Experimental scheme. Germ-free (yellow background) or OligoMM12(green background) infected with a mixture of donor (10-fold excess;S.Tm-B) and recipient (S.Tm-A orS.Tm-A gatABC). Groups: (1)S.Tm-A as recipient in germ-free (black; n = 4), (2)S.Tm-A gatABC as recipient in germ-free (red; n = 3), (3)S.Tm-A as recipient in OligoMM12(black; n = 5), (4)S.Tm-A gatABC as recipient in OligoMM12(red; n = 5), and (5)S.Tm-A as recipient in OligoMM12with 1% galactitol (purple; n = 5). Selective plating to determine (B) fecal loads of recipients + transconjugants (CFU/g feces), (C) proportion of transconjugants (CFU/g feces), (D) fecal loads of transconjugants (CFU/g feces), and (E) fecal loads of transconjugants (CFU/organ) in cecal tissue and mesenteric lymph nodes. Bars, median; dotted lines, detection limit. Two-tailed Mann Whitney-U tests to compare two groups in each panel. p >= 0.05 not significant (ns), p < 0.05 (*), p < 0.01 (**).
