Recombinant NK1 Protein and LEDs: An Innovative Strategy to Counteract Resistant Staphylococcus pseudintermedius and Pseudomonas aeruginosa Strains.

The increase in multi-drug-resistant strains represents a global challenge that strongly underlines the importance of the search for new eco-sustainable strategies. The aim of this work was to suggest a non-antibiotic approach to counteract resistant Staphylococcus pseudintermedius and Pseudomonas aeruginosa strains in planktonic and sessile phases. The proposed strategy includes the combination of natural spliced variant of hepatocyte growth factor NK1, a protein produced by recombinant DNA technology in Pichia pastoris expression system and Light-Emitting Diodes (LEDs). The antimicrobial action was determined by Minimum Inhibitory Concentration, Minimum Bactericidal Concentration, and CFU/ml evaluations. The anti-virulence action was performed by measuring P. aeruginosa motility and twitching and anti-S. pseudintermedius and -P. aeruginosa biofilms. Recombinant NK1 and LEDs alone and combined with each other showed relevant antimicrobial and anti-virulence effects. In particular, when NK1 was combined with LEDs, significant CFU/ml reduction (up to 85.98% reduction with respect to the control) after 24 h of contact, P. aeruginosa swimming/swarming/twitching halos reduction (up to 60% reduction with respect to the control) and bacterial anti-biofilm formation action was obtained. The obtained results demonstrated the innovative and interesting non-antibiotic strategy formed by recombinant NK1 protein and LEDs to affect the S. pseudintermedius and P. aeruginosa growth.