FAMILY ENTEROBACTERIACEAE 443 



FAMILY X. ENTEROBACTERIACEAE RAHN. 

 (Cent. f. Bakt., II Abt., 96, 1937, 280.) 



Gram-negative straight rods. Motile with peritrichous flagella, or non-motile. 

 Grow well on artificial media. All species attack glucose forming acid, or acid and 

 visible gas (H2 present). Characteristically nitrites are produced from nitrates 

 (exceptions in Erwinia only). Antigenic composition is best described as a mosaic 

 which results in serological interrelationships among the several genera, even extend- 

 ing to other families. Many animal parasites, and some plant parasites causing blights 

 and soft rots. Frequently occur as saprophytes causing decomposition of plant mate- 

 rials containing carbohydrates. 



Note : Early attempts to develop a satisfactory basis for the recognition of 

 species among the coliform-dysentery-typhoid group of bacteria are reviewed by 

 Winslow, Kligler and Rothberg (Jour. Bact., 4, 1919, 429). These were largely based 

 on differences in motility, production of indole, ability to liquefy gelatin, and, more 

 particularly, differences in the ability to ferment carbohydrates, especially such com- 

 pounds as glucose, lactose, sucrose, dulcitol and salicin. The more recent attempts 

 to express differences in species of coliform bacteria by means of the IMViC reac- 

 tion are reviewed by Parr (Amer. Jour. Public Health, 26, 1936, 39; Bact. Rev., 

 3, 1939, 1), this cryptic symbol indicating the indole test, methyl red acid deter- 

 mination, acetylmethylcarbinol production (Voges-Proskauer reaction) and the util- 

 ization of salts of citric acid. Stuart, Griffin and Baker (Jour. Bact., 36, 1938, 391) 

 and Griffin and Stuart (Jour. Bact., ^O, 1940, 83) have applied these tests plus 

 cellobiose fermentation to a study of a long series of cultures. 



Capsulated types of coliform bacteria are still placed in this edition of the 

 Manual in a separate genus, Klebsiella, although there is some question about the 

 separation of these from the species in Escherichia and Aerohacter. 



Meanwhile, the Kauffmann and White Antigenic Schema has been successfully 

 applied to the recognition of serological groups and types among salmonellas and 

 related organisms. The groupings recognized are outlined in the Salmonella Sub- 

 committee Reports submitted to the 2nd and 3rd Congresses of Microbiology (Jour. 

 Hyg., 34, 1934, 333 and Proc. 3rd Internat. Cong, for Microbiology, 1940, 832). The 

 successful use of antigenic structure in this field has stimulated a study of the 

 use of H and O antigens as a means of classifying the coliform group (Stuart, Baker, 

 Zimmerman, Brown and Stone, Jour. Bact., 40, 1940, 101) but this method of classi- 

 fying the species of coliform bacteria has not proved particularly helpful as yet. 



During this same period there has been an increasing appreciation of the closeness 

 of the relationship between certain common chromogenic bacteria (Serratia) and 

 the coliform bacteria (Breed and Breed, Cent. f. Bakt., II Abt., 71, 1927, 435). 

 INIoreover, the close relationship between bacteria producing soft rots of living vege- 

 table and other plant tissue (now included in Erwinia) and the coliform bacteria 

 has become more evident in recent studies (Waldee, Iowa State Coll. Jour. Sci., 

 19, 1945, 435). Many intermediate types are found in rotting vegetable materials, 

 these rotting types having the ability to attack protopectin (Burkey, Iowa State 

 Coll. Jour Sci., 3, 1928, 57) but not to cause soft rots of living plant tissue. 



Borman, Stuart and Wheeler (Jour. Bact., 48, 1944, 351) have proposed a rearrange- 

 ment of the species in thg family Enterobacteriaceae which combines many forms 

 that have previously been regarded as separate species, or even as belonging in sepa- 

 rate genera. Only the future can determine which of all of these views best expresses 

 the relationships of the bacteria belonging in the Family Enterobacteriaceae. — The 

 Editors. 



