Background and purpose: E. coli bacteria is detected by culture, serology and molecular methods. In molecular methods PCR products are created using little random primers. The main purpose of this research was to study the genetic diversity of Escherichia coli bacteria. Also, the propinquity of isolated bacteria with two common strains of EnteroPathogenic E. coli (St.₁) and EnteroHaemorrhagic E. coli (St.₂) was studied.

Materials and methods: An experimental study was performed in which 50 E. coli bacteria were isolated from urine samples and re-identified using biochemical tests. DNA was extracted by a kit and PCR products were evaluated after electrophoresis. The matrix of one/zero of bands was entered in Excel and studied by NTSYS_PC2.02 and MVSP 3.2 programs.

Results: Eight primers were used from which 129 bands were produced. The highest number of bands were produced by primer 2 (n=24). We observed 42 polymorphic bands, 10 common bands in all primers, and 22 special bands in each primer. The largest band appeared in primer 1 (17.3 kb) and the smallest band was observed in primers 7 and 8 (80 bp). Based on UPGMA dendrogram pattern and PCoA 3D ordination, four isolates including 33, 47, 48 and 50 showed relative genetic propinquity with St.₁ and St.₂.

Conclusion: Drawing PCoA 3D ordination showed high genetic diversity in isolates, indicating different pollution centers in spreading the bacteria. Fingerprinting of isolates showed high repeatability in technique illustrating its high degree of accuracy and reliability.