Draft Genome Sequences of
            <i>Streptococcus agalactiae</i>
            Serotype Ia and III Isolates from Tilapia Farms in Thailand

Areechon, Nontawith; Kannika, Korntip; Hirono, Ikuo; Kondo, Hidehiro; Unajak, Sasimanas

doi:10.1128/genomea.00122-16

Cited by 12 publications

(5 citation statements)

References 14 publications

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“…ST283 was previously reported from 17/57 (30%) GBS isolated from seven freshwater fish species, including tilapia, on sale for human consumption in Singapore in 2015: these 17 ST283 were found in only 6/586 (1%) fish from ports, but in 11/39 (28%) fish from markets [10]. Two previously reported ST283 were reported from farmed tilapia in Thailand between 2000 and 2014 [9, 25]. One ST491 and one ST1311, (a new SLV of ST491, and also a double locus variant of ST283) were isolated from tilapia in Vietnam in 2006 [9] and 2016 respectively.…”

Section: Resultsmentioning

confidence: 99%

“…Whereas fish-associated CC7 and CC552 are geographically widespread, our literature review, up to December 2017, showed that CC283 had only been confirmed from SE Asia, although serotype III GBS had been described as the cause of disease outbreaks that occurred in 2016 in tilapia farms in Brazil [76]. Serotype III GBS isolates from Brazilian tilapia farms have now been confirmed as ST283, while this paper was in revision, and cluster with ST283 from Asia [25, 77]. This observation, in combination with import records of live Nile tilapia from Singapore to Brazil in 2014, suggests that ST283 may have been introduced into South America from Southeast Asia, underlining the potential threat of Southeast Asian ST283 to expanding aquaculture worldwide.…”

Section: Discussionmentioning

confidence: 96%

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One hypervirulent clone, sequence type 283, accounts for a large proportion of invasive Streptococcus agalactiae isolated from humans and diseased tilapia in Southeast Asia

et al. 2019

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Background In 2015, Singapore had the first and only reported foodborne outbreak of invasive disease caused by the group B Streptococcus (GBS; Streptococcus agalactiae ). Disease, predominantly septic arthritis and meningitis, was associated with sequence type (ST)283, acquired from eating raw farmed freshwater fish. Although GBS sepsis is well-described in neonates and older adults with co-morbidities, this outbreak affected non-pregnant and younger adults with fewer co-morbidities, suggesting greater virulence. Before 2015 ST283 had only been reported from twenty humans in Hong Kong and two in France, and from one fish in Thailand. We hypothesised that ST283 was causing region-wide infection in Southeast Asia. Methodology/Principal findings We performed a literature review, whole genome sequencing on 145 GBS isolates collected from six Southeast Asian countries, and phylogenetic analysis on 7,468 GBS sequences including 227 variants of ST283 from humans and animals. Although almost absent outside Asia, ST283 was found in all invasive Asian collections analysed, from 1995 to 2017. It accounted for 29/38 (76%) human isolates in Lao PDR, 102/139 (73%) in Thailand, 4/13 (31%) in Vietnam, and 167/739 (23%) in Singapore. ST283 and its variants were found in 62/62 (100%) tilapia from 14 outbreak sites in Malaysia and Vietnam, in seven fish species in Singapore markets, and a diseased frog in China. Conclusions GBS ST283 is widespread in Southeast Asia, where it accounts for a large proportion of bacteraemic GBS, and causes disease and economic loss in aquaculture. If human ST283 is fishborne, as in the Singapore outbreak, then GBS sepsis in Thailand and Lao PDR is predominantly a foodborne disease. However, whether transmission is from aquaculture to humans, or vice versa , or involves an unidentified reservoir remains unknown. Creation of cross-border collaborations in human and animal health are needed to complete the epidemiological picture.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 96%

One hypervirulent clone, sequence type 283, accounts for a large proportion of invasive Streptococcus agalactiae isolated from humans and diseased tilapia in Southeast Asia

et al. 2019

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“…The outbreaks of streptococcosis have been related to environmental factors, including warm water temperatures, increased ammonia levels, and low dissolved oxygen [ 11 ]. S. agalactiae infections in tilapia have been reported in global aquaculture in different continents, especially Asia, including Thailand [ 17 , 18 , 19 , 20 , 21 , 22 ], Malaysia [ 23 , 24 , 25 , 26 , 27 ], Indonesia [ 28 , 29 ], Philippines [ 30 ], and China [ 31 , 32 , 33 , 34 ]. Importantly, the emergence of streptococcosis disease can take place anytime during tilapia farming, which may lead to the risk of disease distribution and loss of tilapia production if disease prevention and control are not well managed.…”

