Bacteriological and histological investigation of the effects of purified Salivaricin from Lactobacillus salivarius on Pseudomonas aeruginosa and its biofilm in vitro and in vivo

The aim of this doctoral dissertation was to isolate and identify Pseudomonas aeruginosa strains from wound and burn infections, to determine their antibiotic resistance profiles, and to investigate the antibacterial, antibiofilm, and immunomodulatory effects of Salivaricin—a bacteriocin produced by Lactobacillus salivarius. Among 163 wound and burn samples, 28.57% were identified as P. aeruginosa. Most isolates exhibited multidrug resistance (MDR) and strong biofilm-forming ability. Salivaricin was extracted and purified from L. salivarius using ion-exchange and gel-filtration chromatography. SDS PAGE analysis revealed a single protein band with an estimated molecular weight of approximately 13 kDa, confirming its purity. In vitro assays demonstrated that purified Salivaricin significantly inhibited P. aeruginosa biofilm formation and exhibited higher antibacterial activity than gentamicin. In vivo studies on mice showed that Salivaricin treatment accelerated wound healing, enhanced tissue regeneration, and reduced inflammatory damage. Histopathological evaluations revealed improved dermal repair in treated groups. Moreover, elevated levels of IL-12 and IL-17 indicated that Salivaricin stimulated both innate and adaptive immune responses. These findings suggest that L. salivarius-derived Salivaricin holds promising potential as a biological therapeutic agent against multidrug-resistant P. aeruginosa infections.