PORCINE CONTAGIOUS PLEUROPNEUMONIA : III. INTERRELATIONSHIP OF HEMOPHILUS PLEUROPNEUMONIAE TO OTHER SPECIES OF HEMOPHILUS: NUTRITIONAL, METABOLIC, TRANSFORMATION, AND ELECTRON MICROSCOPY STUDIES

Hemophilus pleuropneumoniae, the causative agent of porcine contagious pleuropneumonia (PCP) is an encapsulated organism that has the metabolic features of the parainfluenza group of Hemophilus in that it requires DPN but not hemin for growth. Its formation of nitrate reductase cytochrome a₁ and non-physiologically reducible cytochrome c₁ in the stationary phase, together with its requirement of electron transport through oxidases for growth are typical of non-hemin-requiring Hemophilus species. It has the closest genetic homology, judged from the capacity of its DNA to induce transformation to streptomycin resistance, with H. parasuis but can be differentiated from this organism on the basis of its growth in defined medium and its marked and characteristic pathogenicity for swine.