淋球菌多重耐药调节基因(mtrR)突变与多重耐药关系的研究

Correlation Between Multiple Resistance of Neisseria Gonorrhoeae and Mutations in mtrR Gene

目的 研究淋球菌多重耐药调节基因mtrR突变与淋球菌多重耐药的关系。 方法 ①纸片扩散法检测 5 2株淋球菌对四种抗生素的敏感性 ;②PCR扩增mtrR基因中最常发生突变的 2 5 0个碱基进行SSCP(单链构象多态性 )分析 ;③根据SSCP的结果选取 11株标本 ,扩增其mtrR基因、测序 ,将其核苷酸序列与标准敏感株ATCC1942 4进行比较。结果 5 2株细菌中有 8株对四种抗生素都敏感 ;对一种抗生素耐药的有 19株 ,只有一株mtrR基因发生点突变 ;对两种抗生素耐药的有 16株 ,其中有两株mtrR基因发生了点突变 ;对三种抗生素和四种抗生素耐药的株菌分别是 7株和 2株 ,它们的mtrR基因都发生了点突变。在这 11株标本中 ,发生 45位gly(GGC)→ (GAC)asp突变的为 5株 ,10 5位his(CAC)→(TAC)tyr突变的为 6株。 结论 ①mtrR基因突变介导淋球菌的多重耐药 ;②mtrR基因 45位 gly(GGC)→ (GAC)asp和 10 5位his(CAC) (TAC)tyr的突变与淋球菌多重耐药的关系密切。

Objective To study the correlation between multi-drug resistance in Neisseria gonorrhoeae and mutations in mtrR gene.Methods ① The susceptibilities of 52 clinical Neisseria gonorrhoeae to four kinds of antibiotic agents were tested by disc diffusion method. ② The fragments who often have mutations were amplified by PCR and examined by SSCP(single strand conformation polymorphism ) technology. ③According to the results of SSCP ,11 strains were selected and their mtrR gene were obtained by PCR; the PCR products of mtrR gene were directly sequenced and their nucleotide sequences were compared to those of susceptible strain ATCC19424. Results ①In the 52 strains of Neisseria gonorrhoeae, 8 strains were susceptible to all antibiotic agents ;the numbers of strains resistant to one antibiotic agent were 19 and only one contained point mutations.In the 16 strains who were resistant to two antibiotic agents, two had point mutation. 7 and 2 strains who were resistant to three and four antibiotic agents respectively all had point mutation. Of 11 strains selected to be sequenced, 5 exhibited substion of 45gly(GGC)→(GAC)asp and 6 had his(CAC)→(TAC)tyr. Conclution ①Mutations within mtrR gene mediate multi-drug resistance in Neisseria gonorrhoeae .②The results suggest that a mtrR mutation in Neisseria gonorrhoeae at Gly-45 or His-105 is associated with multi-drug resistance.