HEMAGGLUTINATING PROPERTIES OF ENTEROAGGREGATIVE ESCHERICHIA-COLI

Many intestinal bacterial pathogens possess hemagglutinating propertie s, which are indicative of their adhesive properties to the intestinal mucosal surface. To understand the bacteria-mucosa interaction, 41 st rains of enteroaggregative Escherichia coli (EAggEC), a recently descr ibed category of diarrheagenic E. coli, isolated mostly from children with diarrhea in Bangladesh, India, Thailand, Central America, and Sou th America were screened for mannose-sensitive hemagglutination and ma nnose-resistant hemagglutination of erythrocytes from humans, rats, mi ce, sheep, cattle, and rabbits. Some strains demonstrated mannose-sens itive hemagglutination of erythrocytes. Most isolates showed mannose-r esistant hemagglutination of erythrocytes from all species except rabb its. The hemagglutination patterns could be classified into 18 groups. Studies with three selected isolates suggested that hemagglutinins ar e cell bound and are protein in nature. On the basis of the pattern of inhibition of hemagglutination by various chemicals, 39 isolates were classified into 19 groups. Hemagglutinations of many isolates were in hibited by sialic acid-containing compounds, suggesting that these com pounds may be the receptors for these organisms on erythrocytes and po ssibly on the intestinal mucosa. These data indicate that strains of E AggEC are a heterogeneous group of organisms with different types of h emagglutinins or adhesins for the intestinal mucosal surface. Also, th e adhesion characteristics of EAggEC strains may be too complex to be assessed by simple hemagglutination tests.