Agar colonies: White, shiny, convex, smooth, glistening, entire. Agar slants: Slimy, white, somewhat translucent, raised growth. Broth: Turbid; thick ring or film. Litmus milk: Acid; no coagulation. Potato: Yellowish, slimy, raised growth. Gas is produced. Indole not produced. Hydrogen sulfide not produced. Acid and gas from glucose. Acid and gas may be produced from lactose. Acid from sucrose, maltose, salicin, arabinose, rham- nose, xylose, mannitol, adonitol, inositol and sorbitol. Acid may or may not be pro- duced from dulcitol. Acetylmethylcarbinol usually produced. Methyl red test negative. Ammonium citrate utilized as a sole source of carbon. Nitrites produced from nitrates. Urea maj' or may not be slowh' decom- posed. Aerobic, facultatively anaerobic. Optimum temperature, 37° C. Pathogenicity: Lethal for mice. Serology: Cultures belonging to this species are classified serologically on the basis of their O and K (capsule) antigens. Kauffmann (Acta Path, et Microbiol. Scand., 26, 1949, 38) and 0rskov (Acta Path, et Microbiol. Scand., 34, 1954, 145) demon- strated four somatic groups in the kleb- siellas, in each of which was found a variety of capsular antigens. Due to technical difficulties caused by the prominent cap- sules possessed by most cultures, the O antigens of Klebsiella cultures usually are not determined, and serological examina- tion is confined to the determination of the capsular antigens of the strains. Through the work of a number of investigators, 72 capsule types have been recognized. Of these, types 1 to 6 inclusive (A to F of the earlier literature) occur in the respiratory tract of man and occasionally are found in other locations. The remaining capsule types exhibit no such preference and are widely distributed in nature. They occur frequently in respiratory and urinary in- fections, in the blood stream and in feces. Comment : From the foregoing, it may be seen that no method has been found to differentiate the majority of Klebsiella pneumoniae cultures from organisms com- monly classified as Aerobacter aerogenes, and this situation has caused confusion. Identical cultures are classified bj^ some workers as types of Klebsiella pneumoniae and by others as Aerobacter aerogenes. The source from which an organism was isolated often has dictated the genus into which it is placed. Until such time as the relationships of the two genera are clarified, it is inevita- ble that confusion will continue. Source: Isolated from the lungs in cases of lobar pneumonia. Habitat: Associated with pneumonia and other inflammations of the respiratory tract. 2. Klebsiella ozaenae (Abel, 1893) Bergey et al., 1925. {Bacillus mucosus ozaenae Abel, Cent. f. Bakt., 13, 1893, 167; Bacillus ozaenae Abel, ibid., 172; Bacterium ozaenae Lehmann and Neumann, Bakt. Diag., 1 Aufl., 2, 1896, 204; Bergey et al., Manual, 2nd ed., 1925, 266.) o.zae'nae. L. fem.n. ozaena ozena; L. fem.gen.n. ozaenae of ozena. Plump rods, 1.25 microns in width and of variable length, occurring singly. Encap- sulated. Non-motile. Gram-negative. Gelatin colonies: Small, white, convex, slimy, translucent. Gelatin stab: Translucent, slimy surface growth. Filiform growth in stab. No lique- faction. Agar slant: Slimy, cream-like, spreading growth. Broth: Turbid; gray ring and sediment. Litmus milk: Unchanged or slightly acid but not coagulated; no gas. Potato : Creamy, spreading growth ; never shows gas production. Indole not produced. Acetylmethylcarbinol not produced. Acid ma}- or may not be produced from glucose; lactose is fermented weakly, if at all (Lehmann and Neumann, Bakt. Diag., 4 Aufl., 2, 1907, 299). Acid and gas from glucose, lactose, sucrose, maltose and mannitol (Julianelle, Jour. Bact., 30, 1935, 536). Nitrites produced from nitrates (Julia- nelle, ibid., 535).
