质粒介导的摩氏摩根菌KL-225对氨基糖苷类和氟喹诺酮类抗生素的耐药

摘要

Objective To study the mechanisms of broad-spectrum resistance in M. morganii KL-225 and lay foundation for the development of novel antibacterial drugs.Methods pKL2683 and pKL5933 in M. morganii KL-225 were extracted and purified, then sequenced. Bioinformatics analysis was performed on the sequencing results to find out possible resistance-related genes. The plasmids were transferred into the M. morganii standard strains and resistance genes were expressed in Escherichia coli for verification.Results qnrD gene carried by pKL2683 increased the fluoroquinolones MICs for KL-225; The pKL5933 plasmid carries aac(6')-Ib-cr4 gene, which increased the aminoglycosides and fluoroquinolones MICs for KL-225.Conclusion M. morganii KL-225 is resistant to aminoglycosides mainly because of the pKL5933 plasmid which carries the aac(6')-Ib-cr4 gene. The aac(6')-Ib-cr4 gene carried by pKL5933 plasmid and qnrD gene carried by pKL2683 plasmid decreased the susceptibility to fluoroquinolones in KL-225. In order to completely clarify the mechanisms of broad-spectrum resistance in M. morganii KL-225, it is necessary to study the genome and other plasmids.%目的 研究摩氏摩根菌KL-225的超广谱耐药机制,为新型抗菌药物的研发奠定基础.方法 提取纯化摩氏摩根菌KL-225的pKL2683和pKL5933质粒,并进行序列测定,将测序结果进行生物信息学分析找到其可能的耐药基因,再通过将质粒转化入摩氏摩根标准菌株和大肠杆菌,对耐药基因进行验证.结果 pKL2683质粒携带的qnrD基因导致氟喹诺酮类抗生素对KL-225的MIC升高;pKL5933质粒携带的aac(6')-Ib-cr4基因导致KL-225对氨基糖苷类和氟喹诺酮类抗生素的MIC升高.结论 摩氏摩根菌KL-225对氨基糖苷类抗生素的耐药主要来源于pKL5933质粒上携带的aac(6')-Ib-cr4基因;pKL2683质粒携带的qnrD基因和pKL5933质粒携带的aac(6')-Ib-cr4基因导致KL-225对氟喹诺酮类抗生素敏感性降低.