Tong Yan Qing, Xin Bing, Zhu Li
Department of Nephrology, The First Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China.
Department of Microbiology, The First Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China.
Jundishapur J Microbiol. 2014 Mar;7(3):e15056. doi: 10.5812/jjm.15056. Epub 2014 Mar 1.
Plasmid transfer among bacteria provides a means for dissemination of resistance. Plasmid Analysis has made it possible to track plasmids that induce resistance in bacterial population.
To screen the presence of herb-resistance plasmid in Escherichia coli strains and determine the transferability of this resistance plasmid directly from E. coli to the Gram-positive, Staphylococcus aureus.
The donor strain E. coli CP9 and recipient strain S. aureus RN450RF were isolated from UTI patients. E. coli CP9 was highly resistant to herbal concoction. Isolates of S. aureus RN450RF were fully susceptible. Total plasmid DNA was prepared and transferred into E. coli DH5α. Transconjugants were selected on agar plates containing serial dilutions of herbal concoction. Resistance plasmid was transferred to susceptible S. aureus RN450RFin triple replicas. The mating experiments were repeated twice.
The identified 45 kb herb-resistance plasmid could be transferred from E. coli CP9 isolates to E. coli DH5α. As a consequence E. coli DH5α transconjugant MIC increased from 0.0125 g/mL to 0.25 g/mL. The plasmid was easily transferred from E. coli CP9 strain to S. aureus RN450RF with a mean transfer rate of 1×10(-2) transconjugants/recipient. The E. coli donor and the S. aureus RN450RF transconjugant contained a plasmid of the same size, which was absent in the recipient before mating. Susceptibility testing showed that the S. aureus RN450RF transconjugant was resistant to herbal concoction.
E. coli herb-resistance plasmid can replicate and be expressed in S. aureus.
细菌间的质粒转移为耐药性传播提供了一种途径。质粒分析使得追踪在细菌群体中诱导耐药性的质粒成为可能。
筛选大肠杆菌菌株中抗草药质粒的存在情况，并直接测定该耐药质粒从大肠杆菌向革兰氏阳性菌金黄色葡萄球菌的可转移性。
供体菌株大肠杆菌CP9和受体菌株金黄色葡萄球菌RN450RF分离自尿路感染患者。大肠杆菌CP9对草药混合剂高度耐药。金黄色葡萄球菌RN450RF的分离株对草药混合剂完全敏感。制备总质粒DNA并将其转入大肠杆菌DH5α。在含有系列稀释草药混合剂的琼脂平板上选择接合子。将耐药质粒以三个重复样本的形式转移至敏感的金黄色葡萄球菌RN450RF。交配实验重复两次。
鉴定出的45 kb抗草药质粒可从大肠杆菌CP9分离株转移至大肠杆菌DH5α。结果，大肠杆菌DH5α接合子的最低抑菌浓度从0.0125 g/mL增加至0.25 g/mL。该质粒很容易从大肠杆菌CP9菌株转移至金黄色葡萄球菌RN450RF，平均转移率为1×10(-2)个接合子/受体。大肠杆菌供体和金黄色葡萄球菌RN450RF接合子含有大小相同的质粒，交配前受体中不存在该质粒。药敏试验表明，金黄色葡萄球菌RN450RF接合子对草药混合剂耐药。
大肠杆菌抗草药质粒可在金黄色葡萄球菌中复制并表达。
