Electrical stimulation disrupts biofilms in a human wound model and reveals the potential for monitoring treatment response with volatile biomarkers.

Abstract

Management of biofilm infections relies on time-consuming laboratory techniques and monitoring treatment by subjective clinical evaluations. Due to these limitations, there is a need to explore alternative strategies. The aims of this study were to assess the feasibility of using volatile organic compound (VOC) biomarkers to monitor treatment response and measure anti-biofilm efficacy of electrical stimulation (ES) in vitro and in human cutaneous wound biofilm models. Staphylococcus aureus (MSSA) and Pseudomonas aeruginosa (PA) biofilms were exposed to ES, ciprofloxacin, or both, with efficacy assessed and quantified by fluorescence staining, enumeration, metabolic assays, and biomass quantification; VOCs were measured by gas chromatography-mass spectrometry. In vitro MSSA and PA and ex vivo PA biofilms exposed to ES showed significantly reduced bacterial viability, metabolic activity, and biomass compared to controls (p < 0.05). There was significant variation in the relative abundance of VOCs in in vitro MSSA and PA and in ex vivo PA biofilms exposed to ES and antibiotic (p < 0.05). 2-methyl-1-propanol was associated with MSSA viability (R = 0.93, p < 0.05), biomass (R = 0.97, p < 0.05), and metabolic activity (R = 0.93, p < 0.05) and 3-methyl-1-butanol was associated with PA biomass (R = 0.93, p < 0.05). We showed that ES and VOC biomarkers are possible options for alternative nonpharmacological antimicrobial management of biofilms and noninvasive monitoring of wound infection treatment responses, respectively.