摘要

抗生素使用的选择性压力是与结核分枝杆菌（MTB）中耐药性发展相关的最重要的风险因素之一。然而，在分子水平上潜在的耐药机制仍然部分不清楚。因此，本研究的目的是研究抗结核治疗引起的新突变的潜在功能作用。我们分析了来自同一患者的两种耐多药TB（MDR-TB）分离株;在开始耐多药结核病治疗之前和之后近一年收集的一个。处理后的分离物表现出升高的乙胺丁醇抗性。我们对两个临床分离株的全基因组进行了测序，并检测到6个影响基因Rv1026，nc0021，Rv2155c，Rv2437和Rv3696c的新型多态性，以及Rv2764c和Rv2765之间的基因间区域。代谢组学方法用于揭示发现的变异对MTB代谢途径的影响。偏最小二乘判别分析显示两种分离物之间存在明显的区别，共涉及175种代谢物。通路分析表明，这些代谢产物主要参与氨基糖和核苷酸糖代谢，β-丙氨酸代谢，硫代谢和半乳糖代谢。治疗后MDR-TB菌株表现出的乙胺丁醇耐药性增加可能与推断的遗传变异有关，这些变异影响了与碳和能源相关的许多代谢物的合成。这可能是该分离株增加乙胺丁醇抗性的主要因素。

Selective pressure from antibiotic use is one of the most important risk factors associated with the development of drug resistance in Mycobacterium tuberculosis (MTB). However, the mechanisms underlying drug resistance at the molecular level remain partly unclear. Therefore, the purpose of this study was to investigate the potential functional effect of novel mutations arising from anti-tuberculosis treatment. We analyzed two multidrug-resistant TB (MDR-TB) isolates from the same patient; one collected before and one almost a year after commencing MDR-TB treatment. The post-treatment isolate exhibited elevated ethambutol resistance. We sequenced the whole genomes of the two clinical isolates and detected six novel polymorphisms affecting the genes Rv1026, nc0021, Rv2155c, Rv2437, and Rv3696c, and the intergenic region between Rv2764c and Rv2765. Metabolomics approach was used to reveal the effect of the found variation on the metabolic pathways of MTB. Partial least squares-discriminant analysis showed a clear differentiation between the two isolates, involving a total of 175 metabolites. Pathway analysis showed that these metabolites are mainly involved in amino sugar and nucleotide sugar metabolism, β-alanine metabolism, sulfur metabolism, and galactose metabolism. The increased ethambutol resistance exhibited by the post-treatment MDR-TB strain could speculatively be linked to the identified genetic variations, which affected the synthesis of a number of metabolites associated with sources of carbon and energy. This may have been the main factor underlying the increased ethambutol resistance of this isolate.

https://www.ncbi.nlm.nih.gov/pubmed/30292007