大黄鱼病原弧菌耐药质粒转移研究

Transfer of drug resistance plasmids from Escherichia coli to pathogenic vibrio

用混合培养法进行耐药质粒从大肠杆菌 (Escherichiacoli)向病原弧菌转移研究 ,结果表明 ,耐药质粒 pBR322和 pBR325可以从大肠杆菌向病原弧菌转移。在混合培养30min后 ,部分弧菌获得耐药质粒 ,质粒的转化率随着培养时间的延长而增大 ;混合培养24h后 ,转化率分别提高至4.62×10-6～1.18×10-5。耐药质粒 pBR322和 pBR325在2株病原弧菌细胞内能较为稳定地遗传 ,在培养初期 (0～1h) ,均未出现质粒丢失 ,随着培养时间的延长 ,有少量细胞因丢失耐药质粒而表现出对药物的敏感性 ;培养72h后 ,质粒 pBR322和 pBR325在副溶血弧菌(Vibrioparahaemolyticus)中的丢失率分别为10 %和9% ,溶藻弧菌(Vibrioalginolyticus)中2种质粒的丢失率分别为22%和19 %。细菌的药敏试验表明不同菌株在获得耐药质粒后对特定药物的抗性大大增强 ,但不同菌株的耐药水平有所不同 ,说明耐药质粒在不同菌株中的表达水平有所不同。

The transfer of drug-resistant plasmid from Escherichia coli to pathogenic vibrios was studied by mixed culturing.Results showed that plasmid pBR322and pBR325could be transferred from E.coli to pathogenic vibrios.Some tested vibrio could be obtained plasmid within30min of mixed culturing.The transfer rate of plasmid increased with inˉcreasing culture time at24h the transfer rate was4.62×10 -6 ～1.18×10 -5 .Drug-resistant plasmid pBR322and pBR325were in pathogenic vibrio.In the initial stages of culture,no plasmid was lost,but as the culture time increased,some vibrio would lose plasmid and became sensitive to antibiotic.72h after culture,plasmids pBR322and pBR325lost in V.parahaemolyticus were10%and9%respectively,while in V.alginolyticus,22%and19%was lost.Bacterial drug-resistance level increased significantly after plasmid was obtained,but variety was seen between different bacteria indicating the expression level of drug-resistant plasmid varied.