A Method for the Rapid Differentiation of Certain Non-pathogenic, Asporogenous Bacilli

Abstract

IT is the experience of most microbiologists that the differentiation of the non-pathogenic, asporogenous, non-pigmented rods is of considerable difficulty. These bacilli form an appreciable part of the air–soil–water microflora and, in materials from marine environments, such as fish, in which our interests are focused, they comprise 60–80 per cent of the total number of species isolated¹. The main difficulty is that, by the usual tests, most of these micro-organisms appear to be biochemically inert, and the classification, based on a series of negative characters, is not very determinative. The types of organism we have in mind are usually classified among the Pseudomonadaceae, Achromobacteriaceae and Bacteriaceae of Bergey² and Prévot³. In Bergey, the Pseudomonadaceae comprises, among others, the genera Pseudomonas, Vibrio and Spirilla, and the Achromobacteriaceae the genera Achromobacter and Flavobacterium. In Prévot, however, the Vibrios are removed from the Pseudomonadaceae and form a genus of the Spirillales, while the Achromobacter and Flavobacterium become genera of the Pseudomonadaceae. Comparison with a recent Russian determinative system⁴ shows even wider divergences, the Achromobacteriaceae disappearing altogether, being grouped as Bacterium spp. under the Bacteriaceae.