324 



MANUAL OF DETERAriXATTVE BACTERIOLOGY 



lactis acidi Leichmann, Cent. f. Bakt., 

 II Abt., 2, 1896, 777 (not Bacterium lactis 

 acidi Marpmann, Ergiinzungshefte Cent, 

 f. allgem. Gesundheitspflege, 2, 1886. 

 117); Der ovaler Coccus, Freudenreich, 

 Cent. f. Bakt., II Abt., 1, 1896, 168; 

 Bacillus lacticus Kruse, in Fliigge, Die 

 Mikroorganismen, 3 Aufl., 2, 1896, 356; 

 Bacterium lacticus Chester, Del. Agr. 

 Exp. Sta., 9th Ann. Rept., 1897, 88; 

 Bacillus acidi paralactici Kozai, Ztschr. " 

 f. Hyg., 31, 1899, 372; Streptococcus para- 

 lacticus Migula, Syst. d. Bakt., 2, 1900, 

 IS; Bacterium lacticum Migula, Syst. d. 

 Bakt., 2, 1900, 405; Bacterium truncatum 

 Migula, Syst. d. Bakt., 2, 1900, 407 

 (Bacillus No. 19 of Adametz; Bacterium 

 punctalum Chester, Man. Determ. Bad., 

 1901, 147; not Bacterium truncatum 

 Chester, ibid., 157; not Bacterium trun- 

 catum. Chester, ibid., 195); Streptococcus 

 grotenfeltii Chester, Manual Determ. 

 Bact., 1901, 67; Lactococcus lactis Bei- 

 jerinck, Arch. Ne^rl. d. Sci. Exact, et 

 Nat., S^r. II, 7, 1901, 213; Streptococcus 

 lacticus Kruse, Cent. f. Bakt., I Abt., 

 Orig., 34, 1903, 737; Streptococcus giin- 

 theri Lehmann and Neumann, Bakt. 

 Diag., 4 Aufl., 2, 1907, 242; Bacillus 

 lactis acidi Sewerin, Cent. f. Bakt., II 

 Abt., 22, 1908, 8 (not Bacillus lactis acidi 

 Marpmann, loc. cil., 120, nor Leichmann, 

 lac. cit., 778); Bacterium leichmanni 

 Wolff, Cent. f. Bakt., II Abt., 24, 1909, 

 57. 



Spheres: Many cells elongated in di- 

 rection of chain; 0.5 to 1 micron; mostly 

 pairs and short chains, with some cultures 

 long chains. Gram-positive. 



Gelatin stab : Filiform to beaded 

 growth. No liquefaction. 



Nutrient agar colonies : Sj^iall , round or 

 oval, gray, entire, slightly raised. Streak 

 culture tends to remain as definite colo- 

 nies throughout, confluent in parts. 



Glucose broth : Turbidity and later 

 sediment. 



Potato: No visible growth. 



Litmus milk : Acid ; complete reduction 

 of litmus before curdling. Young cultures 



entirely reduced with narrow red band 

 at top which widens with ageing. No 

 digestion and no gas produced, but whey 

 may be expressed. 



Acid from glucose, maltose and lac- 

 tose; variable in arabinose, xylose, mal- 

 tose, sucrose, mannitol and salicin. No 

 acid from raffinose, inulin, glycerol or 

 sorbitol. Occasional strains have been 

 noted which fail to ferment lactose (Yaw- 

 ger and Sherman, Jour. Dairy Sci., 20, 

 1937, 83) and others which do ferment 

 raffinose (Orla-Jensen and Hansen, Cent, 

 f. Bakt., II Abt., 86, 1932, 6). 



Starch not hydrolyzed. Sodium hip- 

 purate may be hydrolyzed and esculin is 

 split. 



Ammonia is produced from 4 per cent 

 peptone. 



Temperature relations : No growth at 

 45°C. Some strains survive 60°C for 30 

 minutes. 



Chemical tolerance : Growth with 2 per 

 cent and 4 per cent NaCl but not with 6.5 

 per cent. Final pH in broth 4.5 to 4.0. 

 No growth at pH 9.6 but grows at pH 9.2. 

 Tolerates both 0.01 per cent, 0.1 per cent 

 and 0.3 per cent methylene blue. Bile 

 neither lyses nor inhibits growth. 



Action on blood: No hemolysis; may 

 show greening or no action. 



Serology : Sherman, Smiley and Niven 

 (.Jour. Dairy Sci., 23, 1940, 529) have pro- 

 duced a species-specific group serum for 

 this species. Shattock and Mattick 

 (Jour. Hyg., ^3, 1943, 173) have desig- 

 nated this group as Group N . The above 

 authors are in agreement in feeling that 

 their studies indicate a close serological 

 relationship between Streptococcus lactis 

 and Streptococcus cremoris. Toxin not 

 known. 



Facultative anaerobe. 



Distinctive characters : Growth at 10°C 

 or below and at 40°C but not at 45°C; 

 rapid complete reduction of litmus before 

 curdling milk ; growth in presence of 4 per 

 cent but not 6.5 per cent NaCl ; ammonia 

 produced from peptone; no growth at 

 pH 9.6 but grows at pH 9.2. 



