Glucose metabolism of Haemonchus contortus adults: effects of thiabendazole on susceptible versus resistant strain.

Analyses of the in vitro glucose metabolism of Haemonchus contortus adults have confirmed a complex series of end-products: ethanol, n-propanol, propionate, acetate, and CO2 as the major end-products of catabolism. No difference in end-product accumulation was seen between the cambendazole sensitive (BPL) and cambendazole resistant (CR) strains. Thiabendazole (5 mM) in vitro depressed ethanol, propanol, acetate, and propionate accumulation by approximately 42% in the BPL strain. However, in the resistant strain (CR), these end-product accumulations increased by 50% when the worms were exposed to drug in vitro and 80% when exposed in vivo. Resistance manifested by the CR strain appeared to be associated with the ability to increase its carbon flow in the presence of thiabendazole.