An unusual yellow pigmented Pseudomonas species isolated from chlorinated municipal town water supply.

A Gram-negative non-fermentative rod (GN-NF) which produced a yellow non-diffusible pigment is described. The isolate is typical of the heterotropic population of bacteria present in the chlorinated town water, as supplied to the city of Brisbane, Queensland, Australia. The strain could be not satisfactorily identified by Automatic Microbic Systems (Vitek) or API 20 NE protocols. Characterization tests, performed according to conventional methods, including other morphological and physiological characteristics, indicated a close relationship with the genus Pseudomonas. The phenotype was different from any previously described yellow and non-diffusible pigmented species in the genus Pseudomonas, including P. aureofaciens, P. palleronii, P. paucimobilis, and P. alcaligenes. The town water isolate showed a marked sensitivity to the vibriostatic agent 0/129 (2,4-diamino-6,7,diisopropyl-pteridine phosphate) at a concentration of 150 micrograms.