Modification of dienes mutual inhibition test for epidemiological characterization of Pseudomonas aeruginosa isolates

Pseudomonas aeruginosa is an important cause of community-associated and nosocomial infections related to exposure to aqueous environments. Such infections often occur in the setting of a common-source outbreak, in which case epidemiological characterization of isolates may be necessary. In this preliminary study, a modification of the Dienes mutual inhibition test, ordinarily used to assess the relatedness of swarming Proteus mirabilis strains, was used to study 15 P. aeruginosa isolates, with the results compared to those obtained by ribotype analysis. Complete concordance was noted between the results of the Dienes test and those of ribotyping. These observations suggest that further studies are warranted to assess the utility of the modified Dienes test as a simple, inexpensive, and reliable means for epidemiological typing of P. aeruginosa.