A chemotyping scheme for clinical isolates of Haemophilus influenzae.

A total of 464 Haemophilus influenzae strains, most of them fresh clinical isolates, have been classified by chemotyping --a combination of auxotyping and biotyping. Seven auxotests and four other biochemical tests allowed recognition of 56 types. These were to a degree site-specific. H. influenzae of capsular type b proved almost without exception to belong to one chemotype, and 24 of 33 strains assigned to this chemotype were capsulated. When surgical-ward isolates of H. influenzae were typed, the results suggested that some cross-infection had occurred.