Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, People's Republic of China; Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, Chengdu, People's Republic of China.
Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, People's Republic of China; Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, Chengdu, People's Republic of China.
Plasmid. 2019 Sep;105:102440. doi: 10.1016/j.plasmid.2019.102440. Epub 2019 Sep 6.
The multiresistance gene cfr has a broad host range encompassing both Gram-positive and Gram-negative bacteria, and can be located on the chromosomes or on plasmids. In this study, a novel conjugative plasmid carrying cfr, designated as pPvSC3, was characterized in a Proteus vulgaris strain isolated from swine in China. Plasmid pPvSC3 is 284,528 bp in size and harbors 10 other antimicrobial resistance genes, making it a novel plasmid that differs from all known plasmids due to its unique backbone and repA gene. BLAST analysis of the plasmid sequence shows no significant homology to any known plasmid backbone, but shows high level homology to Providencia rettgeri strain CCBH11880 Contig_9, a strain isolated from surgical wound in Brazil, 2014. There are two resistance-determining regions in pPvSC3, a cfr-containing region and a multidrug-resistant (MDR) region. The cfr-containing region is flanked by IS26, which could be looped out via IS26-mediated recombination. The MDR region harbors 10 antimicrobial resistance genes carried by various DNA segments that originated from various sources. Plasmid pPvSC3 could be successfully transferred to Escherichia coli by conjugation. In summary, we have characterized a novel conjugative plasmid pPvSC3 carrying the multiresistance gene cfr and 10 other antimicrobial resistance genes, and consider that this novel type of plasmid deserves attention.
cfr 多耐药基因具有广泛的宿主范围，包括革兰氏阳性和革兰氏阴性细菌，并且可以位于染色体上或质粒上。在这项研究中，从中国猪源变形杆菌中分离到一株携带 cfr 的新型可接合质粒，命名为 pPvSC3。质粒 pPvSC3 大小为 284528bp，携带 10 个其他抗菌药物耐药基因，由于其独特的骨架和 repA 基因，与所有已知质粒不同，是一种新型质粒。质粒序列的 BLAST 分析显示与任何已知质粒骨架没有显著同源性，但与巴西 2014 年从外科伤口分离的 Providencia rettgeri 菌株 CCBH11880 Contig_9 具有高度同源性。pPvSC3 中有两个耐药决定区，一个是含有 cfr 的区域，另一个是多药耐药（MDR）区域。含有 cfr 的区域被 IS26 侧翼，通过 IS26 介导的重组可以环出。MDR 区域携带 10 个由各种来源的不同 DNA 片段携带的抗菌药物耐药基因。质粒 pPvSC3 可以通过接合成功转移到大肠杆菌中。综上所述，我们对携带多耐药基因 cfr 和 10 个其他抗菌药物耐药基因的新型可接合质粒 pPvSC3 进行了特征描述，认为这种新型质粒值得关注。
