Vaccination experiments on pregnant mice with E. coli vaccines prepared from septicaemic and enteropathogenic strains of E. coli.

Experiments have been carried out with vaccination of pregnant mice against E. coli, followed by i.p. challenge of the offspring at one week of age. With a septicaemic strain the results were highly significant, and the method is therefore recommendable for testing of vaccines against such strains of E. coli. Results were less clear-cut with enteropathogenic strains of E. coli. However, with mortality rates of 40 to 45 % in baby mice born by non-vaccinated mothers and less than 15 % in baby mice born by vaccinated mothers, the difference in percentage mortality seems sufficient to warrant the use of the method also in the control of vaccines against enteropathogenic E. coli strains.