Use of 9-chloro-9-(4-diethylaminophenyl)-10-phenylacridan as a primary medium for recovery of Pseudomonas aeruginosa from clinical specimens

Abstract

Several concentrations of 9-chloro-9-(4-diethylaminophenyl)-10-phenylacridan (C-390), ranging from 5 to 100 micrograms/ml, were incorporated in brain heart infusion agar, MacConkey agar, and xylose-lysine-deoxycholate agar to evaluate the recovery of Pseudomonas aeruginosa from 538 sputum, 174 urine, and 22 stool samples. Seventy-six sputum samples containing P. aeruginosa grew this bacterium alone on brain heart infusion and MacConkey agars with a C-390 concentration of 25 micrograms/ml or greater. Other microorganisms present in these specimens grew only on media without C-390, and significantly less growth was observed on media with less than 20 micrograms of C-390 per ml. In few samples containing Klebsiella pneumoniae (3 of 30) and Serratia spp. (3 of 10), these organisms grew on all C-390 media and concentrations tested. The remaining sputum samples grew other bacteria and yeasts only on media without C-390. Brain heart infusion and MacConkey agars with C-390 were equally effective in recovering P. aeruginosa and suppressing the growth of a wide range of bacteria and yeasts from urine and stool samples. Xylose-lysine-deoxycholate agar with C-390 did not show a selective or suppressive advantage over xylose-lysine-deoxycholate agar alone for recovering P. aeruginosa from stool specimens. These results indicate that use of the correct medium and C-390 concentration would provide a suitable primary medium for inhibiting a wide range of bacteria and yeasts and would select the growth of P. aeruginosa from clinical specimens.