The impact of wound pH on the antibacterial properties of Medical Grade Honey when applied to bacteria present in foot and ankle post-surgical wounds

Abstract Surgical Site Infections (SSIs) are amongst the most troublesome complications following foot and ankle surgery (FAS) and have significant psychosocial and financial burden for both patients and the healthcare system. FAS has been reported to have higher than average post-surgical infections when compared to other orthopaedic subspecialties. Evidence also indicates that patients with diabetes and other co morbidities undergoing FAS are at a much greater risk of developing SSIs. Patients with SSIs face additional exposure to bacteria circulating in hospitals, which are always charged with microbial pathogens. With the growing challenges of antibiotic resistance and the increasingly high numbers of resilient bacteria to said antibiotics, the need for alternative antimicrobial therapies has become critical. Aim: The aim of this study was to investigate the use of medical grade honey (MGH) when altered to environments typically present in wounds (pH6-8). Methods: MGH (Activon) was altered to pH 6, 7 and 8 and experimental inoculums of Pseudomonas aeruginosa (NCTC10782), Escherichia coli , (NCTC10418), Staphylococcus aureus (NCTC10655) and Staphylococcus epidermidis (NCTC 5955) were transferred into each pH adjusted MGH and TSB solution and the positive and negative controls. Results: MGH adjusted to various pH values had the ability to reduce bacteria cell survival in all pH variations for all bacteria tested, with the most bacterial reduction/elimination noted for Staphylococcus epidermidis . No correlations were noted among the pH environments investigated and the colony counts, for which there were small amounts of bacteria survived. Conclusion: This in vitro research would indicate that the antibacterial properties of honey remains the same regardless of the pH environment. MGH could therefore potentially be considered for use on non-infected post-surgical wounds to reduce the bacterial bioburden, the risk of SSIs and ultimately to improve healing outcomes.