384 ■ ORDER IV. EUBACTERIALES 



Genus X. Shigella Castellani and Chalmers, 1919* 

 (Man. Trop. Med., 3rd ed., 1919, 936.) 



Shi.gel'la. M.L. dim. ending -ella; M.L. fem.n. Shigella named for Prof. Kiyoshi Shiga, 

 the Japanese bacteriologist who first discovered the dysentery bacillus in 1898. 



Rods that are non-motile. Gram-negative. Gelatin not liquefied. Indole may or may not 

 be produced. Hydrogen sulfide not produced. Numerous carbohj^drates are attacked with 

 the production of acid but no visible gas (some cultures of serotype Shigella flexneri 6 pro- 

 duce visible gas from glucose and from other fermentable substrates) . Lactose is ordinarily 

 not attacked, but some species attack this sugar very slowly. Salicin, inositol and adonitol 

 are not attacked. Acetylmethylcarbinol is not produced. Methyl red test is usually positive. 

 Ammonium citrate is not utilized. Nitrites are produced from nitrates. May or may not 

 produce trimethylamine from trimethylamine oxide (Wood, Baird and Keeping, Jour. 

 Bact., ^6, 1943, 106). Urea is not hydrolyzed. Aerobic. Possess distinctive antigenic struc- 

 tures. Pathogenic, causing dysenteries, or non-pathogenic species, all living in the bodies 

 of warm-blooded animals. Found in polluted water supplies and in flies. 



See Bensted (Dysentery Bacilli — Shigella. A brief historical review. Canad. Jour. Micro- 

 biol., 2, 1956, 163-174) for a helpful review. 



Key to the species of genus Shigella. 



I. No acid from mannitol. 



A. No acid from arabinose or rhamnose. Indole not produced. 



1. Shigella dysenteriae. 



B. Acid from arabinose; acid may or maj^ not be produced from rhamnose. Indole may 

 or may not be produced. 



1. Acid from rhamnose; late and irregular acid from arabinose. Indole produced. 



2. Shigella schmitzii. 



2. No acid from rhamnose; acid from arabinose slow. Indole not produced (except 

 Type 7). 



3. Shigella arabinotarda (Large-Sachs Group). 

 II. Acid from mannitol. 



A. No acid from lactose. 



1. No acid from rhamnose; acid usually produced from xylose. Agglutination with 

 polyvalent specific serum (Types 1 to 11). 



4. Shigella boydii. 



2. Variable acid production from rhamnose; no acid from xylose or dulcitol. No tri- 

 methylamine from trimethylamine oxide. Agglutination with polyvalent specific 

 serum (Types 1 to 6). 



5. Shigella flexneri. 



3. Acid from dulcitol. Trimethylamine from trimethylamine oxide. 



6. Shigella alkalescens. 



B. Acid from lactose late. 



1. Indole not produced. Agglutination with specific serum. 



7. Shigella sonnet. 



2. Indole produced. 



8. Shigella dispar. 



1. Shigella dysenteriae (Shiga, 1898) dysentery, Ogata, Cent. f. Bakt., 11, 1892, 



Castellani and Chalmers, 1919. (Bacillus of 264 {Bacillus dysenteriae Migula); Bacillus 



Japanese dysentery, Shiga, Cent. f. Bakt., dysenteriae Shiga, Cent. f. Bakt., I Abt., S4, 



IAbt.,:?5, 1898, 599; not Bacillus of Japanese 1898, 817; Bacillus shigae Chester, Man. 



* Prepared by Dr. Julien Dumas, Pasteur Institute, Paris, France, August, 1955. 



