Synergistic Phage-surfactant Combination Clears IgE-promoted Staphylococcus aureus Aggregation in Vitro and Enhances the Effect in Vivo.

Currently, topical treatment with antibiotics is a major strategy for the decolonization of S. aureus, although it results in antibiotic resistance or recolonization of the organism. Recently, the application of bacteriophages in treatment of S. aureus infection has attracted attention; however, a single administration of bacteriophages did not effectively decolonize S. aureus in our first trial in vivo. Using a bacteriophage, pSa-3, and surfactant combination in vitro, we showed an increased (more than 8%) adsorption rate of the bacteriophage on the host. Moreover, the combination increased the eradication of immunoglobulin E-stimulated aggregation, as the surfactant promoted the dissociation of S. aureus aggregates by decreasing the size by 75 and 50% in the absence and presence of IgE, respectively. Furthermore, the combined treatment significantly decolonized the pathogen, with an efficacy double that of the phage-only treatment, and decreased the expression of pro-inflammatory cytokine genes (IL-1beta, IL-12, and IFN- gamma) for 5 days in the second in vivo trial. These results suggest that the bacteriophage-surfactant combination could act as an alternative to antibiotics for S. aureus decolonization in patients with dermatitis.