A) Experimental setup for in vitro challenge with S. Typhimurium. SICs passaged in BHI from pre-, peak, residual, and post-treatment humanized mouse fecal inocula were revived after freezing and passaged twice in BHI. SICs were mixed with S. Typhimurium and S. Typhimurium levels were quantified after 48 h of growth.
B) SICs derived from mice treated with ciprofloxacin are more susceptible to S. Typhimurium. Colonies of S. Typhimurium SL1344 after 48 h of growth with SICs diluted 1:104 and grown aerobically on LB+streptomycin.
C) Single-cell quantification of mCherry-tagged S. Typhimurium 14028s after co-culture with SICs derived from pre- and residual-treatment mice fecal inocula. p-value is from a Student’s two-sided t-test; n=3.