一规模化猪场断奶仔猪腹泻大肠杆菌毒力因子的检测

从疑似断奶仔猪腹泻的仔猪中分离、鉴定出15株病原性大肠杆菌。经O血清型鉴定,11株为0131、4株未定型,所有O131血清型菌株呈β溶血。多重PCR检测毒素基因(STa、STb、LT、SLT-2e)和大肠杆菌粘附素单抗(F4、F5、F6、F41、F18)检测菌毛,O131菌株的毒素为STa、STb、SLT-2e,表达F18粘附素,未定型菌株的毒素为STa,共表达F6和F18粘附素。对15株大肠杆菌用16种抗生素进行药敏试验,结果表明:分离株对阿米卡星、痢特灵、新霉素敏感,而对多种抗生素产生了不同程度的耐药性。运用本场大肠杆菌分离株灭活苗免疫猪群,取得良好效果。

Detection of virulence factors of Escherichia coli strains isolated from piglets with postweaning diarrhea in a large-scale pig farm

The purpose of this study was to characterize pathogenic Escherichia coli strains collected from piglets with postweaning diarrhea in a large-scale pig farm in Anhui province. 15 Escherichia. coli strains isolated from weaned pigs were analysed for their phenotypic or geno-typic properties. O-serogroups of 11 strains were determined while 4 strains were not serogroupable. All isolates of serogroup O131 were he-molytic on blood agar plates. PCR analysis showed that 11 of the isolates harboured the genes for heat-stable enterotoxins I and II , shiga toxin 2e and 4 not-serogroupable strains possessed the genes for heat-stable enterotoxins 1. 0131 strains express F18 fimbriae and not-sero-groupable strains possessed F6 and F18. The drug sensitivity test were performed in 15 E. coli strains to select sensitive drugs. The result of drug sensitivity showed that most of isolated pathogenic bacteria strains were sensitive to Amikacin, Furazolidone and Neomycin, but had the resistance to the routinely used drug. The local isolated strains were used to make inactivated vaccine to immune the piglets and good results were obtained.