Expression of antigenically distinct fimbriae with hemagglutination and HeLa cell adherence properties by an enteroaggregative Escherichia coli strain belonging to the enteropathogenic serogroup

Abstract

An enteroaggregative Escherichia coli (EAggEC) strain (DS92), isolated from a case of infantile diarrhea, was shown to express mannose-resistant hemagglutination and HeLa cell adhering properties when grown at 37 degrees C but not at 28 degrees C. Cellular adherence properties of DS92, which belonged to enteropathogenic serogroup 0125, were shown to correlate well with the expression of fimbriae that were encoded by a 112 kb plasmid. The fimbriae of the EAggEC strain DS92 were composed of 20 kDa subunit proteins and were serologically distinct from fimbrial or non-fimbrial cell surface antigen(s) of other diarrheagenic E. coli strains including the reference EAggEC strain 17-2. Interestingly, the 20-kDa fimbrial protein was found to be antigenically related to 18- and 14.5-kDa cell surface proteins of two other locally isolated EAggEC strains belonging to the enteropathogenic serogroup 086.

Characterization of enteroaggregative Escherichia coli isolates

“…Several bacterial surface factors have been implicated in the aggregative adhesion process: a 38-kDa outer membrane protein [9], a 18-kDa outer membrane associated protein [8], ¢mbriae composed of a 20-kDa subunits [19], but the most extensively described factors are the long bundle forming type ¢m-briae named aggregative adherence factors, AAF/I and /II [10,12]. In our study, only 35% (14/40) of the EAggEC strains tested harbored the aggC accessory gene as detected by PCR and therefore might possess an AAF/I-encoding operon.…”

Characterization of enteroaggregativeEscherichia coliisolates

“…Several bacterial surface factors have been implicated in the aggregative adhesion process: a 38‐kDa outer membrane protein [9], a 18‐kDa outer membrane associated protein [8], fimbriae composed of a 20‐kDa subunits [19], but the most extensively described factors are the long bundle forming type fimbriae named aggregative adherence factors, AAF/I and /II [10, 12]. In our study, only 35% (14/40) of the EAggEC strains tested harbored the agg C accessory gene as detected by PCR and therefore might possess an AAF/I‐encoding operon.…”