Beaudoin M, Higgins R, Harel J, Gottschalk M
Groupe de Recherche sur les Maladies Infectieuses Porcines, Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Quebec, Canada.
FEMS Microbiol Lett. 1992 Dec 1;78(2-3):111-6. doi: 10.1016/0378-1097(92)90011-c.
Five different parameters, time of incubation of the culture, type of culture medium, inoculum, strain of inbred mice, and age of mice, were tested using the LD50 technique to standardize a murine model for the evaluation of the virulence of Streptococcus suis capsular type 2 isolates. A model using 28 day-old mice belonging to CF1 strain appeared to give the best results. The inoculum size was the parameter most influencing the 50% lethal dose obtained with mice. Inoculation with 1-ml volume of a bacterial suspension instead of 0.1 or 0.5 ml decreased the LD50. The standardized model was used to evaluate the virulence of some isolates of known pathogenicity for pigs. The minimum lethal dose was used in the model and it appeared that the virulence of Streptococcus suis capsular type 2 isolates can be measured from highly virulent to totally avirulent.
使用半数致死剂量（LD50）技术对5个不同参数进行了测试，包括培养物的孵育时间、培养基类型、接种物、近交系小鼠品系和小鼠年龄，以标准化一种用于评估2型猪链球菌分离株毒力的小鼠模型。使用CF1品系的28日龄小鼠的模型似乎能给出最佳结果。接种物大小是对小鼠获得的50%致死剂量影响最大的参数。接种1毫升细菌悬液而非0.1或0.5毫升会降低LD50。该标准化模型用于评估一些已知对猪具有致病性的分离株的毒力。模型中使用了最小致死剂量，结果表明2型猪链球菌分离株的毒力可从高毒力到完全无毒力进行测定。
