Achromobacter species (CDC group Vd): morphological and biochemical characterization

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Abstract
Twenty-three isolates of Achromobacter spp. (CDC group Vd) were examined morphologically and biochemically. Gram strains revealed gram-variable bacilli frequently curved or hooked at 1 pole and often coryneform in shape and arrangement. EM revealed the presence of extracellular material in polar accumulations and demonstrated the polar flagella arrangement seen by light microscopy to be lateral. Two Colony types were produced; 1 was minute and watery at 24 h (35.degree. C) progressing to large, mucoid colonies at 48 h, and the other type was shiny, glistening, opaque but nonmucoid. All isolates grew on MacConkey agar and produced catalase, oxidase and urease. Most grew on salmonella-shigella agar, reduced nitrate to nitrite and gas, hydrolyzed esculin, deaminated phenylalanine (2-4 days) and produced H2S in triple sugar iron agar (4-12 days). Oxidation of carbohydrates was weak, delayed, and limited to glucose and xylose. Two isolates also oxidized maltose, mannitol and sucrose. The ability of miniaturized nonfermenter kits to identify Achromobacter spp. was tested. The Minitek and N/F systems, respectively, identified 21 and 19 of the 23 isolates, whereas the Oxi/Ferm identified 13 and the API 20E identified only 3.