Towards Control of<i>Streptococcus iniae</i>

Baiano, Justice C.F.; Barnes, Andrew C.

doi:10.3201/eid1512.090232

Cited by 88 publications

(74 citation statements)

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“…Vaccination against S. iniae is accomplished using formalin inactivated bacterins by intraperitoneal injection of fish under general anaesthetic in tilapia 12 , trout 13 , grouper 9 based on analysis of the first available genome sequences 21 , but these have not been uniformly effective [22][23][24] . With the falling cost of whole genome sequencing, using informatics to identify surface associated and secreted proteins that are conserved across different capsular serotypes has become a fast and cost-effective route to new experimental vaccines that may be cross-protective across multiple serotypes.…”

Section: Oleksandra Silayevamentioning

confidence: 99%

Vaccination against streptococcal infections in farmed fish

Barnes

Silayeva

2016

Microbiol. Aust.

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Aquaculture produces more than 50% of fish for human consumption and, in spite of major improvements since the adoption of injectable vaccines in the 1990s, bacterial diseases still account for considerable losses, particularly in tropical and warm temperate species. Streptococcosis, caused predominantly by Streptococcus iniae and S. agalactiae, manifests as a generalised septicaemia and meningitis followed by rapid mortality. Vaccination against streptococcal infections is difficult as a result of multiple, poorly defined serotypes and consequent vaccine escape (reinfection of previously vaccinated animals). However, genomics applied to reverse vaccinology is providing novel insights into diversity among these aquatic pathogens and is identifying cross-serotype targets that may be exploited for new generation streptococcal vaccines for aquaculture.Aquaculture reached a significant milestone in 2013 as global production for food use overtook beef production for the first time and now accounts for more than 50% of the global seafood supply 1 .Aquaculture has wrestled with social license throughout its rapid growth in developed economies, including Australia, through the

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Section: Oleksandra Silayevamentioning

confidence: 99%

Vaccination against streptococcal infections in farmed fish

Barnes

Silayeva

2016

Microbiol. Aust.

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“…The common histopathologic characteristics of infected fish are septicaemia and meningitis, resulting in high mortality in farmed fish and enormous economic losses in aquaculture [3]. The pathogen could also opportunistically infect elderly humans associated with the handling and preparation of infected fish [4]. While several studies have been conducted on S. iniae, attention to date has mainly focused on the so-called virulence factors SiM protein [2,5].…”

Section: Introductionmentioning

confidence: 99%

Comparative genome analysis of Streptococcus iniae DX09 reveals new insights into niche adaptation and competitive host colonisation ability

Liu¹,

Wang²,

Wang³

2017

Oncotarget

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Streptococcus iniae is a significant pathogen in a variety of marine and freshwater cultured fish species. Previous investigations on S. iniae have been limited to a single virulence gene or genome. However, different strains are associated with varying pathogenicity and niche adaptation properties. For comprehensive characterization of the genetic variations in S. iniae, whole-genome sequencing of S. iniae DX09 (isolated from diseased catfish) was performed and comparative genome analysis with eight S. iniae strains conducted to determine the virulence evolution patterns. Comparative analysis of all sequenced S. iniae revealed genome-genome variations, mainly in two plasticity zones, within genes encoding specific functions, such as the Ess/type VII secretion system and phosphoenolpyruvate-carbohydrate phosphotransferase system, reflecting adaptation to colonisation of specific host habitats. The plasticity zones analyzed in the S. iniae genome may be a paradigm rather than a unique combination of horizontal gene transfer and underlie the emergence of pathogenic Gram-positive bacteria.

