Interaction of insulin with Burkholderia pseudomallei may be caused by a preservative

Abstract

Aim - To re-examine the previously reported in vitro interaction of insulin with Burkholderia pseudomallei, in the light of a suggestion that the interaction may have resulted from the presence of the preservative m-cresol in commercial preparations. Methods - Broth culture studies of B pseudomallei were performed with and without the addition of m-cresol and various preparations of insulin. Results - Growth of B pseudomallei was inhibited by m-cresol at the concentrations found in pharmaceutical insulin preparations, and by the insulin preparation Humulin R, but not by pure insulin. Conclusions - The results of previous experiments may have been confounded by the presence of the preservative m-cresol.