Accuracy of a rapid carbohydrate oxidation microtube method for identification of nonfermentative gram-negative bacilli.

A rapid carbohydrate oxidation microtube system (Carr Microbiologicals, Wichita, Kans.), designed for detecting the saccharolytic activity of gram-negative, nonfermenting bacilli, was evaluated and compared with the conventional oxidation-fermentation method. The oxidation of glucose, maltose, lactose, and xylose was tested with 430 strains of Pseudomonas, Acinetobacter, Achromobacter, Alcaligenes, Moraxella, Flavobacterium, and Bordetella species. More than 95% of the isolates tested gave correct oxidation reactions within 4 h in the rapid carbohydrate oxidation microtubes, whereas oxidation-fermentation media required 24 h to achieve the same sensitivity. The microtube system was found to be simple, accurate, rapid, and economical.