Panels A, D and G: E9034A wild-type ETEC strain; Panels B, E and H: E9034AΔlngA; Panel C, F and I: E9034AΔlngA(pAC-lngA) complemented mutant. Arrow indicates bacterial self-aggregates. Panels A, B, and C are pictures obtained from bacterial suspensions. Scale bar sizes indicated in mm. Panels D, E, and F are pictures obtained by inverted light microscope. Panels G, H, and I are scanning electron microscopy pictures. Arrow indicates pilin-bacterial interactions. Scale bars sizes for Panels D to I indicated in μM. All strains were grown in TB.