[Comparative study of the resistance of hospital and nonhospital strains of Pseudomonas aeruginosa to antibacterial preparations].

The comparative study on 392 hospital and 160 out-of-hospital Pseudomonas aeruginosa strains showed that the hospital strains differed in the levels and spectra of resistance to antibiotics, bacteriostatic and bactericidal concentrations of antiseptics and disinfectants, the resistancevars composition, serogroups and biochemical activity. A scheme for dividing Ps. aeruginosa into resistancevars according to the antibiotic resistance spectra is presented. The hospital strains in this scheme belonged mainly to the variants with a resistance to 3--5 drugs and the out-of-hospital strains belonged to the variants resistant to 1--2 drugs. The biological characteristics of the hospital strains made them more advantageous as compared to the out-of-hospital strains when existing in the hospital ecosystem. The changeability of Pseudomonas aeruginosa is considered to be geographically related (group, interpopulational). The hospital strains of this species were classified as belonging to a higher taxon, i. e. ecological types or variants.