淋球菌ponA基因突变与高水平CMRNG株的关系

Correlation Between High-level Chromosomal-mediated Penicillin-resistant Neisseria Gonorrhoeae and Mutations in ponA

目的探讨淋球菌ponA基因突变与高水平CMRNG株的关系。方法①改良碘量法检测β-内酰胺酶，琼脂稀释法测定58株淋球菌对青霉素的最小抑菌浓度（MIC）。②PCR扩增ponA基因的可变区并进行测序分析。结果①质粒介导的产青霉素酶的淋球菌（PPNG）为24株（41．4％）；青霉素MIC为敏感、中介、耐药分别为2株、18株和38株，有6株MIC值≥4．0mg／L。②标准株ATCC19424及低-中等水平CMRNG株，其ponA基因可变区序列未发生突变，而高水平CMRNG株均发生基因突变，且突变类型一致，在421位leu（CTG）→（CCG）pro。结论淋球菌ponA基因突变与高水平CMRNG株的关系密切。

Objective To evaluate the correlation between high-level CMRNG and mutations in ponA, the gene encoding penicillin-binding protein 1. Methods （1）β-lactamase was determined by a modified iodometric method and the minimum inhibitory concentration （ MIC ） of penicillin was determined by tube dilution method in 58 isolates. （2）Varied-region within the ponA gene was amplified by PCR and directly sequenced. Results （1）Plasmid-mediated penicillinase-producing Neisseria gonorrhoeae were 24 strains （41.4%）. The numbers of strains sensitive, intermediate and resistant to penicillin were 2,18 and 38, respectively. And there were 6 strains with penicillin MIC ≥4. 0 mg/L. （2）In the standard strain ATCC19424 and intermediated-level CMRNG, there were no mutations in varied-region within the ponA gene. All of highlevel CMRNG which had the same mutation exhibited substitution of 421 leu （CTG）→ （CCG）pro. Conclusion Mutations in varied-region within the ponA gene is closely associated with high-level CMRNG.