National Institutes of Health researchers have invented a conjugate vaccine to prevent infection by E. coli 0157: H7, particularly in young children under 5 years of age.
E. coli 0157:H7 is an emerging human pathogen that causes a spectrum of illnesses with high morbidity and mortality, ranging from diarrhea to hemorrhagic colitis and hemolytic-uremic syndrome (HUS). Infection with E. coli 0157:H7 occurs as a result of consumption of water, vegetables, fruits or meat contaminated by feces from infected animals, such as cattle.
The most recent large outbreak in the U.S. was from contaminated bag spinach. The conjugate is composed of the O-specific polysaccharide isolated from E. coli 0157, or other Shiga-toxin producing bacteria, conjugated to carrier proteins, such as nontoxic P. aeruginosa exotoxin A or Shiga toxin 1. A Phase I clinical trial involving adult humans showed the vaccine is safe and highly immunogenic. After one injection containing 25 μg of antigen, adults responded with high titers of bactericidal antibodies.
Similarly, in a Phase II study, 50 2- to 5-year old children in the U.S. were injected with the conjugate vaccines. There were only mild local adverse reactions. More than 90% of the children responded with greater than a tenfold rise of E. coli 0157 antibodies of bactericidal ability. Thus, the conjugates of the invention are promising vaccines, especially for children and the elderly, who are most likely to suffer serious consequences from infection.
Application: Prevention of E. coli 0157 infection
More info: Peter A. Soukas, J.D., 301-435-4646, soukasp@mail.nih.gov
