<i>Streptococcus agalactiae</i> Multilocus sequence type 261 is associated with mortalities in the emerging Ghanaian tilapia industry

Verner–Jeffreys, David W.; Wallis, T.; Cejas, I.C.; Ryder, David; Haydon, David J.; Domazoro, J F; Dontwi, J.; Field, Terence R.; Adjei-Boteng, D; Wood, Gareth; Bean, Tim P.; Feist, Stephen W.

doi:10.1111/jfd.12681

Cited by 41 publications

(46 citation statements)

References 21 publications

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“…In Ghana, Nile tilapia production in 2016 had reached more than 50 000 tonnes, from only 2 000 49 tonnes per year in 2006 (FAO, 2016) with more than 90% of the production derived from high 50 stocking density floating cage systems in Lake Volta. However, as production systems have 51 intensified in the area, the industry has been increasingly affected by a range of disease issues 52 (Jansen, Cudjoe, & Brun, 2018;Verner-Jeffreys et al, 2018). 53…”

Section: Introduction 42mentioning

confidence: 99%

First detection of Infectious Spleen and kidney Necrosis Virus (ISKNV) associated with massive mortalities in farmed tilapia in Africa

Ramírez‐Paredes¹,

Paley

Hunt³

et al. 2019

Preprint

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Section: Introduction 42mentioning

confidence: 99%

First detection of Infectious Spleen and kidney Necrosis Virus (ISKNV) associated with massive mortalities in farmed tilapia in Africa

Ramírez‐Paredes¹,

Paley

Hunt³

et al. 2019

Preprint

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“…However, with the rapid development of the tilapia culture industry, various bacterial diseases frequently outbreak due to intensified culture and high stocking density conditions of intensive farming. Pathogens, such as streptococcosis (Anshary, Kurniawan, Sriwulan, Ramli, & Baxa, ; Verner‐Jeffreys et al., ), edwardsiellosis (Kwon, Nam, Kim, & Kim, ; Park & Jeong, ; Soto, Illanes, Revan, Griffin, & Riofrio, ; Soto et al., ), columnaris disease (Dong, Lafrentz, Pirarat, & Rodkhum, ; Sebastiao, Nomura, Sakabe, & Pilarski, ), francisellosis (Assis, Tavares, Pereira, Figueiredo, & Leal, ; Ortega et al., ; Sebastiao, Pilarski, Kearney, & Soto, ) and motile aeromonas septicaemia (Dong et al., ; Li & Cai, ; Soto‐Rodriguez, Cabanillas‐Ramos, Alcaraz, Gomez‐Gil, & Romalde, ), have resulted in substantial economic losses to the local aquaculture industries.…”

Section: Introductionmentioning

confidence: 99%

Aeromonas shuberti as a cause of multi‐organ necrosis in internal organs of Nile tilapia, Oreochromis niloticus

Liu

Chang

Zhang

et al. 2018

Journal of Fish Diseases

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A disease with white spots in internal organs of Nile tilapia occurred in Zhanjiang, southern China. Multiple, white nodules, 0.8-2.2 mm in diameter, were scattered throughout the liver, spleen and kidney of diseased fish. Signs of nodules reproduced after artificial infection with the isolated strain. Isolated bacteria were Gram-negative, facultative anaerobic, motile, short rod-shaped, with a length of 1.2-2.2 μm. Morphological and biochemical tests, as well as phylogenetic analysis, all strongly indicated that the isolate from tilapia is identical to Aeromonas schubertii (A. schubertii) which temporary named LF1708 strain. Antibiotic sensitivity assays showed the LF1708 is sensitive to 24 of 27 tested antibiotics. Pathogenicity test revealed that the isolate at the dose of 3.75 × 10 CFU/g killed 100% of experimental tilapia within 2 days and the dose of 1 × 10 CFU/g killed 100% of experimental zebrafish within 1 day. Histopathology of diseased tilapia infected with A. schubertii showed numerous necrotic lesions widely distributed in spleen, liver and kidney, and infiltration with a large number of bacteria. To our knowledge, this was the first report that associated A. schubertii with mortality in tilapia.

