Comparison of the PCR and LAMP Techniques in the Diagnosis of Salmonella Infection

Background and Objective: There are several techniques for the diagnosing of salmonella infectious. Several molecular methods such as PCR and hybridization assay have recently been used for the detection of this bacterium. However, these methods require precision instruments for amplification and complex procedures, which are the major obstacles to the widespread use of these methods in relatively small scale clinical laboratories, clinics and the filed laboratories. Recently, a new, rapid and sensitive technique called loop-mediated isothermal amplification (LAMP) was developed. Materials and Methods: In this study we used ۷ different strains of salmonella to compare the PCR with LAMP method. For PCR test we used thermocycler, but The LAMP reaction can be conducted under isothermal conditions by using only one type of enzyme and four primers recognizing six distinct regions. The most important merit of this method is that no denaturation of the DNA template is required, so, technique is simple and no need to thermocycler machine and several temperatures cycles. Results: Conventional PCR method for the detection of Salmonella with standard thermocylcer takes ۳ hrs but, with LAMP method we were able to amplify and detect the salmonella in very simple thermal block made in IRAN. After Optimization of the process it was possible to rapidly detect and identify Salmonella typhi bacteria within ۹۰ minutes. This method was also ۱۰۰ times more sensitive comparing to the PCR method. Conclusion: According to the results, comparing LAMP isothermal amplification method for detection and identification of Salmonella with conventional PCR we have been able to determine the simplicity, speed (۳ times) and the superior sensitivity(۱۰۰ times) of the LAMP to PCR method. This Method is more simple, faster and cheaper (۱۰ times). Another advantage is independence to cyclechr('۳۹')s temperature and thermo-cycling and replacement with one thermo block which is very simple, inexpensive and made in inside the country.

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Key Words: Salmonella ، Isothermal ، PCR ، DNA ، LAMP