STUDIES WITH HAEMOPHILUS PERTUSSIS

Abstract

Until recently little has been known concerning the immunochemistry of the causative organism of whooping cough. Haemophilus pertussis as isolated from patients with the disease in active form is an organism of unique characteristics. It is biochemically inert in standard fermentation reactions; its growth requirements are exacting; it tends to undergo dissociation into three different variant forms which cannot be distinguished morphologically. However, the variants have far less rigid growth requirements and grow readily on simple mediums. Immunologically the organism is of a single type. On the basis of the serologic reactivities of the variant forms, H. pertussis has been classified into four "phases" by Leslie and Gardner.¹ This classification was confirmed by Flosdorf, Dozois and Kimball.² Phase I represents the virulent form as freshly isolated from patients with active whooping cough. Its requirements of growth are met by the medium of Bordet and Gengou. No liquid medium