Growth requirements: Good growth on ordinary laboratory media. Optimum tem- perature, about 30° C. Grows better at temperatures below 30° C. than does Esch- erichia coli Castellani and Chalmers. Usually destroyed in 30 minutes at 60° C, but certain heat-resistant strains may with- stand this exposure (Avers and Johnson, Jour. Agr. Res., S, 1914, 401; Stark and Patterson, Jour. Dairy Sci., 19, 1936, 495). Gas not produced in Eijkmann test when carried out at 45° to 46° C. (Eijkmann, Cent. f. Bakt., I Abt., Orig., 37, 1904, 74; Levine, Epstein and Vaughn, Amer. Jour. Pub. Health, 24, 1934, 505). Comments: Thompson (Jour. Bact., S8, 1934, 41) has reported a variety of this organism which shows a transverse arrange- ment of the capsule. Relationships to other species: Regarded by Escherich {op. cit., 1885, 520) as possibly identical with Hueppe's Milchsiiurebac- terium (Mit. d. kais. Gesund., 2, 1884, 340; Escherichia coli var. acidilactici) . However, because he did not have a culture of Hueppe's organism for comparison, Esch- erich gave the name Bakterium lactis aero- genes to his own organism. Source: Isolated from the feces of breast- fed infants. Habitat: Normally found on grains and plants and, to a varying degree, in water, milk, dairy products and the intestinal canals of man and other animals. Widely distributed in nature. 2. Aerobacter cloacae (Jordon, 1890) Bergey et al., 1923. (Bacillus cloacae Jordan, Rept. Mass. State Bd. of Health, Part II, 1890, 836; also see Jordan, Jour. Hyg., 3, 1903, 1; Bacterium cloacae Lehmann and Neumann, Bakt. Diag., 1 Aufl., 2, 1896, 239; Bergey et al., Manual, 1st ed., 1923, 207.) clo.a'cae. L. noun cloaca a sewer; L. gen. noun cloacae of a sewer. Rods, 0.5 to 1.0 by 1.0 to 2.0 microns, occurring singly. Usually motile by means of peritrichous flagella. Not encapsulated. Gram-negative. Gelatin colonies: Thin, circular, bluish, translucent. Gelatin stab: Slow liquefaction. Liquefy- ing power sometimes lost (Kligler, Jour. Inf. Dis., 15, 1914, 199). Agar colonies: Circular, thick, opaque with white center, entire. Agar slant: Porcelain-white, smooth, glistening, spreading growth. Broth: Turbid; thin pellicle. Litmus milk: Acid; coagulation; gas; slow peptonization. Potato: Yellowish, moist, glistening growth. Indole not produced (Levine, Epstein and Vaughn, Amer. Jour. Pub. Health, 24, 1934, 505; Wilson, Med. Res. Council, London, Spec. Rept. Ser. 206, 1935, 161). Hydrogen sulfide not produced in pep- tone iron agar (Levine, Epstein and Vaughn, op. cit., 1934, 505). Acid and gas from glucose, fructose, galactose, arabinose, xylose, lactose, mal- tose, raffinose, dextrin, salicin, trehalose, mannitol, sorbitol, cellobiose anda-methyl- glucoside. Sucrose usually fermented. Inulin, esculin, starch, dulcitol, rhamnose and protopectin not attacked. Glj'cerol fermented with no visible gas (Kligler, op. cit., 1914, 187; Levine, Amer. Jour. Pub. Health, 7, 1917, 784). Starch rarely fer- mented (Levine, loc. cit.). See Winslow, Kligler and Rothberg (Jour. Bact., 4, 1919, 429) for a review of the literature. Gas ratio: Glucose fermented with at least two volumes of carbon dioxide to one of hydrogen (Rogers, Clark and Davis, Jour. Inf. Dis., 74, 1914,411). Methyl red test negative; Voges-Pro- skauer test positive. Citric acid and salts of citric acid may be utilized as sole sources of carbon (Koser, Jour. Bact., 8, 1923, 493). Uric acid may be utilized as a sole source of nitrogen (Koser, Jour. Inf. Dis., 23, 1918, 377). Sodium hippurate not hj^drolj^zed (Hajna and Damon, Amer. Jour. Hyg., 19, 1934, 545) . Nitrites produced from nitrates. Fecal odor produced. Catalase-positive. Aerobic, facultatively anaerobic. Growth requirements: Good growth on ordinary laboratory media. Optimum tem- perature, between 30° and 37° C. Gas not
