Comparison of ERIC-PCR and RAPD-PCR Discrimination Power for Molecular Typing of Salmonella Typhimurium Isolates

Introduction: Determination of the molecular relationship among Salmonella isolates is important for epidemiological surveillance and control of infections caused by this bacterium. This study aimed to evaluate the discriminatory power of random amplification of enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) and random amplified polymorphic deoxyribonucleic acid-PCR (RAPD-PCR) methods for molecular typing of Salmonella Typhimurium. Methods: Twenty-two S. Typhimurium strains isolated from bovine fecal samples were assessed using ERIC-۱ and ERIC -۲ primers in ERIC-PCR and ۲۳L, P۱۲۵۴, and OPL۱۲ primers in RAPD-PCR methods. Results: Overall, ۹ electrophoretic patterns were observed in the ERIC-PCR of ۲۲ S. Typhimurium, whereas ۴, ۸, and ۱۳ patterns were obtained for ۲۳L, P۱۲۵۴, and OPL۱۲ primers in RAPD-PCR, respectively. For ERIC-PCR, the dendrogram drawn based on these patterns clustered the isolates in ۳ main clusters A, B, and C at ۸۰% similarity with the discrimination index (DI) of ۰.۹۸۲, while the representative values for ۳ RAPD-PCR primers were ۰.۹۲۵, ۰.۹۳۶, and ۰.۹۵۵, respectively. Conclusion: Our findings indicated that ERIC-PCR and RAPD-PCR are reliable, rapid, and powerful techniques for the epidemiological investigations of S. Typhimurium genotypes. However, ERIC-PCR DI was higher than all of the separately performed RAPD-PCR assays as well as DI calculated for cumulative RAPD-PCR results. Hence, ERIC-PCR can be used for the genotyping of S. Typhimurium isolates instead of RAPD-PCR. Nonetheless, composite analysis revealed that by simultaneous applying of both PCR methods, the DI can reach to ۰.۹۹۸, which was the highest DI among the evaluated approaches.