Coinfections of Aeromonas spp., Enterococcus faecalis, and Vibrio alginolyticus isolated from farmed Nile tilapia and African catfish in Egypt, with an emphasis on poor water quality

Abdelsalam, Mohamed; Ewiss, M. A. Zaki; Khalefa, Hanan S.; Mahmoud, Mahmoud; Elgendy, Mamdouh Y.; Abdel-Moneam, Dalia A.

doi:10.1016/j.micpath.2021.105213

Cited by 38 publications

(15 citation statements)

References 31 publications

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“…These agents can cause serious infections and massive mortalities in farmed tilapia. Recently, A. hydrophila , V. alginolyticus , and V. cholera have been identified in Egyptian Nile tilapia farms affected by mass mortality episodes (Abdel‐moneam et al, 2021; Abdelsalam et al, 2021).…”

Section: Discussionmentioning

confidence: 99%

“…Poor water quality parameters, such as high‐water temperature, high organic loads, low dissolved oxygen, and extreme ammonia levels are potent stressors making aquatic animals susceptible to numerous infections (Ali et al, 2020; Elgendy, Soliman, et al, 2015). Fish reared in such poor conditions commonly have compromised immune defence mechanisms and therefore become susceptible to numerous secondary invaders (Abdelsalam et al, 2021).…”

Section: Discussionmentioning

confidence: 99%

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Genetic characterization and antimicrobial profiling of bacterial isolates collected from Nile tilapia (Oreochromis niloticus) affected by summer mortality syndrome

Ali

Mahana

Mohan

et al. 2022

Journal of Fish Diseases

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In recent years, Egyptian tilapia aquaculture has experienced mortality episodes during the summer months. The causative agents responsible for such mortalities have not been clearly identified. A total of 400 fish specimens were collected from affected tilapia farms within five Egyptian governorates. A total of 344 bacterial isolates were identified from the examined fish specimens. Bacterial isolates were grouped into seven genera based on API 20E results. The most prevalent pathogens were Aeromonas spp. (42%), Vibrio spp. (21%), and Streptococcus agalactiae (14.5%). Other emerging infections like, Plesiomonas shigelloides (10%), Staphyloccocus spp. (8%), Pseudomonas oryzihabitans, and Acinetobacter lwoffii (2.3%) were also detected. Sequence analysis of the 16S ribosomal RNA bacterial gene of some isolates, confirmed the phenotypic identification results. The analysis of antibiotic resistance genes revealed the presence of aac(6′)‐Ib‐cr (35.7%), blaCTX gene (23.8%), qnrS (19%), ampC (16.7%), floR (14.3%), sul1, tetA, and van.C1 (2.4%) genes in some isolates. The antimicrobia resistance gene, qac was reported in 46% of screened isolates. Bacterial strains showed variable virulence genes profiles. Aeromonas spp. harboured (act, gcat, aerA, lip, fla, and ser) genes. All Vibrio spp. possessed the hlyA gene, while cylE, hylB, and lmb genes, were detected in S. agalactiae strains. Our findings point to the possible role of the identified bacterial pathogens in tilapia summer mortality syndrome and highlight the risk of the irresponsible use of antibiotics on antimicrobial resistance in aquaculture.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Genetic characterization and antimicrobial profiling of bacterial isolates collected from Nile tilapia (Oreochromis niloticus) affected by summer mortality syndrome

Ali

Mahana

Mohan

et al. 2022

Journal of Fish Diseases

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“…In this study, dissolved oxygen and unionized ammonia values recorded during the eruption of the clinical disease were unfavourable. The vulnerability of fish to infections increased during their exposure to stressful circumstances, such as high stocking densities, inferior water quality, or abrupt changes in water quality measures [ 45 , 46 ]. Therefore, the unfavourable water quality parameters recorded during the mortalities were believed to have predisposed European seabass frys to reported pathogenic agents that worked in synergy to induce the recorded higher mortalities [ 10 , 46 ].…”

Section: Discussionmentioning

confidence: 99%

Mass kills in hatchery-reared European seabass (Dicentrarchus labrax) triggered by concomitant infections of Amyloodinium ocellatum and Vibrio alginolyticus

