Selective culture medium to survey the incidence of Haemophilus species.

A culture medium for the selective isolation of Haemophilus species is described. Bacitracin and nutritional supplements were incorporated in a rich basal agar medium to which rabbit blood was added to distinguish hemolytic species. Colony counts of seven typed strains of H. influenzae on this medium were within practical limits of counts on other media tested for clinical use. The bacitracin medium was as reliable as hemoglobin-agar for detecting H. influenzae and more sensitive for detecting other Haemophilus species in a clinical survey with the advantage of selectivity.