Kiepiela P, Bishop K, Kormuth E, Roux L, York D F
Department of Virology, University of Natal, Durban, South Africa.
Microb Drug Resist. 1998 Winter;4(4):263-9. doi: 10.1089/mdr.1998.4.263.
Progress in understanding the basis of resistance to rifampicin (RifR) has allowed molecular tests for the detection of drug-resistant tuberculosis to be developed. One hundred thirteen strains of Mycobacterium tuberculosis isolated from patients with multidrug resistant tuberculosis (MDR-TB) were investigated for genotypic analysis of RifR by polymerase chain reaction-heteroduplex formation (PCR-HDF) and characterization of mutations by automated DNA sequencing of the rpoB gene. A subset of isolates (22) representative of different mutations as confirmed by sequence analysis were also evaluated by the Line Probe Assay (LiPA). In 106 of the RifR strains, 24 mutations within an 81-bp region of the rpoB gene affecting 13 amino acids were observed. Most isolates (7/8) harboring Leu533 --> Pro codon mutation required minimum inhibitory concentrations (MICs) of < or = 8 microg/ml. There was geographic variation in the frequency of occurrence of particular rpoB mutations, with the Ser531 --> Leu/Trp codon mutation found in 59/113 of isolates. Although there are certain limitations in the use of both the rapid PCR-HDF diagnostic assay and the LiPA for the detection of rifampicin susceptibility of M. tuberculosis, these provide important and convenient tools for identifying and managing patients with MDR-TB.
在理解利福平耐药（RifR）基础方面取得的进展，使得能够开发出用于检测耐药结核病的分子检测方法。对从耐多药结核病（MDR-TB）患者中分离出的113株结核分枝杆菌进行了研究，通过聚合酶链反应-异源双链形成（PCR-HDF）对RifR进行基因分型分析，并通过rpoB基因的自动DNA测序对突变进行表征。对序列分析确认的代表不同突变的一部分分离株（22株）也采用线性探针测定法（LiPA）进行了评估。在106株RifR菌株中，观察到rpoB基因81bp区域内影响13个氨基酸的24个突变。大多数携带Leu533→Pro密码子突变的分离株（7/8）的最低抑菌浓度（MIC）≤8μg/ml。特定rpoB突变的发生频率存在地理差异，59/113的分离株中发现了Ser531→Leu/Trp密码子突变。尽管快速PCR-HDF诊断检测法和LiPA在检测结核分枝杆菌对利福平的敏感性方面都有一定局限性，但它们为识别和管理MDR-TB患者提供了重要且便捷的工具。
