Pyocinovar and serovar characteristics of 91 P.aeruginosa strains isolated from patients and the environment in a hospital for premature children, a child survey hospital and a neonatological hospital. The leading epidemiological markers of P.aeruginosa strains, among them pyocinovar 883722, serovar 6 (a hospital for premature children), pyocinovar 888888, serovar 4 (a child surgery hospital), pyocinovars 888888 and 861322 (a neonatological hospital).