Antibacterial Potential of an Antimicrobial Agent Inspired by Peroxidase-Catalyzed Systems

• Main Authors: Lilit Tonoyan, Gerard T. A. Fleming, Paul H. Mc Cay, Ruairi Friel, Vincent O'Flaherty
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2017-05-01
• Series: Frontiers in Microbiology
• Subjects: iodo-thiocyanate complex (ITC); biocide; iodine; in vitro susceptibility; bactericidal
• Online Access: http://journal.frontiersin.org/article/10.3389/fmicb.2017.00680/full

Antibiotic resistance is an increasingly serious threat to global health. Consequently, the development of non-antibiotic based therapies and disinfectants, which avoid induction of resistance, or cross-resistance, is of high priority. We report the synthesis of a biocidal complex, which is produced by the reaction between ionic oxidizable salts—iodide and thiocyanate—in the presence of hydrogen peroxide as an oxidation source. The reaction generates bactericidal reactive oxygen and iodine species. In this study, we report that the iodo-thiocyanate complex (ITC) is an effective bactericidal agent with activity against planktonic and biofilm cells of Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus and methicillin-resistant S. aureus) bacteria. The minimum bactericidal concentrations and the minimum biofilm eradication concentrations of the biocidal composite were in the range of 7.8–31.3 and 31.3–250 μg ml−1, respectively. As a result, the complex was capable to cause a rapid cell death of planktonic test cultures at between 0.5 and 2 h, and complete eradication of dual and mono-species biofilms between 30 s and 10 min. Furthermore, the test bacteria, including a MRSA strain, exposed to the cocktail failed to develop resistance after serial passages. The antimicrobial activity of the ITC appears to derive from the combinational effect of the powerful species capable of oxidizing the essential biomolecules of bacteria. The use of this composition may provide an effective and efficient method for killing potential pathogens, as well as for disinfecting and removing biofilm contamination.