{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T21:09:26Z","timestamp":1792789766278,"version":"4.5.0"},"reference-count":99,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2026,5,18]],"date-time":"2026-05-18T00:00:00Z","timestamp":1779062400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Pathovet Labs\u2019 internal budget"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pathogens"],"abstract":"<jats:p>Recently, a strain of Streptococcus agalactiae serotype Ia sequence type 7 clonal complex 1 (SaIa ST7 CC1) has emerged in Latin American tilapia aquaculture as an international threat. This study evaluated outbreaks of acute streptococcosis occurring between 2021 and 2025 on commercial Nile tilapia (Oreochromis niloticus) farms in six Latin American countries, aiming to integrate molecular, clinical, pathological, and environmental data. In total, 360 moribund or recently dead fish at various production stages (larvae\/fry, pre-grow-out, and grow-out) were examined, and 25 S. agalactiae isolates were serotyped and subjected to real-time PCR analysis, multilocus sequence typing (MLST), virulence and antimicrobial resistance gene profiling, and antimicrobial susceptibility testing. All isolates belonged to SaIa and shared the same ST7 CC1 MLST profile, forming a highly homogeneous cluster with reference SaIa ST7 CC1 strains previously isolated from tilapia farms in Asia. These results are consistent with the regional spread of a single clonal line. At the larval and fry stages, SaIa ST7 CC1 was associated with hyperacute septicemia, gastrointestinal hemorrhage, and frequent intestinal intussusception, whereas in pre-grow-out and grow-out fish, neurological signs were more prominent, followed by ocular signs, systemic hemorrhages, and coelomic lesions. Histopathological examination showed profuse colonization of the brain, spleen, liver, and intestine by Gram-positive cocci, accompanied by marked acute circulatory and inflammatory lesions and few chronic granulomatous responses, consistent with a rapidly progressing, highly aggressive infectious process. All outbreaks occurred during extended periods of warm water (&gt;32 \u00b0C), with large day\u2013night thermal gradients and reduced dissolved oxygen, suggesting that thermal stress may exacerbate disease expression in affected systems. All SaIa ST7 CC1 strains exhibited phenotypic susceptibility to florfenicol and amoxicillin, whereas 84% (21\/25) and 100% (25\/25) exhibited intermediate susceptibility to oxytetracycline and enrofloxacin, respectively. In total, 5 of the 21 isolates (23.8%) with intermediate susceptibility to oxytetracycline carried tetracycline resistance genes (tetM, tetO). These findings identify SaIa ST7 CC1 as a clinically significant emerging threat associated with thermally facilitated and geographically expanding streptococcosis in tilapia production in Latin America. Immediate priorities include screening imported broodstock using MLST or whole-genome sequencing (WGS), harmonized regional molecular surveillance, climate-adaptive farm management practices, prudent antimicrobial use, and serotype-matched vaccination and breeding strategies that improve both disease and heat resilience.<\/jats:p>","DOI":"10.3390\/pathogens15050545","type":"journal-article","created":{"date-parts":[[2026,5,19]],"date-time":"2026-05-19T16:07:26Z","timestamp":1779206846000},"page":"545","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Streptococcus agalactiae Serotype Ia ST7 CC1 in Farmed Nile Tilapia in Latin America: Age-Dependent Disease Expression and Antimicrobial Susceptibility of an Emerging Clonal Lineage"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1693-7178","authenticated-orcid":false,"given":"Marco","family":"Rozas-Serri","sequence":"first","affiliation":[{"name":"Pathovet Labs, Ribeir\u00e3o Preto 14025-060, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Miguel","family":"Fernandez-Alarcon","sequence":"additional","affiliation":[{"name":"Pathovet Labs, Ribeir\u00e3o Preto 14025-060, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mariene","family":"Miyoko-Natori","sequence":"additional","affiliation":[{"name":"Pathovet Labs, Ribeir\u00e3o Preto 14025-060, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Renata","family":"Galetti","sequence":"additional","affiliation":[{"name":"Pathovet Labs, Ribeir\u00e3o Preto 14025-060, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1431-2665","authenticated-orcid":false,"given":"Ricardo","family":"Harakava","sequence":"additional","affiliation":[{"name":"Instituto Biol\u00f3gico\/IB, S\u00e3o Paulo 04016-035, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mateus","family":"Cardoso-Guimar\u00e3es","sequence":"additional","affiliation":[{"name":"Pathovet Labs, Ribeir\u00e3o Preto 14025-060, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ricardo","family":"Ildefonso","sequence":"additional","affiliation":[{"name":"Pathovet Labs, Ribeir\u00e3o Preto 14025-060, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,5,18]]},"reference":[{"key":"ref_1","unstructured":"FAO (2024). GLOBEFISH Quarterly Tilapia Analysis, FAO. Issue 4."},{"key":"ref_2","unstructured":"Fact.MR (2025). Tilapia Market Forecast and Outlook 2025 to 2035, Fact.MR. Market Analysis Report."