[Report on the differentiation of Haemophilus isolates from chickens. I. Note: cultural and biochemical studies]

Thirty-one isolates of Haemophilus organismus, most of them isolated from respiratory organs of sick chickens, and 3 Haemophilus gallinarum strains from California (USA) were culturally and biochemically investigated. Two groups of Haemophilus strains were differentiated. Of the 23 isolates belonging to group I, 22 were obtained from chickens with Coryza contagiosa gallinarum. One strain was isolated from the eye of a sick chicken. These microaerophilic strains required the V factor only and failed to grow aerobically in serial passage on tryptose agar. Six isolates required chicken serum (not X factor) besides V factor for growth on tryptose agar and they fermented solely xylose. All strains were primarily capsulated and showed iridescent colonies on tryptose agar. They were catalose- and indole negative, produced nitratase; fermented glucose, fructose, mannose, but not trehalose, inulin, salicin, dulcitol, galactose and lactose. Not all of them were capable of fermenting saccharose, maltose, dextrin, sorbitol, xylose and mannitol. The strains 0083 and 0222 from USA were similar to isolates of group I, however they showed a partially different fermentation pattern from that described by Page (1962). After the proposal of Biberstein and White (1969) the Haemophilus strains of group I should be named Haemophilus paragallinarum by reason of their X factor independence and the rules of nomenclature. The 8 isolates of group II grew well aerobically, showed iridescence, were primarily capsulated and required the V factor. These strains were catalase positive, indole negative and produced nitratase; fermented glucose, fructose, mannose, galactose, saccharose and trehalose; but not lactose, inulin, salicin and dulcitol. Some isolates fermented also xylose, maltose, dextrin, sorbitol and mannitol. On the basis of the results of cultural and biochemical investigations these strains were assigned to the group of apathogenic Haemophilus strains described by Page (1962) and Robert et al. (1964).