Transformation Assay for Identification of Psychrotrophic Achromobacters

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Abstract
The finding thay many psychrotrophic, gram-negative, nonmotile, oxidase-positive coccobacilli (achromobacters) are competent for genetic transformation made possible the development of a transformation assay that permits recognition of genetically related strains. Independently isolated achromobacters (109) are genetically related since DNA samples from all of these organisms were able to transform a single competent auxotrophic strain to prototrophy. Genetically interacting bacteria included strains that lacked 1 or more of the characteristics typical for most achromobacters. An oxidase-negative mutant of 1 of these strains reacted positively in the transformation assay, unlike other oxidase negative bacteria. Achromobacters were derived from fish, poultry, irradiated foods, seawater and other sources. One strain previously classified as Micrococcus cryophilus was related to the achromobacters. Two achromobacters had an optimum growth temperature of 35.degree. C and behaved as typical mesophiles. The moraxellae and Acinetobacter were unrelated to the achromobacters by using the transformation assay. The ready demonstration of genetic relatedness provides a new basis for taxonomic grouping of the psychrotrophic achromobacters.