High Efficacy of Ozonated Oils on the Removal of Biofilms Produced by Methicillin-Resistant Staphylococcus aureus (MRSA) from Infected Diabetic Foot Ulcers

Background

Diabetic foot ulcers are slow-healing wounds that are prone to chronic bacterial infection. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most troublesome bacteria found in these wounds, as it resists many standard antibiotics and readily forms biofilms - protective layers of bacteria that stick to wound surfaces and are notoriously difficult to clear. Once a biofilm is established, it can shield bacteria from both antibiotics and the immune system, making infected ulcers harder to heal and increasing the risk of complications. Researchers have been investigating alternative antimicrobial approaches, including ozonated oils, which are plant oils infused with ozone gas to create compounds with antibacterial activity, as a possible tool against these resistant infections.

Study design

This was a laboratory (in vitro) study, not a clinical trial in patients. The research team prepared six ozonated vegetable oils with varying ozone concentrations, ranging from 0.53 to 17 milligrams of ozone per gram of oil. The oils were chemically characterised using peroxide value testing and gas chromatography to assess their fatty acid composition. Their antibacterial activity was then tested against 28 MRSA isolates and 14 methicillin-susceptible Staphylococcus aureus (MSSA) isolates, all originally collected from infected diabetic foot ulcers. Antibacterial testing used the Kirby-Bauer disk diffusion method, a standard technique that measures the zone of bacterial growth inhibition around a treated disk. The oils' ability to prevent and remove biofilms was assessed separately using crystal violet staining assays, which quantify the amount of biofilm and adhered bacterial cells remaining after treatment.

Findings

Most of the bacterial strains tested were inhibited by ozonated oil at a concentration of 4.24 milligrams of ozone per gram of oil. The ozonated oils showed a moderate to high ability to remove bacterial cells already adhered to a surface, and demonstrated a high capacity to eradicate biofilms that had been left to mature for 24 hours. The methicillin-susceptible (MSSA) strains were generally more easily inhibited than the methicillin-resistant (MRSA) strains, though the ozonated oils still showed meaningful activity against the resistant strains. Effectiveness varied between the six oil preparations depending on their ozone concentration and chemical composition.

What the authors concluded

The study authors concluded that ozonated oils show promising potential as a treatment for infections caused by multidrug-resistant bacteria, including MRSA strains isolated from diabetic foot ulcers. They suggested ozonated oils could be considered as an alternative or complementary option to antibiotics for managing skin infections where resistant bacteria and biofilms are a barrier to healing.

Limitations of this study

This research was conducted entirely in a laboratory setting using isolated bacterial strains and oil preparations, not on human patients with active wounds. Results from disk diffusion and biofilm assays in a controlled lab environment do not necessarily translate directly to how ozonated oils would perform on a real, infected diabetic foot ulcer, where wound depth, blood supply, other bacterial species, and the person's overall health all play a role. No data on wound healing time, safety in human use, or clinical outcomes were generated by this study. Further clinical research in patients would be needed before firm conclusions could be drawn about ozonated oils as a treatment for infected diabetic foot ulcers in practice.