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Methylglyoxal-infused honey mimics the anti-Staphylococcus aureus biofilm activity of manuka honey: Potential Implication in Chronic Rhinosinusitis

Authors

  • Joshua Jervis-Bardy MBBS,

    1. Department of Surgery–Otorhinolaryngology, Head and Neck Surgery, University of Adelaide and Flinders University, Adelaide, Australia
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  • Andrew Foreman BMBS (Hons),

    1. Department of Surgery–Otorhinolaryngology, Head and Neck Surgery, University of Adelaide and Flinders University, Adelaide, Australia
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  • Sarah Bray (BSc Hons),

    1. Department of Surgery–Otorhinolaryngology, Head and Neck Surgery, University of Adelaide and Flinders University, Adelaide, Australia
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  • Lorwai Tan PhD,

    1. Department of Surgery–Otorhinolaryngology, Head and Neck Surgery, University of Adelaide and Flinders University, Adelaide, Australia
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  • Peter-John Wormald MD

    Corresponding author
    1. Department of Surgery–Otorhinolaryngology, Head and Neck Surgery, University of Adelaide and Flinders University, Adelaide, Australia
    • Department of Otorhinolaryngology, Head and Neck Surgery, The Queen Elizabeth Hospital, 28 Woodville Road, Woodville, SA 5011 Australia
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  • This work was funded by the Department of Otorhinolaryngology, Head and Neck Surgery, University of Adelaide, with support from the Garnett Passe and Rodney Williams Memorial Foundation.

  • The authors have no funding, financial relationships, or conflicts of interest to disclose.

Abstract

Objectives/Hypothesis:

Low pH, hydrogen peroxide generation, and the hyperosmolarity mechanisms of antimicrobial action are ubiquitous for all honeys. In addition, manuka honey has been shown to contain high concentrations of methylglyoxal (MGO), contributing the relatively superior antimicrobial activity of manuka honey compared to non-MGO honeys. In high concentrations, manuka honey is effective in killing Staphylococcusaureus biofilms in vitro. Lower concentrations of honey, however, are desirable for clinical use as a topical rinse in chronic rhinosinusitis in order to maximize the tolerability and practicality of the delivery technique. This study, therefore, was designed to evaluate the contribution of MGO to the biofilm-cidal activity of manuka honey, and furthermore determine whether the antibiofilm activity of low-dose honey can be augmented by the addition of exogenous MGO.

Study Design:

In vitro microbiology experiment.

Methods:

Five S.aureus strains (four clinical isolates and one reference strain) were incubated to form biofilms using a previously established in vitro dynamic peg model. First, the biofilm-cidal activities of 1) manuka honey (790 mg/kg MGO), 2) non-MGO honey supplemented with 790 mg/kg MGO, and 3) MGO-only solutions were assessed. Second, the experiment was repeated using honey solutions supplemented with sufficient MGO to achieve concentrations exceeding those seen in commercially available manuka honey preparations.

Results:

All honey solutions containing a MGO concentration of 0.53 mg/mL or greater demonstrated biofilm-cidal activity; equivalent activity was achieved with ≥1.05 mg/mL MGO solution.

Conclusions:

MGO is only partially responsible for the antibiofilm activity of manuka honey. Infusion of MGO-negative honey with MGO, however, achieves similar cidality to the equivalent MGO-rich manuka honey.

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