Wystepowanie i charakterystyka siczepÓw Escherichia coli grupy 0157 pochodzących od prosiąt z biegunką

Shiga toxin-producing Escherichia coli (STEC) have been identified as the cause of serious human diseases -hemorrhagic colitis and haemolytic ureic syndrome. The most common serotype implicated in these disorders is E. coli O157:H7 or O157:H7. Cattle appear to be the main reservoir of STEC but other animal species have also been shown to carry these bacteria. In the present study E. coli isolated from weaned pigs with diarrhoea were tested for the rfb O157 gene responsible for biosynthesising E. coli O157 lipopolysaccharide (LPS). It was discovered that 26 out of 270(9.6%) strains tested were of the O157 serogroup but none of them possessed the fliC flagellar (H7) gene. The O157-positive isolates were further analysed by PCR for the presence of STEC virulence marker genes (Shiga toxins, intimin and enterohemolysin) as well as for enterotoxin and funbrial traits. The results of the study show that 10 strains had shiga toxin genes, either stx1 (6 strains) or stx2 (4 isolates); 6 stx1-positive strains also possessed the eae (intimin) genetic marker. Moreover, 2 strains had the ehly (enterohemolysin) gene. The results obtained indicate that pigs may be considered to be a reservoir of E. coli O157 bacteria, which possess several virulence markers potentially pathogenic for humans.