淋球菌对大观霉素耐药基因的初步检测

Detection of mutations associated with spectinomycin resistance in Neisseria gonorrhoeae

目的检测导致大观霉素耐药的淋球菌16SrRNA基因中的突变位点。方法对6株大观霉素耐药淋球菌[最小抑菌浓度（MIC）≥128mg／L]、20株大观霉素敏感菌株（MIC32mg／L和16mg／L各10株）的16SrRNA基因进行DNA扩增和序列测定，分析16SrRNA基因突变情况。结果6株大观霉素耐药淋球菌的16SrRNA基因均发生了突变，其中2株（MIC〉256mg／L）为C1192T突变，1株（MIC256rag／L）为C1344T和T1345A突变，1株（MIC256mg／L）为T990G和T991C突变，1株（MIC128mg／L）为T990G、G1343C和C1344T突变，1株（MIC128rag／L）为T991C突变。20株大观霉素敏感菌株均未发生突变。结论淋球菌16SrRNA基因不同位点突变可能与大观霉素不同程度的耐药相关，C1192T突变可能导致高度耐药，其他单一位点或多位点突变与不同程度的耐药相关。

Objective To detect mutations of 16S rRNA gene in Neisseria gonorrhoeae resistant to spectinomycin. Methods Twenty-six N. gonorrhoeae strains, including 6 spectinomycin-resistant （minimal inhibitory concentration （MIC） ≥ 128 mg/L） and 20 spectinomycin-sensitive （MIC = 32 or 16 mg/L） strains, were investigated in this study. DNA was extracted from. these N. gonorrhoeae strains, and subjected to PCR for the amplification of 16S rRNA gene followed by sequencing. Results Mutations were found in the 16S rRNA gene of all the six spectinomycin-resistant N. gonorrhoeae strains, among which, two with MIC values of 〉 256 mg/L carried Cl192T mutation, and one with a MIC value of 128 mg/L carried T991C mutation. Double mutations were found in two strains with MIC values of 256 mg/L, with C1344T and T1345A in one strain as well as T990G and T991C in the other. Triple mutations, including T990G, G1343C and C1344T, were detected in one strain with a MIC value of 128 mg/L. No mutation was detected in the 16S rRNA gene of the 20 susceptible strains. Conclusions Transversions at various sites in the 16S rRNA gene may contribute to different levels of spectinomycin resistance in N. gonorrhoeae. Among these mutations, C1192T mutation may lead to high-level resistance, and other single-site or multisite mutations to varying degrees of resistance, to spectinomycin in N. gonorrhoeae.