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

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.