Rothwell J, Sangster N
Department of Veterinary Pathology, University of Sydney, NSW, Australia.
Int J Parasitol. 1997 Mar;27(3):313-9. doi: 10.1016/s0020-7519(96)00200-7.
Closantel is an anthelmintic which associates with plasma albumin and is useful for the control of sheep parasites, such as Haemonchus contortus, that ingest blood. However, the utility of closantel for parasite control has been threatened by the emergence of resistance. The mechanisms of resistance are unknown. A closantel-resistant and a closantel-susceptible isolate of H. contortus were compared with respect to the distribution and metabolism of closantel. Neither strain appeared to metabolise closantel in vitro or in vivo. Following treatment of infected sheep with radioactively labelled closantel, isotope levels in closantel-resistant adult H. contortus were significantly lower than in susceptible worms. This reduced accumulation of drug could contribute to closantel resistance by mechanisms such as reduced feeding, failure to dissociate the drug-albumin complex in the gut or increased efflux of closantel from resistant worms.
氯氰碘柳胺是一种与血浆白蛋白结合的驱虫药，可用于控制绵羊寄生虫，如吸血的捻转血矛线虫。然而，氯氰碘柳胺对寄生虫控制的效用受到耐药性出现的威胁。耐药机制尚不清楚。比较了氯氰碘柳胺耐药和敏感的捻转血矛线虫分离株在氯氰碘柳胺分布和代谢方面的差异。两种菌株在体外或体内均未表现出对氯氰碘柳胺的代谢。用放射性标记的氯氰碘柳胺治疗感染绵羊后，氯氰碘柳胺耐药的成年捻转血矛线虫中的同位素水平显著低于敏感虫体。药物积累的减少可能通过减少摄食、无法在肠道中解离药物 - 白蛋白复合物或耐药虫体中氯氰碘柳胺外流增加等机制导致对氯氰碘柳胺产生耐药性。
