[Infant mouse model of "Escherichia coli" infectious diarrhoea (author's transl)].

Three enteropathogenic bovine strains of Escherichia coli (B41, B44 and 17C), carrying K99 antigen (K99+) and producing heat-stable enterotoxin (Ent+), caused infectious diarrhoea when administered orally to Swiss OF1 and CD-1 infant mice. A mortality rate of 40 t0 60% was obtained after administration of 10 E. coli B41 to mice which were less than 48 h old. A mortality rate of 80 to 100% was obtained with 10(3) E. coli B41, selected as reference inoculum. Inoculation of mice older than 48 h with the reference inoculum, resulted in variable responses and decreased mortality rate. After 10 days of age, mice were no longer sensitive to the inoculum. Inoculation of mice with each strain of E. coli in standard conditions (10(3) bacteria, mice less than 48 h old) produced similar mortality rates in OF1 mice. CD-1 mice were more resistant to strain B41 than to strains B44 and 17C. Administration of E. coli K12, to which K99 and Ent+ plasmids had been transferred, produced no pathological change in mice under the same conditions.