E Coli In German Outbreak Has Gene Profile That May Explain Severity

E Coli In German Outbreak Has Gene Profile That May Explain Severity: "E Coli In German Outbreak Has Gene Profile That May Explain Severity
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Academic Journal
Main Category: Infectious Diseases / Bacteria / Viruses
Also Included In: GastroIntestinal / Gastroenterology; Public Health; Genetics
Article Date: 23 Jun 2011 - 11:00 PDT



An analysis of the gene profile of E coli isolated from German patients infected in the current outbreak may explain why it spreads quickly and has severely sickened and killed more people than ever before: it has a unique combination of genes that helps the bacteria cling to the walls of the intestines, deliver toxins to the bloodstream, and resist antibiotics.

Researchers from Germany describe their findings in a study published on Thursday in The Lancet Infectious Diseases.

The ongoing outbreak of Escherichia coli O104:H4 in Germany, with some cases also elsewhere in Europe and North America, is the worst ever recorded: it has sickened over 3,500 people, including 810 who developed haemolytic uraemic syndrome (HUS) and bloody diarrhoea, with 40 deaths in Europe so far.

With HUS, the toxins produced by E coli enter the bloodstream and destroy red blood cells, causing kidney injury.

The current outbreak was traced to bean and seed sprouts grown at a German organic farm.

In this study, researchers from the University of Münster, plus a colleague from the Robert Koch Institute, both in Germany, isolated bacteria from 80 patients whose stool samples had been sent to Gemany's National Consulting Laboratory for Haemolytic Uraemic Syndrome between 23 May and 2 June 2011.

At the Laboratory, which is based at the University of Münster, they screened the DNA in the samples and found that the new strain has a combination of traits from enterohaemorragic E coli (EHEC) and enteroaggregative E coli (EAEC).

EHEC produces a range of poisons called Shiga toxins, while EAEC adheres to the epithelial cells in the lining of the gut.

These traits, which the researchers found by screening for known genes, have been in existence for the last ten years, although they surface rarely.

However, what is new and not seen before, is that the O104:H4 strain in the current outbreak also contains a number of genes that make it resistant to beta-lactams, a class of antibiotics.

The researchers concluded that the unique combination of genes that enhance ability to stick to the gut wall, deliver toxins, and resist a broad class of antibiotics may explain why the infection spread so quickly and killed so many people.

'Characterisation of the Escherichia coli strain associated with an outbreak of haemolytic uraemic syndrome in Germany, 2011: a microbiological study.'
Martina Bielaszewska, Alexander Mellmann, Wenlan Zhang, Robin Köck, Angelika Fruth, Andreas Bauwens, Georg Peters, and Helge Karch.
The Lancet Infectious Diseases, Early Online Publication, 23 June 2011
DOI:10.1016/S1473-3099(11)70165-7

Written by: Catharine Paddock, PhD
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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