798 



HEMOPHILUS 



(2) Atypical H. influenzce — requiring both X and V factors and not producing 

 haemolysis, but differing from typical strains in showing a predominantly bacillary 

 or filamentous morphology, fermenting saccharose and some other substrates more 

 frequently, and less frequently producing indole. 



(3) A small group of haemolytic influenza bacilli that require both the X and V 

 factor for growth. 



We have not, it will be noted, made any reference in the classification given 

 above to Pittman's " smooth " strains. These will be further considered in relation 

 to antigenic structure. 



The H. para-influenzce strains resemble the atypical H. influenzae strains in morphology 

 in fermenting saccharose and other substrates more frequently, and in less frequently 

 producing indole. The fermentation reactions of H. ducreyi have received httle attention. 

 Khairat's (1940) organism, resembUng it in requiring X but not V factor, fermented 

 dextrose, sucrose, maltose and lactose in 2-3 days, and the polysaccharides dextrin, 

 glycogen and starch in 9-10 days. 



The fermentation reactions of //. caniswere studied by Rivers (19226), who records the 

 formation of acid in dextrose, Isevulose, galactose, mannitol, saccharose, and xylose, but 

 not in maltose, lactose, dextrin, arabinose or glycerol. Indole was produced by all strains 

 examined and nitrates were reduced. Fildes (1924) states that H. amis ferments glucose, 

 saccharose and mannitol ; but not lactose, dulcitol or maltose. 



The strains oi H. influenzce-suis tested by Lewis and Shope (1931) are recorded as pro- 

 ducing no change in dextrose, lactose, saccharose, mannitol, dulcitol, glycerol, inulin or 

 arabinose. They produced no indole. They reduced nitrates. It has been noted that 

 some observers have recorded similar negative results with strains of H. influenzfe, and 

 it is doubtful whether this apparent absence of enzymic activity should be taken as diflfer- 

 entiatmg the swine influenza bacillus from the human type in the absence of further 

 evidence. Kirchenbauer (1934), who has studied several strains of this organism, confirms 

 the reduction of nitrates and the absence of indole production. 



H. pertussis, which is sharply differentiated from H. influenzce m other ways, has been 

 recorded by Stillman and Bourn (1920) as faihng to ferment dextrose, laevulose, galactose, 

 maltose, saccharose, dextrin, mannitol, lactose or inuUn, as producing no indole and as 

 failing to reduce nitrates. It produces a hazy zone of haemolysis. H. bronchisepticus 

 resembles H. pertussis in fermentmg none of the commonly used carbohydrates. 



It may be added that H. influenz(P,-suis and H. canis are non-hsemolytic. 



Many of the fermentative reactions within this group appear to be so irregular that 

 they have little value in classification, or in the identification of particular strains. We 

 may, however, tabulate for purposes of reference the reactions that have actually been 

 observed, using -|- and — signs as rough indicators of the frequency with which the 

 various substrates are attacked (Table 52). 



TABLE 52 



Showing the Fermentation Reactions of various Species, or Groups, of H.emophiltc 

 Bacilli, and of the Pertussis Bacillus of Bordet and Gengou. 



