Passive immunization with antibodies against iron-regulated outer membrane proteins protects turkeys from Escherichia coli septicemia.

Escherichia coli septicemia is a common disease of young poultry and several species of mammals. Rabbit antiserum was prepared against iron-regulated outer membrane proteins of E. coli. Eighteen-day-old turkeys were passively immunized with antiserum and challenged by air sac inoculation of 1 X 10(6) to 2 X 10(6) CFU of E. coli O78:K80:H9. Turkeys injected with normal rabbit serum or saline solution before challenge served as controls. Fatalities (8 of 51 turkeys inoculated) occurred only in groups given saline solution or normal rabbit serum. The remaining turkeys were necropsied 96 h after challenge. Passive immunization with antiserum significantly (P less than 0.05) reduced the frequency of bacteremia at 96 h after challenge, the frequency of recovery of E. coli from air sacs, and the severity of gross lesions in inoculated birds as compared with birds given normal rabbit serum or saline solution.