Ragab

Elgendy

Sabry

et al. 2022

International Journal of Veterinary Science and Medicine

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Amyloodiniosis and vibriosis are serious diseases in European seabass ( Dicentrarchus labrax ) hatcheries with noticeable high mortality. This study was conducted on tank-cultured D. labrax frys at a private marine hatchery near Mariout Lake (Alexandria, Egypt). Frys showed a high mortality rate (70%), lethargy, darkening, asphyxia, ascites, and velvety skin appearance. Both infectious agents were presumptively identified in all investigated frys. The identities of the two recovered agents were confirmed by molecular assay and phylogenetic analysis. On the tissue level, histopathological examination of skin, splenic, and renal tissue indicated severe alterations due to the direct impacts of both infections. On the cellular level, scanning electron micrographs showed both protozoal and bacterial pathogens on/in gill epithelial cells in solitary and colonial forms. Vibrio alginolyticus showed variable results for tested antibiotics, with a higher sensitivity to florfenicol. A successful control strategy was strictly adopted to overcome infections and stop mortalities. Copper sulphate and hydrogen peroxide were efficiently applied to tank water to overcome A. ocellatum infections. Further, florfenicol was effectively used to overcome systemic V. alginolyticus infections. The efficacy of treatments was confirmed by the absence of infectious agents in randomly collected fish samples. To the best of the authors’ knowledge, this study is one of the earliest Egyptian studies that dealt with the dilemma of mass kills associated with external parasitic/systemic bacterial infections among hatchery-reared European seabass.

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“…S. sciuri has poor host specificity and has been isolated from human skin, mastitis in cattle, diseased goats, dogs, rice, aquatic animals, and the aquatic environment ( Rahman et al., 2005 ; Abraham et al., 2017 ; Abdelsalam et al., 2021 ). This suggests that its ability to spread among animals, plants, and the environment should be taken seriously.…”

Section: Discussionmentioning

confidence: 99%

Staphylococcus sciuri causes disease and pathological changes in hybrid sturgeon acipenser baerii × acipenser schrencki

Zhang

Xue

Xiao

et al. 2022

Front. Cell. Infect. Microbiol.

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Hybrid sturgeon is the main species of sturgeon cultured in China, with the advantages of a fast growth rate, early sexual maturity, fertile offspring, and more stable genetic traits. In May 2021, a large number of deaths characterized by superficial hemorrhage and liver damage occurred in a sturgeon farm in Yichang, Hubei Province, which posed a significant risk to hybrid sturgeon captive breeding. We isolated a pathogenic bacterium named D-59 from the diseased sturgeon with apparent symptoms. The pathogen was identified as Staphylococcus sciuri using 16S rRNA gene phylogenetic analysis combined with biochemical identification. Regression experiments showed that D-59 exhibited clinical signs similar to those of diseased sturgeon in the farm after intraperitoneal injection into hybrid sturgeon. High-throughput sequencing of gut microbes in D-59-infected sturgeon showed that the number of gut microbial species decreased in infected sturgeon, the number of some intestinal commensal bacteria decreased, and the balance of the intestinal microorganisms was disrupted. Histopathological sections indicated many inflammatory cells, congestion, and even necrosis in the tissue of diseased sturgeon. Analysis of blood indexes revealed an increase in the proportion of mononuclear cells and a decrease in the proportion of lymphocytes in the peripheral blood of diseased sturgeon. Significantly elevated serum levels of aspartate aminotransferase and alanine aminotransferase, whereas alkaline phosphatase, total protein, albumin, and globulin were decreased in diseased sturgeon. Antimicrobial susceptibility tests demonstrated that D-59 is susceptible to florfenicol, enrofloxacin, and neomycin sulfate. This study aimed to highlight the dangers of Staphylococcus sciuri infection during hybrid sturgeon culture and to provide recommendations for diagnosis and treatment.

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Coinfections of Aeromonas spp., Enterococcus faecalis, and Vibrio alginolyticus isolated from farmed Nile tilapia and African catfish in Egypt, with an emphasis on poor water quality

Cited by 38 publications

References 31 publications

Genetic characterization and antimicrobial profiling of bacterial isolates collected from Nile tilapia (Oreochromis niloticus) affected by summer mortality syndrome

Genetic characterization and antimicrobial profiling of bacterial isolates collected from Nile tilapia (Oreochromis niloticus) affected by summer mortality syndrome

Mass kills in hatchery-reared European seabass (Dicentrarchus labrax) triggered by concomitant infections of Amyloodinium ocellatum and Vibrio alginolyticus

Staphylococcus sciuri causes disease and pathological changes in hybrid sturgeon acipenser baerii × acipenser schrencki

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