The identification of pseudomonads and related bacteria in a clinical laboratory

Abstract

Non-fermenting, catalase-positive Gram-negative bacilli that grow on nutrient agar are often isolated in clinical laboratories. We have applied biochemical techniques appropriate to a typical clinical microbiology laboratory, and for the most part described in Cowan and Steel's Manual for the identification of medical bacteria (Cowan, 1974), to 428 clinical isolates and have evolved a scheme for their identification. Organisms were subdivided into groups on the basis of three tests, namely the glucose oxidation-fermentation test and tests for oxidase activity and motility. A choice was then made among other tests to produce indentification tables, containing only the most useful tests, for the various groups. The most complicated table has only 16 tests. This simple system identified 96.5% of the 428 organisms, as well as many subsequent isolates of the more common organisms.