.
  
  
  METHODS
  A total of 50 clinical isolates and three standard strains were tested using this colorimetric method and the BACTEC™ MGIT™ 960 system.
  
  
  RESULTS
  Initial test results showed that the PZA DST results were available in 4-6 days; the overall sensitivity and specificity of the CTC colorimetric method were respectively 97.1% and 81.3% in comparison with the MGIT 960 results.
  
  
  CONCLUSIONS
  These results suggest that the CTC colorimetric method is most rapid among the current PZA DST methods based on culture, and could be used for determining susceptibility to PZA of M. tuberculosis isolates.
authors.affiliation: Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China; University of Chinese Academy of Sciences, Beijing, China.
authors.forename: H
authors.initials: H
authors.lastname: Li
authors.affiliation: Tuberculosis Reference Laboratory, Hubei Provincial Institute of Tuberculosis Control And Prevention, Wuhan, China.
authors.forename: L-P
authors.initials: LP
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China; University of Chinese Academy of Sciences, Beijing, China.
authors.forename: J
authors.initials: J
authors.lastname: Luo
authors.affiliation: Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
authors.forename: J-P
authors.initials: JP
authors.lastname: Yu
authors.affiliation: Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
authors.forename: H
authors.initials: H
authors.lastname: Yang
authors.affiliation: Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
authors.forename: H-P
authors.initials: HP
authors.lastname: Wei
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology*; D003124:Colorimetry; D024881:Drug Resistance, Bacterial; D007538:Isoniazid / Q000494:pharmacology; D008826:Microbial Sensitivity Tests / Q000379:methods*; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000302:isolation & purification; D011718:Pyrazinamide / Q000494:pharmacology*; D012293:Rifampin / Q000494:pharmacology; D012680:Sensitivity and Specificity; D013778:Tetrazolium Salts / Q000737:chemistry
chemical_list: D000995:Antitubercular Agents; D013778:Tetrazolium Salts; C075453:5-cyano-2,3-ditolyltetrazolium; D011718:Pyrazinamide; D007538:Isoniazid; D012293:Rifampin