title: Detection of ofloxacin resistance by nitrate reductase assay inMycobacterium tuberculosisisolates from extrapulmonary tuberculosis.
abstract: BACKGROUND
  Increased use of fluoroquinolones to treat community-acquired infections has led to the decreased susceptibility to Mycobacterium tuberculosis. There is a paucity of data on ofloxacin (OFX) resistance detection by nitrate reductase assay (NRA). Hence, the present study was carried out to find the efficacy of NRA for detection of OFX resistance in M. tuberculosis isolated from extrapulmonary tuberculosis (EPTB) cases.
  
  
  OBJECTIVE
  (1) To compare sensitivity, specificity and median time required to obtain results by NRA with economic variant proportion method (PM) for detection of OFX resistance.(2) To determine the extent of OFX resistance in clinical isolates of M. tuberculosis.
  
  
  METHODS
  Seventy-three M. tuberculosis isolates from cases of EPTB were subjected to economic variant of PM for isoniazid, rifampicin and OFX. NRA was done for detection of OFX resistance.
  
  
  METHODS
  Seventy-three isolates from clinical samples of suspected EPTB received in the Department of Microbiology were included in the study. Drug susceptibility test was performed on Lowenstein-Jensen medium with and without drugs.
  
  
  METHODS
  Of turnaround time was done by Mann-Whitney test on SPSS (version 19, released in 2010, IBM Corp, Armonk NY),P < 0.05.
  
  
  RESULTS
  OFX resistance was seen in nine isolates. The sensitivity and specificity of OFX resistance by NRA was 100% and 96.87%, respectively. Median time required to obtain results by NRA was 10 days as compared to 28 days by PM.
  
  
  CONCLUSIONS
  NRA is a specific and sensitive method for detection of OFX resistance in resource-restricted settings.
authors.affiliation: Department of Microbiology, TNMC and B. Y. L. Nair Charitable Hospital, Mumbai, Maharashtra, India.
authors.forename: Neeta
authors.initials: N
authors.lastname: Shrivastava
authors.affiliation: Department of Microbiology, TNMC and B. Y. L. Nair Charitable Hospital, Mumbai, Maharashtra, India.
authors.forename: Reena
authors.initials: R
authors.lastname: Set
authors.affiliation: Department of Microbiology, TNMC and B. Y. L. Nair Charitable Hospital, Mumbai, Maharashtra, India.
authors.forename: Sheetal
authors.initials: S
authors.lastname: Bankar
authors.affiliation: Department of Microbiology, TNMC and B. Y. L. Nair Charitable Hospital, Mumbai, Maharashtra, India.
authors.forename: Jayanthi
authors.initials: J
authors.lastname: Shastri
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology*; D006801:Humans; D007538:Isoniazid / Q000494:pharmacology; D008826:Microbial Sensitivity Tests / Q000191:economics / Q000379:methods*; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000201:enzymology* / Q000302:isolation & purification; D050901:Nitrate Reductase / Q000032:analysis*; D015242:Ofloxacin / Q000494:pharmacology*; D012293:Rifampin / Q000494:pharmacology; D012680:Sensitivity and Specificity; D013997:Time Factors; D014376:Tuberculosis / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents; D015242:Ofloxacin; D050901:Nitrate Reductase; D007538:Isoniazid; D012293:Rifampin