Figure 11.

Farnesol prevents biofilm development and disrupts established E. cloacae biofilms on ex vivo intact or burned human skin. (A,B) E. cloacae biofilm development on ex vivo human skin is inhibited by exposure to farnesol at 1 mg/mL for 24 h, as visualized by H&E-stained images (A), and quantification of viable bacteria in log₁₀ CFU per cm² of skin (B). (C,D) The same concentration of farnesol (1 mg/mL) is also effective for inhibiting E. cloacae biofilm development on burned ex vivo human skin treated for 24 h, as visualized by H&E-stained images (C), and quantification of viable bacteria in log₁₀ CFU per cm² of skin (D). (E,F) Established E. cloacae biofilms developed for 24 h on ex vivo human skin, and then exposed to farnesol for 24 h (15 mg/mL), have reductions in biofilm development, as visualized by H&E-stained images (E), and quantification of viable bacteria in log₁₀ CFU per cm² of skin (F). (G,H) The same concentration of farnesol (15 mg/mL) is also effective for E. cloacae biofilm development on burned ex vivo human skin treated for 24 h, as visualized by H&E-stained images (G), and quantification of viable bacteria in log₁₀ CFU per cm² of skin (H). The presence of biofilm is indicated by black arrowheads in (A,C,E,G). The gray arrows in (C,G) indicate broken stratum corneum of burned epidermis, which was penetrated by E. cloacae to develop biofilm. Quantitative data in (B,D,F,H) represent the mean ± SD (n = 3 separate pieces of skin) from two independent donors. Ctrl_1 = 3.3% of ethanol; Ctrl_15 = 50% of ethanol.