INTESTINAL OR COLON-TYPHOID GROUP 



269 



infections in cattle. The organism has been found in meat or 

 so-called ptomain-poisoning in the United States. 



Morphology and Staining. Bacillus enteritidis resembles B. 

 coli morphologically. The organism is short and thick, sometimes 

 with a thin capsule, motile by means of numerous or few flagella. 

 It does not produce spores. It stains well or irregularly with the 

 anilin dyes, and is gram-negative. 



Isolation and Culture. The organism has been isolated directly 

 from the blood-stream and the spleen, and from the intestinal con- 

 tents by plate cultures. The cultural characters as reported vary 

 with different authors, probably because different strains were 

 studied. Colonies upon gelatin and agar resemble those of B. coli. 

 Bouillon is clouded, a delicate 

 pellicle may form, and in a few 

 days a whitish sediment collects. 

 A yellowish, glistening layer 

 forms on potato, frequently turn- 

 ing brownish with age. Growth 

 in milk seems to vary with the or- 

 ganism studied. Some have been 

 described as coagulating milk, 

 but the typical form does not, 

 although a slow proteolysis may 

 take place without coagulation. 



Physiology. B. enteritidis is 

 aerobic and facultative an- 

 aerobic. Its optimum growth temperature is between 30 



Fig. 111. Bacillus enteritidis (Kolle 

 and Wassermann). 



and 



40, but it grows well at room-temperature also. The thermal 

 death-point, as determined by Mohler and Buckley, is 58 for 

 twelve minutes. Dextrose is fermented, with production of acid 

 and gas. Lactose is not fermented by the typical strains, although 

 some strains have been reported by a few investigators to ferment 

 this sugar, and the statement is commonly current in texts. Indol 

 is not produced. Gelatin is not liquefied. 



Pathogenesis. Experimental Evidence. B. enteritidis is patho- 

 genic for the guinea-pig, mouse, and pigeon, but not for the 

 cat. The guinea-pig may be fatally infected by intraperitoneal 

 or subcutaneous injections and by ingestion. The same is true 



