The contribution of diffusible toxins of P. aeruginosa to the pathogenesis of experimental pyelonephritis.

Five strains of Pseudomonas aeruginosa differing in their production of various virulence factors were examined for their ability to cause pyelonephritis when injected intravenously into mice. The severity of infection produced was found to correlate with the degree of production in vitro of the protein exotoxin A, except in a strain which also simultaneously produced a protease. A strain which produced both haemolysin and exotoxin A caused a more persistent infection than one which produced more exotoxin A but no haemolysin. These findings support the current view that exotoxin A is the most clearly identifiable virulence factor of Ps. aeruginosa, but suggest that the final outcome of infection may depend on an interplay with other factors produced by individual strain