Pseudomonas aeruginosa: antibiotic susceptibility and genotypic characterization of strains isolated in the intensive care unit.

A prospective study was carried out to assess the incidence and the local antibiotic susceptibility of Pseudomonas aeruginosa in intensive care units (ICUs) and to characterize cross-transmission by using pulsed-field gel electrophoresis as an epidemiologic tool. For this purpose, we screened surveillance cultures and routine clinical cultures from patients admitted to two adult ICUs during a 2-year period. Antibiotic susceptibility was determined by a disk diffusion method. The overall incidence of P. aeruginosa was 19.1 cases per 100 patients. Our findings concerning the antibiotic resistance of clinical isolates were concordant with those of other studies. Genotyping revealed that approximately 53.5% of P. aeruginosa colonization was acquired via cross-transmission; the other cases probably originated from endogenous sources. Cross-colonization seems to make a large contribution to the spread of P. aeruginosa in ICUs.