Vibrio Choleras Asiaticae, Koch (1884). 



CHOLERA SPIRILLUM, COMMA BACILLUS; BACILLE VIRGULE (Fr.). 



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

 nal contents after death. Pound 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. It may, therefore, vary from apparently a straight rod to one 

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

 semble a comma, hence the name comma bacilliis. When two cells 

 remain attached the elongated "S" form results. Grown in liquid 

 media under unfavorable conditions it may form long spirals. The 

 bent rod is a segment of a spirillum and is designated as a vibrio 

 {Pig. H, p. 46). Peculiar involution forms develop in old cultures. 



Motility. — It is actively motile and usually has at one end a 

 single flagellum (Fig. 6 d, p. 36). Hanging-drop cultures (p. 286) 

 should be developed at 37" — motion, spirals and involutions. 



Sporulation. — No resistant form known. Arthrospores (p. 48). 



Anilin dyes. — Stain slowly. Carbolic fuchsin is excellent. It is 

 not stained by Gram's method. 



Growth. — Is fairly rapid at the ordinary temperature. 



Plains. — On gelaiin plates kept at 22°, 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 affar plates, at 37° 

 the large colonies have a peculiar, bn^rht, grayish-brown, transparent appearance, quite 

 distinct from that of the common bacteria present in water and in feces. 



Stafi culture, — Growth occurs, in gelatin, along the entire line of inoculation. At the 

 surface a funnel-shaped liquefaction forms with an air space above, while the lower part 

 contains the subsided growth. The lower part of the puncture gradually widens by lique- 

 faction: growth settles to bottom, and eventually entire contents of tube are liquefied. 



Streak culture. -'-QTi agar \i forms a bright, glistening, whitish growth. Blood-serum 

 is slowly liquefied. On potato, kept in the incubator, it forms a grayish or yellowish brown, 

 thin and rather transparent layer, which resembles somewhat that of the glanders bacillus. 

 At ordinary temperature, no growth unless a mixed culture is used. 



Bouillon.--GTov/th takes place rapidly, especially in the incubator, and a scum or pel- 

 licle forms on the surface. Cultures, 12-24 nours old, on addition of sulphuric acid show a 

 reddish-violet color — the indol reaction^ — due to formation of indol and nitrous acid, 

 .. .. — Milk. — It grows abundantly in sterile milk, without much change; also in sterile water, 



OxYGKN REQUIREMENTS. — Artificial cultures require oxygen. 



Temperature.— Grows at 15°-42°. Optimum at 37°. Killed at 50°. 



Behavior to gelatin. — Liquefies slowly; especially old cultures. 



Immunity. — Subcutaneous or intra-peritoneal injections of the 

 dead or living vibrio yield an anti-infectious serum; injections of the 

 soluble toxin yield an antitoxic serum. The cell contents of the cholera 

 vibrios immunize. Pfeiffer's reaction with the serum of convales- 

 cents, or that of immunized animals or man (Chap. XIV). 



Pathogenesis.— Intravenous injection into rabbits kills rapidly. 

 In guinea-pigs intra-duodenal injections or introduction of cultures 

 into the previously alkalized stomach produce death with choleraic 

 eilects (p. 272). The intraperitoneal injection of agar culture is ex- 

 tremely fatal to guinea-pigs, — rapid fall of temperature. Subcutane- 

 ous injection of pigeons is not fatal — distinction from V. Metchnikovi. 

 Ingestion of cultures produces typical cholera in man. Feeding of 

 cultures to new-born guinea-pigs and rabbits is usually fatal (p. 272). 



Infection. — Takes place along the alimentary canal, through the 

 water, food, contact with freshly soiled matter, etc. The organism 

 grows in the intestines and the soluble poisons which are elaborated 

 there induce the characteristic symptoms of intoxication. 



Diagnosis. — See p. 346. 



1 Dissolve I g. of pepton and 0.5 g. of NaCl in 100 c.c. of ordinary tap-water (Dun- 

 ham's solution). Fill into tubes and sterilize by steam. Then inoculate with the cholera 

 and other vibrios, and place in the incubator over night. The next day add to each culture 

 1-2 drops of sulphuric acid and note the pink color- the indol reaction. 



344 



