FIG. 2.
Interaction of EHEC O157 strain TUV 93-0 (A), EHEC O26 (193 Nalr), and O111 (E45035N and EC920201) (B) with bovine intestinal mucosa. (A) Foci of intimately adherent O157-positive bacteria were observed following the immunostaining of a formalin-fixed, paraffin-embedded section (immunofluorescence assay [IFA]), and typical A/E lesions, accompanied by localized effacement of the brush border, microvillous elongation, were observed by SEM. Similar findings were observed by using EHEC of O26 and O111 serogroups (B). (C) No bacteria of the O157, O26, or O111 serogroup were observed on uninfected explants by either IFA or SEM. Representative micrographs are shown for each reporter technique. Hoechst 33342 (blue, false color), nuclei and bacteria; tetramethyl rhodamine isothiocyanate (TRITC) (red, false color), O157-positive bacteria. Bar = 50 μm (IFA) or 5 μm (SEM).