CHAPTER XXIII 



THE TYPHOID BACILLUS 



(THE EBERTH GAFFKY BACILLUS) 



The typhoid bacillus is present in the blood, urine and feces, sometimes in all 

 three, of typhoid fever patients. It is occasionally present in the urine or feces 

 for weeks, months or years after recovery from typhoid fever. It is variously 

 stated by different observers that from i in 500 to i in 5000 of the inhabitants 

 of a community are typhoid carriers and that these are responsible for from 20 

 to 50 per cent, of all typhoid infections. The typhoid bacillus may be found in 

 ulcers, abscesses and other complications or sequelae of typhoid fever. 



From such sources, especially feces, the organism may be transmitted to 

 soil, water, milk, cooking and serving utensils, and various articles of food. 



Morphology. The typhoid bacillus is 2 to 3 /j. by 0.5 to 0.8 ju, in size is 

 straight, with rounded ends, and has from 12 to 24 lateral flagella which are 

 about 8 n long. It is actively motile. The typhoid bacillus has been described 

 as differing from the colon bacillus in the number of its flagella and in degree of 

 motility. These differences are so variable and slight that differentiation can- 

 not be based. on them. 



Staining. The typhoid bacillus stains with all the common stains and is 

 Gram negative. 



Growth. Culture of the typhoid bacillus is subject to the same conditions 

 as the colon bacillus. Growth of the typhoid bacillus on plain bouillon, agar 

 and gelatin is indistinguishable from that of the colon bacillus. 



Milk is not coagulated and is not acidulated. 



Potato. A typical growth of the typhoid bacillus on potato occurs in 24 

 to 28 hours. It is very scant, colorless and moist, almost or quite invisible. 

 This typical development does not occur always; there may be no growth or 

 the culture may have the same appearance as a colon culture. 



Indol is not produced. There is no spore formation. On media containing 

 any of the sugars the typhoid bacillus does not form gas. Acidulation occurs 

 with glucose but not with lactose nor saccharose. 



Resistance. The typhoid bacillus has the same power of resistance as the 

 colon bacillus to heat, cold, drying, exposure to sunlight and chemical germi- 

 cides. In water saprophytic bacteria tend to destroy typhoid bacilli so that 

 they usually survive but a few days. Cases have been reported in which 

 typhoid bacilli were found alive and virulent in water after 30 days. In ice 

 they remain alive and virulent for months; also in soil under certain conditions. 



Toxin. The typhoid bacillus produces an intracellular toxin. 



Agglutinins occur in the blood of nearly all typhoid patients after the first 

 week of the disease and may be found in the blood of some people weeks, months 



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