Bacterial Opportunistic Pathogens of Fish

Derôme, Nicolas; Gauthier, Jeff; Boutin, Sébastien; Llewellyn, Martin S.

doi:10.1007/978-3-319-28170-4_4

Cited by 59 publications

(39 citation statements)

References 175 publications

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“…Moreover, Proteobacteria also dominate the human skin microbiome [39] and have been suggested to play a role in managing opportunistic bacteria and regulating host-environment relationships [40]. This information is in agreement with the observed expansions of Flavobacteriaceae and other known opportunistic taxa [41] in SAV-infected fish with lowered Proteobacteria abundance.…”

Section: Discussionsupporting

confidence: 74%

Salmonid alphavirus infection causes skin dysbiosis in Atlantic salmon (Salmo salar L.) post-smolts

et al. 2017

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Interactions among host, microbiota and viral pathogens are complex and poorly understood. The goal of the present study is to assess the changes in the skin microbial community of Atlantic salmon (Salmo salar L.) in response to experimental infection with salmonid alphavirus (SAV). The salmon skin microbial community was determined using 16S rDNA pyrosequencing in five different experimental groups: control, 7 days after infection with low-dose SAV, 14 days after infection with low-dose SAV, 7 days after infection with high-dose SAV, and 14 days after infection with high-dose SAV. Both infection treatment and time after infection were strong predictors of the skin microbial community composition. Skin samples from SAV3 infected fish showed an unbalanced microbiota characterized by a decreased abundance of Proteobacteria such as Oleispira sp. and increased abundances of opportunistic taxa including Flavobacteriaceae, Streptococcaceae and Tenacibaculum sp. These results demonstrate that viral infections can result in skin dysbiosis likely rendering the host more susceptible to secondary bacterial infections.

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Section: Discussionsupporting

confidence: 74%

Salmonid alphavirus infection causes skin dysbiosis in Atlantic salmon (Salmo salar L.) post-smolts

et al. 2017

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“…Like mammals, the outer surfaces of fish play critical protective, regulatory and sensory roles, acting as the first line of defense ( Marshall and Bellamy, 2010 ; Peatman et al, 2015 ). However, as an added feature, the epithelia of the skin and gills are coated in a secretion of mucus that is continuously replaced, and comprises immunologically active molecules that arise from the underlying lymphoid tissues which parallel those of the gut, hindering opportunistic pathogens ( Magnadottir, 2010 ; Esteban, 2012 ; Rakers et al, 2013 ; Xu et al, 2013 ; Peatman et al, 2015 ; Derome et al, 2016 ). This mucus layer is also host to an array of indigenous microbiota in which bacteria are predominant ( Esteban, 2012 ; Llewellyn et al, 2014 ; Merrifield and Rodiles, 2015 ; Lokesh and Kiron, 2016 ).…”

Section: Introductionmentioning

confidence: 99%

The Inner Workings of the Outer Surface: Skin and Gill Microbiota as Indicators of Changing Gut Health in Yellowtail Kingfish

et al. 2018

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The mucosal surfaces and associated microbiota of fish are an important primary barrier and provide the first line of defense against potential pathogens. An understanding of the skin and gill microbial assemblages and the factors which drive their composition may provide useful insights into the broad dynamics of fish host–microbial relationships, and may reveal underlying changes in health status. This is particularly pertinent to cultivated systems whereby various stressors may led to conditions (like enteritis) which impinge on productivity. As an economically important species, we assessed whether the outer-surface bacterial communities reflect a change in gut health status of cultivated Yellowtail Kingfish (Seriola lalandi). Active bacterial assemblages were surveyed from RNA extracts from swabs of the skin and gills by constructing Illumina 16S rRNA gene amplicon libraries. Proteobacteria and Bacteroidetes were predominant in both the skin and gills, with enrichment of key β-proteobacteria in the gills (Nitrosomonadales and Ferrovales). Fish exhibiting early stage chronic lymphocytic enteritis comprised markedly different global bacterial assemblages compared to those deemed healthy and exhibiting late stages of the disease. This corresponded to an overall loss of diversity and enrichment of Proteobacteria and Actinobacteria, particularly in the gills. In contrast, bacterial assemblages of fish with late stage enteritis were generally similar to those of healthy individuals, though with some distinct taxa. In conclusion, gut health status is an important factor which defines the skin and gill bacterial assemblages of fish and likely reflects changes in immune states and barrier systems during the early onset of conditions like enteritis. This study represents the first to investigate the microbiota of the outer mucosal surfaces of fish in response to underlying chronic gut enteritis, revealing potential biomarkers for assessing fish health in commercial aquaculture systems.

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“…Previous research has shown that the seawater environment contains up to 10 7 organisms per milliliter [ 3 ], and therefore, represents a rich source of microbes that, under certain conditions, can have negative effects on the host. A delicate balance exists between commensal and opportunistic pathogens, however under certain conditions such as disease or poor environmental conditions this microbial balance can be lost, leading to a dysbiosis where opportunistic species dominate [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

Bacteriomic Profiling of Branchial Lesions Induced by Neoparamoeba perurans Challenge Reveals Commensal Dysbiosis and an Association with Tenacibaculum dicentrarchi in AGD-Affected Atlantic Salmon (Salmo salar L.)

2020

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Amoebic gill disease is a parasitic condition that commonly affects marine farmed Atlantic salmon. The causative agent, Neoparamoeba perurans, induces a marked proliferation of the gill mucosa and focal superficial necrosis upon branchial lesions. The effect that amoebic branchialitis has upon gill associated commensal bacteria is unknown. A 16S rRNA sequencing approach was employed to profile changes in bacterial community composition, within amoebic gill disease (AGD)-affected and non-affected gill tissue. The bacterial diversity of biopsies with and without diseased tissue was significantly lower in the AGD-affected fish compared to uninfected fish. Furthermore, within the AGD-affected tissue, lesions appeared to contain a significantly higher abundance of the Flavobacterium, Tenacibaculum dicentrarchi compared to adjunct unaffected tissues. Quantitative PCR specific to both N. perurans and T. dicentrarchi was used to further examine the co-abundance of these known fish pathogens. A moderate positive correlation between these pathogens was observed. Taken together, the present study sheds new light on the complex interaction between the host, parasite and bacterial communities during AGD progression. The role that T. dicentrarchi may play in this complex relationship requires further investigation.

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Bacterial Opportunistic Pathogens of Fish

Cited by 59 publications

References 175 publications

Salmonid alphavirus infection causes skin dysbiosis in Atlantic salmon (Salmo salar L.) post-smolts

Salmonid alphavirus infection causes skin dysbiosis in Atlantic salmon (Salmo salar L.) post-smolts

The Inner Workings of the Outer Surface: Skin and Gill Microbiota as Indicators of Changing Gut Health in Yellowtail Kingfish

Bacteriomic Profiling of Branchial Lesions Induced by Neoparamoeba perurans Challenge Reveals Commensal Dysbiosis and an Association with Tenacibaculum dicentrarchi in AGD-Affected Atlantic Salmon (Salmo salar L.)

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