General Assessment of Approaches to the Identification of Aquatic Bacterial Pathogens: A Methodological Review

Duman M., Altun S., Satıcıoğlu İ. B.

NORTH AMERICAN JOURNAL OF AQUACULTURE, vol.84, no.3, pp.1-10, 2022 (SCI-Expanded)

  • Publication Type: Article / Article
  • Volume: 84 Issue: 3
  • Publication Date: 2022
  • Doi Number: 10.1002/naaq.10260
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aqualine, Aquatic Science & Fisheries Abstracts (ASFA), BIOSIS, CAB Abstracts, Environment Index, Veterinary Science Database
  • Page Numbers: pp.1-10
  • Bursa Uludag University Affiliated: Yes


In the evolving biosphere, pathogenic microorganisms that cause disease may undergo phenotypic changes. While some of these changes result in new variants or mutants, others lead to the emergence of novel pathogens. Such phenotypic changes as well as advances in technology and analytical methods, and the identification of genomic sequences of microbial DNA have brought about new methodological approaches in the diagnosis of bacterial diseases. Although bacterial identification was originally based on phenotypic characteristics, later researchers claimed that bacteria could be accurately identified by only gene sequencing, and generally by the sequencing of the 16S rRNA gene region. Currently, there is still disagreement between classical microbiologists and those using new genomic sequence technology over the best method for identification. Fish are cold-blooded animals and fish pathogens generally exhibit psychrophilic characteristics. Many bacterial identification systems used to identify mesophilic bacteria remain useless for identifying fish pathogens because their optimum incubation temperatures are 35-37°C. Bacteria pathogenic to piscine species require specific media for their cultivation at lower incubation temperatures (15-28°C), and this limits both their growth in culture and subsequent identification by phenotype-based methods. This review presents a comprehensive overview of the isolation and identification of bacterial fish pathogens by optimal culture conditions, biochemical tests, colorimetric methods for rapid identification systems, MALDI-TOF MS, and immunological and molecular methods, as well as of the detection of uncultivable bacteria and the use of anamnesis. We concluded that the accurate identification of fish pathogens requires the use of different methods, including phenotype- and genotype-based tests, and the evaluation of anamnesis.