620 



ORDER IV. EUBACTERIALES 



Starch hydrolyzed. 



Acetylmethylcarbinol produced (37° C. 

 better incubation temperature than 32° C). 



pH of glucose broth cultures is 5.2 to 8.2 

 in 7 days. 



Citrates utilized. 



Nitrites produced from nitrates. Gas 

 produced from nitrates under anaerobic 

 conditions. 



Growth factors not essential. 



Lecithinase not produced. 



Aerobic, facultatively anaerobic. Growth 

 in glucose broth under anaerobic conditions ; 

 pH is 5.2 or lower at 14 days. Usually a small 

 amount of gas is produced. 



Temperature relations: Optimum, be- 

 tween 32° and 45° C. Maximum, between 

 50° and 56° C. (in water bath). 



Antibiotics obtained from cultures of 

 certain strains are bacitracin (Johnson, 

 Anker and Meleney, Science, 102, 1945, 376) 

 and licheniformin (Callow and Hart, Na- 

 ture, 157, 1946, 334). 



Source: Isolated from cheese. 



Habitat: Widely distributed in soil and 

 food; also common as a laboratory con- 

 taminant. 



6. Bacillus subtilis Cohn, 1872, emend. 

 Prazmowski, 1880. (Cohn, Beitr. z. Biol. d. 

 Pflanzen, 1, Heft 2, 1872, 174; also see Heft 

 3, 1875, 188; and 2, Heft 2, 1876, 249; Praz- 

 mowski, Untersuchungen iiber die Entwick- 

 lungsgeschichte und Fermentwirkung eini- 

 gen Bakterien-Arten. Inaug. Diss., Leipzig, 

 1880.) 



sub'ti.lis. L. adj. stibtilis slender. 



The identity of this species has been the 

 subject of considerable controversy owing 

 to the great variations in cultural charac- 

 ters exhibited by various strains, to the 

 distribution of mislabeled cultures and to 

 confusion with Bacillus cereus. In cases in 

 which an organism is said to be "anthrax- 

 like" or "similar to the anthrax bacillus," 

 it should be remembered that these terms 

 apply to Bacillus cereus and not to Bacillus 

 subtilis. Conn (Jour. Inf. Dis., 46, 1930, 341) 

 concluded that the so-called Marburg strain 

 fitted the earliest recognizable descriptions 

 of this species. His interpretation was ac- 

 cepted by the International Committee on 



Bacteriological Nomenclature (Jour. Bact., 

 33, 1937, 445). 



Rods, 0.7 to 0.8 by 2.0 to 3.0 microns, not 

 in chains, uniformly stained. Not encap- 

 sulated. No shadow-forms. Motile. Gram- 

 positive. Variations: Rods, 0.6 to 1.0 by 

 1.3 to 6.0 microns, or filaments. Long chains. 

 Encapsulated. Shadow-forms. Budding from 

 end of cells. Occasionally non-motile. Rarely 

 Gram-variable. 



Spores, 0.6 to 0.9 by 1.0 to 1.5 microns, 

 ellipsoidal to cjdindrical, central or para- 

 central, thin-walled. Many are formed in 

 48 hours. Variations: 0.5 to 1.0 by 1.0 to 

 2.0 microns. Few are formed in 15 to 21 days. 



Sporulation poor on media made with 

 highly refined agar; much better when crude 

 agar is used or when soil extract is added 

 to the refined agar (Smith and Gordon, un- 

 published data). 



Spore germination is equatorial with 

 splitting of the spore coat along the trans- 

 verse axis (Lamanna, Jour. Bact., 44, 1942, 

 611; Burdon and Wende, Bact. Proc, 1952, 

 46). 



Sporangia not definitely swollen; fre- 

 quently show bipolar staining. 



Gelatin stab : Liquefaction crateriform to 

 stratiform. 



Gelatin agar streak plate: Wide zone of 

 hydrolysis. 



Agar colonies: Rough, opaque, dull, 

 spreading, offwhite. Variations: Smooth to 

 slimy, soft, thin, translucent, dendroid. 

 Yellow, orange or brown. 



Agar slants: Growth abundant, rough, 

 opaque, dull, waxy, spreading. Cream-col- 

 ored to light brown. Variations: Smooth, 

 slimy, thin, translucent, dendroid. Yellow 

 or orange (some strains show a greenish 

 yellow, diffusing pigment when incubated 

 at45°C.). 



Glucose agar slants: Growth heavier and 

 softer than on agar, sometimes pink or 

 brown. 



Glucose asparagine agar slants: Growth 

 abundant. Variation: Scant growth. 



Glucose nitrate agar: Usually abundant, 

 cream-colored growth. 



Soybean agar slants: Growth more abun- 

 dant and softer than on agar. 



