ENTEROHEMORRHAGIC ESCHERICHIA-COLI O157-H7 REQUIRES INTIMIN TO COLONIZE THE GNOTOBIOTIC PIG INTESTINE AND TO ADHERE TO HEP-2 CELLS

In a previous study, enterohemorrhagic Escherichia coli (EHEC) 0157:H7 with a deletion and insertion in the eaeA gene encoding intimin was u sed to establish that intimin is required for the organism to attach t o and efface microvilli in the piglet intestine (M. S. Donnenberg, S. Tzipori, M. L. McKee, A. D. O'Brien, J. Alroy, and J. B. Kaper, J. Cli n. Invest. 92:1418-1424, 1993). However, in the same investigation, a role for intimin in EHEC adherence to HEp-2 cells could not be definit ively demonstrated. To analyze the basis for this discrepancy, we cons tructed an in-frame deletion of eaeA and compared the adherence capaci ty of this mutant with that of the wild-type strain in vitro and in vi vo. We observed a direct correlation between the requisite for intimin in EHEC 0157:H7 colonization of the gnotobiotic piglet intestine and adherence of the bacterium to HEp-2 cells. The in vitro-in vivo correl ation lends credence to the use of the HEp-2 cell adherence model for further study of the intimin protein.