The Beijing family is the most successful genotype of Mycobacterium tuberculosis and responsible for more than a quarter of the global tuberculosis epidemic. As the predominant genotype in East Asia, the Beijing family has been emerging in various areas of the world and is often associated with disease outbreaks and antibiotic resistance. Revealing the origin and historical dissemination of this strain family is important for understanding its current global success. Here we characterized the global diversity of this family based on whole-genome sequences of 358 Beijing strains. We show that the Beijing strains endemic in East Asia are genetically diverse, whereas the globally emerging strains mostly belong to a more homogenous subtype known as “modern” Beijing. Phylogeographic and coalescent analyses indicate that the Beijing family most likely emerged around 30,000 y ago in southern East Asia, and accompanied the early colonization by modern humans in this area. By combining the genomic data and genotyping result of 1,793 strains from across China, we found the “modern” Beijing sublineage experienced massive expansions in northern China during the Neolithic era and subsequently spread to other regions following the migration of Han Chinese. Our results support a parallel evolution of the Beijing family and modern humans in East Asia. The dominance of the “modern” Beijing sublineage in East Asia and its recent global emergence are most likely driven by its hypervirulence, which might reflect adaption to increased human population densities linked to the agricultural transition in northern China.
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.
BackgroundAs one of the poorest provinces in China, Guangxi has a high HIV and TB prevalence, with the annual number of TB/HIV cases reported by health department among the highest in the country. However, studies on the burden of TB-HIV co-infection and risk factors for active TB among HIV-infected persons in Guangxi have rarely been reported.ObjectiveTo investigate the risk factors for active TB among people living with HIV/AIDS in Guangxi Zhuang autonomous region, China.MethodsA surveillance survey was conducted of 1 019 HIV-infected patients receiving care at three AIDS prevention and control departments between 2013 and 2015. We investigated the cumulative prevalence of TB during 2 years. To analyze risk factors associated with active TB, we conducted a 1:1 pair-matched case-control study of newly reported active TB/HIV co-infected patients. Controls were patients with HIV without active TB, latent TB infection or other lung disease, who were matched with the case group based on sex and age (± 3 years).ResultsA total of 1 019 subjects were evaluated. 160 subjects (15.70%) were diagnosed with active TB, including 85 clinically diagnosed cases and 75 confirmed cases. We performed a 1:1 matched case-control study, with 82 TB/HIV patients and 82 people living with HIV/AIDS based on surveillance site, sex and age (±3) years. According to multivariate analysis, smoking (OR = 2.996, 0.992–9.053), lower CD 4+ T-cell count (OR = 3.288, 1.161–9.311), long duration of HIV-infection (OR = 5.946, 2.221–15.915) and non-use of ART (OR = 7.775, 2.618–23.094) were independent risk factors for TB in people living with HIV/AIDS.ConclusionThe prevalence of active TB among people living with HIV/AIDS in Guangxi was 173 times higher than general population in Guangxi. It is necessary for government to integrate control planning and resources for the two diseases. Medical and public health workers should strengthen health education for TB/HIV prevention and treatment and promote smoking cessation. Active TB case finding and early initiation of ART is necessary to minimize the burden of disease among patients with HIV, as is IPT and infection control in healthcare facilities.
The aim of this paper is to evaluate the link between the history of exposure to tuberculosis (TB) in the household and diagnosed TB cases at school, and to compare the detection rate of active TB among household contacts and classroom contacts of adolescent TB cases with the rates among contacts of healthy controls. From November 2016 to December 2017, a prospective matched case-control study was conducted using passively identified index adolescent student cases from the TB surveillance system and healthy controls (matched by county, school type, sex, age and ethnicity). Contacts in households and classrooms of index cases and of controls were investigated. Matched tabulation of 117 case-control pairs revealed exposure to TB in the household as a strong risk factor (odds ratio (OR) = 21.0, 95% confidence interval (CI): 3.4, 868.6). Forty-five (case detection rate 0.69%) and two (case detection rate 0.03%) new active TB cases were detected among 6512 and 6480 classroom contacts of the index cases and controls, respectively. Having an index case in the classroom significantly increased the risk of classmates contracting active TB (OR = 22.5, 95% CI: 5.9, 191.4). Our findings suggested that previous exposure to TB in the household could lead a child to catch TB at school, then spread TB to classmates.
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