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Escherichia coli EIEC

General characteristics

E. coli are Gram-negative, rod-shaped bacteria belonging the family Enterobacteriaceae

E. coli is a normal inhabitant of the intestines of all animals, including humans. When aerobic culture methods are used, E. coli is the dominant species found in faeces. Normally E. coli serves a useful function in the body by suppressing the growth of harmful bacterial species and by synthesizing appreciable amounts of vitamins. A minority of E. coli strains are capable of causing human illness by several different mechanisms. Among these are the enteroinvasive (EIEC) strains. It is unknown what foods may harbour these pathogenic enteroinvasive (EIEC) strains responsible for a form of bacillary dysentery.

Disease symptoms

Enteroinvasive E. coli (EIEC) may produce an illness known as bacillary dysentery. The EIEC strains responsible for this syndrome are closely related to Shigella spp.

Following the ingestion of EIEC, the organisms invade the epithelial cells of the intestine, resulting in a mild form of dysentery, often mistaken for dysentery caused by Shigella species. The illness is characterized by the appearance of blood and mucus in the stools of infected individuals.

Infective dose -- The infectious dose of EIEC is thought to be as few as 10 organisms (same as Shigella ).

Diagnosis

The culturing of the organism from the stools of infected individuals and the demonstration of invasiveness of isolates in tissue culture or in a suitable animal model is necessary to diagnose dysentery caused by this organism.

More recently, genetic probes for the invasiveness genes of both EIEC and Shigella spp. have been developed.

Associated foods

It is currently unknown what foods may harbour EIEC, but any food contaminated with human faeces from an ill individual, either directly or via contaminated water, could cause disease in others.

Outbreaks have been associated with hamburger meat and non-pasteurised milk.

Prevention

Enterobacteria (incl. E.coli ) are heat-sensitive and will be killed by thorough heating (over 70 °C). Raw or undercooked foods and cross-contamination, when cooked material comes into contact with raw produce or contaminated materials (cutting boards), are the main causes of infection. Proper cooking and hygienic food handling thus can prevent enterobacterial infections to a large extend.

Risk populations

All people are subject to infection by this organism.

Sources:

The bad bug book : http://www.cfsan.fda.gov/~mow/intro.html