title: Rapid molecular screening for multidrug-resistant tuberculosis in a resource-limited region of China.
abstract: OBJECTIVE
  To investigate the molecular characteristics of MDR and XDR strains circulating in Chongqing, China.
  
  
  METHODS
  The drug target genes conferring for rifampicin (RIF), isoniazid (INH), ethambutol (EMB), ofloxacin (OFLX) and kanamycin (KAN) resistance were screened by DNA sequencing to determine the mutation frequencies in this area.
  
  
  RESULTS
  Drug susceptibility of 208 MDR isolates revealed that 132 (63.46%) were resistant to streptomycin (SM), 96 (46.15%) to ethambutol (EMB), 51 (24.52%) to ofloxacin (OFLX), and 26 (12.50%) to kanamycin (KAN); six (2.88%) isolates had XDR profiles. In comparison with the drug susceptibility phenotype, the sensitivity of drug resistance by DNA sequencing was 91.83% for RIF, 87.50% for INH, 66.67% for EMB, 74.51% for OFLX and 53.85% for KAN resistance. 12.50% of EMB- and 1.27% of OFLX-susceptible isolates were harboured genetic mutations in embB and gyrA, respectively.
  
  
  CONCLUSIONS
  Our findings demonstrate that the hot-spot regions localised in rpoB, katG and inhA genes serve as excellent markers for the corresponding drug resistance, while EMB, OFLX or KAN drug-resistant TB cases may not be identifiable by scanning embB, gyrA, rrs and eis promoter in Chongqing, indicating that further studies on the drug resistance mechanisms of EMB, OFLX and KAN are urgently needed to elucidate the low sensitivity between genomic substitutions and drug-resistant phenotype.
authors.affiliation: Yongchuan Hospital, Chongqing Medical University, Chongqing, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Zhang
authors.forename: Beizhong
authors.initials: B
authors.lastname: Liu
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Wang
authors.forename: Yu
authors.initials: Y
authors.lastname: Pang
mesh_terms: D000995:Antitubercular Agents / Q000627:therapeutic use; D001426:Bacterial Proteins / Q000235:genetics; D002681:China; D004269:DNA, Bacterial / Q000032:analysis*; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004977:Ethambutol / Q000627:therapeutic use; D005798:Genes, Bacterial; D006801:Humans; D007612:Kanamycin / Q000627:therapeutic use; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000235:genetics*; D015242:Ofloxacin / Q000627:therapeutic use; D010641:Phenotype; D017422:Sequence Analysis, DNA; D013307:Streptomycin / Q000627:therapeutic use; D018088:Tuberculosis, Multidrug-Resistant / Q000188:drug therapy / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D007612:Kanamycin; D004977:Ethambutol; D015242:Ofloxacin; D013307:Streptomycin
keywords: China; Chine; caracterización molecular; caractérisation moléculaire; molecular characterisation; multidrug resistance; multirresistencia; multirésistance; tuberculose; tuberculosis