Effect of Subtilisin-like Proteinase of Bacillus pumilus 3–19 on Pseudomonas aeruginosa Biofilms

Pseudomonas aeruginosa is a common device-associated pathogen and also a model object in biofilm research. In this study biofilm growth dynamics of Pseudomonas aeruginosa RSC-2 strain on different culture media was described. It was shown that Mueller-Hinton broth is more suitable for biofilm growth than Lysogeny broth. In vitro biofilm surface was investigated using scanning electron microscopy. Staining with Congo red dye demonstrated that the observed strain can produce amyloid-like fibers that play important role in biofilms and are proposed to be a target for proteinase treatment. The effect of subtilisin-like proteinase of Bacillus pumilus 3–19, trypsin, and proteinase K on biofilm was studied. All of these proteinases can destroy biofilms depending on the time of incubation and enzyme activity. After 4 h of incubation, 18–47% of biofilms were destroyed, which can be linked to the resistance of amyloid proteins to proteolytic degradation. However, an increase in the incubation time (to 24 h) led to complete destruction of biofilm.