人芽囊原虫人工感染昆明小鼠的实验研究

目的:了解人芽囊原虫(B.hominis)人工感染昆明小鼠后在肠道内寄生、自然病程和治疗情况,观察肠道内环境对其寄生的影响。方法:从腹泻患者粪便中分离培养人芽囊原虫,昆明小鼠分为接受免疫抑制剂处理组、非免疫抑制剂处理组和正常对照组。分别经口人工感染不同数量的人芽囊原虫。感染后第2天粪便检查观察感染情况,感染第6天处死各组2/3实验鼠,各肠段分别取肠内容物涂片镜检虫体寄生情况,观察各段肠腔内环境(pH值、肠道菌群)。观察剩余实验鼠的自然病程,2周后对未愈小鼠给予甲硝唑治疗,观察治疗效果。结果:粪便检查人芽囊原虫检出率为83.3%(75/90)。剖杀后观察pH值在6.5～7.5的肠段有虫体寄生,回盲部(pH7.04±0.16)和盲肠(pH7.1±0.15)部位多见,主要寄居在肠腔和/或附着在肠粘膜表面。各组实验鼠肠道菌群没有差别。68.4%(13/19)的剩余阳性实验鼠多在7～10天内自愈,2周后仍未愈者甲硝唑治疗100%(6/6)有效。结论:人芽囊原虫主要寄生在小鼠回盲部的肠腔和粘膜表面,肠道pH值对人芽囊原虫寄生有影响,甲硝唑治疗效果好。

Experimental study on Kunming mice infected experimentally with Blastocystis Hominis

Objective: To understand the parasitism, natural course and treatment of Blastocystis Hominis (B. hominis) which artificially infected to Kunming mice, observe the impact of internal environment of intestinal tract on parasitism of Blastocystis Hominis.Methods: B.hominis was isolated from patient with diarrhea. Kunming mice were divided into different groups: group with immunosuppressant, group without immunosuppressant and control group. Mice were infected artificially with different quantities of B.hominis. Infection of B.hominis was checked by fecal examination at 2 th day after infection, and at 6 th day, 2/3 of the mice in each group were killed and parasitism of B.hominis, internal environment (pH and microbial population) were observed. Natural course of residue experimental mice was observed and mice not recovered within 2 weeks were treated by metronidazole. Results: The infected rate of B.hominis in experimental mice was 83.3 %(75/90). B.hominis were parasitized inintestine with pH 6.5～7.5, and mainly located in enteric cavity and on the surface of mucosa of ileocolon (pH 7.04±0.16)and cecum(pH 7.1±0.15). There is not difference of microbial population in enteric cavity among different groups. 68.4%(13/19)positive mice were naturally recovered in 7～10 days. Other mice not recovered within 2 weeks were treated by metronidazole and 100 %( 6/6) were effective.Conclusion: B.hominis mainly locates in enteric cavity and on the surface of mucosa of ileocolon. pH of enteric cavity is impacted on parasitism of B.hominis. Treatment of metronidazole is effective to B.hominis infection.