ABSTRACT
Escherichia coli is a Gram-negative bacillus belonging to the Enterobacteriaceae within the Class gammaproteobacteria. It is part of the normal flora of the gastrointestinal (GI) tract. However, several pathovars exist causing neonatal meningitis, pyelonephritis and six pathovars causing gastroenteritis: Enteropathogenic E coli, Enterotoxigenic E coli, Enteroinvasive E. coli Enterohemorrhagic E. coli, Enteroaggregative E. coli and diffusely adherent E. coli all having different virulence properties. E.coli is a common cause of septicemia and can complicate any of the above presentations. The virulence properties are on plasmids or integrated into the genome as pathogenicity islands. The structure of the cell wall is typical for most Gram-negative organisms consisting of lipopolysaccharide comprising Lipid A, inner core and the outer antigenic component. Lipid A activates the immune system of the host leading to a pro-inflammatory response. Management of E. coli disease is complicated by multiple antibiotic resistant strains.
