农业生物技术学报2025，Vol.33Issue(8)：1800-1811,12.DOI:10.3969/j.issn.1674-7968.2025.08.013
仔猪腹泻大肠杆菌的分离鉴定及黄连解毒汤对其致病性的影响
Isolation and Identification of Escherichia coli in Diarrheic Piglets(Sus scrofa domesticus)and the Effects of Huang-lian-jie-du Decoction on Its Pathogenicity
摘要
Abstract
Eschericha coli is the main pathogen causing diarrhea in piglets(Sus scrofa domesticus),Huanglian-jie-du decoction(HLJDD)can be used to prevent and control E.coli diarrhea in livestock and poultry.However,whether it can act on the pathogenic bacteria and reduce their pathogenicity has rarely been reported.This study aimed to investigate the effect of HLJDD on the pathogenicity of E.coli in diarrheic piglets.A total of 32 anal swab samples were collected from piglets with diarrhea,and bacterial isolation,culture,biochemical and molecular biological identification,and virulence gene detection were performed.Potential pathogenic strains were selected for pathogenicity analysis in mice(Mus musculus),drug sensitivity tests,and antibiotic resistance gene detection.Based on this,HLJDD was used for in vitro intervention,with its MIC determined using a two-fold dilution method,and qPCR was employed to assess the effects of HLJDD on the virulence and antibiotic resistance genes of pathogenic strains.Finally,the impact of HLJDD intervention on mouse survival rates was explored through pathogenicity tests.The result showed that a total of 21 bacterial strains were isolated from the collected samples,and biochemical identification and 16S rRNA gene testing showed that all isolates were E.coli.Virulence gene detection indicated that only 3 isolates carried the high pathogenicity island(HPI)iron-repressible protein 2(irp2).One strain carrying the irp2 gene was randomly selected for pathogenicity testing in mice,revealing that this strain was pathogenic with an LD50 of 4.4×106 CFU.Further testing showed that this pathogenic strain was resistant to 9 antibiotics,including penicillin,tetracycline,and erythromycin,and carried β-lactam and tetracycline resistance genes temoneira beta-lactamase(TEM)and tetracycline resistance protein A(tetA).The intervention results of HLJDD showed that its MIC against pathogenic bacteria was 250 mg/mL.Further qPCR results showed that HLJDD intervention could significantly inhibit the expression of irp2,TEM,and tetA of the pathogenic bacteria,and reduce the mortality rate of the pathogenic bacteria in mice,prolonging their survival time.This study provides a reference for the prevention and treatment of diarrhea in piglets and lays the foundation for the development of new antimicrobial drugs.关键词
仔猪腹泻/大肠杆菌/黄连解毒汤/耐药基因/毒力基因Key words
Piglet diarrhea/Escherichia coli/Huang-lian-jie-du decoction/Drug resistance genes/Virulence gene分类
农业科技引用本文复制引用
张丰裕,蔡燕子,史艳,纪鹏,华永丽,袁子文,魏彦明..仔猪腹泻大肠杆菌的分离鉴定及黄连解毒汤对其致病性的影响[J].农业生物技术学报,2025,33(8):1800-1811,12.基金项目
甘肃省自然科学基金(25JRRA364) （25JRRA364）
甘肃省青年科技基金计划(21JR7RA846) （21JR7RA846）
甘肃农业大学公招博士科研启动项目(GAU-KYQD-2020-4) （GAU-KYQD-2020-4）
财政部和农业农村部国家现代农业产业技术体系(CARS-37) （CARS-37）
