FAMILY LACTOBACTERIACEAE 



323 



at pH 9.6. Not tolerant of 0.01 per cent 

 and 0.1 per cent methylene blue. 



No action on blood. 



Serology : No cross reaction with Lance- 

 field Group D (Sherman, Jour. Bact., 35, 

 1938,81). 



Facultative anaerobe. 



Distinctive characters : High growth 

 temperature (50°C) and heat resistance 

 (60° to 65°C). Inability to ferment mal- 

 tose and salicin. Inhibited by 2 per cent 

 NaCl, Nutritive requirements in 

 medium. 



Source : Milk and milk products. Used 

 as a starter in making Swiss cheese. 



10. Streptococcus equinus Andrewes 

 and Horder. (Lancet, 2, 1906, 712.) 

 From Latin equinus, of horses. 



Spheres: Occurring in short chains ; the 

 chains are longer in broth than in milk 

 and some cultures give extremely long 

 chains in broth. Gram-positive. 



Gelatin stab : Little or no growth at 

 20°C. Not liquefied. 



Litmus milk: No visible change, grows 

 poorly (with 2 per cent added glucose 

 there is little reduction of litmus). 



Acid from glucose, fructose, galactose, 

 maltose and usually from sucrose and 

 salicin; raffinose and inulin are seldom 

 fermented; arabinose, xylose, lactose, 

 mannitol and glycerol are not fermented. 

 The salicin-negative strains correspond to 

 Streptococcus ignavus Holman, Jour. Med. 

 Res., 34, (N. S. 29), 1916, 377. 



Starch is not hydrolyzed under ordi- 

 nary conditions of test (poured plate) ; it 

 may be hydrolyzed by streak cultures on 

 a very favorable medium. Sodium hip- 

 purate is not split. Esculin is hy- 

 drolyzed slowly, failure in three days, 

 becomes positive in seven. 



Ammonia not produced from 4 per cent 

 peptone. 



Temperature relations : Minimum 21 °C. 

 Growth at 45°C, seldom at 47°C, and no 

 growth at 48°C. Sometimes survives 

 60°C for 30 minutes . 



Chemical tolerance : Growth in 2 per 

 cent NaCl but not in 4 per cent and 6.5 



per cent. Final pH in glucose broth 4.5 

 to 4.0 ; no growth at pH 9.6. Some strains 

 tolerate 0.01 per cent but none tolerate 

 0.1 per cent methylene blue. 



Action on blood : Greening (alpha on 

 horse blood) varying to weak but definite. 

 No hemolysis. 



Serology unknown, but no cross reac- 

 tion with Lancefield Group D (Sherman, 

 •Tour. Bact., 35, 1938, 81). 



Facultative anaerobe. 



Distinctive characters : Minimum tem- 

 perature of growth (20°C) and high maxi- 

 mum temperature of growth (47°C) ; poor 

 growth in milk, even with added glu- 

 cose; failure to ferment lactose. 



Sources : Human and bovine feces ; hu- 

 man mouth, urine and inflammatory exu- 

 dates (pathogenicity not established). 

 Andrewes and Horder (loc. cit.) failed to 

 find it in feces of fox and stoat. 



Habitat : Predominating organism in 

 the intestine of horses. 



11. Streptococcus lactis (Lister) Loh- 

 nis. {Bacteriiuii lactis Lister, Quart. 

 .Jour. Micro. Sci., 13, 1873, 380; 18, 1878, 

 177; Lohnis, Cent. f. Bakt., II Abt., 22, 

 1909, .553. ) From Latin lac, milk. 



The following organisms are generally 

 regarded as identical with Streptococcus 

 lactis Lohnis. See Breed, in Jordan and 

 Falk, The Newer Knowledge of Bacteri- 

 ology and Immunology, Chicago, 1928, 

 383. 



Streptococcus acidi lactici Grotenfelt, 

 Fortschr. d. Med., 7, 1889, 121; Micro- 

 coccus acidi paralactici Nencki and Sie- 

 ber, Monatschr. f. Chem., 10, 1889, 532; 

 Bacillus No. 19, Adametz,Landw. Jahrb., 

 18, 1889, 227; Eine bestimmte Bacte- 

 rienart, Giinther and Thierfelder, Arch, 

 f. Hyg., 25, 1895, 164; Bacillus acidi 

 lactici Esten, Storrs Agric. Exper. Sta. 

 Conn., Ann. Rep. for 1896, 1897, 44 (not 

 Milchsaurebacterium, Hueppe, Mitt. d. 

 kais. Gesundheitsamte, 2, 1884, 340, 

 which is Bacillus acidi lactici Zopf, Die 

 Spaltpilze, 3 Aufl., 1885, 87); Bacterium 

 giintheri Lehmann and Neumann, Bakt. 

 Diag., 1 Aufl., 2, 1896, 197; Bacterium 



