A METHOD OF TYPING HAEMOPHILUS INFLUENZAE BY THE PRECIPITIN REACTION

Abstract

A method of typing H. influenzae by the pre-cipitin reaction is described. The procedure consists of dissolving the bacterial culture in 90% phenol to destroy the specificity of the somatic proteins followed by alcoholic precipitation of the denatured proteins and type specific polysaccharide. The carbohydrate is extracted from the precipitate with saline and portions of the saline extract added to samples of the 6 type specific antisera. A positive test is indicated only by a marked turbidity, which develops within 5 min. after mixing and denotes the extraction of at least 0.01 mg. of polysaccharide. A strong positive test is, of course, regularly obtained in the case of cultures shown to be encapsulated by the usual capsular swelling technique. However, the method was devised as an attempt to ascertain whether non-typable (by the capsular swelling technique) derivatives of strains of known type or non-typable, but suspected respiratory pathogens, isolated from clinical material, contained detectable quantities of any of the known type-specific polysaccharides.