Enterohaemorrhagic Escherichia coli O157:H7 (EHEC) was recognised as a human pathogen following outbreaks of haemorrhagic colitis (HC) in the USA, 1982. Since then EHEC became an emerging food-related pathogen causing a wide variety of diseases in human including mild to bloody diarrhoea, haemorrhagic colitis (HC) that can lead to the life threatening haemolytic uremic syndrome (HUS). EHEC infection is a severe public health problem in developed countries. In 1996, there was an outbreak involving more than 6000 people in Japan. In the United States, the number of EHEC infections could be as high as 20 000 per a year, of which about 250 are deadly. The source of infection is mostly eating undercooked ground beef. In Hungary, there have only been sporadic cases detected so far. With several virulence factors involved in its pathogenesis, EHEC is a classic pathogenic model organism. All isolates have one or two bacteriophage encoded toxins, called Shiga toxin (Stx), a serotype specific virulence plasmid of cc. 60 MDa (pO157) and a pathogenecity island (pai). pO157 promotes the EHEC adherence both in vivo and in vitro, but so far there is no cloned pO157-specific EHEC adhesin. pO157 encodes Katalase peroxidase (KatP), Serine protease (EspP), EHEC-haemolysin (enterohaemolysin) and a type II secretion pathway operon. EHEC-pai is a 43.3 kb length extraneous DNA that contains all the genes necessary for causing attaching effacing lesions. Diagnosis is mostly based on the detection of Stx through its cytotoxic effect on Vero cells, with the help of Stx-antibodies, by hybridisation using Stx specific DNA probes or by DNA amplification (PCR). The antibiotic therapy of EHEC infections is not without risk and further studies are needed to elucidate its benefits. There are encouraging results of using a Stx-receptor analogue to develop drugs or vaccines.
|Translated title of the contribution||Epidemiology, pathogenesis and diagnosis of human diseases caused by enterohaemorhagic Escherichia col/0157:h7. Review article|
|Number of pages||9|
|Journal||Magyar Allatorvosok Lapja|
|Publication status||Published - Dec 1 1998|
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