耐多药结核分枝杆菌对氨基糖苷类及多肽类药物交叉耐药相关基因突变特征分析

目的：分析抗结核药物链霉素（SM）、卡那霉素（KAN）、卷曲霉素（CAP）在耐多药结核分枝杆菌（MDR-TB）中交叉耐药与其耐药基因突变之间的相关性。方法：选择125 株MDR-TB临床分离株进行SM、KAN、CAP敏感性检测，并对相关耐药基因rrs、tlyA 、eis 启动子、rpsL 进行测序和分析。结果：125 株MDR-TB临床分离株中，SM耐药+KAN耐药菌株9 株（占7.2%），SM耐药+CAP耐药菌株4 株（占3.2%），KAN耐药+CAP耐药菌株2株（占2%），对SM+KAN+CAP全部耐受的菌株6株（占4.8%）。测序显示，125株MDR-TB菌株中均发现tlyA的33A-G突变；eis 启动子突变有4株，均出现在KAN耐药相关菌株中；rrs 突变共发现14株突变，8种突变型，其中1401A-G类型突变为5 株，530 环状区域突变为3 株。利用rrs 检测SM+KAN耐药的敏感度为33.33%，检测SM+CAP耐药的敏感度为40%，检测KAN+CAP耐药的敏感度为50%，检测SM+KAN+CAP耐药的敏感度为50%。结论：SM、KAN、CAP之间存在交叉耐药的情况，rrs 基因的530环状区域突变和1401A-G位点突变与三者间交叉耐药相关，利用该基因突变检测交叉耐药具有一定的参考意义。

The characteristics of gene mutations associated with cross-resistance to aminoglycosides and peptides in MDR-TB

Objective: To analyze the association between the cross-resistance of streptomycin (SM),kanamycin (KAN) and capreomycin (CAP) and mutations of genes in muti-drug resistant tuberculosis (MDRTB)isolates. Methods: 125 clinical isolates of MDR-TB were revived, drug susceptibility testing to SM, KANand CAP was performed using proportion method, and PCR and sequencing were conducted for the four selected genes (rrs, tlyA, eis promoter, rpsL). Results: Of 125 MDR-TB strains, 7.2% (9/125) were resistant to SM+ KAN, 3.2% (4/125) resistant to SM+CAP, 2% (2/125) resistant to KAN+CAP, and 4.8% (6/125) were all resistant to SM+KAN+CAP. Sequencing showed that the 33A-G mutation of tlyA gene was found in all 125 MDR-TB strains. Four strains of eis promoter mutation were found, all of which werefound in KAN resistant-relatedstrains. A total of 14 mutations, with 8 types of mutation, were found in the rrs gene mutation, of which the 1401A-G type mutation was found in 5 strains, and the mutation in 530 loop region was found in 3 strains. The sensitivity to SM+KAN resistance detection by rrs gene was 33.33%, the sensitivity to SM+CAP resistance detection was 40%, the sensitivity to KAN+CAP resistance detection was 50%, and the sensitivity to SM+ KAN+CAP resistance detection was 50%. Conclusion: Cross-resistance was found between SM, KAN and CAP.The 530 loop region mutations and 1401A-G mutation in rrs of MTB were associated with the cross-resistance toSM, KAN and CAP. The detection of SM, KAN and CAP cross-resistance by rrs mutation is of significance for reference.