research V THIS ARTICLE IS REPRINTED FROM THE JOURNAL OF WOUND CARE VOL 25, NO 2, FEBRUARY 2016 V © 2016 MA H EALTHCARE LTD In vitro activity of an engineered honey, medical-grade honeys, and antimicrobial wound dressings against bioflm-producing clinical bacterial isolates O Objective: Honey is recognised to be a good topical wound care agent owing to a broad-spectrum of antimicrobial activity combined with healing properties. Surgihoney RO (SH1) is a product based on honey that is engineered to produce enhanced reactive oxygen species (ROS) and has been reported to be highly antimicrobial.The objective was to investigate the ability of the engineered honey and its comparators to prevent bioflm formation in vitro. O Method: We tested the ability of three medical-grade honeys SH1, Activon manuka honey (MH) and Medihoney manuka honey (Med), alongside fve antimicrobial dressings (AMDs) to prevent the formation of bioflms by 16 isolates. Honeys were serially double diluted from 1:3 down to 1:6144 and the lowest dilution achieving a statistically signifcant reduction in biomass of at least 50%, compared with untreated controls, was recorded. O Results: Although all the honeys were antibacterial and were able to prevent the formation of bioflms, SH1 was the most potent, with effcacy at lower dilutions than the medical honeys for fve isolates, and equivalent dilutions for a further six. Additionally, SH1 was superior in antibacterial potency to three commercially available AMDs that contain honey. O Conclusion: SH1 is effective at preventing biofms from forming and is superior to medical honeys and AMDs in in vitro tests. O Declaration of interest: Surgihoney RO was provided free of charge for testing by Matoke Holdings, UK and the hospital pharmacy provided the other honeys and dressings.This paper presents independent research funded by the National Institute for Health Research (NIHR).The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. antibacterial; biofilms; honey; hydrogen peroxide; wounds F. D. Halstead, 1,2,3 BSc, MSc, PGCert; M. A. Webber, 2,3 PhD, Senior Research Fellow; M. Rauf, 1,2,3 BSc Student; R. Burt, 1,2,3 Student; M. Dryden 4,5 MBBS, MD, FRCPath, Consultant Microbiologist; B. A. Oppenheim, 1,2 MB, BCh, FFPath, Consultant Microbiologist; 1 Queen Elizabeth Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK 2 NIHR Surgical Reconstruction and Microbiology Research Centre, Queen Elizabeth Hospital, Birmingham, UK 3 Institute of Microbiology and H oney has been recognised to be a good wound care agent, possessing both anti- microbial and healing properties. 1,2 The spectrum of antibacterial activity is broad (with 37 genera of bacteria shown to be susceptible), 3–5 and a range of medical honeys exist on the market (for example, chestnut, manuka, thyme, Revamil, manufactured by Bfactory Health Products, Multiforal and Medihoney). 6 Their mecha- nism of action is thought to be multifactorial; due to the honey preparation itself (in terms of physical properties including pH and hyperosmolarity), and the innate antibacterial components of honey (meth- ylglyoxal, bee defensin-1, and hydrogen peroxide (H 2 O 2 ). 6 To date, antibacterial resistance to honey has not been detected. 7,8 Despite a 5000-year history as a topical antiseptic, a major limitation of natural honeys is that the hon- ey may not be of a predictable and consistent qual- ity, since the production depends on a large number of factors (for example, the foral source, the species of bee, geographical location, harvesting process, and subsequent storage conditions). 6 This has impli- cations for large-scale production. There are also variation between the formulations of medical- grade honeys, although these are generally stand- ardised in preparation. Surgihoney RO (SH1) is a licensed sterile product based on natural organic honey from a variety of sources. It has been developed for wound care and as a prophylactic dressing agent for wounds. It has been engineered (through a proprietary engineering proc- ess) so that it produces consistently high levels of antibacterial activity through reactive oxygen species (ROS). 9 ROS causes oxidative damage due to the pro- duction of hydroxyl radicals, leading to restricted bac- terial growth and DNA degradation. 10,11 Further proto- type formulations exist, in addition to SH1, which have enhanced production of H 2 O 2 . This means, the- oretically, that antibacterial activity can be set at a higher potency if required. 12 In vitro studies by Dryden et al. 13,14 have shown