E. coli O104:H4

E. coli O104:H4 is a strain of E. coli (Escherichia coli) that can cause a life-threatening kidney condition called hemolytic uremic syndrome (HUS). Unlike its more common relative, E. coli O157:H7, E. coli O104:H4 is found only in humans and not in cattle and other ruminants. This strain of E. coli was responsible for the major E. coli outbreak in Germany in June 2011.


 * "What most predominantly differentiates O104 from O157 is its adoption of numerous traits not typically found congregated in one strain: Not only does it produce the noxious Shiga toxin of the virulent enterohemorrhagic strains, it also possesses defensive enteroaggregative traits --a combined mouthful of properties much more difficult to tolerate physically than verbally.


 * "The term "enteroaggregative" refers to sticky strains of the bacteria that group together --aggregate -- into a "stacked-brick pattern" and cling to intestinal tracts. Once there, they induce heavy mucus production in their host's intestines, which they then use for both protection and sustenance.


 * "Enteroaggregative E. coli are known to cause persistent diarrhea, but are historically unrelated to hemorrhaging and hemolytic-uremic syndrome (HUS), the acute kidney disease caused by Shiga toxin-producing enterohemorrhagic E. coli.


 * "O157 is enterohemorrhagic, but not enteroaggregative. The bacteria do not aggregate together, but they possess cell structures that help them adhere to intestines, where they produce the Shiga toxin known for inflicting HUS and making E. coli a household name among pathogens.


 * "By comparison, O104 clumps together and spurs mucus production for protection while also releasing Shiga toxin into the bloodstream, an adaptation that has resulted in at least 826 cases of HUS in [a 2011 outbreak in Germany] ."

Causes of Infection and Outbreaks
Because E. coli lives in human feces, infections and outbreaks of E. coli O104:H4 are inevitably related to exposure to human feces, for example, via people who do not wash their hands after using the toilet. According to the Mayo Clinic:ref>E. coli Causes, Mayo Clinic, Accessed June 19, 2011.


 * "Human and animal feces may pollute ground and surface water, including streams, rivers, lakes and water used to irrigate crops. Drinking or inadvertently swallowing untreated water from lakes and streams can cause E. coli infection.


 * "Although public water systems use chlorine, ultraviolet light or ozone to kill E. coli, some outbreaks have been linked to contaminated municipal water supplies. Private wells are a greater cause for concern. Some people have been infected after swimming in pools or lakes contaminated with feces."

Some speculate that use of sewage sludge as fertilizer may represent a risk of E. coli exposure.

Related Sourcewatch articles

 * E. coli
 * E. coli O157:H7
 * E. coli outbreak in Germany in June 2011
 * Sewage sludge

External Resources

 * E. coli, Centers for Disease Control

External Articles

 * James Andrews, O104:H4 May Change How We Deal With E. coli, Food Safety News, June 16, 2011.