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本文对11株动物源体外诱导的环丙沙星抗性沙门氏菌的m ar操纵子基因marO,marR,marA,marB,soxR,soxS和acrR基因(包括启动子区)的点突变进行检测,结果显示在沙门氏菌诱导株中marR,soxR和acrR基因检测到新突变,而marO,marA,marB和soxS基因未发现突变。应用实时荧光定量PCR对诱导株的marA和soxS基因及外排泵基因acrA,acrB和tolC的mRNA表达水平进行检测,结果表明这些基因的表达量均显著增加,且marA,soxS和acrAB-tolC的mRNA表达水平与沙门氏菌诱导株的多重耐药表型(M ar表型)相关,环丙沙星诱导株对其它氟喹诺酮类药物和结构不相关的抗生素均产生耐药。本研究结果表明沙门氏菌诱导株的调控基因突变和mar操纵子介导的acrAB-tolC的表达上调均贡献了沙门氏菌诱导株的氟喹诺酮抗性和Mar表型,且诱导株的marR,soxR和acrR基因突变与氟喹诺酮抗性和Mar表型具有相关性。
In this paper, we detected the point mutation of mar ar, marr, marA, marB, soxR, soxS and acrR genes (including the promoter region) of the m ar operon gene of ciprofloxacin- New mutations were detected in the marR, soxR and acrR genes in Salmonella-induced isolates, whereas no mutations were found in the marO, marA, marB and soxS genes. The mRNA expression levels of marA, soxS and efflux pump genes acrA, acrB and tolC in induced plants were detected by real-time fluorescence quantitative PCR. The results showed that the expression levels of these genes were significantly increased, and the expression levels of marA, soxS and acrAB-tolC The mRNA expression level was correlated with the multi-resistant phenotype of the Salmonella-induced strain (M ar phenotype). Ciprofloxacin-induced strains were resistant to other fluoroquinolones and structurally unrelated antibiotics. The results of this study indicate that the mutations of Salmonella-induced strains and the up-regulation of mar operon-mediated acrAB-tolC contribute to the fluoroquinolone resistance and Mar phenotype of the Salmonella-induced strains, and the marR, soxR and acrR genes of the induced strains Mutations were associated with fluoroquinolone resistance and Mar phenotype.