Xuzhou Vocational College of Bioengineering, Jiangsu, 221006, Xuzhou, China.
College of Veterinary Medicine, Inner Mongolia Agricultural University, Huhhot, 010018, Inner Mongolia, China.
Sci Rep. 2024 Jul 5;14(1):15494. doi: 10.1038/s41598-024-64256-5.
Anal swabs of 1-month-old Holstein calves with diarrhea were collected from an intensive cattle farm, and a highly pathogenic Escherichia coli strain was obtained by isolation and purification. To study the virulence and resistance genes of pathogenic E. coli that cause diarrhea in calves, a strain of E. coli E12 isolated from calf diarrhea samples was used as experimental material in this experiment, and the virulence of the E12 strain were identified by the mouse infection test, and the whole genome map of the E12 strain were obtained by whole-genome sequencing and analyzed for genome characterization. The results showed that the lethality of strain E12 was 100%, the total length of E12-encoded genes was 4,294,530 bp, Cluster of Orthologous Groups of proteins (COG) annotated to 4,194 functional genes, and the virulence genes of sequenced strain E12 were compared with the virulence genes of sequenced strain E12 from the Virulence Factors of Pathogenic Bacteria (VFDB), which contained a total of 366 virulence genes in sequenced strain E12. The analysis of virulence genes of E12 revealed a total of 52 virulence genes in the iron transferrin system, 56 virulence genes in the secretory system, 41 virulence genes in bacterial toxins, and a total of 217 virulence genes in the Adhesin and Invasins group. The antibiotic resistance genes of sequenced strain E12 were identified through the Antibiotic Resistance Genes Database (ARDB) and Comprehensive Antibiotic Research Database, and it was found that its chromosome and plasmid included a total of 127 antibiotic resistance genes in four classes, and that E12 carried 71 genes related to the antibiotic efflux pumps, 36 genes related to antibiotic inactivation, and 14 antibiotic target alteration and reduced penetration into antibiotics, and 6 antibiotic resistance genes, and the resistance phenotypes were consistent with the genotypes. The pathogenic E. coli that causes diarrhea in calves on this ranch contains a large number of virulence and resistance genes. The results provide a theoretical basis for the prevention and treatment of diarrhea and other diseases caused by E. coli disease.
从一个集约化奶牛场采集了 1 月龄患有腹泻的荷斯坦小牛的肛拭子，并通过分离和纯化获得了一株高致病性大肠杆菌。为了研究引起犊牛腹泻的致病性大肠杆菌的毒力和抗性基因，本实验以从犊牛腹泻样本中分离的大肠杆菌 E12 株为实验材料，通过小鼠感染试验鉴定 E12 株的毒力，并通过全基因组测序获得 E12 株的全基因组图谱，并对基因组特征进行分析。结果表明，E12 株的致死率为 100%，E12 株编码基因的总长度为 4294530bp，蛋白质簇同源群（COG）注释到 4194 个功能基因，测序菌株 E12 的毒力基因与来自病原菌毒力因子数据库（VFDB）的测序菌株 E12 的毒力基因进行了比较，测序菌株 E12 共包含 366 个毒力基因。E12 的毒力基因分析显示，铁转铁蛋白系统共有 52 个毒力基因，分泌系统 56 个毒力基因，细菌毒素 41 个毒力基因，黏附素和入侵素组共 217 个毒力基因。通过抗生素耐药基因数据库（ARDB）和综合抗生素研究数据库（CARD）对测序菌株 E12 的抗生素耐药基因进行鉴定，发现其染色体和质粒共包含四类 127 个抗生素耐药基因，E12 携带 71 个与抗生素外排泵相关的基因、36 个与抗生素失活相关的基因、14 个与抗生素靶位改变和减少抗生素渗透相关的基因，以及 6 个抗生素耐药基因，耐药表型与基因型一致。该牧场引起犊牛腹泻的致病性大肠杆菌携带大量毒力和耐药基因，为大肠杆菌病引起的腹泻等疾病的防治提供了理论依据。
