Comparing Fluorescent Loop-Mediated Isothermal Amplification and PCR in Detecting Salmonella

Background and Salmonella is a group of Enterobacterias that cause infectious diseases in human and animals. Typhoid, bacteremia, enterocolitis and salmonellosis which are caused by this bacterium are considered major health concerns in developing countries, such as Iran. Quick, accurate, reliable and early diagnosis is vital to prevent Salmonella outbreak. There are various diagnosis methods such as immunoassay and culture, PCR, and Real time PCR for detection of salmonella in contaminated samples. These methods require long time for diagnosis, numerous bacterial colonies, expensive laboratory equipments and expert lab personnel. Therefore, this study used a new method to avoid the disadvantages of previous methods. We used Loop-Mediated isothermal amplification of DNA (LAMP) with two fluorescent probes. Then it was compared with PCR. In this study four Salmonella isolations were used for PCR, LAMP, and LAMP using fluorescent probes. The time to identify Salmonella in PCR method was three hours compared to two hours in LAMP method, while this time reduced to 70 min using LAMP with fluorescent Prob. LAMP with two fluorescent probes is a fast, accurate, economic and practical method with more level of coverage in medical diagnosis laboratories, legal medicine, and agricultural researches. Other advantages of this method are temperature independency and no thermo cycling by replacement of PCR machine with simple and very cheap thermo block instrument. Moreover, detection is more accurate than turbidity detection in simple LAMP.