Abstract
Addition of human urokinase, a serine proteinase, to in-vitro cultures of Pseudomonas aeruginosa strain M2 enhanced bacterial growth. The enhancement of growth depended on the dose of urokinase (10-12,500 units) and the enzymic activity of the protein. Other mammalian proteolytic enzymes (trypsin, chymotrypsin, polymorphonuclear leucocyte elastase, thrombin and plasmin) tested did not affect bacterial growth in vitro. Experiments with clinical isolates of Candida albicans, Klebsiella pneumoniae and Staphylococcus aureus from burn patients indicated that urokinase could enhance the in-vitro growth of all of these micro-organisms. However, some strain-to-strain variation was noted in the extent of this enhancement. These results indicate that urokinase, which could be released into burn injury sites from either damaged tissues or inflammatory cells, is capable of enhancing the growth of several micro-organisms that commonly infect patients with thermal injuries, particularly under oxygen-limited conditions and when few micro-organisms are present.