[Genetic and physicochemical analysis of the resistance of Pseudomonas aeruginosa strains to gentamycin and other antibiotics].

The genetic and physicochemical mechanisms of antibiotic resistance were studied in 50 clinical strains of P. aeruginosa resistant to gentamicin. The serotypes and pyocinotypes of the bacteria were determined. The spectra and levels of antibiotic resistance and the plasmid profiles of the strains were estimated. It was shown that 16 multiresistant isolates had identical spectra and levels of antibiotic resistance, belonged to the same serotype and pyocinotype and were characterized by the absence of the extrachromosomal DNA, which indicated the circulation of the same polyresistant strain in hospital. Plasmids with identical molecular weights and antibiotic resistance spectra were detected in 14 strains belonging to different serotypes and pyocinotypes. These plasmids determined synthesis of the same aminoglycoside inactivating enzymes: APH (3') and AAC (3). Epidemiologic distribution of the same high molecular R plasmid among the clinical strains of P. aeruginosa is suggested.