E, BR0NCHISEPTICU8 809 



H. pertussis 



Isolation. — Isolated by Bordet and Gengou (1906) from cases of whooping cough, and now 

 recognized as the causal organism of that disease. 



Morphology. — H. pertussis bears a general resemblance to H. influenzce in its morphology. 

 The cell-form is more constant, being usually of the short bacillary type. Longer 

 bacillary or thread forms may occur, but they are relatively uncommon. 



Growth Requirements. — H. pertussis is not dependent on either the V factor or the X factor 

 for growth. On first isolation it requires a complex medium, the most suitable 

 bemg that devised by Bordet and Gengou, containing blood, potato extract and 

 glycerol. It can, however, be trained to grow on agar. The optimal temperature 

 for growth is in the near neighbourhood of 37° C. 



Growth on Solid Media. — On the Bordet-Gengou medium H. pertussis gives smooth, dome- 

 shaped, gUstening colonies, with an entire edge. They are more opaque than those 

 of H. influenzce, and are greyish as well as glistening. They have been likened not 

 inappropriately to a bisected pearl, less appropriately to a small drop of mercury. 

 When fully developed they tend to be rather larger than the colonies of H. influenzce ; 

 but they develop more slowly and the characteristic appearances described above 

 are often not obvious in less than 48-72 hours' incubation. 



Growth in Liquid Media. — In serum H. pertussis gives a uniform turbidity with a slight 

 deposit, which is sometimes sUghtly flocculent. 



Resistance. — H. pertussis is killed by exposure to a temperature of 55° C. for 30 minutes. 



Biochemical Activities. — H. pertussis does not ferment any sugar. It does not form indole, 

 or reduce nitrates. It produces a hazy zone of haemolysis. 



Antigenic Structure. — H. pertussis in the normal smooth phase constitutes a single antigenic 

 type. In artificial culture, particularly on a relatively unfavourable medium, it gives 

 rise to rough, or partiaUy rough, variants, with a different antigenic structure. 

 The antigen characterizing the S form, and the endotoxin of H. pertussis are sero- 

 logically related to the corresponding substances in H. parapertussis and H. bronchi- 

 septicus. 



Pathogenicity. — H. pertussis is the cause of whooping cough in man. Injected in large 

 doses into laboratory animals it gives rise to a fatal toxsemic infection very similar 

 to that produced by H. influenzce. Introduced intranasally or intratracheally, it 

 produces a fatal broncho-pneumonic infection. 



H. parapertussis 



An organism isolated by Eldering and Kendrick (1937) from cases of whooping 

 cough in the United States, which differs from H. pertussis (a) in producing a 

 brown pigment on certain blood media, (b) in producing catalase, and (c) in having 

 an S somatic antigen and an endotoxin which are apparently distinct from, though 

 related to, those in H. pertxissis. 



H. bronchisepticus 



Synonyms. — B. bronchisepticus, Br. bronchiseptica. 



Isolation. — By Ferry (1911) in the United States, and by M'Gowan (1911) in Edinburgh 

 from dogs affected with distemper. 



Habitat. — Strict parasite, occurring in several different species of animals, and sometimes 

 in man. 



Morphology. — Similar to H. pertussis, but is motile by peritrichate flageUa. 



Cultural Characteristics. — Grows fairly well on nutrient agar media, producing small, 

 round, convex amorphous colonies, with smooth ghstening surface, of butyrous 

 consistency. Grows best under aerobic conditions ; no growth under strictly 

 anaerobic conditions. In agar shake cultures, growth is almost entirely on the 

 surface. Some strains are hsemolytic. 



