Enteropathogenic
E. coli(EPEC) is an important diarrhoeal
pathogen that induces characteristic
lesions on the host
intestine termed attaching and
effacing (A/E)
lesions. In this study we have examined the contribution of a large gene, efa1, which is present in all A/E
pathogens, to the adherence
phenotype of EPEC. An efa- derivative of EPEC JPN15 was constructed and this
mutant was significantly less adherent to
epithelial cells than the parent strain. The JPN15 efa- derivative was FAS-positive, produced EspA filaments and showed comparable levels of EspA
secretion to JPN15. In addition,
polyclonal antibodies raised to Efa1 partially inhibited the adherence of JPN15 to cultured
epithelial cells. In further work, we showed that human and rabbit hosts infected with an A/E
pathogen produced
antibodies to Efa1 and we observed that the truncated form of efa1 present in
EHEC O157:H7 was specific to that
serotype. Generally efa1 was present in its entirety in the genomes of other A/E
pathogens. Overall our data suggest that Efa1 has
host cell binding activity, at least in
tissue culture, and that it is produced during
infection. These findings suggest that Efa1 may play a direct role in the
pathogenesis of
infections caused by A/E
pathogens.
