布鲁菌利福霉素耐药与rpoB基因突变的相关性研究

Sdudy on correlation between rifamycin-resistance and rpoB gene mutation in Brucella

目的采用现代分子生物学技术,应用MSW理论观测布鲁菌耐药问题,探讨布鲁菌在利福霉素选择压力下出现的突变特征。方法富集1010cfu/mL布鲁菌,采用琼脂稀释法测定利福平和利福布丁对布鲁菌的最低抑菌浓度及防突变浓度。PCR扩增不同药物浓度筛选出的耐药突变株的rpoB基因并测序。结果利福平和利福布丁对布鲁菌的防突变浓度分别为460 mg/L和512 mg/L,细菌耐药选择指数为115和728。筛选出的耐药突变株中均检测出rpoB基因突变。结论调整药物剂量可防止对利福霉素耐药的布鲁菌突变株的富集。布鲁菌的利福霉素耐药株中H536Y突变体最为稳定。

Objective It is to investigate the mutant characteristic of Brucella to rifamycin by detecting rifamycin resistance of Brucella through modern molecular biology technique in the mutant selection window （ MSW）. Methods The Brueella was enriched and the bacterial concentrations were adjusted to 1010 colony forming units per milliliter. The minimal inhibitory con- centration （MIC） and MPC of rifampicin and rifabutin for Brucella were determined by agar plate dilution method. The rpoB of Bruclla mutants were selected in the MSW by PCR method and sequencing. Results The MPCs of rifampicin and rifabutin for Brucella were 460 mg/L and 512 mg/L, and the value of MPC/MICs was 115 and 728 respectively. The rpoB gene was changed in Brucella mutants selected in the MSW. Conclusion Adjustment of the drug dose may limit the enrichment of mac- rolide-resistant Brocella mutant. The mutant H536Y in resistant strains of Brucella to rifamycin is stabilized.