Wooley R E, Brown J, Gibbs P S, Nolan L K, Turner K R
Department of Medical Microbiology, College of Veterinary Medicine, University of Georgia Athens 30602.
Avian Dis. 1994 Jan-Mar;38(1):141-5.
Colonization of the intestinal tracts of newly hatched chicks with Escherichia coli was attempted by swabbing test organisms onto the air-shell of 19-day-old embryos. Test organisms consisted of two virulent E. coli isolates, one avirulent isolate, and one laboratory-derived mutant of the avirulent isolate carrying a recombinant plasmid coding for Colicin V production. Chicks were cultured weekly for 3 weeks for total E. coli and for the test organisms using selective media. Control chicks were sampled on weeks 1 and 5, and the normal E. coli intestinal microflora were examined for the production of colicins. The two virulent E. coli isolates maintained colonization of the chicks for the 3-week test period, with titers decreasing from 10' to 10'- colony-forming units (CFU)/g of intestine. The avirulent isolate and laboratory mutant did not consistently colonize the intestinal tracts. The majority of intestinal samples taken from the control chicks at 1 and 5 weeks had colicin-producing E. coli that were inhibitory to the test organisms.
通过将测试微生物涂抹在19日龄胚胎的气室蛋壳上，尝试使刚孵化出的雏鸡肠道被大肠杆菌定殖。测试微生物包括两种有毒力的大肠杆菌分离株、一种无毒力分离株，以及一种携带编码产大肠杆菌素V重组质粒的无毒力分离株的实验室衍生突变体。使用选择性培养基，每周对雏鸡进行3周的培养，以检测总大肠杆菌和测试微生物。在第1周和第5周对对照雏鸡进行采样，并检查正常大肠杆菌肠道微生物群中大肠杆菌素的产生情况。在为期3周的测试期内，两种有毒力的大肠杆菌分离株在雏鸡肠道中持续定殖，其滴度从每克肠道10⁷降至10⁵菌落形成单位（CFU）。无毒力分离株和实验室突变体并未始终在肠道中定殖。在第1周和第5周从对照雏鸡采集的大多数肠道样本中，产大肠杆菌素的大肠杆菌对测试微生物具有抑制作用。
