Modified DMEM xenic culture medium for propagation, isolation and maintenance of Balantioides coli.

Balantioides coli is a known ciliated zoonotic protozoan that mainly causes diarrhea in humans and pigs. An efficient and reliable culture system for this parasite remains unavailable until now. In this study, a modified Dulbecco's modified eagle medium (DMEM) with pH 7.0-7.5, containing 5 mg/mL starch and 20% new calf serum, was optimized for propagation of B. coli at 28°C-32°C. At the growth-peaking stage, the average trophozoite density was up to 12,970 trophozoites per milliliter. A reproducible protocol for isolation and maintenance of this parasite was also developed based on the modified DMEM culture medium. Moreover, cloning results of B. colipopulations showed that 250 trophozoites in 3 mL modified DMEM medium were the minimal number of trophozoites that propagated to the growth-peaking stage, and finally obtained the individual population. However, less than 250 trophozoites failed to continuously grow in the modified DMEM culture medium under the optimal conditions for growth of B. coli. These data showed that the modified DMEM culture medium is an ideal and efficient medium for propagation and maintenance of B. coli in vitro and will help studies on its biology, genome, transcriptome, proteome, and drug screening.

[Advances in researches of balantidiosis].

Balantidiosis is a disease infected with Balantidium coli, and swine is the main infection source. The infection of B. coli may cause diarrhea, extra intestinal infection and co-infection with other pathogens and even intestinal necrosis. Strengthening the manure management of both human and livestock, paying attention to personal hygiene and labor protection, and timely treatment of the patients are the main measures to control balantidiosis.