广东地区结核分枝杆菌利福布丁耐药株rpoB全基因序列突变特征

摘要

In order to elucidate the mutation features of entire rpoH gene in RBU-resistant clinical isolates of M. tuberculosis in Guangdong, the drug susceptibility test was performed by conventional proportional method for 130 clinical isolates of M. tuberculosis, of which 100 isolates were resistant to RBU and the other 30 were susceptible isolates. Then the entire rpoB genes of the 130 strains of Mr. tuberculosis were amplified and sequenced, and the sequenced results were processed by software of clustalx. There were no mutations in the RBU-susceptible isolates, but 24 kinds of mutations and 121 mutation points were found in the 100 RBU-resistant isolates, of which 106 mutation points occurred inside the RRDR and 15 novel mutation points located outside the RRDR including 3 single mutation pointsC V176F, P206R, H323Y) and 12 combined mutation points. The most frequent mutation codons were 531(70%) and 526(20%). Double mutation rate accounted for 21% and the single mutation rate was 79%. The susceptible isolates of M. tuberculosis in Guangdong had no mutations in rpoB gene, while RBU-resistant isolates had 100% mutation rate in rpoB gene. The 531 and 526 were the most frequent mutation points. There were no combined mutations among 531,526 and 516. Of 9 kinds of mutations were found inside the RRDR and 15 novel mutations were identified outside the RRDR including 3 single mutations (V176F,P206R and H323Y) at the beginning of the rpoB gene.%目的 分析广东地区结核分枝杆菌利福布丁耐药株rpoB全基因序列突变特征.方法 常规比例法检出100株结核分枝杆菌利福布丁(rifabutin,RBU)耐药株,30株敏感株,扩增rpoB全基因序列并进行序列测定,Clustal×软件比对所测序列突变情况.结果 利福布丁敏感株rpoB基因无突变；利福布丁耐药株有24种突变类型,121个突变位点,其中106个在利福平耐药决定区(rifampin resistance determining region,RRDR)之内,15个在RRDR之外,包括3个是单点突变(V176F,P206R,H323Y)和12个联合突变；常见突变位点分别是531(70％)和526(20％)；两位点联合突变率21％,单点突变率79％.结论 广东结核分枝杆菌敏感株rpoB基因不发生突变,利福布丁耐药株rpoB基因突变率100％,最常见突变位点分别是531和526.516、526和531之间不发生联合突变.RRDR之内鉴定出9种突变位点,RRDR之外鉴定出15个新突变位点,包括3个单点突变V176F,P206R和H323Y,位于rpoB基因起始端.