148 

 VIBRIO OF ASIATIC CHOLERA. Koch (1884). 



BACILLUS, COMMA BACILLUS, SPIRILLUM OF ASIATIC CHOLERA. 



Origin. In the excreta of cholera patients, also in the intesti- 

 nal contents after death. Found several times in the water supply. 



Form. Usually appears as a short, rather thick rod with 

 rounded, narrowed ends, and with a more or less decided bend or 

 twist. May therefore vary from apparently a straight rod to one 

 bent in the form of a half circle. Usually the bend is such as to 

 resemble a comma, hence the name, comma bacillus. When two 

 cells remain attached the elongated " 8 " form results. Grown in 

 liquid media under unfavorable conditions may form long spirals. 

 As the usual form, the bent rod, is a segment of a spirillum it is des- 

 ignated as a \ ibrio. Peculiar involution forms develop in old cul- 

 tures. 



Motility. Is actively motile ; has at one end a single flageilum. 



Speculation. Has no highly resistant form. Has been said 

 to form arthrospores. 



Anilin Dyes. Stains slowly with simple anilin dyes. Carbolic 

 fuchsine is excellent. Is not stained by Gram's method. 



Growth Is fairly rapid at ordinary temperature. 



Plates. Un gelatin plates kept at 22 C, characteristic colonies develop 

 in 15-20 hours. The colonies appear as small, white points, which gradually 

 reach the surface and produce a rather slow liquefaction so that funnel-shaped 

 depressions form. After several days the plate becomes wholly liquefied. 

 Under the microscope the colonies show an irregular, rough border; have a 

 white or pale-yellow color, and the contents are coarsely granular, as if made 

 up of broken glass. A faint rosy hue surrounds the border. On agar plates, 

 at 37 the large colonies have a peculiar bright grayish-brown transparent ap- 

 pearance, quite distinct from common bacteria of water and feces. 



Stich Cu Mures. Growth in gelatin along the entire line of inoculation. 

 At the surface a funnel-shaped liquelaction forms with an air space above, 

 while the lower part contains the subsided growth. The lower part of the 

 sticli gradually widens by liquefaction, the growth settles to the bottom and 

 eventually the entire contents of the tube are liquefied. 



Streak Cultures. On agar it forms a bright, glistening, whitish growth. 

 Blood-serum is slowly liquefied. On potatoes, kept in the incubator it forms 

 a grayish or yellowish brown, thin uml rather transparent lnyer, which re- 

 sembles somewhat that of glanders bacillus on the same medium. 



Bouillon. Growth takes place rapidly, especially in the incubator, and 

 a folded scum forms on the surface. Cultures, 12-^4 hours old, on addition of 

 sulphuric acid, show a reddish violet color the indol reaction due to forma- 

 tion of indol and nitrous acid. 



Milk. Grows abundantly in sterilized milk, without much change; and 

 also in sterilized water. 



Oxygen requirements. In artificial cultures requires oxygen- 



Temperature. Grows oetween 35 and 42 C. The optimum 

 is at or about 37 C. Above 53 it is killed. 



Behavior to Gelatin. Liquefies. 



Pathogenesis. Intravenous injection in rabbits kills rapidly. 

 In guinea-pigs intraduodenal injections or introduction of cultures 

 into the previously alkalinized stomach produces death with choleraic 

 effects. Intraperitoneal injections of the pure bacillus from agar 

 cultures are extremely fatal to guinea-pigs, producing rapid fall of 

 temperature. Bacterial cellular proteids, soluble poisonous pro- 

 ducts. Infection of man with pure cultures produces typical cholera. 

 It is therefore recognized and accepted as the cause of Asiatic 

 cholera. 



Infection. -Takes place along the alimentary canal, through 

 the water, food, contact with soiled matter, etc. 



NOTE. Make impression preparations of the colonies. Also place in 

 two sterilized plugged tubes, tap-water solution of 1 per cent, peptone and 

 1 per cent. Na Cl. Sterilize the peptone tubes in steam sterilizer. Then inocu- 

 late with cholera vibrio, place in incubator over night and then apply the 

 indol test. 



