[Antibiotic resistance in clinical strains of Pseudomonas aeruginosa isolated from 1979-1984].

The levels and spectra of drug resistance were determined in 530 strains of P. aeruginosa isolated in hospitals of three cities of the USSR within 1979-1984. Their conjugative R plasmids were searched for and distribution of various type resistance determinants in the composition of these plasmids was investigated. The results were compared with the findings of analogous studies on clinical strains of P. aeruginosa isolated within 1976-1979. It was shown that there were a rise in the relative number of the strains resistant to kanamycin and a decrease in the occurrence of the P. aeruginosa strains resistant to streptomycin, tetracycline and sulfanilamides. The frequency of the kanamycin, carbenicillin and gentamicin resistance genes in the composition of the detected conjugative R plasmids increased. Hybridization of 32P-labeled probes containing various type antibiotic resistance determinants with strains of P. aeruginosa ML (PAO) containing conjugative R plasmids was indicative of wide spread of genes determining APH(3')II and APH(3") and determinants of classes A and C in the composition of the studied plasmids.