Research: E. coli proteins cooperate to cause devastating illness

10 February 2006

Three proteins from pathogenic E. coli bacteria cooperate to cause a potentially lethal diarrhoea.

Although most strains of E. coli live happily and harmlessly in our gut, others are deadly killers. The enteropathogenic strain of E. coli causes hundreds of thousands of infant deaths worldwide each year.

Wellcome Trust Senior Research Fellow Professor Brendan Kenny and colleagues at the University of Newcastle upon Tyne have discovered how this pathogenic strain has such devastating effects.

Diarrhoeal disease caused by E. coli has long been linked to 'effacement' – the loss of the tiny folds (absorptive microvilli) on the cells lining the gut wall. The Newcastle group has found that effacement depends on three proteins injected into the gut wall cell by the bacterium, and that the micovilli material is absorbed into the bacterial cell, not shed into the gut.

In addition, they discovered that enteropathogenic E. coli rapidly inactivates a crucial transporter protein (SGLT-1) that plays a vital role in the absorption of water from the gut – normally about six litres a day.

The rapid inhibition of SGLT-1 could explain why the diarrhoea occurs so quickly and why severe cases do not respond to oral rehydration therapy, which depends on SGLT-1 activity.

External links

• Dean P et al. Potent diarrheagenic mechanism mediated by the cooperative action of three enteropathogenic Escherichia coli-injected effector proteins. Proc Natl Acad Sci USA 2006;103(6):1876–81.