CHAPTER XXXII 

 BACILLUS BOTULINUS 



Bacillus botulinus has been found in various meat products, especially sau- 

 sage, less frequently in eggs, cheese, butter and beans. 



Morphology. Four to 8 /* long, 0.5 to i /x wide, with rounded ends, arranged 

 singly, in groups and short chains. It is said to be motile. 



Staining. Stains with all the usual stains and is Gram positive. 



Growth. Bacillus botulinus is an obligate anaerobic organism growing best 

 at 25C. to 3OC. It grows best in meat, especially pork. 



FIG. 25. BACILLUS BOTULINUS. 

 Some individuals containing spores. (After van Ermengen.) 



Media containing glucose show gas formation, gelatin is liquefied, milk is 

 not coagulated. 



Bacillus botulinus forms spores which are situated near the extremity of the 

 bacillus and are slightly wider than it, causing a bulge. Spores are killed in a 

 short time at 8oC. in a moist state. Bacillus botulinus cannot survive in brine 

 containing more than 6 per cent, of salt. 



Toxin. Bacillus botulinus produces a powerful extracellular toxin which 

 accumulates in sausages, meat pies, etc., containing the organism. A tempera- 

 ture of iooC. destroys this toxin. 



Pathogenesis. Bacillus botulinus does not infect man, but when food con- 

 taining its toxin is eaten the toxin is absorbed and acts as a powerful poison, 

 causing death in 25 per cent, of cases. Following the ingestion of toxin a 

 period of incubation, never less than 6 hours, elapses before the onset of 

 symptoms. Impairment of vision, disturbance of speech, increased saliva- 



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