The Effect Of The Medium And Source Of Growth Factors On The Satellitism Test For Haemo-Philus Species

Abstract

Three types of nutrient agar were examined for their suitability in determining the X and V requirements of Haemophilus influenzae and H. parainfluenzae. The 80 strains tested were either from type culture collections or freshly isolated. Twenty-six strains required V factor only and 54 both X and V factors when proteose peptone agar was employed with blood as a source of X. On a nutrient agar prepared from Oxoid Nutrient Broth no. 2, when haemin was used as the source of X factor the distribution was almost exactly reversed; 51 strains appeared to be V-dependent and only 27 X- and V-dependent. When tests were carried out on proteose peptone agar with added sodium oleate and thiamin (a medium providing essential growth requirements for Haemophilus with the exception of X and V factors), 43 strains were X and V dependent and 37 dependent on V only. The use of this last medium for satellitism tests is suggested.