Effects of organic acids produced by a potential probiotic strain on pseudomonas aeruginosa quorum sensing and virulance factors

Pathogen bacteria produce a series of virulance factors to infect host and cause diseases. It is known that many different Gram negative pathogen communicate with each other by producing N-acyl-homoserine lacton derivative signal molecules to regulate the production of virulence factors. It's been discovered that this communication method, named as quorum sensing, is used in the regulation of diverse bacterial factors like bioluminescence, antibiotic biosynthesis, plasmid conjugation and the production of virulence factors as biofilm formation. Virulence mechanisms of Pseudomonas aeruginosa, which causes various types of infections in humans, are also regulated by quorum sensing following the production of signal molecules. The production of virulence factors has importance in the pathogenity formation. Nowadays, biotechnological researches are focused on the development of AHL antagonists. The use of these types of molecules is considered to be a new treatment approach for blocking communication between bacteria and reducing virulence, therefore improving infection control. In this study, potential probiotic properties of isolated Pediococcus acidilactici strain was determined and a high performance liquid chromatography method was performed for quantification of its lactic acid. Lactic acid was combined with clinical Pseudomonas aeruginosa isolates at sub inhibitor concentrations to evaluate its effects on quorum sensing system and virulence factors. It has been determined that lactic acid has an inhibitory effect on short-chain AHL production and swarming-swimming-twitching motility, elastase, protease, pyocyanin and biofilm production of Pseudomonas aeruginosa isolates that regulated by the quorum sensing system.