Trichomonas hominis cultured without Bacteria

Trichomonas hominis , like most other intestinal parasites 1 , is usually cultured in vitro in a Dobell–Laidlaw biphasic medium (horse serum, rice starch and Ringer's solution to which is added 15 per cent liquid horse serum) 2 . Growth of T. hominis in that medium occurs only when associated with bacteria. At 25° C. the equilibrium between bacteria and protozoa is optimum, and after forty days of incubation, Trichomonas are still numerous and lively. In such conditions, the maximum protozoal concentration attained is about 200,000 cells/c.c.