Tarbiat Modares University Infection Epidemiology and Microbiology 2588-4107 12 1 2026 02 01 Microbial Isolation and Comparison of Antibiotic Resistance Pattern in Rainbow Trout (Oncorhynchus mykiss) from Chaharmahal-va-Bakhtiari Province, Iran (2022-2023) 77 85 28719 10.66224/iem.12.1.77 EN Maryam Karimi-Dehkordi Department of Veterinary, Shk.C., Islamic Azad University, Shahrekord, Iran 0000-0001-6086-2014 Mohammad Ghasemi Shamsabadi Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord, Iran Majid Gholami-Ahangaran Department of Veterinary, Shk.C., Islamic Azad University, Shahrekord, Iran Journal Article 2025 10 05 Background: Increased antibiotic resistance due to the overuse and misuse of antibiotics is a severe threat to both the aquaculture industry and human health. This study aimed to determine the antibiotic resistance pattern of bacteria isolated from rainbow trout. Materials & Methods: A total of 79 and 120 fish samples were collected in 2022 and 2023, respectively. Swab samples were enriched in TSB (tryptic soy broth) and cultured on TSA (tryptic soy agar). The grown colonies were evaluated for Aeromonas hydrophila, Lactococcus garvieae, Streptococcus iniae, and Yersinia ruckeri. Antibiotic resistance patterns against 10 common antibiotics were evaluated. Findings: In this study, four types of bacteria (A. hydrophila, L. garvieae, S. iniae, and Y. ruckeri) were isolated. The results of antibiotic resistance analysis during 2022-2023 showed that in all isolated bacteria, the percentage of antibiotic resistance against enrofloxacin and florfenicol was higher in 2023 than in 2022. Conclusion: The isolated bacteria had different resistance patterns, these patterns could be used as a guide for selecting appropriate antibiotics to control infectious diseases in rainbow trout. This finding may be due to improper administration of these antibiotics in rainbow trout production.

https://iem.modares.ac.ir/article_28719_19f560c0fc2e02c530e64152bb9ec137.pdf