Chapman H D
Parasitology. 1976 Dec;73(3):265-73. doi: 10.1017/s0031182000046953.
The development of resistance by the Houghton strain (H) of E. tenella to robenidine has been studied in the laboratory, by serially passaging the strain in chickens fed increasing concentrations of drug. Resistance to robenidine developed more readily in experiments using larger numbers of birds with higher numbers of oocysts in the inoculum. Both these factors increased the parasite population and increased the chance of selecting parasites resistant to the drug. E. tenella (H) was made resistant to 264 ppm robenidine and showed no cross-resistance to other anticoccidial agents. Resistance arose in a series of 'steps' as the concentration of drug was increased. E. tenella (H) was continuously passaged at concentrations ranging from 2 to 33 ppm of robenidine. After 16 passages, lines passaged at 2,4 and 8 ppm were not resistant to 33 ppm robenidine, suggesting that the degree of resistance developed was dependent upon the drug selection pressure.
已在实验室中研究了柔嫩艾美耳球虫霍顿株（H）对罗苯哒唑产生耐药性的情况，方法是在给鸡投喂浓度不断增加的药物时，对该菌株进行连续传代。在使用更多数量的鸡且接种物中卵囊数量更多的实验中，对罗苯哒唑的耐药性更容易产生。这两个因素都增加了寄生虫种群数量，并增加了选择对该药物耐药的寄生虫的机会。柔嫩艾美耳球虫（H）对264 ppm的罗苯哒唑产生了耐药性，并且对其他抗球虫药没有交叉耐药性。随着药物浓度的增加，耐药性以一系列“步骤”出现。柔嫩艾美耳球虫（H）在罗苯哒唑浓度为2至33 ppm的范围内连续传代。传代16次后，在2、4和8 ppm浓度下传代的品系对33 ppm的罗苯哒唑不耐药，这表明产生的耐药程度取决于药物选择压力。
