en Infectious disease (Molecular and Cellular aspects) Infectious disease (Molecular and Cellular aspects) Original Article Original Article Cholera is an infection of the small intestines caused by the bacterium V. cholerae. It is a major cause of health threat and also a major cause of death worldwide and especially in developing countries. The major virulence factor produced by V. cholerae during infection is the cholera toxin. Total mRNA extraction and reverse transcription was performed for making ctxAB cDNA. Relative Real-Time PCR analysis showed unequal enterotoxin production in V. cholerae strains. The results showed that, classical strain produces cholera toxin more than El Tor strain. Vibrio cholerae, RT-qPCR, ctxAB expression 9 13 http://ijmcmed.org/browse.php?a_code=A-10-70-1&slc_lang=en&sid=1 Seyed Mahmoud Amin Marashi parsmicrob@gmail.com 10031947532846003663 10031947532846003663 No Cellular and Molecular Biology Research Center (CMBRC), Babol University of Medical Sciences, Babol, Iran. Ramazan Rajabnia Ramazan69@yahoo.com 10031947532846003664 10031947532846003664 No Infectious Diseases & Tropical Medicine Research Center, Department of Microbiology and Immunology, Babol University of Medical Sciences, Babol, Iran. Abbas Ali Imani Fooladi Imanifouladi.a@gmail.com 10031947532846003665 10031947532846003665 No Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran. Zohreh Hojati z.hojati@sci.ui.ac.ir 10031947532846003666 10031947532846003666 No Genetics Division, Biology Department, Faculty of Sciences, University of Isfahan, Isfahan, Iran. Sharareh Moghim sh_moghim@yahoo.com 10031947532846003667 10031947532846003667 No Department of Microbiology, Isfahan University of Medical Sciences, Isfahan, Iran. Bahram Nasr Esfahani Nasr@hlth.mui.ac.ir 10031947532846003668 10031947532846003668 Yes Department of Microbiology, Isfahan University of Medical Sciences, Isfahan, Iran.