[Characteristics of hospital strains of Pseudomonas aeruginosa].

A total of 745 P. aeruginosa strains from patients with purulent inflammatory processes, 216 strains from the environment of a surgical hospital and 35 strains from carriers were studied with respect to 30 cultural and biochemical signs of P. aeruginosa. 19.8% of the strains were found to form no pigment, and in 14.8% of the strains delayed pigment formation was observed (on days 3-10). The most stable signs were motility (99.6%), growth in Simmons citrate agar (97.6%), growth at 42 degrees C (97.4%), arginine decarboxylase activity (96.8%). In 77.0% of the strains glucose assimilation in Hiss liquid medium, in 85.6% glucose oxidation in the OF test, in 90.8% the formation of urease and in 93.2% the formation of gelatinase were observed. Among the strains isolated from the environment, P. aeruginosa variants, atypical with respect to their main differentiating signs, were isolated significantly more frequently.