FOS and bacterial infectious disease with sepsis: Resistant (4 mg/L) sub-population frequency: 3.6 × 10−6 CFU/mL; in vitro synergistic concentrations were 1–2–4 mg/L for FOS and 1–2 mg/L for VAN at 24 h. In vivo combination was significant and effective in reducing bacteremia rates in 57% (n = 8 out of 14) of mice treated.