title: Xpert MTB/RIF and GenoType MTBDRplus assays for the rapid diagnosis of bone and joint tuberculosis.
abstract: BACKGROUND
  Bone and joint tuberculosis (BJTB) constitutes about 10-20% of the extrapulmonary tuberculosis (EPTB) cases in China. The GenoType MTBDRplus assay (MTBDR) has been endorsed by the World Health Organization (WHO) for the diagnosis of pulmonary TB (PTB), while the Xpert MTB/RIF assay (Xpert) has also been endorsed by the WHO for the diagnosis of both PTB and EPTB. The diagnostic utility of these two techniques for BJTB was investigated prospectively.
  
  
  METHODS
  Sixty pus specimens were obtained from orthopedic patients. Smear, culture, Xpert, and MTBDR assays were performed for each specimen, and MGIT 960-based drug susceptibility testing (DST) was conducted for all of the isolates recovered. The diagnostic efficiency of Xpert and MTBDR was evaluated on the basis of bacteriological examination and the composite reference standard (CRS).
  
  
  RESULTS
  Fifty of the 60 patients were considered to have BJTB according to the CRS. The sensitivities of smear, culture, Xpert, and MTBDR were 26% (13/50), 48% (24/50), 82% (41/50), and 72% (36/50) respectively, while the specificities of all of the tests were 100% (10/10). Xpert was 100% concordant with MGIT 960-based DST for the detection of rifampicin resistance. MTBDR had a sensitivity of 83.3% and a specificity of 100% for the detection of rifampicin resistance and a sensitivity of 85.7% and specificity of 100% for the detection of isoniazid resistance.
  
  
  CONCLUSIONS
  With their high sensitivities, short turnaround times, and ability to diagnose TB and detect drug resistance simultaneously, both Xpert and MTBDR are feasible as diagnostic tools for BJTB in clinical practice.
authors.affiliation: National Clinical Laboratory on Tuberculosis, Beijing Key Laboratory for Drug-resistant Tuberculosis Research, Ma-Chang Rd 97, Beijing 101149, China.
authors.forename: Yunting
authors.initials: Y
authors.lastname: Gu
authors.affiliation: National Clinical Laboratory on Tuberculosis, Beijing Key Laboratory for Drug-resistant Tuberculosis Research, Ma-Chang Rd 97, Beijing 101149, China.
authors.forename: Guirong
authors.initials: G
authors.lastname: Wang
authors.affiliation: Department of Orthopedics, Beijing Bone and Joint Tuberculosis Diagnosis and Treatment Center, Beijing Chest Hospital, Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Institute, Beijing, China.
authors.forename: Weijie
authors.initials: W
authors.lastname: Dong
authors.affiliation: National Clinical Laboratory on Tuberculosis, Beijing Key Laboratory for Drug-resistant Tuberculosis Research, Ma-Chang Rd 97, Beijing 101149, China.
authors.forename: Yunxu
authors.initials: Y
authors.lastname: Li
authors.affiliation: National Clinical Laboratory on Tuberculosis, Beijing Key Laboratory for Drug-resistant Tuberculosis Research, Ma-Chang Rd 97, Beijing 101149, China.
authors.forename: Yifeng
authors.initials: Y
authors.lastname: Ma
authors.affiliation: National Clinical Laboratory on Tuberculosis, Beijing Key Laboratory for Drug-resistant Tuberculosis Research, Ma-Chang Rd 97, Beijing 101149, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Shang
authors.affiliation: Department of Orthopedics, Beijing Bone and Joint Tuberculosis Diagnosis and Treatment Center, Beijing Chest Hospital, Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Institute, Beijing, China. Electronic address: qinsb@sina.com.
authors.forename: Shibing
authors.initials: S
authors.lastname: Qin
authors.affiliation: National Clinical Laboratory on Tuberculosis, Beijing Key Laboratory for Drug-resistant Tuberculosis Research, Ma-Chang Rd 97, Beijing 101149, China. Electronic address: huanghairong@tb123.org.
authors.forename: Hairong
authors.initials: H
authors.lastname: Huang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D024881:Drug Resistance, Bacterial; D005260:Female; D005838:Genotype; D006801:Humans; D007538:Isoniazid / Q000494:pharmacology; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000235:genetics; D016133:Polymerase Chain Reaction; D012293:Rifampin / Q000494:pharmacology; D012680:Sensitivity and Specificity; D014394:Tuberculosis, Osteoarticular / Q000175:diagnosis* / Q000382:microbiology; D055815:Young Adult
chemical_list: D007538:Isoniazid; D012293:Rifampin
keywords: Bone and joint tuberculosis; GenoType MTBDRplus; Xpert MTB/RIF