Broes A, Fairbrother J M, Larivière S, Jacques M, Johnson W M
GREMIP, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Quebec, Canada.
Infect Immun. 1988 Jan;56(1):241-6. doi: 10.1128/iai.56.1.241-246.1988.
Twenty-two enterotoxigenic Escherichia coli (ETEC) O8:KX105 strains isolated from 1- to 7-week-old diarrheic piglets were examined for virulence properties. Thirteen strains caused acute watery diarrhea in orally infected, colostrum-deprived newborn piglets, whereas the remaining nine did not. The enteropathogenic strains colonized the small intestine, albeit with lower intensity than classical porcine ETEC. They produced the heat-stable STb and heat-labile LT enterotoxins, whereas the nonenteropathogenic strains produced the STb enterotoxin alone. None of the E. coli O8:KX105 strains exhibited mannose-resistant hemagglutination with erythrocytes from 12 species. Ten of the enteropathogenic and two of the nonenteropathogenic strains were positive for mannose-sensitive hemagglutination. These strains produced rodlike fimbriae 3 to 5 nm in diameter, whereas no fimbriae were detected on the other strains. None of the 22 strains produced the fimbrial antigens F4, F5, F41, F2, F3, FY(Att 25), and F165. Of the 13 enteropathogenic strains, 10 expressed the F6 antigen in the intestines of infected piglets but not in cultures. The other three enteropathogenic strains apparently lacked all of the known fimbrial antigens from porcine ETEC.
对从1至7周龄腹泻仔猪分离出的22株产肠毒素大肠杆菌（ETEC）O8:KX105菌株进行了毒力特性检测。13株菌株在经口感染、未摄入初乳的新生仔猪中引起急性水样腹泻，而其余9株则未引起。致病菌株定殖于小肠，尽管其定殖强度低于经典猪ETEC。它们产生耐热的STb和不耐热的LT肠毒素，而非致病菌株仅产生STb肠毒素。所有大肠杆菌O8:KX105菌株均未对来自12个物种的红细胞表现出甘露糖抗性血凝反应。10株致病菌株和2株非致病菌株对甘露糖敏感血凝反应呈阳性。这些菌株产生直径为3至5纳米的杆状菌毛，而在其他菌株上未检测到菌毛。22株菌株均未产生菌毛抗原F4、F5、F41、F2、F3、FY(Att 25)和F165。在13株致病菌株中，10株在感染仔猪的肠道中表达F6抗原，但在培养物中不表达。其他三株致病菌株显然缺乏猪ETEC所有已知的菌毛抗原。
