Chapter IX Biotyping and Serotyping of Pasteurella haemolytica

Abstract

This chapter presents the procedure for the biotyping and serotyping of Pasteurella haemolytica . The genus Pasteurella consists of pleomorphic, gram-negative, nonmotile rods, characterized by a fermentative carbohydrate metabolism. Being oxidase positive, they are readily differentiated from members of Enterobacteriaceae , to which the same description applies. They grow poorly or not at all on the usual selective plating media for enteric organisms. In triple-sugar-iron agar (TSI), they produce acidity throughout, without gas or hydrogen sulfide formation, a reaction not typical of Enterobacteriaceae , except certain yersinias, which are further distinguishable from Pasteurella species by being motile and growing freely on MacConkey agar. P. haemolytica is most readily distinguished from P. multocida by its failure to produce indole and its production of a usually narrow haemolytic zone, sometimes no bigger than the colony itself, on bovine or ovine blood agar. Typing, both in the cultural and serological sense has served as a useful tool in the search for an understanding of diseases related to P. haemolytica .