Muth W L, Counter F T, Richardson K K, Fisher L F
Lilly Research Laboratories, A Division of Eli Lilly and Company, Indianapolis, IN 46285.
J Ind Microbiol. 1993 Jul;11(4):253-7. doi: 10.1007/BF01569598.
The colonizing potential of Escherichia coli K12 containing a vector coding for somidobove (bovine somatotropin) was determined. Treated male and female Fischer-344 rats were given a single oral gavage inoculum of sucrose with/without tetracycline (15 micrograms/ml). Untreated control animals received similar drinking water regimes. All animals survived until termination. There were no clinical signs of toxicity observed and no treatment-related effect upon body weight, food consumption, or efficiency of food utilization. Fresh fecal samples were collected from each rat every 24 h following inoculation and the population of the marked strain was quantitated until no bacterial colonies were observed for two consecutive days. While all inoculated rats were positive at 24 h, by 72 and 96 h all had become negative for the test (marked) strain, as were the corresponding control group throughout the test. The frozen stock of the marked strain used as the positive control demonstrated that the agar plates were selective for the test strain. Fourteen days following inoculation, all groups of rats were killed and the gastrointestinal tracts removed and treated to recover the marked strain. There was no evidence of the marked strain in the gastrointestinal tract of any from any group. Thus, the E. coli K12 host/vector system used in this experiment does not colonize the gastrointestinal tract of Fischer-344 rats.
测定了含有编码牛生长激素（somidobove，即牛生长激素）载体的大肠杆菌K12的定殖潜力。对经过处理的雄性和雌性Fischer-344大鼠进行单次口服灌胃接种含/不含四环素（15微克/毫升）的蔗糖。未处理的对照动物接受类似的饮水方案。所有动物均存活至实验结束。未观察到毒性的临床症状，且对体重、食物消耗或食物利用效率没有与处理相关的影响。接种后每24小时从每只大鼠收集新鲜粪便样本，并对标记菌株的数量进行定量，直至连续两天未观察到细菌菌落。虽然所有接种的大鼠在24小时时呈阳性，但到72小时和96小时时，所有大鼠的测试（标记）菌株均变为阴性，整个测试过程中相应的对照组也是如此。用作阳性对照的标记菌株的冻存菌液表明琼脂平板对测试菌株具有选择性。接种后14天，处死所有大鼠组，取出胃肠道并进行处理以回收标记菌株。任何组的大鼠胃肠道中均未发现标记菌株的证据。因此，本实验中使用的大肠杆菌K12宿主/载体系统不会在Fischer-344大鼠的胃肠道中定殖。
