Thursday, June 02, 2011

Why Health Authorities Are So Worried About Europe's Mutant E. Coli Outbreak

Health officials were worried enough about an unusually virulent outbreak of food-borne illness from the E. coli bacteria, which has infected more than 1,500 people in Germany and killed at least 17. But the concern jumped to another level on Thursday when the World Health Organization (WHO) announced that the responsible pathogen was a strain of E. coli that they believe had never before been seen by scientists.

According to the Beijing Genomics Institute in China, which has been working with German scientists on the outbreak, the new strain is dangerous:

Bioinformatics analysis revealed that this E. coli is a new strain of bacteria that is highly infectious and toxic.

This is a new serotype — not previously involved in any E. coli outbreaks. Comparative analysis showed that this bacterium has 93% sequence similarity with the EAEC 55989 E. coli strain, which was isolated in the Central African Republic and known to cause serious diarrhea. This new strain of E. coli, however, has also acquired specific sequences that appear to be similar to those involved in the pathogenicity of hemorrhagic colitis and hemolytic-uremic syndrome. The acquisition of these genes may have occurred through horizontal gene transfer. The analysis further showed that this deadly bacterium carries several antibiotic resistance genes, including resistance to aminoglycoside, macrolides and Beta-lactam antibiotics: all of which makes antibiotic treatment extremely difficult.

The preliminary genetic analysis indicates that the new strain is a mutant, the combination of two distinct groups of E. coli: enteroaggregative E. coli (EAEC) and enterohemorrhagic E. coli (EHEC). As is often the case when germs get together and start splicing, the result is not good for people, as Liverpool University biologist Dr. Paul Wigley told the BBC Thursday:

One nasty bacteria seems to have acquired a toxin from another nasty bacteria which has resulted in an even nastier bug. It seems it is producing two toxins which cause the damage and lead to bloody diarrhea and damage to tissues including the kidneys.

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