Evaluation of 9-chloro-9-[4-(diethylamino)phenyl]- 9,10-dihydro-10-phenylacridine hydrochloride (C-390) in broth and agar media for identification of Pseudomonas aeruginosa.

Brain heart infusion broth and Mueller-Hinton agar containing the compound 9-chloro-9-[4-(diethylamino)phenyl]- 9,10-dihydro-10-phenylacridine hydrochloride (C-390) were evaluated as selective media for identifying Pseudomonas aeruginosa. Of the 192 Pseudomonas spp. and 68 additional oxidase-positive or glucose-nonfermenting gram-negative organisms tested, only P. aeruginosa (120 of 121 isolates) and certain strains of Pseudomonas cepacia, Aeromonas hydrophila, and Achromobacter xylosoxidans were able to grow in brain heart infusion broth containing 15 micrograms of C-390 per ml. When production of green or yellow-green pigment after overnight growth on Mueller-Hinton agar containing 30 micrograms of C-390 per ml was used as the criterion for identification, only P. aeruginosa produced a positive test (96% sensitivity and 100% specificity). The agar medium, therefore, can provide a single differential medium for the overnight identification of P. aeruginosa.