792 



HEMOPHILUS 



named H. bronchisepticus. The nutritional requirements of most of these species 

 have been studied in some detail by various observers, with results that may be 

 summarized as follows : 



With regard to the Koch-Weeks bacillus, the statements in the literature are 

 somewhat contradictory (see Kristensen 1922) ; thus, some authors have stated 

 that this organism grows on ascitic agar and hydrocele-fluid agar. Later studies 

 by Fildes (1923) and by Knorr (1924), however, show quite clearly that the 

 strains, isolated by them from cases of muco-purulent conjunctivitis, behave 

 in exactly the same way as H. influenzce, and require both the X and the V 

 factor. 



H. canis is unable to synthesize the X factor, and is therefore dependent on 

 hsematin, or some similarly-acting substance. It can, however, synthesize the 



V factor, and hence it does not show the 

 phenomenon of satellitism, but can itself 

 induce the formation of satellite colonies 

 of H. influenzce (see Friedberger 1903, 

 Krage 1910, Odaira 1911, Eivers 1922&, 

 Kristensen 1922, Fildes 1923, Valentine 

 and Rivers 1927). H. ducreyi resembles 

 H. canis in its growth requirements 

 (Lwoff and Pirosky 1937). Khairat 

 (1940) has described a hsemophilic bacil- 

 lus from a human endocardial lesion 

 having the same X and V factor require- 

 ments as H. canis. 



H. influenzce- suis requires both the 

 X and V factors for its growth, resem- 

 bling in this as in almost all other respects 

 the human influenza bacillus (Lewis and 

 Shope 1931). 



H. para-influenzce requires V but not 

 X factor for growth. It shows the 

 phenomenon of satellitism. H. pertussis 

 and H. bronchisepticus differ from the 

 other species within this genus in being capable of growth in the absence of both 

 the X and V factors. For primary isolation of H. pertussis Bordet and Gengou 

 (1906) employed an agar medium containing blood, glycerine and potato extract, 

 and this medium, with various minor modifications, is still used for this purpose. 

 Even on first isolation H. pertussis and H. iyifluenzce show differences in their 

 nutritional requirements. The former grows well on media containing large 

 amounts of blood and vegetable extract, poorly on media containing the X and 

 V factors in the absence of other blood or tissue constituents ; the latter grows 

 better on Fildes' or Levinthal's medium than on media of the Bordet-Gengou 

 type (see Gundel and Schliiter 1933). On subculture in the laboratory 

 these differences become more marked. H. pertussis can readily be trained 

 to grow on serum agar, and, with slightly more difficulty, on ordinary agar. 

 There is, however, general agreement that on such media the organism rapidly 

 loses its natural virulence (see below). These relations are clearly shown in 

 Table 51. 



Fig. 167. 



Showing satellite growth of H. inflvenzce in 

 the neighbourhood of hremolytic colonies 

 of Staph, aureus on blood agar. 



