ABSTRACT
A total of 33 local E. coli isolates were used in this study. These isolates were biochemically and serologically identified as O1, O2, O6, O78 and O126. Four sets of oligonucleotide primer sequences were designed specifically for 16SrRNA, STX, Sth and eaeA genes. DNA and Plasmids were extracted and polymerase chain reaction was optimized for each. 16SrRNA gene primer successfully amplified with all serotypes giving rise a product mass of 204 bp, while STX gene primer was amplified with O1, O2 an dO78 serotypes in a specific band at 323 bp. At the same time the specific primers of Sth gene get a 171 bp molecular weight product only with O6 serotype meanwhile the eaeA gene primers successfully amplified only with O126 serotype giving rise a molecular weight band at 200 bp. In conclusion, PCR assay was able to differentiate between the different serotypes of E. coli in the suspected samples saving time, money and effort