Reduced Bacterial Burden of the Skin Surrounding the Shoulder Joint Following Topical Protocatechuic Acid Application Results of a Pilot Study

Background: Reducing the rising health-care burden associated with shoulder surgical site infection (SSI) is of paramount importance. The purpose of this study was to investigate the antimicrobial efficacy of protocatechuic acid (PCA) as a topical reagent for surgical skin antisepsis surrounding the shoulder joint. Methods: This was a 2-phase skin-disinfection trial involving the human shoulder. The shoulders of healthy volunteers were randomized to topical treatment with PCA (a 10% concentration of PCA in Phase I [11 subjects] and a 17% concentration in Phase II [12 subjects]), with a control of isopropyl alcohol (IPA) applied to the contralateral shoulder. Mechanical scraping was performed for skin harvest following reagent application, and samples were sent for aerobic and anaerobic culture. Sterilization rates and bacterial counts were determined for each treatment group, and the proportion of subjects with persistent Cutibacterium acnes colonization following topical application of PCA was determined using DNA sequencing analysis. Results: The topical application of 10% PCA was associated with significantly higher aerobic and anaerobic sterilization rates (90.9% and 81.8%, respectively) compared with treatment with IPA (p = 0.0143 and p = 0.0253, respectively). The topical application of 17% PCA was associated with a significantly higher anaerobic sterilization rate (83.3%) and trended toward a significantly higher aerobic sterilization rate (91.7%) compared with treatment with IPA (p = 0.0143 and p = 0.083, respectively). C. acnes was identified in 18.2% and 0% of subjects following treatment with 10% and 17% PCA, respectively. Conclusions: The topical application of PCA was associated with a reduction in the bacterial burden of human shoulder skin and demonstrated dose-dependent antimicrobial activity against C. acnes in young, healthy subjects. Clinical studies in a shoulder surgical population are warranted to determine the potential for application in surgical skin antisepsis to reduce shoulder SSI. Level of Evidence: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.