Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 13 6 2021 12 15 793 800 Mohammad Sholeh Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran Ebrahim Kouhsari Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran; Laboratory Sciences Research Center, Golestan University of Medical Sciences, Gorgan, Iran Malihe Talebi Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran Masoumeh Hallajzadeh Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran Forough Godarzi Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran Nour Amirmozafari Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran 2021 04 11 2021 08 12 Background and Objectives: Due to the reduced susceptibility of clinical Clostridioides difficile strains in hospitals to various antimicrobial agents, the importance of antimicrobial susceptibility testing (ASTs) has increased. This study aimed to investigate the toxin gene profiles and the antimicrobial resistance of C. difficile isolated from hospitalized patients suspected of having Clostridioides difficile infection (CDI) in Tehran, Iran. Materials and Methods: The stool samples were obtained from a hospitalized patients. The samples were shocked by alcohol and the patients cultured on cycloserine-cefoxitin-fructose agar in anaerobic Conditions. Toxin assay was performed for detection of toxinogenic isolates. An antibiotic susceptibility test was done. Furthermore, their genome was extracted for PCR to confirm C. difficile and detect toxin gene profile. Results: Toxigenic C. difficile were identified in 21 of the 185 stool samples (11.3%). PCR detected seven toxin gene profiles; the highest prevalence was related to tcdA+B+, cdtA+B- toxin gene profile (57.1%). There were 14.3% and 28.6% resistant rates of the isolates towards vancomycin and metronidazole with the toxin gene profiles; tcdA+B+, cdtA±B+; and tcdA+B-, cdtA-B+. All resistant isolates to moxifloxacin, clindamycin, and tetracycline were belonged to the toxin gene profiles; tcdA+B+, cdtA+B+; tcdA+B+, cdtA+B-, and tcdA-B+, cdtA+B-. Conclusion: Relative high resistance was detected towards metronidazole and vancomycin, although, still have acceptable activity for CDI treatment. However, a proper plan for the use of antibiotics and more regular screening of C. difficile antibiotic resistance seems necessary. https://ijm.tums.ac.ir/index.php/ijm/article/view/3091 https://ijm.tums.ac.ir/index.php/ijm/article/download/3091/1407