Escherichia coli tem um predomínio anormal em pacientes com doença inflamatória intestinal (DII), mas a razão deste aumento numérico é desconhecida. Amostras de E. coli (131) foram isoladas de biópsias retais de 27 pacientes com retocolite ulcerativa (RCU), 8 pacientes com doença de Chron (DC) e 19 controles. E. coli enteroagregativa (EAEC) foram detectadas no ensaio de adesão de 3 horas a células HEp-2 em 71,4% dos pacientes com DII e em 26,3% dos controles (P<0,02). As cepas de pacientes com DC foram negativas para outros marcadores. Duas cepas invasivas foram detectadas entre pacientes com RCU, três deles tinham cepas com plasmídio de adesão agregativa (pAA) e fímbria de adesão agreagativa (aggR) e outras quatro possuíam o gene attaching and effacing (eae). Nenhuma cepa abrigava locus associado à invasão (ial) e antígeno plasmidial de invasão (ipaH). De acordo com esses resultados, EAEC é o grupo dominante encontrado na mucosa colônica de pacientes com DII, mas somente aquelas encontradas em pacientes com RCU abrigam marcadores de virulência tradicionais.

Escherichia coli are increased in inflammatory bowel disease (IBD) patients, but the reason for this elevation is unknown. Amongst their properties is the interaction with cultured epithelial cells. Rectal biopsies from 27 ulcerative colitis (UC), 8 Crohns disease (CD) and 19 control patients were cultured for E. coli, given 131 isolates. Enteroagregative E. coli (EAEC) strains, as detected in 3h adherence assays to HEp-2 cells, were found in 71.4% of 35 IBD patients and in 26.3% of controls (P<0.02). Two highly invasive strains were detected among UC patients, three of whom had also strains with both plasmid of aggregative adhesion (pAA) and aggregative adherence fimbriae R (aggR) and another four E. coli attaching and effacing (eae). No strains had invasion-associated locus (ial) and invasion plasmid antigen H (ipaH), and those from CD were also negative for other markers. According to these results, EAEC are the dominant E. coli group found in the colonic mucosa of IBD patients, but only those found in UC patients seem to harbor traditional virulence markers.