Caprylic acid and glyceryl trinitrate combination for eradication of biofilm

Abstract

There is a growing need for biocompatible, broad-spectrum, nonantibiotic, antimicrobial treatments because of the frequent ineffectiveness of antibiotics against biofilms and the increasing incidence of antibiotic resistance. In this study, we demonstrate rapid and complete biofilm eradication in an in vitro model with synergistic combinations of glyceryl trinitrate and caprylic acid against resistant Gram-positive, Gram-negative, and fungal biofilms.

FIG 1

Results of 2-h exposure to 0.05% CAP plus 0.04% GTN solution against microbial biofilms. The combination of 0.04% GTN plus 0.05% CAP showed significant eradication compared to that of 0.04% GTN alone (P < 0.001 for MRSA and MRSE, P = 0.01 for C. albicans) or 0.05% CAP alone (P = 0.048 for MRSA, P = 0.017 for MRSE, P = 0.01 for C. albicans). Five-percent dextrose was present in the medical GTN employed in these studies and was also tested as a control to assess its effect on biofilm viability; 0.05% caprylate ion (deprotonated CAP at neutral pH) was tested to assess the effect of protonation of CAP on biofilm viability. All solutions were tested at pH 4.5 to 4.75, except the Mueller-Hinton broth and caprylate ion controls (neutral pH).