title: Selection of mutations to detect multidrug-resistant Mycobacterium tuberculosis strains in Shanghai, China.
abstract: Novel tools are urgently needed for the rapid, reliable detection of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of Mycobacterium tuberculosis. To develop such tools, we need information about the frequency and distribution of the mycobacterial mutations and genotypes that are associated with phenotypic drug resistance. In a population-based study, we sequenced specific genes of M. tuberculosis that were associated with resistance to rifampin and isoniazid in 242 phenotypically MDR isolates and 50 phenotypically pan-susceptible isolates from tuberculosis (TB) cases in Shanghai, China. We estimated the sensitivity and specificity of the mutations, using the results of conventional, culture-based phenotypic drug susceptibility testing as the standard. We detected mutations within the 81-bp core region of rpoB in 96.3% of phenotypically MDR isolates. Mutations in two structural genes (katG and inhA) and two regulatory regions (the promoter of mabA-inhA and the intergenic region of oxyR-ahpC) were found in 89.3% of the MDR isolates. In total, 88.0% (213/242 strains) of the phenotypic MDR strains were confirmed by mutations in the sequenced regions. Mutations in embB306 were also considered a marker for MDR and significantly increased the sensitivity of the approach. Based on our findings, an approach that prospectively screens for mutations in 11 sites of the M. tuberculosis genome (rpoB531, rpoB526, rpoB516, rpoB533, and rpoB513, katG315, inhA-15, ahpC-10, ahpC-6, and ahpC-12, and embB306) could detect 86.8% of MDR strains in Shanghai. This study lays the foundation for the development of a rapid, reliable molecular genetic test to detect MDR strains of M. tuberculosis in China.
authors.affiliation: Key Laboratory of Medical Molecular Virology, Institutes of Biomedical Sciences and Institute of Medical Microbiology, Fudan University, Shanghai 200032, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Luo
authors.forename: Ming
authors.initials: M
authors.lastname: Zhao
authors.forename: Xia
authors.initials: X
authors.lastname: Li
authors.forename: Peng
authors.initials: P
authors.lastname: Xu
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Gui
authors.forename: Sam
authors.initials: S
authors.lastname: Pickerill
authors.forename: Kathryn
authors.initials: K
authors.lastname: DeRiemer
authors.forename: Jian
authors.initials: J
authors.lastname: Mei
authors.forename: Qian
authors.initials: Q
authors.lastname: Gao
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics*; D002681:China; D015331:Cohort Studies; D003470:Culture Media; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D005838:Genotype; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods*; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D010641:Phenotype; D012680:Sensitivity and Specificity; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis* / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents; D001426:Bacterial Proteins; D003470:Culture Media