摘要: Escherichia coli has long been recognised as a major cause of diarrhoea but new technologies only recently enabled the definition pathogenetic mechanisms and causative agents more precisely. All E. possess somatic (O) antigens. Most, not all, are motile organisms therefore also have flagellar (H) These two antigens form basis serotyping system. In addition, these bacteria elaborate variety virulence factors which confer distinctive pathophysiological properties.