title: Transmission of Mycobacterium tuberculosis in China: a population-based molecular epidemiologic study.
abstract: BACKGROUND
  Understanding the transmission of Mycobacterium tuberculosis is essential for the development of efficient tuberculosis control strategies. China has the second-largest tuberculosis burden in the world. Recent transmission and infection with M. tuberculosis, particularly drug-resistant strains, may account for many new tuberculosis cases.
  
  
  METHODS
  We performed a population-based molecular epidemiologic study of pulmonary tuberculosis in China during 1 July 2009 to 30 June 2012. We defined clusters as cases with identical variable number tandem repeat genotype patterns and identified the risk factors associated with clustering, by logistic regression. Relative transmission rates were estimated by the sputum smear status and drug susceptibility status of tuberculosis patients.
  
  
  RESULTS
  Among 2274 culture-positive tuberculosis patients with genotyped isolates, there were 705 (31.0%) tuberculosis patients in 287 clusters. Multidrug-resistant (MDR) tuberculosis (adjusted odds ratio [aOR], 1.86; 95% confidence interval [CI], 1.25-2.63) and infection with a Beijing family strain (aOR, 1.56; 95% CI, 1.23-2.96) were associated with clustering. Eighty-four of 280 (30.0%) clusters had a putative source case that was sputum smear negative, and 30.6% of their secondary cases were attributed to transmission by sputum smear-negative patients. The relative transmission rate for sputum smear negative compared with sputum smear-positive patients was 0.89 (95% CI, .68-1.10), and was 1.51 (95% CI, 1.00-2.24) for MDR tuberculosis vs drug-susceptible tuberculosis.
  
  
  CONCLUSIONS
  Recent transmission of M. tuberculosis, including MDR strains, contributes substantially to tuberculosis disease in China. Sputum smear-negative cases were responsible for at least 30% of the secondary cases. Interventions to reduce the transmission of M. tuberculosis should be implemented in China.
authors.affiliation: Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Institutes of Biomedical Sciences and Institute of Medical Microbiology, Shanghai Medical College, Fudan University.
authors.forename: Chongguang
authors.initials: C
authors.lastname: Yang
authors.affiliation: Department of Tuberculosis Control, Shanghai Municipal Center for Disease Control and Prevention.
authors.forename: Xin
authors.initials: X
authors.lastname: Shen
authors.affiliation: Tuberculosis Control Center of Heilongjiang Province, Harbin.
authors.forename: Ying
authors.initials: Y
authors.lastname: Peng
authors.affiliation: Guangxi Zhuang Autonomous Region Center for Disease Control and Prevention, Nanning.
authors.forename: Rushu
authors.initials: R
authors.lastname: Lan
authors.affiliation: Henan Center for Disease Control and Prevention, Zhengdong New District, Zhengzhou.
authors.forename: Yuling
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Sichuan Center for Disease Control and Prevention, Chengdu.
authors.forename: Bo
authors.initials: B
authors.lastname: Long
authors.affiliation: Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Institutes of Biomedical Sciences and Institute of Medical Microbiology, Shanghai Medical College, Fudan University.
authors.forename: Tao
authors.initials: T
authors.lastname: Luo
authors.affiliation: Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Institutes of Biomedical Sciences and Institute of Medical Microbiology, Shanghai Medical College, Fudan University.
authors.forename: Guomei
authors.initials: G
authors.lastname: Sun
authors.affiliation: Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Institutes of Biomedical Sciences and Institute of Medical Microbiology, Shanghai Medical College, Fudan University.
authors.forename: Xia
authors.initials: X
authors.lastname: Li
authors.affiliation: Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Institutes of Biomedical Sciences and Institute of Medical Microbiology, Shanghai Medical College, Fudan University.
authors.forename: Ke
authors.initials: K
authors.lastname: Qiao
authors.affiliation: Department of Tuberculosis Control, Shanghai Municipal Center for Disease Control and Prevention.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Gui
authors.affiliation: Department of Tuberculosis Control, Shanghai Municipal Center for Disease Control and Prevention.
authors.forename: Jie
authors.initials: J
authors.lastname: Wu
authors.affiliation: Henan Center for Disease Control and Prevention, Zhengdong New District, Zhengzhou.
authors.forename: Jiying
authors.initials: J
authors.lastname: Xu
authors.affiliation: Tuberculosis Control Center of Heilongjiang Province, Harbin.
authors.forename: Fabin
authors.initials: F
authors.lastname: Li
authors.affiliation: Sichuan Center for Disease Control and Prevention, Chengdu.
authors.forename: Dingyue
authors.initials: D
authors.lastname: Li
authors.affiliation: Guangxi Zhuang Autonomous Region Center for Disease Control and Prevention, Nanning.
authors.forename: Feiying
authors.initials: F
authors.lastname: Liu
authors.affiliation: Department of Tuberculosis Control, Shanghai Municipal Center for Disease Control and Prevention.
authors.forename: Mei
authors.initials: M
authors.lastname: Shen
authors.affiliation: Department of Tuberculosis Control, Songjiang District Center for Disease Control and Prevention, Shanghai, People's Republic of China.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Hong
authors.affiliation: Department of Tuberculosis Control, Shanghai Municipal Center for Disease Control and Prevention.
authors.forename: Jian
authors.initials: J
authors.lastname: Mei
authors.affiliation: School of Medicine, University of California, Davis.
authors.forename: Kathryn
authors.initials: K
authors.lastname: DeRiemer
authors.affiliation: Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Institutes of Biomedical Sciences and Institute of Medical Microbiology, Shanghai Medical College, Fudan University.
authors.forename: Qian
authors.initials: Q
authors.lastname: Gao
mesh_terms: D000328:Adult; D000368:Aged; D000995:Antitubercular Agents; D000068476:Beijing; D002681:China / Q000453:epidemiology; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D018598:Minisatellite Repeats; D017720:Molecular Epidemiology; D009169:Mycobacterium tuberculosis / Q000235:genetics*; D016017:Odds Ratio; D012044:Regression Analysis; D012307:Risk Factors; D013183:Sputum / Q000382:microbiology; D013997:Time Factors; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis / Q000382:microbiology / Q000635:transmission*; D014397:Tuberculosis, Pulmonary / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission*; D014505:Urban Population / Q000706:statistics & numerical data*
chemical_list: D000995:Antitubercular Agents; D004269:DNA, Bacterial
keywords: China; molecular epidemiology; recent transmission; tuberculosis
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