Observations on the pH of a Culture Medium and on Cultures of Trichomonas foetus

Abstract

A medium which does not require any blood serum has been used in this laboratory for several years. Directions for its preparation are as follows: Beat eight eggs in 100 cc of saline (Rees, 1937) to which has been added one per cent of Lilly's liver extract No. 343. After mixing, tube in 2to 3-cc amounts, slant and coagulate. Cover the coagulated slant with 8to 10-cc of plain saline, stopper with cotton, and sterilize by autoclaving at 115 lbs for 15 to 20 minutes. No blood is used in the medium at any time. Various concentrations of the liver extract were tried both in the egg and in the covering saline, and one per cent added to the egg gave as good or better results than other combinations. The trichomonads may live in this medium for as long as 30 days at incubator temperature. The life expectancy of a given culture is not as long as that reported by Schneider (1942) for his medium, but the liver extract mixture would seem to have certain other advantages. Routine transfers are made at 10to 14-day intervals. The liquid portion of the medium is clear, there is little or no sediment, and the egg slant does not disintegrate on long standing. Clouding of the saline indicates most types of bacterial contamination. Isolations have been made from several cases of trichomoniasis and several different strains of trichomonads have been transferred from other media to the one here described. The new medium will support the growth of the protozoan in the absence of all bacteria.