In Vitro Efficacy of Antimicrobial Wafers Against methicillin-resistant Staphylococcus Aureus

Abstract

Background: Lyophilized wafers have been developed as vehicles for the storage and delivery of therapeutic compounds to exuding wounds. The primary objective of this study was to incorporate a selection of antimicrobial compounds in karaya wafers and measure their efficacy against methicillin-resistant Staphylococcus aureus. Methods: Four antimicrobial compounds, including an antibiotic, were incorporated within karaya gels and freeze–dried to a shaped-disc form suitable for in vitro testing against methicillin-resistant S. aureus. Disc diffusion and Franz diffusion methods were used to quantify the utility and efficacy of these ‘antimicrobial wafers‘. Flow rheology and scanning electron microscopy were also used to aid gel and wafer characterization. Results: Lyophilized wafers swelled in simulated wound fluid and released the contained compounds with mixed effect. Povidine–iodine and chlorhexidine were most effective in protein-free buffer while the action of neomycin sulfate was enhanced by the presence of bovine serum albumin. Silver sulfadiazine was the least effective overall.

Ethical conduct of research

No patients or animals were used in this study and the antibiotic-resistant strain of Staphylococcus aureus is a Category 2 pathogen according to the Advisory Committee on Dangerous Pathogens and was used appropriately within a Category 2 class laboratory.

Financial & competing interests disclosure

This work was supported by the Institute of Health & Welfare Research and the School of Pharmacy & Life Science, both at Robert Gordon University, Aberdeen, UK. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript.