Search

Background: Beijing sub-pedigree 2 (BSP2) and T sub-lineage 6 (TSL6) are two clades belonging to Beijing and T family of Mycobacterium tuberculosis (MTB), respectively, defined by Bayesian population structure analysis based on 24-loci mycobacterial interspersed repetitive unit-variable number of tandem repeats (MIRU-VNTR). Globally, over 99% of BSP2 and 89% of TSL6 isolates were distributed in Chongqing, suggesting their possible local adaptive evolution. The objective of this paper is to explore whether BSP2 and TSL6 originated by their local adaptive evolution from the specific isolates of Beijing and T families in Chongqing., Methods: The genotyping data of 16 090 MTB isolates were collected from laboratory collection, published literatures and SITVIT database before subjected to Bayesian population structure analysis based on 24-loci MIRU-VNTR. Spacer Oligonucleotide Forest (Spoligoforest) and 24-loci MIRU-VNTR-based minimum spanning tree (MST) were used to explore their phylogenetic pathways, with Bayesian demographic analysis for exploring the recent demographic change of TSL6., Results: Phylogenetic analysis suggested that BSP2 and TSL6 in Chongqing may evolve from BSP4 and TSL5, respectively, which were locally predominant in Tibet and Jiangsu, respectively. Spoligoforest showed that Beijing and T families were genetically distant, while the convergence of the MIRU-VNTR pattern of BSP2 and TSL6 was revealed by WebLogo. The demographic analysis concluded that the recent demographic change of TSL6 might take 111.25 years., Conclusions: BSP2 and TSL6 clades might originate from BSP4 and TSL5, respectively, by their local adaptive evolution in Chongqing. Our study suggests MIRU-VNTR be combined with other robust markers for a more comprehensive genotyping approach, especially for families of clades with the same MIRU-VNTR pattern.

Objective: To describe the current situation and explore risk factors to irregularly antipulmonary tuberculosis(TB) drugs taking in smear positive TB patients., Methods: Four out of the forty counties in Chongqing were randomly sampled according to the levels of social and economic development. Totally, 405 new patients with smear positive tuberculosis were systematically sampled and a household survey was carried out. A multiple logistic regression model was fitted to explore the risk factors to irregularly anti-TB drugs taking., Results: Of valid 401 cases, 50 (12.47%) did not take their drugs regularly and the top 3 reasons for irregular drugs taking were: (1) Adverse effects; (2)Economic hardship; (3) Stopped taking drugs when symptom disappeared. Results from multiple logistic regression analysis showed that factors as: self-perceived economical burden, awareness on TB before being infected and awareness on the fact that if anti-TB drugs can be stopped if the symptoms disappeared, were statistically significant to irregularly drugs taking., Conclusion: Strengthening health education program and alleviation of economical burden might serve as two effective measures for regularly drugs taking among TB patients.