Section: Introductionmentioning

confidence: 99%

Trial Evaluation of Protection and Immunogenicity of Piscine Bivalent Streptococcal Vaccine: From the Lab to the Farms

et al. 2022

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Streptococcosis is one of the major diseases that causes devastation to farmed fish, leading to significant economic losses all around the world. Currently, two serotypes of Streptococcus agalactiae, serotype Ia and III, have been identified as virulent strains and major causative agents of the disease in farmed Nile tilapia (Oreochromis niloticus Linn.) in Thailand. Upon inactivated vaccine development, monovalent inactivated whole-cell vaccines demonstrated high specific antibody production against homologous serotypes and limited production with heterologous serotypes. However, for higher efficacy, a bivalent streptococcal vaccine was designed to maximize protective immunity to both serotypes. Interestingly, our bivalent vaccine could successfully induce specific antibody production against both serotypes with similar levels, and the response could extend over the 8 weeks of the experimental period. Evaluation of vaccines in the laboratory scale revealed relative percent survival (RPS) of vaccinated tilapia to serotype Ia (81.2 ± 9.4%) and serotype III (72.2 ± 4.8%), respectively. The efficacy of the bivalent vaccine showed significant RPS higher than the monovalent vaccine (p < 0.05) at 30 days, and the protection of all those vaccines was reduced thereafter. Evaluation of the vaccine in a farm trial in different locations in Thailand revealed the efficacy of the bivalent vaccine in increasing the production yield by greater than 80% in all tested farms in 2015 and 2021. Taken together, this study affirms the efficacy of the bivalent streptococcal vaccine in the prevention of streptococcus disease in Nile tilapia, which could be used in different areas. This vaccine development could be effectively applied in the tilapia culture industry.

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“…However, our understanding of the piscine GBS at the whole genome level is currently limited. Although some complete genome sequences and draft genome sequences of piscine GBS isolates have been recorded so far (Areechon et al 2016;Facimoto et WGS analysis and phenotypic characteristics has not been reported. Here, this is the rst report on draft genomes of GBS S03 and S07 isolated from Schizothorax prenanti with different pathogenicity and drugresistance.…”

Section: Introductionmentioning

confidence: 99%

Comparative Analysis of Streptococcus Agalactiae S03 and S07 Isolated From Schizothorax Prenanti With Different Antibiotic Resistance and Virulence

Deng¹,

Li²,

Geng³

et al. 2021

Preprint

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Streptococcus agalactiae (GBS), is an important Gram-positive pathogen of ﬁsh aquaculture worldwide. In this study, we performed a comparative analysis of GBS S03 and S07 isolated from Schizothorax prenanti and explored the association between phenotypic antibiotic resistance as well as virulence and the genomic characteristics. Antimicrobial sensitivity tests on 12 common antibiotics using the disc diffusion method revealed that the S03 showed resistance to seven antibiotics, while S07 showed sensitivity to the tested antibiotics. Pathogenicity analysis demonstrated greater virulence of S07 than S03. Then, the occurrence of antibiotic resistance and virulence genes was identified using whole-genome sequence (WGS) of S03 and S07. There were mefE, tetO, lnuB, lsaE, APH3', and sat-4 resistance genes present only in S03 genome. And just S03 had gyrA and parC genes mutations. In addition to 51 virulence genes in both S03 and S07 genomes, S07 additionally carried virulence genes associated with invasion, such as SAN_1519, rfbA and cylE genes. There was complete concordance between genotypic evidence and phenotypic characteristics. Virulence factors and phylogenetic analysis showed that S03 and human sources shared an extremely close evolutionary relationship. Our findings provide important proof for using WGS as an effective tool of phenotypic predictions of GBS.

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Draft Genome Sequences of Streptococcus agalactiae Serotype Ia and III Isolates from Tilapia Farms in Thailand

Cited by 12 publications

References 14 publications

One hypervirulent clone, sequence type 283, accounts for a large proportion of invasive Streptococcus agalactiae isolated from humans and diseased tilapia in Southeast Asia

One hypervirulent clone, sequence type 283, accounts for a large proportion of invasive Streptococcus agalactiae isolated from humans and diseased tilapia in Southeast Asia

Trial Evaluation of Protection and Immunogenicity of Piscine Bivalent Streptococcal Vaccine: From the Lab to the Farms

Comparative Analysis of Streptococcus Agalactiae S03 and S07 Isolated From Schizothorax Prenanti With Different Antibiotic Resistance and Virulence

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