Oral pseudomonas aeruginosa immunization enhances survival in mice subsequently burned and infected with P. aeruginosa

Mice fed 0 serotype-specific strains of P. aeruginosa for two weeks, had increased titers of IgM but not IgG antibodies to the strains fed. Immunized mice, burned and infected with P. aeruginosa, showed significant 0 serotype-specific enhanced survival. Survival of mice fed several 0 serotype-specific strains simultaneously increased when these mice were burned and infected with P. aeruginosa homologous to those fed except when a high exotoxin A producing strain was used. Mice fed purified exotoxin A showed an increased LD₅₀ when injected with graded toxin doses. Feeding both 0 serotype-specific P. aeruginosa plus exotocin A increased survival even with burn and infection using the high toxin producing strain. We conclude that feeding P. aeruginosa antigens provides successful immunization which avoids the effects of parental adminstration.