en عفوني Infectious Diseases پژوهشي Research <div style="text-align: justify;"><strong>Background: </strong>The increasing resistance of human microbial pathogens to the available antibacterial compounds is a significant threat, resulting in the search for new antibiotic resources such as plants and probiotics. Therefore, this study aimed to evaluate the antibacterial effect of ethanolic and methanolic extracts of <em>Urtica dioica, Mentha longifolia</em>, and bacteriocin purified from a probiotic bacteria using the standard disk diffusion method against some pathogenic strains.<br> <strong>Materials&nbsp; and&nbsp; methods:</strong> Ethanolic/methanolic extract of <em>U.&nbsp; dioica,&nbsp; M.&nbsp; longifolia,</em> and bacteriocin from probiotic bacteria were prepared by the standard methods. The effect of different concentrations of the extracts on some antibiotic-resistant bacteria was evaluated using the standard disk diffusion method by measuring the diameter of the growth inhibition zone.<br> <strong>Results:</strong> The disk diffusion test showed that the bacteriocin <em>Lactobacillus casei</em> had more growth inhibitory effects on the tested bacterial strains than the methanolic and ethanolic extracts of <em>U.&nbsp; dioica</em>&nbsp; and <em>M.&nbsp; longifolia</em>. Bacteriocin extract of <em>L.&nbsp; casei</em> exhibited significant antibacterial activity at the concentrations of 12 and 18 mg/mL (P&le;0.05) against antibiotic-resistant bacteria, while a 12 mm zone of inhibition was observed in the concentration of 1.5 mg/mL against Salmonella&nbsp; enterica&nbsp; serovar Typhimurium (<em>S. Typhimurium</em>).<br> <strong>Conclusion:</strong> According to the agar well diffusion method results, the bacteriocin producing <em>L. casei</em> has an extensive range of antibacterial spectrum against resistant bacteria. It can be used as an alternative to antimicrobia agents for the treatment of infections caused by resistant bacteria. It is suggested that in future research, the cytotoxicity of the extracts be evaluated in vitro/in vivo studies.</div> Lactobacillus casei, Urtica dioica, Mentha longifolia, resistant bacteria 163 170 http://rmm.mazums.ac.ir/browse.php?a_code=A-10-1062-2&slc_lang=en&sid=1 Masoumeh Kiani m.kianii2018@gmail.com 10031947532846009136 10031947532846009136 No Department of microbiology, faculty of medicine, Shahid Sadoughi University of medical sciences, Yazd, Iran Abazar Pournajaf abazar¬_pournajaf@yahoo.com 10031947532846009137 10031947532846009137 No Infectious Diseases and Tropical Medicine Research Center, Health Research Center, Babol University of Medical Sciences, Babol, Iran Thelma Zareh thelmazareh@gmail.com 10031947532846009138 10031947532846009138 No University of Surrey, Business school, Guildford, United Kingdom Mohsen Karami karami158@yahoo.com 10031947532846009139 10031947532846009139 No Infectious Diseases and Tropical Medicine Research Center, Health Research Center, Babol University of Medical Sciences, Babol, Iran Mojtaba Taghizadeh Armaki mojtabataghizade@yahoo.com 10031947532846009140 10031947532846009140 No Infectious Diseases and Tropical Medicine Research Center, Health Research Center, Babol University of Medical Sciences, Babol, Iran Mehrdad Gholami mehrdad_gholami90@yahoo.com 10031947532846009141 10031947532846009141 Yes Department of Microbiology and Virology, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran