Rebers P A, Christianson G G, Laird G A, Symanowski J
National Animal Disease Center, Ames, Iowa 50010.
Appl Environ Microbiol. 1989 Jan;55(1):106-8. doi: 10.1128/aem.55.1.106-108.1989.
Blood agar, prepared with Trypticase (BBL Microbiology Systems, Cockeysville, Md.) soy agar and 5% defibrinated bovine blood, is used for testing the potency of live Pasteurella multocida and Pasteurella haemolytica vaccines, but its potential for variation makes it undesirable to use in a standard assay method. Tests done with RPMI 1640 and Trypticase soy medium indicated that the benefits obtained by adding defibrinated blood to the Trypticase soy agar medium were more likely due to neutralization of toxic components than to the presence of transferrin or iron as growth factors. Reduction of toxic components in the Trypticase soy agar medium was accomplished by replacing agar with agarose and by autoclaving glucose as a separate solution to produce the replacement medium. The replacement medium was prepared by autoclaving three separate solutions--Trypticase soy broth without glucose; glucose; and agarose--cooling to 55 degrees C, and mixing and then pouring the mixtures into petri dishes. The growth obtained with this medium as judged by determination of the number of CFU and the colony sizes of P. multocida or P. haemolytica was equal to or better than those obtained with blood agar.
血琼脂由胰蛋白酶大豆琼脂（BBL微生物系统公司，马里兰州科基斯维尔）和5%脱纤维牛血制备而成，用于检测多杀巴斯德氏菌和溶血巴斯德氏菌活疫苗的效力，但其变异性使其不适用于标准检测方法。在RPMI 1640和胰蛋白酶大豆培养基上进行的试验表明，向胰蛋白酶大豆琼脂培养基中添加脱纤维血所获得的益处，更可能是由于有毒成分的中和作用，而非转铁蛋白或铁作为生长因子的存在。通过用琼脂糖替代琼脂，并将葡萄糖作为单独溶液进行高压灭菌来制备替代培养基，从而减少胰蛋白酶大豆琼脂培养基中的有毒成分。替代培养基的制备方法是将三种单独的溶液进行高压灭菌——不含葡萄糖的胰蛋白酶大豆肉汤；葡萄糖；以及琼脂糖——冷却至55摄氏度，混合后倒入培养皿中。通过测定多杀巴斯德氏菌或溶血巴斯德氏菌的CFU数量和菌落大小来判断，用这种培养基获得的生长情况与用血琼脂获得的生长情况相当或更好。
