WHO New EHEC pathogen triggers infections

WHO: EHEC strain of the current wave of infection so far unknown

03/06/2011

The search for the origin of the EHEC pathogen HUSEC 41 (also called O104: H4) is still in full swing. Meanwhile, the World Health Organization (WHO) has stated that preliminary genetic testing has concluded that the new pathogen strain is a mutated form of two known Enterohemorrhagic Escherichia coli bacterial strains.

The EHEC bacterial strain, now identified as the cause of the severe EHEC infection, has never been isolated in patients before, according to WHO expert on food safety, Hilde Kruse. The particularly aggressive EHEC pathogen HUSEC 41, which is currently blamed for the more common EHEC symptoms, such as bloody bowel movements, is now „known but never occurred during an outbreak“, said a spokeswoman for WHO on Friday in Geneva. Based on the molecular and genetic characteristics of the pathogen, the competent authorities can now much easier to detect the corresponding EHEC infections and in the search for the infection route or the source of the outbreak, the specific properties of HUSEC 41 could be helpful, the experts hope.

Where does the new EHEC strain come from??
But where does the new, extremely aggressive bacterial strain of Enterohemorrhagic Escherichia coli (EHEC) actually come from? While health authorities are feverishly researching the acute cause of the prevalence of EHEC infections, critics are questioning the conditions under which the highly-susceptible strain could develop and why it is currently spreading so rapidly. Since ruminants are considered to be the main reservoir of EHEC bacteria, the improper handling of the feces of the animal was quickly suspected. In addition, it was suggested that the use of antibiotics in animal husbandry could be responsible for the resistance of the pathogens to the corresponding drugs. In addition, the Münster-based EHEC expert Professor Helge Karch made the previous outbreaks „not species-appropriate feeding“ in factory farming, responsible for the spread of the pathogens. Because the grain-concentrate mixtures used favor the spread of aggressive EHEC pathogens, according to the expert. As early as 1998, US researchers Cornell University researchers in Ithaca, New York had presented a study in which the fed grain-concentrate mixtures were blamed as the cause of increased spread of EHEC pathogens.

Feed methods in mass animal farming favor EHEC spread
The US scientists found that the grain-concentrate mixture in the stomach of the animals was only incompletely broken down and then undigested into the intestine. The food began to ferment in the intestine and the contained EHEC pathogens slowly got used to the acidic environment. As a result, the pathogens were also more resistant to human stomach acid, the US scientists reported. In addition, 250,000 EHEC cells per gram were detected in the intestinal contents of the animals receiving cereal concentrates, whereas ruminants receiving hay or grass had only 20,000 EHEC cells per gram of intestinal contents. In the animals that received hay and grass, the pathogens were also less resistant to gastric acid, the US researchers reported in 1998 in the journal „Science“. Thus, the suspicion suggests that the spread, which is threatening to humans EHEC pathogens, mainly favored by the feed methods of factory farming.

Rapid spread of EHEC pathogens
At present, the unusually rapid spread of EHEC pathogens is at least partly attributable to the production structures in food production. Due to the globalized mass production of food, the dangerous pathogens can spread disproportionately fast. It is therefore hardly surprising that the World Health Organization (WHO) is currently reporting increased EHEC infections from twelve countries. According to the WHO, 502 cases of haemolytic uremic syndrome (HUS) and 1,122 EHEC infections have been reported, with Austria, the Czech Republic, Denmark, France, the Netherlands, Norway, Spain, Sweden, the United Kingdom, Switzerland and the United Kingdom as the main infection country US are affected. The new pathogen strain is believed to spread along supply chains in the food industry. But if the first people are infected on the spot, the dangerous pathogens can also be relatively easily transmitted from person to person, which accelerates the spread of infection. According to the WHO, 470 people in Germany currently suffer from the life-threatening hemolytic uremic syndrome caused by EHEC and 1,064 have EHEC infection. (Fp)

Also read:
Green cucumbers no EHEC transmitter
EHEC Causes: The pathogen on the trail
Symptoms of EHEC infection
First deaths from EHEC infections
No antibiotic in EHEC
Enigmatic infections caused by EHEC pathogens
Doctors are testing new therapy for EHEC infection

Picture: Urs Mücke