title: Identification of Mycobacterium tuberculosis and rifampin resistance in clinical specimens using the Xpert MTB/RIF assay.
abstract: OBJECTIVE
  The Xpert MTB/RIF assay is a novel real-time polymerase chain reaction technique for the detection of the Mycobacterium tuberculosis (MTB) complex and rifampin (RIF) resistance. We evaluated the performance of this assay in identifying MTB and resistance to RIF in clinical specimens.
  
  
  METHODS
  We analyzed clinical specimens from 383 patients with suspected TB who were hospitalized at a secondary hospital in Korea. Specimens were processed using the Xpert MTB/RIF assay, acid-fast bacilli smear and culture, and drug susceptibility test (DST).
  
  
  RESULTS
  Among the 444 clinical samples analyzed, the Xpert MTB/RIF assay identified MTB in 56 (13.8%) of 405 respiratory specimens, but did not detect MTB in the remaining 39 non-respiratory specimens. Of the 65 pulmonary TB patients, 52 (80.0%) were confirmed by using mycobacterial culture as a reference standard. The sensitivity, specificity, PPV, and NPV of the Xpert MTB/RIF assay were 73.85%, 99.03%, 94.12%, and 94.72%, respectively. Among five patients with RIF resistance determined by the Xpert MTB/RIF assay, four (80%) were confirmed as suffering from multidrug-resistant (MDR) TB by DST.
  
  
  CONCLUSIONS
  The Xpert MTB/RIF assay appears to be an accurate, simple, and useful technique for detecting MTB, especially in respiratory specimens. However, RIF resistance, if detected, should be verified with DST.
authors.affiliation: Departments of Internal Medicine Lung Research Institute and.
authors.forename: Cheol-Hong
authors.initials: CH
authors.lastname: Kim
authors.affiliation: Departments of Internal Medicine Lung Research Institute and hskim0901@empal.com ighyun@hallym.or.kr.
authors.forename: In Gyu
authors.initials: IG
authors.lastname: Hyun
authors.affiliation: Departments of Internal Medicine Lung Research Institute and.
authors.forename: Yong Il
authors.initials: YI
authors.lastname: Hwang
authors.affiliation: Departments of Internal Medicine Lung Research Institute and.
authors.forename: Dong-Gyu
authors.initials: DG
authors.lastname: Kim
authors.affiliation: Departments of Internal Medicine Lung Research Institute and.
authors.forename: Chang Youl
authors.initials: CY
authors.lastname: Lee
authors.affiliation: Departments of Internal Medicine Lung Research Institute and.
authors.forename: Myung Goo
authors.initials: MG
authors.lastname: Lee
authors.affiliation: Departments of Internal Medicine Lung Research Institute and.
authors.forename: Ki-Suck
authors.initials: KS
authors.lastname: Jung
authors.affiliation: Departments of Internal Medicine.
authors.forename: Heungjeong
authors.initials: H
authors.lastname: Woo
authors.affiliation: Laboratory Medicine, Hallym University College of Medicine, Chuncheon and.
authors.forename: Jeongwon
authors.initials: J
authors.lastname: Hyun
authors.affiliation: Laboratory Medicine, Hallym University College of Medicine, Chuncheon and hskim0901@empal.com ighyun@hallym.or.kr.
authors.forename: Hyun Soo
authors.initials: HS
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Korea.
authors.forename: Myung Jae
authors.initials: MJ
authors.lastname: Park
mesh_terms: D024881:Drug Resistance, Bacterial / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000379:methods*; D011933:Reagent Kits, Diagnostic; D012293:Rifampin; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis / Q000382:microbiology
chemical_list: D011933:Reagent Kits, Diagnostic; D012293:Rifampin
keywords: pulmonary tuberculosis; real-time polymerase chain reaction; rifampin