434 



THE SALMONELLA GROUP 



Vaccinated media. A normal growth takes place on media which have 

 served for the growth of the typhoid and paratyphoid A bacilli. On the 

 other hand on media which have served for the growth of the colon bacillus 

 the culture is poor ; and on media on which the paratyphoid B bacillus has 

 been grown it is very inconstant. 



Cultural differences between the paratyphoid A. bacillus and the 

 paratyphoid B. bacillus. 



Cultures on gelatin. 

 Cultures in broth. 



PARATYPHOID A. 



Scanty and transparent 

 (like typhoid). 



Cloudy ; no pellicle. 



PARATYPHOID B. 



Thick and opaque (like 

 the colon bacillus). 



Cloudy ; pellicle very 

 common. Often fsecal 

 odour. 



SECTION III. BIOLOGICAL PROPERTIES. 

 1. Biochemical reactions. 



(a) Action on carbohydrates. The paratyphoid B. bacillus forms acid 

 and gas when sown in glucose, mannite, dulcite, Isevulose, galactose, arabinose, 

 maltose and sorbite, but gives rise to neither -acid nor gas in lactose, saccharose, 

 salicin, raffinose, and inulin. 



(/?) Indol production. The paratyphoid B. bacillus produces no indol 

 even when incubated in peptone water for 10 days. 



(7) Neutral red media. Very often the colour of the medium is reduced 

 but the change is not constant (vide paratyphoid A). 



2. Toxins. 



Cultures of paratyphoid B. contain soluble toxins. A dose of 5-9 c.c. 

 of a nitrate of a culture on Martin's broth (2-8 days at 37 C.) is fatal to 

 guinea-pigs when inoculated sub-cutaneously. Franchetti prepared a toxin 

 which was fatal to rabbits in doses of 1 c.c. per kg. of body weight when 

 inoculated intra-venously, by making an emulsion of cultures in sterile 

 distilled water, shaking for 2 days, centrifuging and heating to 44 C. for 

 3 hours. 



Cathcart grew the paratyphoid B. bacillus on agar in Roux bottles, washed 

 off the growth with distilled water or normal saline solution, added a little 

 toluol and after repeatedly shaking for 8-10 days and then heating to 60 C. 

 for half an hour obtained an endotoxin which proved fatal to mice in doses 

 of 0*1 c.c. intra-peritoneally in 24 hours. This toxin is thermostable at 

 100 C. 



