Fig. 6. Model of P. aeruginosa population dynamics following bloodstream infection.

PA populations with unique complexity arise in the lungs, liver, and spleen of intravenously infected animals. The bottleneck sizes at 24 hpi within the liver and lung are similar (mean N_b′ values for all mice are shown in parentheses); however, their founding populations are distinct. Very few organisms establish infection in the gallbladder (GB), but the founders ultimately expand to very high numbers. Bacteria released from the GB through the bile into the small intestine become the principal source of PA excreted in the feces.