2256. Efficacy of a Novel Synergistic Polygalacturonic + Caprylic Acid + Nitroglycerin Antimicrobial Wound Ointment Against Common Wound Pathogens in a Time-to-Kill Biofilm Eradication Model
Session: Poster Abstract Session: New Antibiotics in Development
Saturday, October 29, 2016
Room: Poster Hall
Background: Microbial contamination of chronic wounds delays healing particularly when biofilms are present. Historically, honey has been widely used as an ointment to aid in healing chronic wounds; however, clinical trials with honey have shown mixed results. Hence there remains a need for a low-cost ointment that can significantly improve outcomes with microbially-contaminated wounds. In this study we examined the antimicrobial synergy of polygalacturonic acid (PG) and caprylic acid (CAP), as well as the efficacy of an antimicrobial wound ointment based on the PG + CAP combined with nitroglycerin (GTN) and compared it to MediHoney against various wound pathogens. CAP and PG have been designated as “generally recognized as safe” by regulatory agencies for topical use.

Methods: Combinations of PG+CAP were tested for efficacy and synergy in a time-to-kill biofilm eradication model. The GTN+PG+CAP wound combination was added to a carboxymethylcellulose (CMC) + propylene glycol (PPG) ointment base previously approved for treating chronic wounds. The GTN+PG+CAP in CMC-PPG base was tested for efficacy in a time-to-kill biofilm eradication model. Briefly, bacterial or yeast biofilm were grown on silicone discs for 24 hrs. Each biofilm colonized disc was exposed to PG, CAP, PG + CAP, GTN+PG+CAP in CMC-PPG, CMC-PPG base alone, or MediHoney for 15min, 30 min, 60min, or 120 minutes. Subsequently the discs were sonicated for 15 minutes and plated and the number of viable colonies enumerated. CMC-PPG base was used as a control and MediHoney was used as a comparator.

Results: PG+ CAP showed synergy compared to individual components by reducing time to eradication by at least half for MRSA (60 vs 15 min), PS (15 vs 60min), and C. albicans (30 vs 120min). The addition of GTN further increased the synergy for C glabrata (15 vs 60 min). The novel GTN+PG+CAP wound ointment was highly efficacious in time to eradication compared to MediHoney against MRSA, CRE E. coli, VRE, C. albicans, and C. glabrata (>120min eradication for MediHoney compared to <60min eradication GTN+PG+CAP; p<0.05 for all organisms).

Conclusion: Novel GTN+PG+CAP ointment has potent broad-spectrum efficacy for eradicating biofilms compared to MediHoney. Further efficacy testing is planned in a clinical setting.

Joel Rosenblatt, PhD1, Ruth Reitzel, MS2, Ray Hachem, MD, FIDSA3, Anne-Marie Chaftari, MD2 and Issam Raad, MD, FIDSA, FSHEA2, (1)1515 Holcombe - Suite FCT12.6030, UT MD Anderson Cancer Center, Houston, TX, (2)Infectious Diseases, Infection Control & Employee Health, University of Texas MD Anderson Cancer Center, Houston, TX, (3)University of Texas, M.D. Anderson Cancer Center, Houston, TX

Disclosures:

J. Rosenblatt, the University of Texas MD Anderson Cancer Center: Inventor of the Caprylic Acid - Glycerol Trinitrate Combination Technology and Shareholder , licensed by Novel Anti-Infective Technologies, LLC in which UTMDACC, Dr. Raad and Dr. Rosenblatt are shareholders. and Licensing agreement or royalty

R. Reitzel, None

R. Hachem, None

A. M. Chaftari, None

I. Raad, Merck: Grant Investigator , Grant recipient
Pfizer: Speaker's Bureau , Speaker honorarium
Allergan: Grant Investigator , Grant recipient

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