Genomic polymorphism of enterococcus faecalis isolated from clinical cases using two methods of ERIC-PCR and BOX-PCR

Background: The genome of Enterococcus has a large number of repetitive sequences that are randomly distributed over DNA. In ERIC-PCR, a separate pattern is obtained for each strain and is considered a separate type. Prokaryotic and eukaryotic genomes include dispersed repeat sequences that are relatively short non-coding, and dispersed in the bacterial genome. BOX-PCR and ERIC-PCR primers are complementary to these repeat sequences and allow for dedicated binding and unique BOX-PCR fingerprint patterns and ERIC-PCR with reproducibility capability.

Methods: In this cross-sectional descriptive study, based on previous studies and 95% confidence level using the formula n = z2P (1-P)/d2 and acceptable error 0.05, total of 60 Enterococcal Faecalis strains were cultured from sterile specimens on KF agar medium and incubated at 37°C for 24h and were identified by biochemical tests of suspected Enterococcal Faecalis. DNA samples were extracted and BOX-PCR and ERIC-PCR tests were performed.

Results: All strains were distinguished in 25 distinct clusters at the level of similarity of 58%. Also, by analyzing the ERIC-PCR results, all strains were segregated into 15 separate clusters at a similar level of 58%.

Conclusion: Molecular fingerprinting with BOX-PCR has a better subtraction and differentiation than ERIC-PCR for typing bacterial isolates and is widely used in epidemiological studies and trace source of infection and taxonomy.