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“…Molecular serotyping indicated that all Queensland and Honduras aquatic strains belong to serotype Ib but Queensland isolates belong to sequence type (ST)-261 while Honduras strains are ST-260. Both ST-260 and ST-261 have been identified infecting aquatic animals previously with ST-260 isolates found in tilapia from Brazil and Costa Rica and occupying clonal complex (CC) 552 along with ST-552 and ST-553 strains also isolated from tilapia in Latin America (27), whilst ST-261 has been isolated from tilapia in USA, China, Ghana and Israel (9, 13, 30).…”

Section: Resultsmentioning

confidence: 99%

“…agalactiae have substantial impact on the aquaculture industry, particularly the production of warm fresh water species such as tilapia ( Oreochromis spp. )(9–12). Most outbreaks to date in freshwater farmed fish have resulted from infection by highly adapted strains of GBS with genomes that are 10-15% smaller than their terrestrial conspecifics (13).…”

Section: Introductionmentioning

confidence: 99%

“…agalactiae revealed that the majority of isolates associated with aquatic environments and hosts fall within serotypes Ia and Ib, in which Ia isolates belong to ST-7 in clonal complex (CC) 7 and ST-103 in CC103 (12, 18, 24–28). Serotype Ib strains isolated in Central and South America are ST-260 and ST-552 in CC552 (27, 29) and strains isolated in Australia, Israel, Belgium, China, Ghana, USA and Southeast Asia belong to ST-261 (5, 6, 9, 13, 29–31). Serotype III is commonly causative of disease in humans, but has also been isolated from fish in Thailand, China and recently in Brazil (26, 32–34).…”

Section: Introductionmentioning

confidence: 99%

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Microevolution of aquaticStreptococcus agalactiaeST-261 from Australia indicates dissemination via imported tilapia and ongoing adaptation to marine hosts or environment

Kawasaki

Delamare-Deboutteville

Bowater³

et al. 2018

Preprint

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Streptococcus agalactiae (GBS) causes disease in a wide range of animals. The serotype 1b lineage is highly adapted to aquatic hosts, exhibiting substantial genome reduction compared with terrestrial con-specifics. Here we sequence genomes from 40 GBS isolates including 25 from wild fish and captive stingrays in Australia, six local veterinary or human clinical isolates, and nine isolates from farmed tilapia in Honduras and compare with 42 genomes from public databases. Phylogenetic analysis based on non-recombinant core genome SNPs indicated that aquatic serotype Ib isolates from Queensland were distantly related to local veterinary and human clinical isolates. In contrast, Australian aquatic isolates are most closely related to a tilapia isolate from Israel, differing by only 63 core-genome SNPs. A consensus minimum spanning tree based on core genome SNPs indicates dissemination of ST-261 from an ancestral tilapia strain, which is congruent with several introductions of tilapia into Australia from Israel during the 1970s and 1980s. Pan-genome analysis identified 1,440 genes as core with the majority being dispensable or strain-specific with non-protein-coding intergenic regions (IGRs) divided amongst core and strain-specific genes. Aquatic serotype Ib strains have lost many virulence factors during adaptation, but six adhesins were well conserved across the aquatic isolates and might be critical for virulence in fish and targets for vaccine development. The close relationship amongst recent ST-261 isolates from Ghana, USA and China with the Israeli tilapia isolate from 1988 implicates the global trade in tilapia seed for aquaculture in the widespread dissemination of serotype Ib fish-adapted GBS.ImportanceStreptococcus agalactiae (GBS) is a significant pathogen of humans and animals. Some lineages have become adapted to particular hosts and serotype Ib is highly specialized to fish. Here we show that this lineage is likely to have been distributed widely by the global trade in tilapia for aquaculture, with probable introduction into Australia in the 1970s and subsequent dissemination in wild fish populations. We report variability in the polysaccharide capsule amongst this lineage, but identify a cohort common surface proteins that may be a focus of future vaccine development to reduce the biosecurity risk in international fish trade.

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Streptococcus agalactiae Multilocus sequence type 261 is associated with mortalities in the emerging Ghanaian tilapia industry

Cited by 41 publications

References 21 publications

First detection of Infectious Spleen and kidney Necrosis Virus (ISKNV) associated with massive mortalities in farmed tilapia in Africa

First detection of Infectious Spleen and kidney Necrosis Virus (ISKNV) associated with massive mortalities in farmed tilapia in Africa

Aeromonas shuberti as a cause of multi‐organ necrosis in internal organs of Nile tilapia, Oreochromis niloticus

Microevolution of aquaticStreptococcus agalactiaeST-261 from Australia indicates dissemination via imported tilapia and ongoing adaptation to marine hosts or environment

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