title: Diagnostic usefulness of the GenoType MTBDRplus assay for detecting drug-resistant tuberculosis using AFB smear-negative specimens with positive TB-PCR result.
abstract: BACKGROUND
  The aim of this study was to evaluate the diagnostic accuracy of the GenoType MTBDRplus assay in detecting drug-resistant tuberculosis (DR-TB) by using acid-fast bacilli (AFB) smear-negative specimens with positive TB-PCR results.
  
  
  METHODS
  The MTBDRplus assay was performed with 2 different categories of 117 samples, including AFB smear-positive specimens (n = 53) and AFB smear-negative specimens (n =64), which exhibited positive TB-PCR results, at a single institution. The results were retrospectively compared with the results of the phenotypic drug susceptibility test (DST), for reference.
  
  
  RESULTS
  A total of 105 tests were finally analyzed. Of these, 54 tests were conducted using AFB smear-negative specimens with positive TB-PCR results. The MTBDRplus assay for these 54 samples demonstrated a sensitivity of 100%, specificity of 98%, positive predictive value (PPV) of 75%, and negative predictive value (NPV) of 100% in detecting rifampicin resistance. With these same species, the sensitivity, specificity, PPV, and NPV values for the MTBDRplus assay were 83.3%, 97.9%, 83.3%, and 97.9%, respectively, for the detection of isoniazid resistance. The overall correlation between the MTBDRplus assay and phenotypic DST demonstrated excellent agreement for detection of rifampicin resistance (κ = 0.847) and for detection of INH resistance (κ = 0.812), respectively.
  
  
  CONCLUSIONS
  The MTBDRplus assay can be used effectively even on AFB smear-negative specimens from TB patients, when the TB-PCR is positive. This result might help clinicians to manage patients with suspected DR-TB in difficult situations.
authors.affiliation: a Division of Pulmonology, Department of Internal Medicine , Institute of Chest Disease, Severance Hospital, Yonsei University College of Medicine , Seoul ;
authors.forename: Young Seok
authors.initials: YS
authors.lastname: Lee
authors.affiliation: b Division of Pulmonary Allergy and Critical Care Medicine, Department of Internal Medicine , Busan Paik Hospital, Inje University College of Medicine , Busan ;
authors.forename: Hye-Rim
authors.initials: HR
authors.lastname: Kang
authors.affiliation: b Division of Pulmonary Allergy and Critical Care Medicine, Department of Internal Medicine , Busan Paik Hospital, Inje University College of Medicine , Busan ;
authors.forename: Si-Hyeong
authors.initials: SH
authors.lastname: Lee
authors.affiliation: b Division of Pulmonary Allergy and Critical Care Medicine, Department of Internal Medicine , Busan Paik Hospital, Inje University College of Medicine , Busan ;
authors.forename: Yunmi
authors.initials: Y
authors.lastname: Kim
authors.affiliation: b Division of Pulmonary Allergy and Critical Care Medicine, Department of Internal Medicine , Busan Paik Hospital, Inje University College of Medicine , Busan ;
authors.forename: Mi-Yeong
authors.initials: MY
authors.lastname: Kim
authors.affiliation: c Department Laboratory Medicine , Busan Paik Hospital, Inje University College of Medicine , Busan ;
authors.forename: Jeong Hwan
authors.initials: JH
authors.lastname: Shin
authors.affiliation: d Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine , Chungnam National University Hospital , Daejeon ;
authors.forename: Jae Young
authors.initials: JY
authors.lastname: Moon
authors.affiliation: b Division of Pulmonary Allergy and Critical Care Medicine, Department of Internal Medicine , Busan Paik Hospital, Inje University College of Medicine , Busan ;
authors.forename: Hyun-Kyung
authors.initials: HK
authors.lastname: Lee
authors.affiliation: e Department of Pulmonary and Critical Care Medicine , Hallym University Kangdong Sacred Heart Hospital , Seoul ;
authors.forename: So Young
authors.initials: SY
authors.lastname: Park
authors.affiliation: e Department of Pulmonary and Critical Care Medicine , Hallym University Kangdong Sacred Heart Hospital , Seoul ;
authors.forename: Eun-Kyung
authors.initials: EK
authors.lastname: Mo
authors.affiliation: e Department of Pulmonary and Critical Care Medicine , Hallym University Kangdong Sacred Heart Hospital , Seoul ;
authors.forename: Yong Bum
authors.initials: YB
authors.lastname: Park
authors.affiliation: e Department of Pulmonary and Critical Care Medicine , Hallym University Kangdong Sacred Heart Hospital , Seoul ;
authors.forename: Soo-Yoon
authors.initials: SY
authors.lastname: Moon
authors.affiliation: f Department of Pharmacology and Clinical Trial Center , Inje University Busan Paik Hospital , Busan , Republic of Korea.
authors.forename: Minkyung
authors.initials: M
authors.lastname: Oh
authors.affiliation: b Division of Pulmonary Allergy and Critical Care Medicine, Department of Internal Medicine , Busan Paik Hospital, Inje University College of Medicine , Busan ;|e Department of Pulmonary and Critical Care Medicine , Hallym University Kangdong Sacred Heart Hospital , Seoul ;
authors.forename: Yousang
authors.initials: Y
authors.lastname: Ko
mesh_terms: D000328:Adult; D000368:Aged; D000995:Antitubercular Agents / Q000494:pharmacology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D058889:Molecular Typing / Q000379:methods*; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012189:Retrospective Studies; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis* / Q000382:microbiology*
chemical_list: D000995:Antitubercular Agents
keywords: AFB smear-negative specimen; MTBDRplus; Mycobacterium tuberculosis