FIG. 3.

Elements of the P. aeruginosa accessory genome are associated with increased virulence in P. aeruginosa clinical isolates. The genomes of 35 P. aeruginosa isolates cultured from the airways of patients with ventilator-associated pneumonia were examined for the presence of three components of the accessory genome: exoU, NR-I, and NR-II. The laboratory strain PAO1 was included as a control. The exoU gene is part of PAPI-2, and NR-I and NR-II are cargo regions carried by PAGI-5. Virulence was quantified by measuring the LD₅₀ in a mouse model of acute pneumonia. The y axis has been inverted such that higher bars represent increased levels of virulence. All three genetic elements are found more commonly in highly pathogenic strains. (Adapted from reference 192 with permission. Copyright 2003 Infectious Diseases Society of America.)