Complex typing of Pseudomonas aeruginosa strains isolated in an intensive care unit [a note].

A total of 2637 Gram-negative facultatively pathogenic bacteria were isolated in the László Central Hospital for Infectious Diseases during a 5-year-period from clinical samples of patients of the Respiratory Intensive Care Unit; 28 further strains were cultured from hospital personnel and fomites. Pseudomonas aeruginosa, Klebsiella and Acinetobacter spp. were most frequently isolated. Complex typing (determination of O serogroup, phage pattern, pyocin type, antibiogram and plasmid pattern) of P. aeruginosa strains showed the predominance of serogroup O11 (62%), but the isolates differed from each other by other characteristics. Conjugation experiments showed no common resistance plasmids in the tested population.