Background:
Verotoxin-producing E. coli (VTEC) is known as the major cause of hemorrhagic colitis and hemorrhagic uremic syndrome. The most common method of detecting VTEC is to detect serotype O157. since 50-80% of VTEC belong to serotype O157. The
conventional method of detecting E. coli O157 is the identification of colorless colonies on the sorbitol-MacConkey agar and the agglutination test with E. coli O157 antiserum. But the culture method for verotoxin assay is too complicated for
general
laboratory to perform as routine test. In order to confirm verotoxin-producing strain, we performed a polymerase chain reaction (PCR) amplification of the verotoxin gene.
Methods:
PCR amplification was performed on a colony detected E. coli O157, using the two sets of primer pairs to amplify fragments of the genes coding verotoxin 1 and vertoxin2, respectively.
Results:
Identification results of Vitek GNI card was E. coli, possible O 157 : H7 as code number of 3001641366, showing sorbitol-negative, lysine decarboxylase-positive and ornithine decarboxylase-positive. An 130 bp-sized segment and a 220 bp-sized
segment
were amplified. The 130 bp segment corresponded to the verotoxin 1 gene, but the significance of the other segment was unclear.
Conclusions:
The PCR method we have described here may be helpful to detected VTEC from the stool directly and to detect VTEC other than E. coli O157 and sorbitol fermenter E. coli O157 as well as sorbitol nonfermenter E. coli O 157.
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