过表达puuC大肠杆菌对氨基糖苷类抗生素的耐受性分析

    Analysis of puuC Overexpression on Aminoglycoside Antibiotic Tolerance in Escherichia coli

    • 摘要: 为探究编码γ-谷氨酰-γ-氨基丁醛脱氢酶(γ-glutamyl-γ-aminobutyraldehyde dehydrogenase)的puuC基因在细菌抗生素耐受中的作用及作为新耐药靶点的潜力,构建了大肠杆菌puuC过表达株(BW25113-puuC),以携带空质粒的野生型菌株(BW25113-pCA24N)为对照,进行了针对庆大霉素和卡那霉素的杀伤测试、最小抑菌浓度(MIC)和生长曲线测定,并进一步检测其对β-内酰胺类和喹诺酮类抗生素的耐受性差异。结果表明:过表达puuC能显著提高大肠杆菌在庆大霉素和卡那霉素处理下的存活率,且MIC未升高,表现为耐受而非耐药;同时,过表达puuC的大肠杆菌对β-内酰胺类抗生素亦具一定耐受性,但对喹诺酮类抗生素无明显耐受。研究结果显示,puuC 主要介导大肠杆菌对氨基糖苷类抗生素耐受,说明其所在的腐胺代谢通路可能成为抗细菌耐药策略的潜在干预靶点。

       

      Abstract: To investigate the role of puuC, which encodes γ-glutamyl-γ-aminobutyraldehyde dehydrogenase, in bacterial antibiotic tolerance and its potential as a novel target for combating antibiotic resistance, we constructed an Escherichia coli puuC-overexpressing strain(BW25113-puuC)and used a wild-type strain carrying an empty plasmid(BW25113-pCA24N)as the control. Killing assays with gentamicin and kanamycin, minimum inhibitory concentration(MIC)determination, and growth curve analysis were performed. We further compared the tolerance of the puuC-overexpressing strain to β-lactam and quinolone antibiotics. The results showed that overexpression of puuC significantly increased the survival of E. coli under gentamicin and kanamycin treatment without increasing the MIC, indicating tolerance rather than resistance. Moreover, the puuC-overexpressing strain exhibited some tolerance to β-lactam antibiotics but no obvious tolerance to quinolones. These findings suggest that puuC mainly mediates E. coli tolerance to aminoglycoside antibiotics, and that the putrescine metabolic pathway in which its encoded enzyme participates may serve as a potential intervention target for strategies to combat bacterial antibiotic resistance.

       

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