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Propionibacterium
Propionibacterium a nonspore-forming, gram-positive, and nonmotile rod that measures 0.5–0.8 × 1.0–1.5 μ. In young cultures, the rods are twisted and slightly branched, while in older cultures they are coccoid. Propionibacteria form yellow, orange, or red colonies and grow under both aerobic and anaerobic conditions. They are nonpathogenic and live in dairy products (except milk) and in the rumen and intestine of ruminants. Propionibacteria are the causative agents of propionic-acid fermentation. They ferment glucose, lactose, and other carbohydrates; they also ferment some alcohols, forming propionic and acetic acids and CO2 as a result. Enzymes that contain propionibacteria are used in cheese-making: the openings and the flavor and aroma of Swiss cheese are largely determined by propionic-acid fermentation. Propionibacteria are used in the microbiological synthesis of vitamin B12. Various nutrient media that contain cobalt are used to grow propionibacteria. A. A. IMSHENETSKII Propionibacterium
Propionibacterium [pro″pe-on″ĭ-bak-te´re-um] a genus of gram-positive, anaerobic, rod-shaped bacteria, found as saprophytes in humans, animals, and dairy products. P. ac´nes (also known as Corynebacterium acnes) is a normal skin inhabitant and can cause chronic infections of the blood and bone marrow. P. granulo´sum (also known as Corynebacterium granulosum) causes abscesses.Propionibacterium (prō'pē-on'ē-bak-tē'rē-ŭm), Avoid the misspellings Propionobacterium and Proprionibacterium.A genus of nonmotile, non-spore-forming, anaerobic to aerotolerant bacteria (family Propionibacteriaceae) containing gram-positive rods that are usually pleomorphic, diphtheroid, or club shaped, with one end rounded, the other tapered or pointed. Some cells may be coccoid, elongate, bifid, or even branched. The cells usually occur singly, in pairs, in V and Y configurations, short chains, or clumps in "Chinese character" arrangement. The metabolism of these organisms is fermentative, and the products of fermentation include combinations of propionic and acetic acids. These organisms occur in dairy products, on human skin, and in the intestinal tracts of humans and other animals. They may be pathogenic. The type species is Propionibacterium freudenreichii.Pro·pi·on·i·bac·te·ri·um (prō'pē-on-i-bak-tēr'ē-ŭm) A genus of nonmotile, non-spore-forming, anaerobic to aerotolerant bacteria containing gram-positive rods that are usually pleomorphic, diphtheroid, or club-shaped, with one end rounded, the other tapered or pointed. The cells usually occur singly, in pairs, in V and Y configurations, short chains, or clumps. These organisms occur in dairy products, on human skin, and in the intestinal tracts of humans and other animals. They may be pathogenic. The type species is P. freudenreichii. |