Abstract
A new selective medium, designated GCHB, was developed for the isolation of Actinobacillus actinomycetemcomitans from clinical specimens. A sole inhibitory substrate was used, bacitracin at 100 u/ml. All serotypes (a to g) of A. actinomycetemcomitans strains grew well on the medium. The average growth recovery of A. actinomycetemcomitans on GCHB medium was 89.1% of that on nonselective blood medium. Growth of Haemophilus aphrophilus was significantly inhibited on the medium with an average recovery of 0.01%. The proportion of contaminating bacteria among total cultivable bacteria from clinical samples on GCHB was one to ten times lower than that on TSBV.
