Clinic for Avian, Reptile and Fish Medicine, University of Veterinary Medicine Vienna, Vienna 1210, Austria.
Int J Parasitol. 2012 Sep;42(10):893-901. doi: 10.1016/j.ijpara.2012.07.007. Epub 2012 Aug 17.
Based on clonal cultures of Histomonas meleagridis, monoxenic cultures have, to our knowledge for the first time, been established in a liquid medium. The faecal flora was exchanged for defined bacterial strains by selective destruction of the initial bacteria with a variety of antibiotics, keeping the flagellate alive. The growth of the protozoan parasite was found to depend on the bacteria, especially on their energy metabolism. Escherichia coli was found to strongly support the growth of the parasite, whereas Salmonella enterica serovar Typhimurium and Pseudomonas aeruginosa were less efficient. Confocal laser microscopy showed that H. meleagridis could take up green fluorescent protein-tagged E. coli DH5α, suggesting that bacteria serve as a food supply for the protozoa. By exchanging the bacterial flora for E. coli strain DH5α in H. meleagridis cultures that underwent continuous in vitro passages, it was possible to show that the in vivo attenuation process was independent of the bacteria. Furthermore, the gut flora in infected turkeys had no negative effect on the protozoan's virulence. Consequently, attenuation depends not on the bacteria in the culture but on the in vitro passages. Finally, the experiments provided evidence that the infection of turkeys with H. meleagridis enabled infection of the liver with E. coli.
基于火鸡组织滴虫的克隆培养，我们首次在液体培养基中建立了单养培养。通过用各种抗生素选择性地破坏初始细菌来交换粪便菌群，同时保持鞭毛虫的存活，从而实现了对定义细菌菌株的交换。研究发现，原生动物寄生虫的生长依赖于细菌，特别是它们的能量代谢。研究发现大肠杆菌强烈支持寄生虫的生长，而沙门氏菌血清型 Typhimurium 和铜绿假单胞菌的效率较低。共聚焦激光显微镜显示，火鸡组织滴虫可以摄取绿色荧光蛋白标记的大肠杆菌 DH5α，表明细菌是原生动物的食物来源。通过将细菌菌群交换为经历连续体外传代的火鸡组织滴虫培养物中的大肠杆菌 DH5α，证明体内衰减过程与细菌无关。此外，感染火鸡的肠道菌群对原生动物的毒力没有负面影响。因此，衰减不依赖于培养物中的细菌，而是依赖于体外传代。最后，实验提供了证据表明，火鸡感染火鸡组织滴虫可导致大肠杆菌感染肝脏。
