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目的研究次抑菌浓度的大环内酯类抗生素对肺炎支原体(Mycoplasma pneumoniae,Mp)敏感株耐药的诱导作用,并探讨Mp的耐药机制。方法对104株Mp临床株进行药物敏感试验,检测5种常见大环内酯类抗生素对Mp临床分离株的最小抑菌浓度(Minimum inhibitory concentration,MIC),筛选Mp敏感株;分别用次抑菌浓度的红霉素、阿奇霉素和吉他霉素对Mp敏感株诱导10代后,比较诱导前后Mp株的MIC值,分析耐药诱导情况;PCR扩增诱导前后Mp株耐药决定区基因并进行序列测定,通过BLAST软件对编码序列进行比对,分析诱导前后耐药决定区基因23SrRNA,核糖体蛋白L4和L22的突变情况。结果 104株Mp临床株中共分离出11株大环内酯类抗生素敏感株,经诱导耐药后有2株存在核糖体蛋白L22T279C突变;3株存在核糖体蛋白L4突变,其中两株存在C162A、A430G突变,1株存在A209T突变。未检出23SrRNA基因突变。结论次抑菌浓度的大环内酯类药物可诱导Mp耐药,其诱导耐药机制可能与核糖体L4及L22基因突变有关。
Objective To study the induction of Mycoplasma pneumoniae (Mp) sensitive strains by macrolide antibiotics with secondary bacteriostatic concentration and to explore the mechanism of Mp resistance. Methods 104 strains of Mp clinical strains were subjected to drug sensitivity test. The minimum inhibitory concentrations (MICs) of 5 common macrolide antibiotics against Mp clinical isolates were detected and Mp sensitive strains were screened. The concentration of erythromycin, azithromycin and gentamicin Mp sensitive strains after induction of 10 generations, comparing the MIC values before and after induction of Mp strains, analysis of drug resistance induction; PCR amplification before and after induction of Mp strain resistance-determining region genes and sequence The mutations of the 23SrRNA, ribosomal protein L4 and L22 genes were analyzed by BLAST software. Results A total of 11 strains of macrolide antibiotics were isolated from 104 strains of Mp clinical isolates. Two strains of L22T279C were found to be ribosomal protein after resistance induction. Three strains had ribosomal protein L4 mutations, of which two were C162A, A430G mutation and 1 strain has A209T mutation. No 23SrRNA gene mutation was detected. Conclusions Secondary antibacterial macrolides can induce Mp resistance, and the mechanism of its induction of drug resistance may be related to the mutation of ribosomal L4 and L22 genes.