Characterization of Shiga toxigenic Escherichia coli isolated from foods.
The aim of this study was to characterize Shiga toxigenic Escherichia coli (STEC) by PCR using strains isolated from ham, beef, and cattle in Colombia. A total of 189 E. coli strains were tested for the presence of the uidA, stx1, and stx2 genes, and identification was confirmed by the automated PCR BAX system for E. coli O157:H7. Genes encoding Shiga-like toxins (stx) were found in eight (6.06%) of 132 strains previously isolated from minced beef; four (50%) of these strains yielded amplification products for both toxin genes (stx1 and stx2), and four (50%) yielded products only for the stx2 toxin. None of the strains analyzed were positive by PCR for the presence of the single base-pair mutation in the uidA gene from E. coli O157:H7; these results were confirmed by the BAX system analysis. A multiplex PCR assay was standardized for the three genes. Results from this study confirmed previous data about the low prevalence of E. coli O157:H7 and Shiga-like toxins in Colombia and is the first known report of the prevalence of non-O157 enterohemorrhagic E. coli in this country.
Martínez
Aida Juliana
AJ
Laboratory of Food Microbial Ecology (LEMA), Los Andes University kra. 1a 18A-10, Bogotá, Colombia.
Bossio
Carolina Paba
CP
Durango
Adriana Coral
AC
Vanegas
Maria Consuelo
MC
D003105:Colombia; D019453:Escherichia coli O157 / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D008461:Meat Products / Q000382:microbiology*; D009154:Mutation; D016133:Polymerase Chain Reaction / Q000379:methods*; D015995:Prevalence; D022622:Shiga Toxin 1 / Q000096:biosynthesis / Q000235:genetics; D022641:Shiga Toxin 2 / Q000096:biosynthesis / Q000235:genetics; D022603:Shiga Toxins / Q000096:biosynthesis / Q000235:genetics*; D054323:Shiga-Toxigenic Escherichia coli / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism
D022622:Shiga Toxin 1; D022641:Shiga Toxin 2; D022603:Shiga Toxins