Identification and analysis of pathogenic bacteria causing outbreaks in Indian major carp aquaculture of Tripura

Abstract

ObjectiveThe objective of this study was to investigate bacterial disease outbreaks in Indian major carp from aquaculture systems in Tripura, India, and identify the bacterial species associated with these outbreaks.MethodsA 3‐year surveillance was conducted in 8 districts of Tripura, during which 9 bacterial disease outbreaks were recorded. Fourteen bacterial strains isolated from diseased Indian major carp were selected and identified using phenotypic, molecular (16S rRNA gene), and phylogenetic analysis. In‐vitro pathogenicity studies were performed to assess the potential pathogenicity of the isolated bacteria.ResultsThe selected isolated strains were preliminarily identified under the genera Aeromonas (9 isolates), Acinetobacter (1 isolate), Citrobacter (3 isolates), and Pseudomonas (1 isolate). Molecular and phylogenetic analysis confirmed the species of the isolated bacteria, including Aeromonas jandaei (with strains COF_AHE09 and COF_AHE61), Aeromonas veronii (with strains COF_AHE13, COF_AHE52, COF_AHE55, COF_AHE56, and COF_AHE62), Aeromonas hydrophila (with strains COF_AHE51 and COF_AHE58), Acinetobacter pittii (with strain COF_AHE14), Citrobacter freundii (with strains COF_AHE20, COF_AHE57, and COF_AHE59), and Pseudomonas aeruginosa (with strain COF_AHE54). Behavioral and clinical signs observed in the diseased fish, such as lethargy, skin hemorrhaging, ulcers, fin and tail rot, pop eye, distended abdomen, scale loss, and skin discoloration, indicated the presence of bacterial septicemia. The in‐vitro pathogenicity studies highlighted the potential role of these bacteria in disease development, especially under environmental stress.ConclusionThis study provides valuable insights into the diversity of bacterial species associated with bacterial disease outbreaks in Indian major carp from aquaculture systems in Tripura. It serves as the first comprehensive investigation of its kind, contributing to our understanding of bacterial infections in Indian major carp.

Identification and Antimicrobial Sensntivity Studies of Aeromonas Species Associated with Bacterial Septicemia of Esox lucius in Xinjiang, China

“…Although the main pathogen causing bacterial septicemia in freshwater fish is A. hydrophila, other pathogens may be involved, such as A. veronii (Legario et al, 2023), E. ictalurii (Chen et al, 2020), and A. jandaei (Mazumder et al, 2021). Mixed pathogenic infections have been reported in other cultivated fish; e.g., outbreak of bacterial septicemia in Indian carp caused by mixed infection by A. hydrophila and Pseudomonas aeruginosa (Laltlanmawia et al, 2023) and in wild-type zebrafish caused by A. hydrophila and A. veronii, with A. hydrophila being more pathogenic than A. veronii (Chandrarathna et al, 2018).A. hydrophila, A. jandaei, A. dhakensis isolated from freshwater ornamental fish showing signs of septicaemia (Jagoda et al, 2014).…”

“…MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions, or products referred to in the content. 2 2017), carp ( Laltlanmawia et al, 2023), and wild-type zebrafish (Chandrarathna et al, 2018); and hemorrhagic sepsis in these species (Janda, 1991).…”