Some Factors Affecting the Growth of Bordetella pertussis

Abstract

SUMMARY: Bordetella pertussis incubated in liquid media is prevented from multiplying by autoclaved cysteine and is rapidly killed by another substance, possibly a peroxide. The inhibition by autoclaved cysteine is overcome by serum albumin and the inhibition by ‘peroxide’ is overcome by red blood corpuscles, haemin, or ferrous sulphate sterilized by filtration. In a medium containing casein hydrolysate and yeast extract, logarithmic growth may continue for 40-50 hr. at one rate and then may change to a slower rate which continues for a further 20-30 hr. before growth stops. The initial growth rate can be maintained throughout by adding high concentrations of whole blood. The yield of organisms is proportional to the concentration of glutamic acid up to 0.3% (w/v). It is possible that growth at greater concentrations is stopped by the high pH value caused by the oxidation of glutamate. Omission of casein hydrolysate decreases the yield of bacteria. A larger yield is obtained by the use of a large inoculum of bacteria with adherent blood.