Physiological diversity in clinical isolates of Pseudomonas aeruginosa.

The results of 91 characteristics selected from 165 tests performed on 127 clinical and other isolates of Pseudomonas aeruginosa were subjected to numerical analysis. Only one cluster, representing a single biotype of the species, was revealed at a similarity (SSM) level of 95% and above. Ten melanogenic and six of the non-melanogenic isolates studied gave diverse atypical results in many of the tests; these strain appear to be aberrant forms of the species.