Deadly E. coli Bacteria Bind Themselves to Cells with Fimbrial Adhesins

​The deadly E. coli bacteria bind to intestinal cells using miniature sticky hairs which the researchers call fimbrial adhesins. The discovery was made by a research group led by Academy Research Fellow Anton Zavialov at the Department of Chemistry of the University of Turku in cooperation with researchers from the Imperial College London.

– The atomic resolution structure of fimbrial adhesin from this bacterial strain, which we determined in Turku, revealed that they consist of long chains of small protein subunits firmly attached to each other. Each of these subunits can bind to a certain human protein that is exposed on the cell surface. Because several subunits can bind to several protein molecules simultaneously, the bacterial hair anchors tightly to the human cell, says Dr. Zavialov.

Recently Dr. Anton Zavialov and Dr. Urpo Lamminmäki, a leading expert in development of synthetic antibodies at the Department of Biotechnology, received a three-year funding from the S. Juselius Foundation to develop adhesion-blocking antibodies. These antibodies could treat bacterial infections that are resistant to antibiotics.

E. coli Bacteria Caused an Epidemic in Germany

Doctoral Candidate Natalia Pakharukova at the Department of Chemistry is carrying out her doctoral dissertation on the miniature sticky hairs of the bacteria, i.e. the fimbrial adhesins. She is part of Zavialov’s research group and is excited about the discovery.

– Fimbrial adhesins are highly immunogenic, so it is very possible that we can develop antibodies that bind to them. Antibodies raised against the fimbrial adhesins can block the binding of the bacteria to the cell and stop the infection, says Pakharukova.

In 2011, an outbreak of an intestinal infection caused by E. coli bacteria affected 4137 people in Germany, of whom, 896 developed a severe complication called hemolytic-uremic syndrome (HUS) and 54 died. HUS causes deterioration of red blood cells and a decrease in the number of thrombocytes which can lead to a sudden, life-threatening kidney failure.

The outbreak in Germany induced an agricultural crisis in Europe and Russia banned the import of fresh vegetables. The infection was caused by a novel pathogenic strain of Shiga toxin producing Escherichia coli O104:H4, which is characterised by an unusually aggressive nature and rapid spread. The high frequency of HUS is associated with a tight binding of the bacteria to the human intestine, which facilitates the absorption of Shiga toxin by the human cells.

The study has been published in the esteemed PLOS Pathogens journal.