Monday, 23 September 2013

Taxon of the Day: Escherichia coli

E. coli magnified 10,000 times

Taxon of the Day ventures into the kingdom of bacteria with today's well-known subject. Escherichia coli is a bacteria that inhabits the gut of both animals and people and these days seems to be everywhere and in everything, from your handbag to your watercress. Although only one species, it includes hundreds of strains and serotypes - some good, some bad and some potentially life-threatening. E. coli found in human intestines are mostly harmless and help us to digest food, but others, like the strain officially known as VTEC O157 Phage type 2 VT2, is not so pleasant. VTEC is the abbreviation used for verocytotoxin, the cause of gastrointestinal disease producing  E. coli, of which O157 is the most common strain in the UK. Just recently a leading supermarket chain (in the UK) came to nationwide attention for recalling all of its own brand of watercress due to an outbreak thought to trace back to its produce. As of yet no proof of contamination has been found, but as a precautionary measure due to the many numbers of people who fell ill and were treated in hospital, it was felt necessary to act. It is reported that approximately 1000 cases of E. coli per year are treated in the UK. Transmission can occur in direct and indirect ways, most likely in the above case (if in fact true), it came through eating the watercress that had been contaminated by the faeces of infected animals through the soil.

The etymology of Escherichia coli, relates to the German physician Theodor Escherich (1857-1911) who discovered it in 1885. He did not originally name it after himself, which we all know is a no-no in taxonomy etiquette, but by a subsequent taxonomist who reclassified his original taxon.  coli is the Latin genitive of colon, referring to the intestine that this bacteria inhabits.

While E. coli may be considered the bane of consumers, supermarkets and health workers alike, it is frequently a friend to researchers because of its genetic simplicity and/or fast growth rates. It has been used as an aid in completing the Human Genome Project and as a potential new biofuel among many other positive uses.  It has also been the inspiration, along with other pathogens, for artist Luke Jerram to produce some dramatic art, proving that the agents of our pain can have the most striking and beautiful form when blown in glass!

CoL Annual Checklist: Escherichia coli
CoL contributor: Bacteriology Insight Orienting System
Image copyright: Public Domain

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