结核分枝杆菌链霉素耐药基因突变特征分析

目的 了解广东地区链霉素耐药结核分枝杆菌rpsL、rrs基因突变特征。方法 对137株链霉素耐药、166株链霉素敏感的结核分枝杆菌临床分离株应用聚合酶链式反应技术（PCR）扩增rpsL、rrs基因片段，并进行测序、分析比对。结果 137株链霉素耐药菌株中， 118株存在rrs或者rpsL基因突变，突变率86.13%；其中92株存在rpsL基因突变（突变率为67.15%），主要分布在43位氨基酸（70株）与88位氨基酸（20株），其中43位氨基酸突变类型为K→R（AAG→AGG，49.64%）和K→T（AAG→ACG，1.46%），88位氨基酸突变类型为K→R（AAG→AGG，13.14%）、K→T（AAG→ACG，0.73%）和K→Q（AAG→CAG，0.73%），并有2株存在39、43位氨基酸的联合突变，即T→T（ACC→ACT）联合K→T（AAG→ACG）突变（1.46%）； 47株存在rrs基因突变（突变率为34.31%），包括8种核苷酸突变，主要分布在1401位A→G（13.14%）、514位A→C（8.76%）、517位C→T（6.57%），2株存在514、1401位核苷酸A→C；A→G的联合突变；15株存在rpsL与rrs基因的同时突变；166株链霉素敏感菌株中，7株存在rpsL基因突变，13株存在rrs基因突变。结论 广东地区链霉素耐药结核分枝杆菌株的rpsL、rrs基因突变具有其自身特点，存在地域差异。

Mutation characteristics of streptomycin resistance genes in Mycobacterium tuberculosis

Objective To understand the mutation characteristics of rpsL and rrs genes in streptomycin-resistant Mycobacterium tuberculosis in Guangdong area. Methods rpsL and rrs gene fragments in 137 streptomycin-resistant and 166 streptomycin-sensitive clinical isolates of Mycobacterium tuberculosis were amplified by PCR and sequenced and compared. Results Among 137 strains of streptomycin-resistant strains, 118 strains had rrs or rpsL gene mutations, and the mutation rate was 86.13%; 92 strains had rpsL gene mutations with the mutation rate of 67.15%, and were mainly distributed at amino acid 43 (70 strains) and amino acid 88 (20 strains). The amino acid 43 mutations were K→R (AAG→AGG, 49.64%) and K→T (AAG→ACG, 1.46%), and amino acid 88 mutation was K→R (AAG→AGG, 13.14%), K→T (AAG→ACG, 0.73%) and K→Q (AAG→CAG, 0.73%), and there were the joint mutations of amino acid 39 and 43 in two strains: T→T (ACC→ACT) combined K→T (AAG→ACG) mutations (1.46%); 47 strains had rrs gene mutations (mutation rate: 34.31%), including 8 nucleotide mutations, mainly distributed at position 1401 A→G (13.14%) , 514 A→C (8.76%), 517 C→T (6.57%); 2 strains had nucleotides co-mutation at position 514 and 1401 (A→C; A→G); 15 strains had the simultaneous mutation of rpsL and rrs; among 166 strains of streptomycin-sensitive strains, 7 had rpsL gene mutations and 13 had rrs gene mutations. Conclusions The rpsL and rrs gene mutations of streptomycin-resistant Mycobacterium tuberculosis strains in Guangdong region have their own characteristics, and there are regional differences.