Lack of association ofEscherichia coliexhibiting both mannose-resistant haemagglutination and diffuse adherence to Hep-2 cells with acute diarrhoea in children

Abstract

SUMMARYStool specimens from 631 children with acute diarrhoea and from 277 healthy controls were tested for the presence of non-enteropathogenic, non-enterotoxigenic Escherichia coli strains which mediated mannose-resistant haemagglutination of human erythrocytes (MRHA +). Fifty-nine (349%) of 169 isolated MRHA + strains but none of 210 MRHA-strains exhibited diffuse adherence (DA+) to HEp-2 cells. DA + strains were found in 37 (5-9 %) children with diarrhoea and in 22 (7-9%) controls. MRHA+/DA+ strains in comparison to MRHA+/DAstrains significantly less frequently expressed P fimbriae (10-7 vs. 736 %), haemolysin production (12-5 vs. 63-2 %), and MRHA of other species erythrocytes (214 vs. 84%).These data demonstrate that E. coli which exhibit the diffuse pattern of adherence to HEp-2 cells also cause MRHA of human erythrocytes. Since these strains were found with similar frequencies in children with and without diarrhoea it seems that DA is not a marker of enteropathogenicity of E. coli.

EnteroaggregativeEscherichia coliassociated with an outbreak of diarrhoea in a neonatal nursery ward

“…Twenty-three E. coli O4 isolates were saved. The confirmation of serogroup of these isolates, tests for hydrophobicity and for mannose-resistant haemaglutination of human erythrocytes (MRHA), and for enterotoxin production on CHO K-l cells (LT) and in the infant mouse (ST) were carried out as previously described [5,13]. The production of VT was assayed on Vero cells according to Karmali [14].…”

“…DAEC bind uniformly to the entire surface of HEp-2 cells, whereas EAggEC exhibit a third distinct pattern of adherence, so-called aggregative adherence (AA), characterized by 'stacked brick' aggregates of bacteria attached to the surface of cultured cells and, sometimes, to the glass surface between cells [1,2]. Epidemiological studies performed to date have yielded conflicting results on the role of DAEC and EAggEC as causative agents of diarrhoeal diseases [3][4][5][6][7][8][9][10].…”