Taxonomic Significance of Respiratory Quinones and Fumarate Respiration in Actinobacillus and Pasteurella

The lipoquinones and associated respiratory functions of 34 cultures representing 17 bacterial species hitherto assigned to the genus Actinobacillus or Pasteurella were investigated. Strains representing recognized Actinobacillus or Pasteurella species regularly contained desmethylmenaquinones and were capable of anaerobic electron transport with fumarate as a terminal acceptor when grown in oxygen-limited cultures. On aeration, the majority of the strains produced ubiquinones in addition to desmethylmenaquinones, with inter- and intraspecific variations. The use of lipoquinone patterns and features indicating fumarate respiration, such as stimulation of oxygen-limited growth by fumarate, in the classification and identification of Actinobacillus, Pasteurella, and phenotypically similar organisms is discussed.