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MANUAL OF DETERMINATIVE BACTERIOLOGY 



COCCUS inulinaceus may be considered as 

 identical with Streptococcus hovis as de- 

 scribed here. The so-called Bargen 

 streptococcus (Bargen, Jour. Amer. 

 Med. Assn., 83, 1924, 332; Arch. Int. 

 Med., 45, 1930, 559) is also considered to 

 be Streptococcus bovis. 



Spheres : Occurring in pairs and chains. 

 Capsulated in milk. Gram-positive. 



Gelatin stab : No liquefaction. 



Litmus milk: Acid, curdled in 3 to 5 

 days, followed by reduction of the litmus. 



Acid from glucose, fructose, mannose, 

 galactose, maltose, lactose, sucrose, raffi- 

 nose and salicin; sometimes from manni- 

 tol, sorbitol, inulin, arabinose and treha- 

 lose. Not from glycerol . 



Starch is hydrolyzed by typical strains 

 but not by variety inulinaceus. Esculin 

 is hydrolyzed but not sodium hippurate. 



Nitrites not produced from nitrates. 



Ammonia not produced from 4 per cent 

 peptone. 



Temperature relations : Optimum 

 temperature 35°C. When freshly iso- 

 lated, maximum 45°C. No growth at 

 22°C or below. Survives 60°C for 30 

 minutes, but not 65°C. 



Chemical tolerance : 2 per cent NaCI 

 growth, 4 per cent NaCl no growth, 6.5 

 per cent NaCl no growth. Final pH in 

 glucose broth 4.5 to 4.0. No growth at 

 pH 9.6. May tolerate 0.01 per cent 

 methylene blue but not 0.1 per cent. 

 Tolerant of bile and not soluble. 



Action on blood: Not hemolytic; the 

 changes exhibited vary from greening 

 (alpha) to no observable change (gamma). 



Soluble hemolysin : Absent. 



Toxin : Absent. 



Serology: Some cross reaction with 

 Lancefield Group D (Sherman, Jour. 

 Bact., 35, 1938,81). 



Facultative anaerobe. 



Distinctive characters : Greening or no 

 change in blood ; a higher maximum tem- 

 perature of growth than Streptococcus 

 salivarius and distinctly higher thermal 

 resistance (60°C for 30 minutes); hy- 

 drolysis of starch and usually ferments 

 arabinose and sometimes mannitol. 



Source : Saliva, feces and intestinal con- 

 tents of cattle ; milk of cows ; sometimes 

 abundantly present in human feces (Bar- 

 gen's coccus) in health and disease. The 

 variety inulinaceus is sometimes abun- 

 dant in the bovine throat. 



Habitat : Bovine mouth and alimentary 

 tract where it is the predominating strep- 

 tococcus. 



9. Streptococcus thermophilus Orla- 

 Jensen. (Maelkeri-Bacteriologi, 1916, 

 37; The Lactic Acid Bacteria, 1919, 136.) 

 From Greek thermus, heat; philus, 

 loving. 



Spheres : 0.7 to 0.9 micron, with pointed 

 ends, occurring singly and in short chains. 

 Gram-positive. 



Gelatin stab: No liquefaction. 



Nutrient agar: Small, pin-point, gray, 

 circular colonies. In streak cultures 

 growth is scanty, beaded and gray. Fas- 

 tidious in nutritive requirements needing 

 appropriate carbohydrates added to pep- 

 tone-infusion media (especially lactose 

 and sucrose). Viability on laboratory 

 media low. 



Broth: Fine granular sediment; usu- 

 ally in very long chains, especially at 

 45°C. 



Litmus milk : Acid, curdled, followed 

 by partial reduction of the litmus. 



Acid from glucose, fructose, lactose, 

 and sucrose; seldom ferments raffinose 

 and arabinose. No acid from maltose, 

 dextrin, inulin, glycerol, mannitol, sor- 

 bitol or salicin. 



No hydrolysis of sodium hippurate or 

 esculin. Starch may be hydrolyzed on a 

 favorable medium. 



Ammonia not formed from 4 per cent 

 peptone. 



Temperature relations : Optimum 40° 

 to 50°C. Minimum 20°C. No growth 

 at 53°C. Survives 60° and 65°C for 30 

 minutes. Thermal death point 72° to 

 74°C. 



Chemical tolerance : Extremely sensi- 

 tive to salt, no growth with 2 per cent, 4 

 per cent and 6.5 per cent NaCl . Final pH 

 in glucose broth 4.5 to 4.0. No growth 



