FAMILY X. LACTOBACILLACEAE 



513 



Erythrogenic toxin associated with scarlet 

 fever rash produced by most strains. 



Source: Originally isolated from infected 

 wounds by Rosenbach (op. cit., 1884, 22). 

 Also found in the human mouth, throat and 

 respiratory tract and in inflammatory 

 exudates, blood stream and lesions in human 

 disease of varied character. Occasionally 

 encountered in the udder of the cow and in 

 laboratory animals. May be found in dust 

 from sick rooms, hospital wards, schools, 

 theaters and other public places. 



Habitat: Primarily the human body, 

 where it causes the formation of pus or even 

 fatal septicemias. 



2. Streptococcus equisiniilis Frost and 

 Engelbrecht, 1936. (Type B, Ogura, Jour. 

 Jap. Soc. Vet. Sci., 8, 1929, 174; Frost and 

 Engelbrecht, A Revision of the Genus Strep- 

 tococcus, privately published, 1936, 3 pp.; 

 also see The Streptococci, 1940, 45; Human 

 C, Sherman, Bact. Reviews, 1, 1937, 35.) 



e.qui.si'mi.lis. L. noun equvs horse; L. 

 adj. similis resembling; M.L. adj. equisi- 

 inilis literally horse-like, but intended to 

 mean "resembling Streptococcus equi". 



Morphology and general cultural charac- 

 teristics resemble those of Streptococcus 

 pyogenes. Matt colonies are characteris- 

 tically produced. Gram-positive. 



Serology: Belongs to Lancefield's group 

 C. Several types have been established. 

 Griffith's agglutinative types 7, 20 and 21 

 belong to this species. The type-specific 

 antigens are proteins digestible with tryp- 

 sin. 



Action on blood: Beta hemolytic. Soluble 

 hemolysins produced, one of which is iden- 

 tical with streptolysin O. 



Fibrinolytic. 



Temperature relations: No growth at 10° 

 or 45° C. Does not survive 60° C. for 30 

 minutes. 



Tolerance tests : Fails to grow in presence 

 of 6.5 per cent NaCl or at pH 9.6. Does not 

 grow in skim milk containing 0.1 per cent 

 methylene blue, but Edwards (Kentucky 

 Agr. Exp. Station Bull. 356, 1935) reported 

 growth in an infusion-casein digest broth 

 containing 0.000025 molar methylene blue, 

 thus indicating a tolerance to methylene 

 blue higher than that of Streptococcus pyo- 



genes. Occasionally grows on 40 per cent bile 

 blood agar. 



Litmus milk: Lactose-fermenting strains 

 produce an acid reaction. Milk may be 

 curdled; litmus not reduced before curdling. 



P^inal pH in glucose broth, between 4.6 and 

 5.4. 



Acid from glucose, maltose, sucrose and 

 trehalose. Glycerol fermented when incu- 

 bated aerobically. May or may not ferment 

 lactose and salicin. No acid from arabinose, 

 raffinose, inulin, mannitol or sorbitol. 



Starch and esculin may or maj- not be 

 hydrolyzed. Gelatin not liquefied. Sodium 

 hippurate not hydrolyzed. 



Ammonia produced from arginine. 



Distinctive characters: Members of this 

 species may be confused with Streptococcus 

 pyogenes but may be differentiated from the 

 latter by their ability to ferment glycerol 

 aerobically and to hydrolyze starch and by 

 their generally greater tolerance to methyl- 

 ene blue and bile. For positive identifica- 

 tion, the Lancefield precipitin technique 

 must be relied upon. 



Source: Occasionally associated with 

 erysipelas and puerperal fever. The normal 

 human nose and throat, vagina and skin. 

 Sometimes found in respiratory tract of 

 domestic animals. 



Habitat: Human upper respiratory tract 

 and vagina. 



3. Streptococcus zooepidcniicus Frost 

 and Engelbrecht, 1936. (Animal pj-ogenes, 

 Type A of Edwards, Jour. Bact., 27, 1934, 

 527; Frost and Engelbrecht, A Revision of 

 the Genus Streptococcus, privately pub- 

 lished, 1936, 3 pp. ; also see The Streptococci, 

 1940, 25; Streptococcus pyogenes animalis 

 Seelemann, Deutsche tierarzt. Wchnschr., 

 50, 1942, 8 and 48.) 



zo.o.e.pi.de'mi.cus. Gr. noun zoum an 

 animal; Gr. adj. epidemius among people, 

 prevalent, epidemic; M.L. adj. zooepidemi- 

 cus prevalent among animals. 



Morphology and general cultural charac- 

 teristics resemble those of Streptococcus 

 pyogenes. Mucoid colonies are common. May 

 produce capsular hyaluronic acid. 



Serology: Belongs to Lancefield's group 

 C. 



Action on blood: Beta hemolvtic. The 



