CHAPTER 22 

 VIBRIO AND SPIRILLUM 



VIBRIO 



Definition. — Vibrio. 



Short, curved, rigid rods, arranged singly or united into s-forms or spirals. 

 Motile by a single polar flagellum, which is usually relatively short. (Some species 

 may have two or three polar flagella.) Non-sporing. Usually Gram-negative. 

 Aerobic and facultatively anaerobic. Many species liquefy gelatin and are active 

 ammonifiers. Commonly found in water. Most species are saprophytic ; a few 

 are pathogenic to man. 



Type species. Vibrio cholerce. 



The first member of this group to be described was F. cliolercE, vphich was found 

 by Koch (1886) in the dejecta of cholera patients. In 1888 Gamaleia (1888a) 

 isolated a vibrio from the blood and intestinal contents of chickens dying from a 

 cholera-like disease at Odessa ; to this organism he gave the name of F. metch- 

 nikovi. During the next 10 years a large number of other vibrios, more or less 

 resembling the cholera vibrio, were isolated from different sources, such as well, 

 river, and sea water, the faeces of man and animals, cheese, and intestinal abscesses 

 of pigs (Dunbar 1893, Smith 1894, Dieudonne 1894, Kutscher 1895, Gotschlich 

 1895, 1906, Ruffer 1907, Crendiropoulo 1912, Craster 1913). The differentiation 

 of many of these organisms from F. cholerce proved impossible, until the introduc- 

 tion of the Pfeiffer test in 1894 (see Chapter 63). Even with the help of this 

 test, it was not always possible to decide whether they were different species, or 

 were merely variants of the main species. Since the chief interest of the vibrios — 

 at least to the medical bacteriologist — has been their relationship to F. cholerce, 

 it follows that a careful systematic study of the saprophytic species has not yet 

 been made. For this reason it is premature to attempt a classification of the 

 members of this group. 



Morphology and Staining. — The vibrios are short, curved rods, looking like 

 commas. In size they vary considerably, from about 1 to 5 /^ in length and about 0-3 

 to 0-6 n in breadth ; the commas may appear long, thin, and delicate, or short, 

 stunted and thick. They are arranged singly, in s-shaped or occasionally semicircular 

 pairs, or in short chains. In fluid media spirals are often formed, and in old cultures 

 a variety of forms may be seen ; most of these are very small, looking like granules 

 and staining poorly ; but there are larger, swollen, shadow forms resembling 

 bottles or clubs. When freshly isolated the resemblance to a comma is most 

 striking ; but after long subculture in the laboratory the vibrios frequently lose 

 their curved shape, and are then not unlike coliform bacilli. The organisms are 



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