University of Isfahan Journal of Microbial Biology 3060-7647 6 23 2017 09 23 A rapid and specific detection of pathogenic serovar Salmonella typhimurium by loop-mediated isothermal amplification method (LAMP) A rapid and specific detection of pathogenic serovar Salmonella typhimurium by loop-mediated isothermal amplification method (LAMP) 85 94 21665 10.22108/bjm.2017.21665 FA Hadi Ravan Assistant professor of Biochemistry, Department of Biology, Faculty of Science, Shahid Bahonar University of Kerman, Kerman, Iran Mojdeh Amandadi M.Sc. student of Biochemistry, Department of Biology, Faculty of Science, Shahid Bahonar University of Kerman, Kerman, Iran Journal Article 2016 05 03 Introduction:Salmonella serovar typhimurium is one of the most important foodborne pathogens and common causes of salmonellosis that in some conditions lead to septicemia or even death in humans. Therefore, the present study sought to detect this pathogenic serovar using loop-mediated isothermal amplification (LAMP) assay. Materials and methods: In the present study, six special primers were used to amplify STM4497 gene and accordingly to detect Salmonella typhimurium strains. The detection of the amplified products was performed by both turbidity and gel electrophoresis methods. Furthermore, the efficiency of LAMP assay for the detection of Salmonella typhimurium strains was examined in several artificially contaminated chicken meat samples. Results: The specificity of the assay was evaluated by various isolates of Salmonella and non-Salmonella, and positive results were only obtained from Salmonella typhimurium isolates. The detection limit of the assay was determined to be 10 CFU/reaction, which was lower than the previously developed competing assays. The results of the assay on artificially contaminated chicken meats showed that this assay enables detecting Salmonella typhimurium strains with a detection limit 103 CFU/mL without pre-enrichment and 10 CFU/mL after a four-hour pre-enrichment. Discussion and conclusion: As a result of a high sensitivity and specificity of the method as well as its low cost per assay, it could be concluded that the present LAMP assay is a powerful, accurate, and efficient method for detecting pathogenic serovar Salmonella typhimurium in food-processing industries and diagnostic laboratories. Introduction:Salmonella serovar typhimurium is one of the most important foodborne pathogens and common causes of salmonellosis that in some conditions lead to septicemia or even death in humans. Therefore, the present study sought to detect this pathogenic serovar using loop-mediated isothermal amplification (LAMP) assay. Materials and methods: In the present study, six special primers were used to amplify STM4497 gene and accordingly to detect Salmonella typhimurium strains. The detection of the amplified products was performed by both turbidity and gel electrophoresis methods. Furthermore, the efficiency of LAMP assay for the detection of Salmonella typhimurium strains was examined in several artificially contaminated chicken meat samples. Results: The specificity of the assay was evaluated by various isolates of Salmonella and non-Salmonella, and positive results were only obtained from Salmonella typhimurium isolates. The detection limit of the assay was determined to be 10 CFU/reaction, which was lower than the previously developed competing assays. The results of the assay on artificially contaminated chicken meats showed that this assay enables detecting Salmonella typhimurium strains with a detection limit 103 CFU/mL without pre-enrichment and 10 CFU/mL after a four-hour pre-enrichment. Discussion and conclusion: As a result of a high sensitivity and specificity of the method as well as its low cost per assay, it could be concluded that the present LAMP assay is a powerful, accurate, and efficient method for detecting pathogenic serovar Salmonella typhimurium in food-processing industries and diagnostic laboratories.

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