Caprylic and Polygalacturonic Acid Combinations for Eradication of Microbial Organisms Embedded in Biofilm

Abstract

There is a need for non-antibiotic, antimicrobial compositions with low toxicity capable of broad-spectrum eradication of pathogenic biofilms in food preparation and healthcare settings. In this study we demonstrated complete biofilm eradication within 60 min with synergistic combinations of caprylic and polygalacturonic (PG) acids in an in vitro biofilm eradication model against representative hospital and foodborne infectious pathogen biofilms (methicillin-resistant Staphylococcus aureus, multidrug-resistant Pseudomonas aeruginosa, Candida albicans, Escherichia coli, and Salmonella enteritidis). Antimicrobial synergy against biofilms was demonstrated by quantifying viable organisms remaining in biofilms exposed to caprylic acid alone, PG acid alone, or combinations of the two. The combinations also synergistically inhibited growth of planktonic organisms. Toxicity of the combination was assessed in vitro on L929 fibroblasts incubated with extracts of caprylic and PG acid combinations using the Alamar Blue metabolic activity assay and the Trypan Blue exclusion cell viability assay. The extracts did not produce cytotoxic responses relative to untreated control fibroblasts.

In Vivo Reduction of Medium‐ to Long‐Chain Fatty Acids by Carboxylic Acid Reductase (CAR) Enzymes: Limitations and Solutions

“…[22] Of the respective acid, aldehyde and alcohol, the fatty acid is the most tolerated compound. [23] However, relatively low concentrations of aliphatic acids and derivatives cause growth inhibition, cell membrane perforation and leakage, thus disrupting the electron transport chain, uncoupling oxidative phosphorylation and ultimately diminish ATP production. [24] A concentration of 30 mM octanoic acid, e. g., caused 46 % of increased leakage of ions in E. coli K-12 MG1655 cell membranes.…”

Pilot Ex Vivo and In Vitro Evaluation of a Novel Foley Catheter with Antimicrobial Periurethral Irrigation for Prevention of Extraluminal Biofilm Colonization Leading to Catheter-Associated Urinary Tract Infections (CAUTIs)

“…is might be the primary reason for the difference in time to fully colonize the catheter shaft; in the case of the model, it took one day whereas in the physiologic system it typically takes at least an extra day [17]. e PG + CAP antimicrobial combination was previously shown to be effective in eradicating biofilms of a wide range of organisms [9]. We also demonstrated that it had very low cytotoxicity towards human fibroblasts.…”

“…Caprylic acid is a naturally occurring fatty acid present in significant quantities in breast milk, coconut oil, and other natural fluids. It has been designated generally regarded as safe by regulatory agencies and has been safely used in intravenous parenteral nutrition formulations, as a dietary supplement, and topically for skin, hair, and wound care [9,18]. Polygalacturonic acid is naturally derived from pectin and typically isolated from citrus rind of apple pomace [18].…”

“…Polygalacturonic acid is naturally derived from pectin and typically isolated from citrus rind of apple pomace [18]. Polygalacturonic acid is also generally regarded as safe and has been used medically in hydrocolloid wound care dressings and as an emulsifying pharmaceutical excipient in a range of pharmaceutical formulations [9]. Here, we showed that it could be placed in a thickened fluid that could be delivered through the external surface irrigating Foley catheter where it could flow in a countercurrent direction to the direction of colonization.…”

“…In previous studies, we have demonstrated in an in vitro biofilm colonization model [9] complete broad-spectrum biofilm eradication by the combination of 1% polygalacturonic (PG) acid and 0.4% caprylic acid (CAP). In order to disinfect the external surface of the Foley catheter, we created an irrigation solution treatment based on this combination (1% PG + 0.4% CAP).…”