Escherichia coli: Old problem, new pathology

Abstract

Iako se za prisustvo Escherichia coli u organizmu ljudi i životinja kao komensala zna odavno, tek u novije vreme joj se pridaje značaj kao uzročniku bolesti kod ljudi i životinja. Bolest koju izaziva ova bakterija vezuje se za nove varijante – sojeve (npr. verotoksični 0157: H7) koji zbog toksičnog delovanja imaju različitu patogenezu i kliničku sliku koja je do sada bila vezivana za klasičnu E. coli. Naime, dokazana je povezanost prisustva odre|enih sojeva ove bakterije kod životinja, kod kojih nema pojave kliničkih simptoma, i obolelih ljudi koji su dolazili u kontakt sa ovim životinjama. S obzirom na to da se infekcija sa E. coli prenosi i putem namirnica animalnog porekla, a u skladu sa važe}im pravilima o higijenskoj ispravnosti namirnica, sve više se pridaje značaj izolaciji i identifikaciji ove bakterije na klaničnoj liniji. Tako|e, prihva}ena je neophodnost skrininga (screening) u populaciji životinja, kao osnovnog koraka u kontroli i eradikaciji patogena. Podaci o rasprostranjenosti verotoksične E.coli i broju prijavljenih slučajeva infekcije kod ljudi u Srbiji su oskudni i ne daju pravu sliku epizootiološko-epidemiološke situacije. Verotoksična E.coli se u protekle dve decenije pojavila kao važan uzrok morbiditeta i mortaliteta kod ljudi i životinja. Zbog velikog broja slučajeva povezanih, direktno ili indirektno, sa namirnicama za ishranu ljudi, postojali su i veliki ekonomski gubici.

Even though the presence of Escherichia coli in the organism of humans and animals as a commensal has been known for a long time, attention has been paid to it only recently as the cause of diseases in humans and animals. The disease that is caused by this bacteria is linked to new variants-strains (eg. Verotoxic 0157:H7) which have, due to the toxic effects, a pathogensis and clinical picture that differs from those which have so far been linked to the conventional E.coli. Namely, it has been proved that there is a connection between the presence of certain strains of this bacteria in animals in which there is no occurrence of clinical symptoms, and diseased humans who had come into contact with these animals. Since infection with E.coli is transferred also through food items of animal origin, and in keeping with the valid regulations on hygiene safety of food items, increasing importance is placed on the isolation and identification of this bacteria on the slaughter line. It has also been accepted that it is necessary to apply screening among animal populations, as the basic step in the control and eradication of pathogens. There are few data on the distribution of verotoxic E.coli and the number of reported cases of infection in humans in Serbia, and they do not provide the real picture of the epizootiological-epidemiological situation. Verotoxic E.coli occurred over the past two decades as an important cause of morbidity and mortality in humans and animals. Due to the large number of cases that are linked, directly or indirectly, with food items of animal origin, there have been major economic losses as well.