Tracevska T, Jansone I, Baumanis V, Marga O, Lillebaek T
Laboratory of Molecular Microbiology, Biomedical Research and Study Centre, University of Latvia, Riga.
Int J Tuberc Lung Dis. 2003 Nov;7(11):1097-103.
Predominant genotypes of Mycobacterium tuberculosis include the Beijing family, which has caused large tuberculosis outbreaks and has been associated with increased virulence and multidrug resistance (MDR).
To search for the Beijing genotype among Latvian MDR patients to characterise their DNA isolates at the molecular level.
MDR isolates were spoligotyped and tested for gene mutations by automatic nucleotide sequencing.
Of 109 isolates examined, 95 were located in six clusters of 2 to 63 isolates each. The 63 isolates in the largest cluster had an identical pattern corresponding to the Beijing genotype. The remaining isolates were of a non-Beijing genotype and formed another large group whose similarity ranged from 72% to 100%. Mutations in the rpoB and katG genes were compared in the Beijing and non-Beijing strains. In both groups, the rpoB gene mutations predominated in codons S531L (52.2%) and D516V (14.7%). Double mutations in the rpoB gene were observed in 8.2% of the isolates, most of them located among Beijing-type isolates. The katG gene mutation S315T (98.4%) was prevalent among all isolates.
Molecular analysis of MDR isolates of M. tuberculosis demonstrates that the Beijing genotype, most likely due to recent transmission, is prevalent in Latvia among MDR patients and that this genotype can be associated with double mutations.
结核分枝杆菌的主要基因型包括北京家族，该家族已引发大规模结核病疫情，并与毒力增强和多重耐药性（MDR）相关。
在拉脱维亚的多重耐药患者中寻找北京基因型，以在分子水平上对其DNA分离株进行特征分析。
对多重耐药分离株进行间隔寡核苷酸分型，并通过自动核苷酸测序检测基因突变。
在检测的109株分离株中，95株位于6个簇中，每个簇有2至63株。最大簇中的63株分离株具有与北京基因型相对应的相同模式。其余分离株为非北京基因型，形成了另一个相似度在72%至100%之间的大组。比较了北京菌株和非北京菌株中rpoB和katG基因的突变。在两组中，rpoB基因突变主要发生在密码子S531L（52.2%）和D516V（14.7%）。在8.2%的分离株中观察到rpoB基因的双重突变，其中大多数位于北京型分离株中。katG基因突变S315T（98.4%）在所有分离株中普遍存在。
结核分枝杆菌多重耐药分离株的分子分析表明，北京基因型很可能由于近期传播，在拉脱维亚的多重耐药患者中普遍存在，并且该基因型可能与双重突变有关。
