Researchers from the U.S. and abroad have developed a transcutaneous (needle-free) vaccine delivered through a patch applied to the skin that protects mice from C. difficile infection.
Clostridium difficile is the leading cause of nosocomial diarrhea worldwide with more than 300,000 cases reported each year in the U.S. alone. The recent emergence of a new highly virulent strain has increased the need for effective preventative treatment methods.
Toxins A and B are the two major virulence factors expressed by C. difficile. Toxin A initiates infection allowing toxin B to access underlying cells. In the study researchers developed a vaccine including anti-toxin A antibodies and transcutaneously immunized mice, some also with the cholera toxin and some without, over a period of 42 days. Mice immunized with both C. difficile toxin A and cholera toxin displayed prominent immune responses to both toxins and blood from immunized mice was capable of neutralizing C. difficile toxin A in a cell culture test.
"Our results suggest that transcutaneous immunization with C. difficile toxin A may be a feasible immunization strategy against C. difficile, an important cause of morbidity and mortality against which current preventative strategies are failing," say the researchers.
They report their findings in the June 2007 issue of the journal Infection and Immunity. (C. Ghose, A. Kalsy, A. Sheikh, J. Rollenhagen, M. John, J. Young, S.M. Rollins, F. Qadri, S.B. Calderwood, C.P. Kelly, E.T. Ryan. 2007. Transcutaneous immunization with Clostridium difficile toxoid A induces systemic and mucosal immune responses and toxin A-neutralizing antibodies in mice. Infection and Immunity, 75. 6: 2826-2832).
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