Toxic Genes and Antibiotic Resistance Patterns in Vibrio Parahaemolyticus Isolates From Caught Fish of the Caspian Sea Publisher



Yazdanpanah E ; Rajabi Z ; Maftoon H ; Mirbagheri SZ ; Soltan Dalal MMS
Source: Archives of Razi Institute Published:2025

Abstract

Vibrio parahaemolyticus (V. parahaemolyticus) is a marine bacterium widely recognized as a predominant causative agent of bacterial foodborne outbreaks globally. The objective of our study was to determine the prevalence of toxin-producing genes and antibiotic resistance patterns in V. parahaemolyticus isolates obtained from fish caught in the Caspian Sea. We conducted a descriptive cross-sectional study, involving 220 fish samples from four fish species (Rutilus kutum, Mugilidae, Cyprinus carpio and Perca). Samples underwent enriched and culture for bacteriological and biochemical examination. Isolates were confirmed using the 16S rRNA flagella-specific gene of V. parahaemolyticus and then subjected to antimicrobial susceptibility testing using the diskdiffusion method. Additionally, PCR was employed to detect three virulence genes (toxR, tdh, and trh genes). Out of a total of 220 fish samples, 40 (18.2%) were found to be contaminated with V. parahaemolyticus. All 40 confirmed isolates possessed the toxR gene, and 29 (72.5%) harbored the tdh gene, while none of them contained the trh gene. The majority of the isolates were susceptible to ciprofloxacin (97.5%) and chloramphenicol (92.5%), but resistant to amoxicillin (95%) and doxycycline (95%). These findings provide valuable insights into microbial contamination of fish caught in the Caspian Sea and highlight the need for control measures due to the high prevalence of V. parahaemolyticus in seafood and the subsequent presence of multi drug resistance (MDR) isolates. © 2025 Elsevier B.V., All rights reserved.