Page:Bergey's manual of determinative bacteriology.djvu/548

 Jensen, 1919. (Streptococcus hollandicus Weigmann, quoted from Kramer, Die Bakteriologie in ihren Beziehungen zur Landwirtschaft und den Landw. Techni- schen Gewerben, Wien, 1890; Orla-Jensen, TheLacticAcid Bacteria, 1919, 132; 5«rep<o- coccus lactis B, Aj-ers, Johnson andMudge, Jour. Inf. Dis., 34, 1934, 29.) cre.mo'ris. L. noun cremor juice; cream; L. gen. noun cremoris of cream. Spheres or ovoid cells elongated in direc- tion of the chain; 0.6 to 1.0 micron in di- ameter (often larger than Streptococcus lactis) ; form long chains, especially in milk, but some cultures occur predominantly as pairs. Gram-positive. Serology: Possesses group-specific anti- gen (group N) of Streptococcus lactis (Sher- man, Smiley and Niven, Jour. Dairy Sci., 23, 1940, 529; Swartling, Jour. Dairy Res., 18, 1951, 256; Briggs and Nevvland, Jour. Dairy Res., 19, 1952, 160). Many serological types are known to exist. Action on blood: Slight greening (alpha hemolytic) to indiiferent (gamma hemo- lytic). Temperature relations: Growth at 10° and below but not at 40° C. Optimum, below 30° C. May survive 60° C. for 30 minutes. Tolerance tests: No growth in broth con- taining 4 per cent NaCl. Growth not ini- tiated in broth adjusted to pH 9.2. No growth in milk containing 0.3 per cent methylene blue. Growth on 40 per cent bile blood agar. Litmus milk: Acidified, curdled, litmus completely reduced before curdling. No digestion. Final pH in glucose broth, between 4.0 and 4.6. Acid from glucose and lactose. May or maj' not ferment trehalose and salicin. Rarely ferments maltose, sucrose, raffinose or mannitol. Arabinose, xj-lose, inulin, glyc- erol and sorbitol not fermented. Starch, gelatin and sodium hippurate not hydrolyzed. Esculin may or may not be split. Ammonia not produced from arginine. Comments: Members of this species are commonly employed in commercial dairy starters. Like Streptococcus lactis, some strains ferment citric acid when incor- porated with a fermentable sugar with the production of carbon dioxide, acetic acid and diacetyl. Some cultures produce an antibiotic-like substance that is active against other lactic acid bacteria. This substance is distinct from nisin, the antibiotic from Streptococcus lactis (Oxford, Biochem. Jour., 38, 1944, 178). Related species : Although closely related, this species can be distinguished readily from Streptococcus lactis by its inability to grow at 40° C., in a 4 per cent NaCl broth or in a medium adjusted to pH 9.2. Also, it fails to produce ammonia from arginine, and the majority of the strains fail to fer- ment maltose. Source: Raw milk and milk products; commercial starters for butter and cheese manufacture. Habitat: Probably of plant origin. Addendum: Species incertae sedis. De- scriptions of species to which no name has been given or of poorly defined species, the taxonomic relationships of which are not clear: 1. Streptococcus sp. Serological group E. (Brown, Frost and Shaw, Jour. Inf. Dis., 38, 1926, 381; Lancefield, Jour. Exp. Med., 57, 1933, 571.) Spherical or ovoid cells occurring in pairs or chains of medium length. Serology: Constitutes Lancefield's group E. Several serological types are known to occur. May cross react with group C. Action on blood: Strongly hemolytic (beta). Some non-hemolytic strains have been reported. The streptolysin produced is very acid-stable (Todd, Jour. Path. Bact., 39, 1934, 299). Not fibrinolytic. Temperature relations: No growth at 10° or at 45° C. Does not survive 60° C. for 30 minutes. Tolerance tests: Does not grow in broth containing 6.5 per cent NaCl or at pH 9.6. No growth in 0.1 per cent methylene blue milk or in 10 per cent bile blood agar. Litmus milk: Acid, but not curdled. No digestion. Final pH in glucose broth, between 4.2 and 4.8.