Pseudomonas aeruginosa proteases: purification procedures for an enzymatic standard.

Pseudomonas aeruginosa may cause severe infections in debilitated patients. Strains of this microorganism produce several extracellular space proteins, some of which are believed to be virulence factors. There are experimental correlations between the ability to produce proteases and virulence. Treatment of bacteria with subinhibitory concentrations of antimicrobial agents frequently increases bacterial phagocytosis, intracellular killing, and suppresses the production of bacterial virulence factors, including extracellular enzymes. We suggest a simple method for production, purification and quantitation of Pseudomonas aeruginosa extracellular proteases suitable for use in investigations of their role as virulence factors.