Stephens J F, Anderson E L
Poultry Science Department, Clemson University, Clemson, South Carolina 29631.
Appl Microbiol. 1967 Nov;15(6):1468-72. doi: 10.1128/am.15.6.1468-1472.1967.
Newly hatched chicks were inoculated in the yolk sacs with standardized suspensions of Salmonella anatum, S. heidelberg, or S. infantis. At intervals between 3 and 48 hr postinoculation, chicks from each group were sacrificed, the average number of viable cells per yolk sac was determined, and liver tissue from each chick was examined for Salmonella. Growth patterns of the three species were almost identical when each chick was inoculated with about 3.5 million cells, but S. heidelberg was recovered more frequently from the liver, and caused a much higher percentage of mortality than did either S. anatum or S. infantis. When 100-fold dilutions of the suspension of S. heidelberg were used, mortality and recovery rates of the bacterium from the liver were directly related to the number of cells injected. The logarithmic growth phase was lengthened as the number of cells in the inocula was decreased; consequently, there was little difference in the average number of S. heidelberg cells per yolk sac at 36 or 48 hr postinoculation regardless of number of cells injected. Results of these trials indicated that factors other than rate of multiplication in the yolk sac are responsible for observed differences between Salmonella species in degree of pathogenicity for baby chicks.
刚孵出的雏鸡通过卵黄囊接种了标准的鸭沙门氏菌、海德堡沙门氏菌或婴儿沙门氏菌悬液。在接种后3至48小时的不同时间间隔，处死每组的雏鸡，测定每个卵黄囊中活细胞的平均数，并检查每只雏鸡的肝脏组织中是否存在沙门氏菌。当给每只雏鸡接种约350万个细胞时，这三种菌的生长模式几乎相同，但从肝脏中更频繁地分离到海德堡沙门氏菌，并且其导致的死亡率比鸭沙门氏菌或婴儿沙门氏菌高得多。当使用100倍稀释的海德堡沙门氏菌悬液时，该菌的死亡率和从肝脏中的分离率与注射的细胞数直接相关。随着接种物中细胞数的减少，对数生长期延长；因此，无论注射的细胞数多少，接种后36或48小时每个卵黄囊中海德堡沙门氏菌细胞的平均数几乎没有差异。这些试验结果表明，除了在卵黄囊中繁殖速率之外的其他因素导致了观察到的沙门氏菌不同种类对雏鸡致病性程度的差异。
