Document Type : Original Article


Department of Fisheries Health, Central Fisheries Research Institute, Trabzon, Turkiye


Russian sturgeon (Acipenser gueldenstaedtii) is an endangered fish species and also an important resource for the sturgeon aquaculture industry in Turkiye. Recently, a fatal and persistent bacterial disease occurred in the reared sturgeon kept in a trout farm in Turkiye. The disease outbreak has been with notable external signs including petechial hemorrhages and systemic anemia. This outbreak lasted for six weeks, and cumulative mortality reached around 35.00 - 40.00%. In this study, no parasitic and viral agents were observed in the sturgeons. Citrobacter gillenii was isolated from the diseased fish and identified by biochemical and molecular methods including API 20E and 20NE and 16S rRNA gene region sequencing, respectively. As a result, C. gillenii was identified for the first time in Russian sturgeon in Turkiye. The sequence was also deposited under the Genbank with MW057770 accession number. According to the result of disc diffusion method, bacteria were sensitive to enrofloxacin, streptomycin, amoxicillin and oxytetracycline and resistant to penicillin, trimethoprim/sulfamethoxazole, florfenicol and erythromycin. Also, ampC, sul1 and floR resistance genes were detected in the isolated bacteria. The results of this study provide important information for the diagnosis and treatment of this newly emerged disease of Russian sturgeon.


