Sensitization of avian pathogenic Escherichia coli to amoxicillin in vitro and in vivo in the presence of surfactin

The purpose of this study is to assess the antibiotics adjuvant effect of surfactin for boosting the treatment effect of amoxicillin. Surfactin is used as a surfactant to mediate flux of mono- and divalent cations, such as calcium, across lipid bilayer membranes. In this study, we demonstrated that surfactin can increase the activity of amoxicillin against avian pathogenic Escherichia coli (APEC) in vitro with antimicrobial assays such as minimum inhibitory concentrations (MIC) and fractional inhibitory concentration (FIC). Additionally in the model of chick infection, surfactin exerted adjuvant effects with amoxicillin against APEC by lowering the numerical value of mortality and liver bacterial loads, and regulating the expression of inflammatory cytokines et al. We concluded that surfactin can act as a novel antimicrobial adjuvant with amoxicillin against AEPC infection in chicken.