Bacterial strains and growth conditions

All bacterial strains used in this study are listed in Supplementary Table S1. All experiments were performed in lysogeny broth (LB) medium (tryptone: 10 g/L, yeast extract: 5 g/L, NaCl: 5 g/L). Where applicable, the growth medium was supplemented with ampicillin (100 µg/ml) and/or chloramphenicol (25 µg/ml).

In EAEC isolate 55,989 the gene cluster coding for AAF/III (agg3DCBA) was replaced by the chloramphenicol resistance cassette of pKD3 using the lambda Red recombination system [²⁵]. The resulting strain E. coli 55989 agg3::cat was hereafter named EAEC 55989 agg3⁻.