目的：研究分离自首次复治肺结核病患者的结核分枝杆菌（Mycobacterium tuberculosis, Mtb）临床菌株对利福平的耐药性, 及其与rpoB基因利福霉素耐药决定区（rifampicin resistance determining regions, RRDR）位点突变间的相关性。方法：收集2013年2月至2013年12月国内19家医院的首次复治肺结核患者的Mtb, 进行利福平药敏检测;使用PCR技术检测Mtb的rpoB基因RRDR位点突变。结果：来自全国12个省19家医院共141例患者的141株临床菌株获得药敏结果, 而RRDR位点测序分析显示首次复治结核患者中有53%（75/141）对利福平耐药。RRDR DNA测序共检测到72株Mtb存在rpoB耐药突变区突变, 其中71株的突变发生在RRDR, 主要突变位点分别为531位（42株）、526位（11株）和516位（10株）。有75株Mtb对利福平耐药, 其中70株（93.3%）检测到rpoB突变, 69株的突变发生在RRDR;除了2株L511P、H526N突变的Mtb对利福平敏感, 70株rpoB突变株均对利福平耐药。对于复治结核患者, 检测RRDR突变判断利福平耐药有较高的特异度。结论：首次复治肺结核病患者对利福平耐药率较高, Mtb耐利福平与rpoB基因RRDR突变密切相关, RRDR突变检测可以用于快速鉴定复治肺结核病患者的Mtb利福平耐药。
Objective: To observe the association between mutation of rifampicin resistance determining regions (RRDR) of rpoB gene and rifampicin resistance in rifampicin-resistant Mycobacterium tuberculosis(Mtb) strains isolated from initial retreatment pulmonary tuberculosis. Methods: Mtb isolates from pulmonary tuberculosis patients who had previous treated were collected. Drug susceptibility was identified through BACTEC 960 and Roche medium; rpoB gene mutation was analyzed by polymerase chain reaction (PCR). Results: A total of 141 isolates from 141 patients in 19 hospitals from 12 provinces across the country were tested for drug sensitivity and analysis of RRDR loci sequencing. Point mutations were identified in 72 strains by sequencing and 71 were in RRDR. The main mutation sites included codon 531 (42 strains), 526 (11 strains) and 516 (10 strains). Seventy-five strains were resistant to rifampicin (RFP), of which 70 (93.3%) had rpoB mutation and 69 were in RRDR. Only two strains with RRDR mutation (L511P and H526N mutant Mtb) were sensitive to rifampicin, and 70 rpoB mutation strains were resistant to rifampicin. Conclusions: The rifampicin-resistance in Mtb isolates from initial retreatment pulmonary tuberculosis is associated with rpoB gene RRDR mutation. RRDR mutation detection can be used for rapid identification of rifampicin-resistant Mtb in retreated patients.
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