title: Genetic diversity of multidrug-resistant tuberculosis in a resource-limited region of China.
abstract: OBJECTIVE
  To gain an insight into the genetic diversity of multidrug-resistant (MDR) Mycobacterium tuberculosis isolates in Chongqing Municipality, an MDR tuberculosis (MDR-TB) epidemic region of China.
  
  
  METHODS
  In this study, a total of 208M. tuberculosis isolates from smear-positive TB patients in Chongqing were genotyped by spoligotyping and mycobacterial interspersed repetitive unit-variable number tandem repeat typing (MIRU-VNTR). In addition, statistical analysis was performed to evaluate the distributions of drug susceptibility patterns and demographic data among different genotypes.
  
  
  RESULTS
  Our results showed that 156 MDR M. tuberculosis strains (75.0%) belonged to the Beijing genotype, while the other 52 strains (25.0%) were non-Beijing genotype. The proportion of Beijing genotype in the re-treated patient group was significantly higher than that in the new patient group (p=0.013), while drug resistance and demographic characteristics showed no statistically significant associations with Beijing genotype (p>0.05). In addition, the 208 strains were clustered into 193 genotypes using a 10-locus VNTR set; the cumulative clustering rate was 12.98% and the HGDI was 0.9991.
  
  
  CONCLUSIONS
  Beijing genotype was the predominant genotype among the isolates from MDR-TB cases in Chongqing. The re-treated MDR-TB cases were more likely to be attributed to Beijing genotype infection. The 10-locus VNTR set demonstrated a good discrimination power for genotyping MDR M. tuberculosis isolates circulating in Chongqing Municipality.
authors.affiliation: Yongchuan Hospital, Chongqing Medical University, Chongqing, China; National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, No. 155, Changbai Road, Changping District, Beijing, 102206, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Tuberculosis and Thoracic Tumor Research Institute, Beijing Chest Hospital, Capital Medical University, Beijing, China.
authors.forename: Jun
authors.initials: J
authors.lastname: An
authors.affiliation: National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, No. 155, Changbai Road, Changping District, Beijing, 102206, China.
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Wang
authors.affiliation: National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, No. 155, Changbai Road, Changping District, Beijing, 102206, China. Electronic address: pangyu@chinatb.org.
authors.forename: Yu
authors.initials: Y
authors.lastname: Pang
mesh_terms: D000328:Adult; D000368:Aged; D002681:China; D003710:Demography; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D006295:Health Resources; D006801:Humans; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D018088:Tuberculosis, Multidrug-Resistant / Q000382:microbiology*; D055815:Young Adult
keywords: Genotyping; Multidrug resistance; Mycobacterium tuberculosis