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“…Many instances of zoonoses have been reported as a result of handling infected fish, which typically results in a bacteremic cellulitis (17,28,56). The severity of an S. iniae infection is due in part to the ability to rapidly disseminate from the site of infection through the bloodstream and invade systemic tissues (34).The complex pathogenicity of S. iniae, and other systemic streptococcal pathogens, is reflected in the diversity of genes that are critical to a successful infection (3,22,55). Several classical streptococcal virulence factors have been shown to be important for the virulence of S. iniae, including the SivS/Rregulated streptolysin S (sagA) and CAMP factor (cfi) (4, 31), as well as the major surface M protein (siM) (30).…”

mentioning

confidence: 99%

“…The complex pathogenicity of S. iniae, and other systemic streptococcal pathogens, is reflected in the diversity of genes that are critical to a successful infection (3,22,55). Several classical streptococcal virulence factors have been shown to be important for the virulence of S. iniae, including the SivS/Rregulated streptolysin S (sagA) and CAMP factor (cfi) (4, 31), as well as the major surface M protein (siM) (30).…”

mentioning

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The Streptococcus iniae Transcriptional Regulator CpsY Is Required for Protection from Neutrophil-Mediated Killing and Proper Growth In Vitro

Allen

Neely

2011

Infect Immun

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The ability of a pathogen to metabolically adapt to the local environment for optimal expression of virulence determinants is a continued area of research. Orthologs of the Streptococcus iniae LysR family regulator CpsY have been shown to regulate methionine biosynthesis and uptake pathways but appear to influence expression of several virulence genes as well. An S. iniae mutant with an in-frame deletion of cpsY (⌬cpsY mutant) is highly attenuated in a zebrafish infection model. The ⌬cpsY mutant displays a methionine-independent growth defect in serum, which differs from the methionine-dependent defect observed for orthologous mutants of Streptococcus mutans and Streptococcus agalactiae. On the contrary, the ⌬cpsY mutant can grow in excess of the wild type (WT) when supplemented with proteose peptone, suggesting an inability to properly regulate growth. CpsY is critical for protection of S. iniae from clearance by neutrophils in whole blood but is dispensable for intracellular survival in macrophages. Susceptibility of the ⌬cpsY mutant to killing in whole blood is not due to a growth defect, because inhibition of neutrophil phagocytosis rescues the mutant to WT levels. Thus, CpsY appears to have a pleiotropic regulatory role for S. iniae, integrating metabolism and virulence. Furthermore, S. iniae provides a unique model to investigate the paradigm of CpsY-dependent regulation during systemic streptococcal infection.Our understanding of the diverse repertoire of transcriptional signaling networks that orchestrate optimal expression of virulence genes dependent upon the metabolic status of the cell is quickly expanding (49,60). Metabolic adaptations to the various environments encountered by a pathogen within a host prove to be tremendously complex (14). Recent work on streptococcal pathogens has revealed components of these regulatory pathways that relate the nutritional status of the cell to the control of growth phase and expression of virulence genes (1,21,23,24,36,40,51).Streptococcus iniae is a major aquatic pathogen (15, 16) that causes an invasive systemic infection with severe bacteremia culminating in meningoencephalitis (2). Many instances of zoonoses have been reported as a result of handling infected fish, which typically results in a bacteremic cellulitis (17,28,56). The severity of an S. iniae infection is due in part to the ability to rapidly disseminate from the site of infection through the bloodstream and invade systemic tissues (34).The complex pathogenicity of S. iniae, and other systemic streptococcal pathogens, is reflected in the diversity of genes that are critical to a successful infection (3,22,55). Several classical streptococcal virulence factors have been shown to be important for the virulence of S. iniae, including the SivS/Rregulated streptolysin S (sagA) and CAMP factor (cfi) (4, 31), as well as the major surface M protein (siM) (30). S. iniae also contains a polysaccharide capsule that functions for protection from phagocytic clearance in whole blood (32,34,39). Furthermore, sev...

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Towards Control ofStreptococcus iniae

Abstract: Recently identified virulence factors can lead to new approaches, such as vaccination programs at fish farms.

Cited by 88 publications

References 40 publications

Vaccination against streptococcal infections in farmed fish

Vaccination against streptococcal infections in farmed fish

Comparative genome analysis of Streptococcus iniae DX09 reveals new insights into niche adaptation and competitive host colonisation ability

The Streptococcus iniae Transcriptional Regulator CpsY Is Required for Protection from Neutrophil-Mediated Killing and Proper Growth In Vitro

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