Factors governing the response of Pseudomonas aeruginosa to hypothiocyanous acid.

Pseudomonas aeruginosa remains a significant challenge to human medicine as it causes acute and chronic infections at several locations in the body, including the lung and eyes. P. aeruginosa is a very versatile, highly adaptable, opportunistic pathogen due to its large genome, ability to form protective biofilms and metabolic adaptation. Targeted, susceptibility-guided antibiotic therapy represents the best clinical approach to treat P. aeruginosa infections. However, due to the emergence of antibiotic resistance and the lack of a vaccine, it is critical to accelerate the development of novel, antipseudomonal therapies. Hypothiocyanous acid (HOSCN) occurs naturally in the human body and serves as an antimicrobial reactive oxidant in mucosal secretions, including the airway surface liquid, saliva, tears and milk. Mucosal peroxidase enzymes generate HOSCN from its substrates, thiocyanate (SCN-) and H2O2. HOSCN has been reported to kill P. aeruginosa in vitro which indicates its potential to be used as a new mechanism to target this bacterium. This review article provides a brief overview of the human clinical relevance of P. aeruginosa and summarizes current knowledge on the in vitro antibacterial efficacy and mechanism of action of HOSCN against this pathogen. This work also reviews the mechanisms by which P. aeruginosa attempts to adapt to the antibacterial actions of HOSCN.