E. Coli or escherichia coli are gram negative, rod shaped, motile or non motile, non spore producing facultative anaerobic bacteria which live in the lower intestine of all warm blooded animals. E. Coli species that are capable of propulsion do so by means of a ‘flagella’ which is a whip like tail.
Most types of e. coli are absolutely harmless and are part of the normal and necessary flora of warm blooded species. In fact they are very necessary because they produce vitamin K as a bi product of their metabolic activity and by existing in great numbers help by preventing other pathogenic bacteria from colonizing the gut.
Some species of e.coli are pathogenic which means that they can cause desease. The strains that are pathogenic are 0157:H7 and 0111:B4. This particularly virulent capacity was transferred to these e.coli bacteria from shigella bacteria which passed shiga toxin to e.coli by means of bacteriofages which are a type of viral species. Both these strains of e.coli have the capability of transferring their virulent qualities to other bacteria around them by means of their sex pilus which is a needle like protrusion from the side of their body wall by which they insert the DNA codes necessary for the production of virulent qualities into bacteria next to them. One such virulent quality is the ability to resist certain anti biotics.
The very virulent strains of coli such as 0157:H7 and 0111:B4 are capable of causing serious intestinal illness particularly in the very young, old and the immunologically compromised. However it must be stressed that the majority of common e.coli outbreaks are mild and cause only diarrhea and mild temperature increase. More serious virulent cases can cause complications such as hemolytic-uremic syndrome.
E. coli toxins can be heat tolerant or heat labile. This quality makes the boiling of water to kill e. coli unsure and in such a case water should be boiled in a pressure cooker, if available, for at least twenty minutes. Another alternative would be to only drink safe bottled water if possible. E. coli bacteria which escape from the intestine into the abdominal cavity through means of a perforated ulcer, intestinal lesion or a ruptured appendix will cause peritonitis and be life threatening if not treated promptly with antibiotics such as streptomycin and gentamycin to which e.coli are very sensitive. E. Coli which are associated with the intestinal mucosa lawyer can be found in greater numbers in conditions such as Crohns disease, iritable bowel disorder and ulcerative colitis.
E.coli is contracted through contact with contaminated food or water sources in which the content of the gut as come into direct or ‘indirect’ contact with food or water. Severe cases of e. Coli infection can resemble cholera.
New strains of E.coli are continually being produced by the process of mutation. Some strains may develop traits that are harmful to the host animal. E.coli prefers to reproduce at the temperature of 37 degrees Celsius but some strains have shown the capacity to reproduce at temperatures of up to 49 degrees Celsius.
E. coli has been found in agricultural produce such as spinach. In 2006 there was a famous outbreak of contaminated spinachin the US due to the fact that bovine feces polluted a spinach field which was at the bottom of the hill on which a herd of cattle were kept. In this case all the spinach was recalled and destroyed.
E. coli contamination can be prevented for the most part by maintaining a correct food hygiene policy in the kitchen and by using reputable food suppliers.