332 



MANUAL OF DETERMINATIVE BACTERIOLOGY 



Gelatin: Poor growth. No lique- 

 faction. 



Semi-solid agar (Veillon) : After 24 

 hours colonies 1 to 2 mm in diameter, reg- 

 ular, lenticular; .sometimes with complex- 

 processes. 



Blood agar: No change or slight 

 greening. 



Martin broth: Rapid growth. Uni- 

 form turbidity which slowly settles. 



Martin glucose broth : Abundant 

 growth. Abundant sediment. Medium 

 strongly acidified. 



Peptone water: Particulate sediment. 



Milk: Very acid. Coagulated in 24 

 hours, without retraction of clot and not 

 peptonized. 



Serum broth (1:2): Rapid growth. 

 Coagulation by acidification. 



Proteins not attacked. 



Neutral red broth : Changed to fluores- 

 cent yellow. 



Acid from glucose, fructose, galactose, 

 maltose and lactose. Acid from sucrose 

 by some strains. The acid produced is 

 lactic acid. No acid from arabinose, 

 glycerol, mannitol, dulcitol, inulin or 

 starch. 



Optimum pH 6.0 to 8.5. 



Temperature relations : Optimum 36° 

 to 38°C. Poor growth at 26°C. No 

 growth below 22°C. Killed in half an- 

 hour at 70°C or in ten minutes at 80°C. 



Pathogenic for guinea pigs and mice, 

 causing small abscesses; sometimes kills 

 in 48 hours. 



No toxin and no hemolysin. 



Strict anaerobe. 



Distinctive characters : Strongly acidi- 

 fies media. Coagulates milk. 



Source : Lochia and uterus in puerperal 

 sepsis; gangrene of the lung; pleurisy; 

 bronchiectasis ; appendicitis. 



Habitat : Human respiratory and di- 

 gestive tracts and vagina. 



24. Streptococcus evolutus Pr^vot. 

 {Streptococcus Sch., Graf and Wittneben, 

 Cent. f. Bakt., I Abt., Orig., 39, 1925, 

 443; Streptococcus Schwarzenbeck, Ford, 

 Textb. of Bact., 1927,455; also see Weiss 



and Mercado, Jour. Inf. Dis., 62, 

 1938, 181.) From Latin evolutus, un- 

 rolled. 



Description taken in part from Prevot, 

 Ann. Sci. Nat., Ser. Bot., 15, 1933, 

 199. 



Spheres : 0.7 to 1.0 micron, average 0.7 

 micron, occurring in pairs or in short and 

 long chains. Pleomorphic. Often ap- 

 pear as short ovoid rods with rounded 

 ends. Gram-positive. 



Gelatin : Liquefaction. 



Deep agar colonies : Lenticular or 

 rosettes. Growth occurs about 1 cm 

 beneath the surface ; after a transfer the 

 second generation may show a ring of 

 growth in the middle of this sterile zone. 

 This is the characteristic alternate zones 

 appearance. Colonies usually become 

 brownish with age. 



Glucose broth: Abundant growth, re- 

 sembling bread crumbs. Medium 

 strongly acidified (pH 5). A small quan- 

 tity of lactic acid produced. 



Peptone broth: Rapid growth. No 

 general turbidity. Precipitating floccu- 

 lent growth on the wall of the tube. 



Blood agar: No change, sometimes 

 greening. 



Peptone water: Flocculent growth. 

 No turbidity. Lidole not formed. 



Litmus milk: Acid. Curdled in 24 

 hours, clot retracts and fragments. 

 Slight peptonization with some strains. 



Strongly acid in glucose, fructose, 

 galactose, sucrose, lactose and maltose. 

 Arabinose sometimes fermented. 



Egg white not attacked. 



Pathogenicity : Most strains not pa- 

 thogenic, some produce slight local swell- 

 ing subcutaneously with little pus in 

 guinea pigs and mice. 



Optimum pH 6.0 to 8.5. 



Optimum temperature 36° to 38°C. 

 No growth below 22°C. 



Strict anaerobe at first, becoming facul- 

 tative with subsequent transfers. 



Viability short aerobically and several 

 months anaerobically. 



Distinctive characters : Growth in al- 



