Objective: To determine the in vitro antimicrobial efficacy of three types of sugar and conduct a pilot clinical study with a view to developing a protocol for a randomised controlled trial (RCT).
Method: In the in vitro studies three types of granulated sugar (Demerara, granulated beet sugar and granulated cane sugar) were tested to determine their minimum inhibitory concentrations (MICs) against 18 Gram-negative and Gram-positive bacteria in a micro-titre broth dilution assay; growth inhibition of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa in different concentrations of sugar (0.38-25%) was also tested over 12-hours in an agar diffusion assay. The pilot clinical study selected patients from a vascular surgical ward and a vascular outpatient department. All had acute or chronic exuding wounds, some of which were infected. White granulated sugar was applied to the wounds. The following parameters were assessed: surface area; wound characteristics including pain, malodour, appearance (slough/granulation); exudate level; pain level and bacterial load. Patients with diabetes had their blood sugar levels checked daily. All patients completed a short health questionnaire at the start and end of the study. Staff completed a satisfaction questionnaire at the end of the study. The study period was 21 days.
Results: In vitro tests demonstrated that sugar inhibits bacterial growth. All three types of sugars had MICs ranging from 6-25% in the bacterial strains tested. The diffusion tests showed that strains were able to grow well in low concentrations of sugar but were completely inhibited in higher concentrations. The two granulated sugars were found to be slightly more effective than Demerara sugar, so the latter was excluded from the clinical pilot study. Twenty-two patients (20 inpatients and two outpatients) with sloughy or necrotic wounds were recruited into the clinical study. Two patients had MRSA and two had Staphylococcus colonisation at baseline. Blood sugar levels remained stable in the seven patients with insulin-dependent diabetes mellitus. All wounds were clean/debrided in a mean of 11.13 days. Pain and malodour reduced markedly. Patient and staff surveys revealed overwhelming support for the sugar therapy.
Conclusion: The pilot study achieved its aim of developing a protocol for a RCT. Preliminary data suggest that sugar is an effective wound cleansing and is safe to use in patients with insulin-dependent diabetes. In vitro studies demonstrate that sugar inhibits bacterial growth.
Conflict of interest: None.