Indian Journal of Animal Research
SCOPUSWeb of Science
  • Year: 2025
  • Volume: 59
  • Issue: 3

Prevalence, Antimicrobial Resistance and Resistance Gene Cassettes Detection in Bacterial Pathogens Isolated from Freshwater Ornamental Fishes

  • Author:
  • Nallaiah Hemamalini1,*, Seerappalli Aran Shanmugam1, Ayyathurai Kathirvelpandian2, Agarwal Deepak1, Venkatachalam Kaliyamurthi1, Eswaran Suresh1, Selvaram Ezhilmathi3
  • Total Page Count: 9
  • Page Number: 467 to 475

1Institute of Fisheries Post Graduate Studies, Tamil Nadu Dr. J. Jayalalithaa Fisheries University, Vaniyanchavadi, Chennai-603 103, Tamil Nadu, India

2ICAR-National Bureau of Fish Genetic Resources, PMFGR Centre, Kochi-682 018, Kerala, India

3Dr. M.G.R. Fisheries College and Research Institute, Ponneri-601 204, Tamil Nadu, India

*Corresponding Author: Nallaiah Hemamalini, Institute of Fisheries Post Graduate Studies, Tamil Nadu Dr. J. Jayalalithaa Fisheries University, Vaniyanchavadi, Chennai-603 103, Tamil Nadu, India, Email: hemamalini5695@gmail.com

Online Published on 07 July, 2025.

Abstract

Antimicrobial resistance (AMR) is a rising concern in the global aquaculture sector due to the rampant prophylactic use of antibiotics. This study is aimed to determine the AMR pattern in freshwater ornamental fishes.

Fish pathogens were isolated and identified from infected Guppy and Molly collected from ornamental fish farms. Antibiotic susceptibility testing (ABST) using disc diffusion with 36 antibiotics was performed following the disc diffusion method. The resistance gene cassettes such as Class 1 and Class 2 integron were also detected from resolved isolates.

Fish pathogens were isolated and identified as Aeromonas hydrophila, A. dhakensis, A. veronii, A. sobria, Bacillus subtilis, Comamonas testosteroni, Edwardsiella tarda, Enterobacter cloacae, Enterococcus faecalis, Kurthia gibsonii and Klebsiella aerogenes. Shannon Weiner diversity index of resolved isolates was found to be 1.366 and 2.101 for Guppy and Molly, respectively. ABST results showed an elevated resistance pattern for A. veronii, E. faecalis (Guppy), K. aerogenes, B. subtilis, E. faecalis, C. testosteroni (Molly) with higher multiple antibiotic resistance indexes (>0.33). Meanwhile, all the recovered isolates were susceptible to sulphafurazole, enrofloxacin, norfloxacin and ciprofloxacin. Detection of class 1 integron in genomic and plasmid DNA reminds the rapid spread of the AMR gene through horizontal gene transfer.

Keywords

Antimicrobial resistance, Fish pathogens, Integrons, Multiple antimicrobial resistance, Ornamental fish