  1. TurkStat Turkey Statistical Institute. Available at: Access date: 15. 08.2018.
  2. Dadras H, Hayatbakhsh MR, Golpour A. Dietary administration of common sage (Salvia officinalis) and coneflower (Echinacea angustifolia) extracts affects growth, blood parameters and ımmune responses of beluga, Huso huso. Turk J Fish Aquat Sci 2020; 20(5): 367-374.
  3. Rahmati‐Holasoo H, Soltani M, Masoudifard M, et al. Nephroblastoma in bester sturgeon, a cultured hybrid of Huso huso × Acipenser ruthenus: Diagnostic imaging, clinical and histopathological study. J Fish Dis 2018; 41(7): 1093-1101.
  4. Radosavljević V, Milićević V, Maksimović-Zorić J, et al. Sturgeon diseases in aquaculture. Vet Arh 2019; 12(1): 5-20.
  5. Akbulut B, Zengin M, Çiftçi Y, et al. Stimulating sturgeon conservation and rehabilitation measures in Turkey: an overview of major projects (2006-2009). J Appl Ichthyol 2011; 27(2): 415-419.
  6. Ture M, Ozcelep T, Akbulut B. et al. Disease of Russian sturgeon (Acipenser gueldenstaedtii) caused by Aeromonas Genet Aquat Org 2018; 2(2): 43-47.
  7. Xu J, Zeng X, Jiang N, et al. Pseudomonas alcaligenes infection and mortality in cultured Chinese sturgeon, Acipenser sinensis. Aquaculture 2015; 446(1): 37-41.
  8. Kayiş Ş, Er A, Kangel P, et al. Bacterial pathogens and health problems of Acipenser gueldenstaedtii and Acipenser baerii sturgeons reared in the eastern Black Sea region of Turkey. Iran J Vet Res 2017; 18(1): 18-24.
  9. Sanz Rainbow trout mortalities associated with a mixed infection with Citrobacter freundii and IPN virus. Bull Eur Ass Fish Pathol 1991; 11(1): 222-224.
  10. Sato N, Yamane N, Kawamura T. Systemic Citrobacter freundii infection among Sunfish mola mola in Matsushima aquarium. Nippon Suisan Gakkai Shi 1982; 48(11): 1551-1557.
  11. Öztürk RC, Altınok I. Bacterial and viral fish diseases in Turkey. Turk J Fish Aquat Sci 2014; 14(4): 275-229.
  12. Kayis S, Capkin E, Fikri B, et al. Bacteria in rainbow trout (Oncorhynchus mykiss) in the Southern Black Sea Region of Turkey - a survey. Isr J Aquac 2009; 61(4): 339-344.
  13. Duman M, Saticioglu IB, Buyukediz AG, et al. Molecular characterization and antimicrobial resistance profile of atypical Citrobacter gillenii and Citrobacter isolated from diseased rainbow trout (Oncorhynchus mykiss). J Glob Antimicrob Resist 2017; 10: 136-142.
  14. OIE, Fish Diseases Commission. Diagnostic Manual for aquatic animal diseases. 2000. Available at: Accessed 09 Aug, 2022.
  15. Altuntaş C, Ogut H. Monthly occurrence and prevalence of viral haemorrhagic septicaemia virus (VHSV) in whiting Merlangius merlangus. Dis Aquat Organ 2010. 88(2): 107-113.
  16. Ture M, Altinok I, Alp H. Effects of cage farming on antimicrobial and heavy metal resistance of Escherichia coli, Enterococcus faecium, and Lactococcus garvieae. Microb Drug Resist 2018; 24(9): 1422-1430.
  17. CLSI 2014. Clinical and laboratory standards institute. Performance standards for antimicrobial susceptibility testing; Twenty-Fourth ınformational supplement, M100-S24. Available at: Accessed 09 Aug, 2022.
  18. Capkin E, Terzi E, Altinok I. Occurrence of antibiotic resistance genes in culturable bacteria isolated from Turkish trout farms and their local aquatic environment. Dis Aquat Organ 2015; 114(2): 127-137.
  19. Marshall B, Tachibana C, Levy SB. Frequency of tetracycline resistance determinant classes among lactose-fermenting coliforms. Antimicrob Agents Chemother 1983; 24(6): 835-840
  20. Ounissi H, Courvalin P. Nucleotide-sequence of the gene ereA encoding the erythromycin esterase in Escherichia coli. Gene 1985; 35(3): 271-278
  21. Kerrn MB, Klemmensen T, Frimodt-Møller N, et al. Susceptibility of Danish Escherichia coli strains isolated from urinary tract infections and bacteraemia, and distribution of sul genes conferring sulphonamide resistance. J Antimicrob Chemother 2002; 50(4):513-516.
  22. Van TT, Chin J, Chapman T, et al. Safety of raw meat and shellfish in Vietnam: an analysis of Escherichia coli isolations for antibiotic resistance and virulence genes. Int J Food Microbiol 2008; 124(3): 217-223.
  23. Schmidt AS, Bruun MS, Larsen JL, et al. Characterization of class 1 integrons associated with R-plasmids in clinical Aeromonas salmonicida isolates from various geographical areas. J Antimicrob Chemother 2001, 47(6): 735-743.
  24. Olesen I, Hasman H, Aarestrup FM. Prevalence of beta-lactamases among ampicillin-resistant Escherichia coli and Salmonella isolated from food animals in Denmark. Microb Drug Resist 2004;10(4): 334-340.
  25. Schwartz T, Kohnen W, Jansen B, et al. Detection of antibiotic-resistant bacteria and their resistance genes in waste water, surface water, and drinking water biofilms. FEMS Microbiol Ecol 2003; 43(3): 325-335.
  26. Weisburg WG, Barns SM, Pelletier DA, et al. 16S ribosomal DNA amplification for phylogenetic study. J Bacteriol 1991; 173(2): 697-703.
  27. Hall TA. BioEdit: A user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT. Nucleic Acids Symp Ser 1999; 4(1): 95-98.
  28. Thompson JD, Higgins DG, Gibson. CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequence weighting, position-specific gap penalties and weight matrix choice. Nucleic Acids Res 1994; 22(22), 4673-4680.
  29. Kumar S, Stecher G, Li M, et al. MEGA X: molecular evolutionary genetics analysis across computing platforms. Mol Biol Evol 2018; 35(6): 1547-1549.
  30. Saitou N, Nei M. The neighbor-joining method: a new method for reconstructing phylogenetic trees. Mol Biol Evol1987; 4(4): 406-425.
  31. Kimura M. A simple method for estimating evolutionary rate of base substitutions through comparative studies of nucleotide sequences. J Mol Evol1980: 16(2): 111-120.
  32. Felsenstein J. Confidence limits on phylogenies: An approach using the bootstrap. Evolution 1985; 39(4): 783-791.
  33. Sağlam YS, Işik N, Arslan A, et al. Aeromonas hydrophila and Yersinia ruckeri ısolations and pathological examinations of the rainbow trout (Oncorhynchus mykiss 1792) in Erzurum Region [Turkish]. Atatürk Üniversitesi Vet Bil Derg 2006; 1(1-2): 6-10.
  34. Aoki T, Takahashi A. Class D tetracycline resistance determinants of R plasmids from the fish pathogens Aeromonas hydrophila, Edwardsiella tarda, and Pasteurella piscicida. Antimicrob. Agents. Chemother 1987; 31(8): 1278-1280.
  35. Ture M, Alp H. Identification of bacterial pathogens and determination of their antibacterial resistance profiles in some cultured fish in Turkey. J Vet Res. 2016; 60(2): 141-146.