en ميکروبيولوژي Microbiology پژوهشي Research <div style="text-align: justify;"><span style="font-size:11pt"><span style="line-height:150%"><span style="unicode-bidi:embed"><span calibri="" style="font-family:"><strong><span style="color:#0e101a">Background:</span></strong><em><span style="color:#0e101a">&nbsp;E. coli</span></em><span new="" roman="" style="font-family:" times="">&nbsp;O157:H7-related food poisoning is one of the most well-known causes of bloody diarrhea illness around the world. Therefore, devising a rapid, highly sensitive, and convenient detection technique for this species is crucial.&nbsp;In this work, we optimized a colorimetric Loop-mediated isothermal amplification (LAMP) for detecting&nbsp;the intimin gene from <em><span style="color:#0e101a">E. coli</span></em>&nbsp;O157:H7.</span></span></span></span></span><br> <span style="font-size:11pt"><span style="line-height:150%"><span style="unicode-bidi:embed"><span calibri="" style="font-family:"><strong><span style="color:#0e101a">Methods:</span></strong><span new="" roman="" style="font-family:" times="">&nbsp; In this study, <i>eae</i> (intimin), one of the virulence factors of <em><span style="color:#0e101a">E. coli</span></em>&nbsp;O157:H7, was selected as the target gene, and specific primers were designed for the sequence of this gene using the Primer Explorer V5 software. The LAMP reaction was optimized with three variable factors of MgSO₄ concentration, temperature, and incubation time,</span> <span new="" roman="" style="font-family:" times="">in a traditional (separate) way and by Taguchi </span><span lang="X-NONE" new="" roman="" style="font-family:" times=""><span style="color:black">experimental </span></span><span new="" roman="" style="font-family:" times="">design.</span> <span new="" roman="" style="font-family:" times="">Finally, the LAMP products were visualized by 2% agarose gel electrophoresis stained with ethidium bromide or green fluorescence (SYBR green I) and the pink fluorescence (KBC power load), which can be observed using the naked eye.&nbsp;</span></span></span></span></span><br> <span style="font-size:11pt"><span style="line-height:150%"><span style="unicode-bidi:embed"><span calibri="" style="font-family:"><strong><span style="color:#0e101a">Results:</span></strong><span new="" roman="" style="font-family:" times="">&nbsp;The LAMP reaction was optimized at 63&deg;C and 8 mM MgSO₄ for 40 min. Also, the naked eye can readily visualize the LAMP products within 40 minutes and have a detection limit of 3.2&times;10⁴ CFU/mL according to 0.38 fg from the genome. Designed primers based on the gene sequence proved their specificity by testing 4 species of other common foodborne pathogenic microorganisms.&nbsp;</span></span></span></span></span><br> <span style="font-size:11pt"><span style="line-height:150%"><span style="unicode-bidi:embed"><span calibri="" style="font-family:"><strong><span style="color:#0e101a">Conclusion:</span></strong><span new="" roman="" style="font-family:" times="">&nbsp;The rapid, sensitive, one-step-visually developed LAMP assay could be of interest for screening functions in food analytical laboratories without special equipment or trained personnel.</span></span></span></span></span><br> &nbsp;</div> Colorimetric LAMP assay, Food poisoning, E. coli O157:H7, Detection, Optimization. 115 122 http://rmm.mazums.ac.ir/browse.php?a_code=A-10-903-8&slc_lang=en&sid=1 Alaleh Valiallahi avaliallahi92@gmail.com 100319475328460011338 100319475328460011338 Yes Faculty of Chemistry and Chemical Engineering, Malek Ashtar University of Technology Mehdi Zeinoddini zeinoddini@modares.ac.ir 100319475328460011339 100319475328460011339 No Faculty of Chemistry and Chemical Engineering, Malek Ashtar University of Technology Shirin Jalili jalili.shirin@yahoo.com 100319475328460011340 100319475328460011340 No Research Institute of Law Enforcement Science and Social Studies, Tehran, Iran