National JALMA Institute for Leprosy & Other Mycobacterial Diseases (ICMR), Agra, India.
Indian J Med Res. 2011 Jun;133(6):618-26.
BACKGROUND & OBJECTIVES: Due to the inability to cultivate Mycobacterium leprae in vitro and most cases being paucibacillary, it has been difficult to apply classical genotyping methods to this organism. The objective of this study was therefore, to analyze the diversity among M. leprae strains from Uttar Pradesh, north India, by targeting ten short tandem repeats (STRs) as molecular markers.
Ninety specimens including 20 biopsies and 70 slit scrappings were collected in TE buffer from leprosy patients, who attended the OPD of National JALMA Institute for Leprosy and Other Mycobacterial Diseases, Tajganj, Agra, and from villages of Model Rural Health Research Unit (MRHRU) at Ghatampur, Kanpur, Uttar Pradesh. DNA was extracted from these specimens and ten STRs loci were amplified by using published and in-house designed primers. The copy numbers were determined by electrophoretic mobility as well as sequence analysis. Phylogenetic analysis was done on variable number of tandem repeats (VNTRs) data sets using start software.
Diversity was observed in the cross-sectional survey of isolates obtained from 90 patients. Allelic index for different loci was found to vary from 0.7 to 0.8 except for rpoT for which allelic index was 0.186. Similarity in fingerprinting profiles observed in specimens from the cases from same house or nearby locations indicated a possible common source of infection. Such analysis was also found to be useful in discriminating the relapse from possible reinfection.
INTERPRETATION & CONCLUSIONS: This study led to identification of STRs eliciting polymorphism in north Indian strains of M. leprae. The data suggest that these STRs can be used to study the sources and transmission chain in leprosy, which could be very important in monitoring of the disease dynamics in high endemic foci.
由于无法在体外培养麻风分枝杆菌，且大多数病例为少菌型，因此难以应用经典的基因分型方法对该病原体进行分析。本研究旨在通过以 10 个短串联重复序列（STR）作为分子标记，分析来自印度北方北方邦的麻风分枝杆菌菌株的多样性。
从印度北方阿格拉 Tajganj 的国家 JALMA 麻风病和其他分枝杆菌病研究所的 OPD 以及北方邦 Ghatampur 的模型农村卫生研究单位（MRHRU）的村庄收集了 90 份包括 20 份活检和 70 份刮片的标本，置于 TE 缓冲液中。从这些标本中提取 DNA，并用已发表和内部设计的引物扩增 10 个 STR 基因座。通过电泳迁移率和序列分析确定拷贝数。使用 start 软件对可变数串联重复（VNTR）数据集进行了系统发育分析。
从 90 名患者中获得的分离株的横断面研究中观察到了多样性。不同基因座的等位基因指数在 0.7 至 0.8 之间变化，而 rpoT 的等位基因指数为 0.186。来自同一房屋或附近位置的病例标本的指纹图谱相似性表明可能存在共同的感染源。这种分析还有助于区分复发与可能的再感染。
本研究确定了在印度北方菌株的麻风分枝杆菌中引起多态性的 STR。数据表明，这些 STR 可用于研究麻风病的来源和传播链，这对于监测高流行地区的疾病动态非常重要。
