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目的明确亚抑菌浓度头孢他啶在大肠埃希菌生物膜抑制过程中对胞外多糖和pga基因的影响。方法采用标准琼脂平板倍比稀释法检测细菌最低抑菌浓度,采用96孔板结晶紫染色法检测生物膜形成能力,采用苯酚-硫酸法测定胞外多糖含量,pgaABCD基因表达采用RT-PCR扩增。结果大肠埃希菌对氨苄西林和氟喹诺酮类耐药率较高,而对阿米卡星和碳青霉烯类全部敏感。亚抑菌浓度头孢他啶对大肠埃希菌生物膜形成、胞外多糖产生能力和pgaABCD基因表达均有显著抑制作用,但其降低程度不完全一致。结论亚抑菌浓度头孢他啶在抑制生物膜形成过程中能降低大肠埃希菌胞外多糖产生和pga基因表达,但其与生物膜降低程度存在差异性。
Objective To determine the effect of cefotiadin on the expression of extracellular polysaccharides and pga gene during the inhibition of Escherichia coli biofilm by sub-bacteriostasis. Methods The minimum inhibitory concentration (MIC) of bacteria was detected by standard agar plate fold dilution method. The biofilm formation ability was detected by crystal violet staining in 96-well plate. The content of exopolysaccharide was determined by phenol-sulfuric acid method. The expression of pgaABCD gene was amplified by RT- . Results Escherichia coli had a high resistance to ampicillin and fluoroquinolones, but was sensitive to both amikacin and carbapenems. Sub-bacteriostasis concentration ceftazidime significantly inhibited the biofilm formation, extracellular polysaccharide production and pgaABCD gene expression in Escherichia coli, but the degree of reduction was not completely the same. Conclusion Sub-bacteriostasis concentration ceftazidime can reduce the production of extracellular polysaccharide and the expression of pga gene in Escherichia coli during biofilm formation, but it is different from the biofilm reduction.