A Pilot Study of the Antibacterial Activity of Topical Fatty Acids

Introduction: Bacterial biofilms have been found in most chronic wounds and are believed to be the source of on-going inflammation. Most antimicrobial treatments have limited effects and are known to be cytotoxic. Approaches which either physically remove or use physical chemistry mechanisms have begun to show promise. Another line of possible treatment which is emerging is targeting of the bacteria’s metabolism. In the wound, bacteria primarily metabolize sugars and proteins, but little is known about their lipid metabolism.

Purpose: We have begun to investigate a topically applied oil which may have both physical/chemical removal and antibacterial metabolism-based activities.

Materials and Methods: An ex vivo porcine skin explant model was used to establish a functional S. aureus biofilm for 5 days. The wounds were then treated with either an oil or with moistened gauze. The wounds were re-treated daily with either oil or more saline. Six explants per day from each group were harvested and viable bioburden and biofilm were assessed.

Results: The initial bioburden was 4.8 log10 CFU/ml with 3.64 log10 CFU/ml of biofilm. At Day 1, the bioburden in the oil treated samples were reduced to 1.8 log10 CFU/ml while the control increased to 9.0 log10 CFU/ml. The bioburdens in both groups remained the roughly the same every day thereafter.  Oddly, the biofilm numbers did not change. In another experiment using the 24 hr incubation used for the biofilm assessment still had the total levels around 1.0 log10 CFU/ml.

Conclusions: The immediate results from the total bioburden assessment are exciting, but still not certain due to the results seen for the biofilms.  An imaging-based study to directly visualize the biofilm has begun and will be used to clarify the ambiguity. These results are very exciting given the potential for a nutritive pro-healing oil to also have an antibacterial activity.