[Preparation and testing of polyvalent EDTA-Na-extract vaccine from Escherichia coli strains pathogenic to Swine]

Monovalent vaccines were prepared of E. coli strains with pathogenicity to swine by means of a technique described elsewhere. A polyvalent vaccine was obtained by mixing the monovalent vaccines. This polyvalent vaccine was tested by criteria usually applied to vaccine of E. coli strains with pathogenicity to man, and it exhibited the same quality characteristics.