title: GeneXpert: A new tool for the rapid detection of rifampicin resistance in mycobacterium tuberculosis.
abstract: OBJECTIVE
  To evaluate the diagnostic accuracy of GeneXpert assay for the detection of rifampicin resistance in mycobacterium tuberculosis using conventional drug susceptibility testing as gold standard.
  
  
  METHODS
  This cross-sectional study was conducted at Jinnah Hospital, Lahore, / Allama Iqbal Medical College, Lahore, Pakistan, from January 2012 to December 2014, and comprised clinically and radiologically diagnosed tuberculosis suspected cases. Pulmonary and extra-pulmonary specimens were collected from strong tuberculosis suspects. All specimens were processed for Ziehl Neelsen staining, Lowenstein-Jensen culture and GeneXpert assay. All mycobacterium tuberculosis positive cases on Lowenstein-Jensen culture were further processed for drug susceptibility testing.
  
  
  RESULTS
  Of the 2,200 cases, 840(49.46%) were positive for mycobacterium tuberculosis on GeneXpert assay. Of them, 134(15.6%) cases showed rifampicin resistance on GeneXpert assay. The sensitivity, specificity, positive predictive value and negative predictive value of GeneXpert assay for rifampicin resistance were 127(98.3%), 704(99.1%), 127(94.7%) and 704(99.4%), respectively, by comparing the results with drug susceptibility testing.
  
  
  CONCLUSIONS
  GeneXpert assay was an extremely helpful diagnostic tool for the detection of rifampicin resistance in tuberculosis suspects with fairly high sensitivity and specificity along with short turnout time.
authors.affiliation: Department of Pathology, Allama Iqbal Medical College, Lahore, Pakistan.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Saeed
authors.affiliation: Department of Pathology, Allama Iqbal Medical College, Lahore, Pakistan.
authors.forename: Shagufta
authors.initials: S
authors.lastname: Iram
authors.affiliation: Department of Pathology, Allama Iqbal Medical College, Lahore, Pakistan.
authors.forename: Shahida
authors.initials: S
authors.lastname: Hussain
authors.affiliation: Department of Microbiology, University of Health Sciences, Lahore, Pakistan.
authors.forename: Adeel
authors.initials: A
authors.lastname: Ahmed
authors.affiliation: Department of Community Medicine, Allama Iqbal Medical College, Lahore, Pakistan.
authors.forename: Mamoon
authors.initials: M
authors.lastname: Akbar
authors.affiliation: Department of Pathology, Akhtar Saeed Medical and Dental College, Lahore, Pakistan.
authors.forename: Maleeha
authors.initials: M
authors.lastname: Aslam
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology*; D003430:Cross-Sectional Studies; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods*; D058889:Molecular Typing / Q000379:methods; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000235:genetics; D010154:Pakistan / Q000453:epidemiology; D012293:Rifampin / Q000494:pharmacology*; D014376:Tuberculosis / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents; D012293:Rifampin
keywords: GeneXpert MTB/RIF assay, Mycobacterium tuberculosis, Rifampicin resistance, Drug susceptibility testing. 