Figure 2.

(A) Abundance of Pseudomonas aeruginosa and Staphylococcus aureus in patients with simultaneous positive cultures. P. aeruginosa was slightly more abundant than S. aureus (medians, 6.52 vs. 6.42; P = 0.02 by Wilcoxon signed-rank test), but the difference may be biologically insignificant. (B) Scatter diagram displaying abundance of S. aureus and P. aeruginosa in double-positive cultures. Because many points are superimposed, the number of cultures within a 1-log range of titer are indicated at the top right corner of each log unit and graphically depicted by the background shading. Some double-positive cultures had dominant P. aeruginosa, whereas others had dominant S. aureus. Few had low abundance of both organisms. There was weak negative correlation between S. aureus and P. aeruginosa abundance (Spearman rho = −0.067, P = 0.02). n = 107 patients, 1,195 double-positive cultures.