Use of a calf salmonellosis model to evaluate the therapeutic properties of trimethoprim and sulphadiazine and their mutual potentiation in vivo

Abstract

Using an established disease model of acute salmonellosis in calves, and basing the evaluation of chemotherapeutic efficacy on mortality, trimethoprim and sulphadiazine were shown to exhibit marked synergism in vivo. Both parenteral and oral methods of administration were effective and daily intravenous doses were shown to have high efficacy in spite of the short plasma half-life (one hour) of trimethoprim in the calf. Blood levels of trimethoprim were thus shown to be of little value as a prediction of efficacy.