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"747","DOI":"10.3856\/vol51-issue5-fulltext-3071","article-title":"Economic analysis of Nile tilapia (Oreochromis niloticus) production based on farm size and number of rearing tanks","volume":"51","author":"Robledo","year":"2023","journal-title":"Lat. Am. J. Aquat. Res."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Siddique, M.A.B., Mahalder, B., Haque, M.M., and Ahammad, A.K.S. (2025). Impact of climatic and water quality parameters on Tilapia (Oreochromis niloticus) broodfish growth: Integrating ARIMA and ARIMAX for precise modeling and forecasting. PLoS ONE, 20.","DOI":"10.1371\/journal.pone.0313846"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"200240","DOI":"10.1016\/j.cirep.2025.200240","article-title":"Review on climate change, microbial resilience, and disease risks in global aquaculture systems","volume":"9","author":"Jeyachandran","year":"2025","journal-title":"Comp. Immunol. Rep."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"120184","DOI":"10.1016\/j.envres.2024.120184","article-title":"The Escalating threat of climate change-driven diseases in fish: Evidence from a global perspective\u2014A literature review","volume":"263","author":"Okon","year":"2024","journal-title":"Environ. Res."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Islam, M.A., Kunda, M., Harun-Al-Rashid, A., Sunny, A.R., Mithun, M.H., Sazzad, S.A., and Bhuiyan, M.K.A. (2025). Can Climate-Resilient Tilapia Cage Culture Support Sustainable Livelihoods in Flood-Prone Bangladesh?. Water, 17.","DOI":"10.3390\/w17040585"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"13937","DOI":"10.1038\/s41598-019-50303-z","article-title":"The effects of water temperature on the juvenile performance of two tropical damselfishes expatriating to temperate reefs","volume":"9","author":"Djurichkovic","year":"2019","journal-title":"Sci. Rep."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"2183","DOI":"10.1007\/s00484-022-02347-6","article-title":"Effect of environmental factors on growth performance of Nile tilapia (Oreochromis niloticus)","volume":"66","author":"Nader","year":"2022","journal-title":"Int. J. Biometeorol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"679","DOI":"10.1016\/j.fsi.2016.06.058","article-title":"RNA-Seq revealed the impairment of immune defence of tilapia against the infection of Streptococcus agalactiae with simulated climate warming","volume":"55","author":"Wang","year":"2016","journal-title":"Fish. Shellfish. Immunol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"212","DOI":"10.1016\/j.mimet.2009.11.010","article-title":"A multiplex PCR assay for the direct identification of the capsular type (Ia to IX) of Streptococcus agalactiae","volume":"80","author":"Imperi","year":"2010","journal-title":"J. Microbiol. Methods"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"265","DOI":"10.1016\/j.vetmic.2014.04.013","article-title":"Increasing of temperature induces pathogenicity of Streptococcus agalactiae and the up-regulation of inflammatory related genes in infected Nile tilapia (Oreochromis niloticus)","volume":"172","author":"Kayansamruaj","year":"2014","journal-title":"Vet. Microbiol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2639","DOI":"10.3389\/fmicb.2018.02639","article-title":"Transcriptome and Proteome of Fish-Pathogenic Streptococcus agalactiae Are Modulated by Temperature","volume":"9","author":"Tavares","year":"2018","journal-title":"Front. Microbiol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"682","DOI":"10.14202\/vetworld.2024.682-689","article-title":"Impact of temperature on the virulence of Streptococcus agalactiae in Indonesian aquaculture: A better vaccine design is required","volume":"17","author":"Lusiastuti","year":"2024","journal-title":"Vet. World"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"5094","DOI":"10.1038\/s41598-025-87980-y","article-title":"Alterations and resilience of intestinal microbiota to increased water temperature are accompanied by the recovery of immune function in Nile tilapia","volume":"15","author":"Wu","year":"2025","journal-title":"Sci. Rep."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"e0056824","DOI":"10.1128\/spectrum.00568-24","article-title":"Dissecting the impact of heat stress on heat-shock response and skin microbiota in farmed fish in a recirculating aquaculture system in Singapore","volume":"13","author":"Ng","year":"2025","journal-title":"Microbiol. Spectr."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"110294","DOI":"10.1016\/j.fsi.2025.110294","article-title":"Heat stress induces oxidative stress and weakens the immune system in catfish Clarias magur: Evidence from physiological, histological, and transcriptomic analyses","volume":"161","author":"Singh","year":"2025","journal-title":"Fish. Shellfish. Immunol."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Guijarro, J.A., Cascales, D., Garc\u00eda-Torrico, A.I., Garc\u00eda-Dom\u00ednguez, M., and M\u00e9ndez, J. (2015). Temperature-dependent expression of virulence genes in fish-pathogenic bacteria. Front. Microbiol., 6.","DOI":"10.3389\/fmicb.2015.00700"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Mahieddine, F.C., Mathieu-Denoncourt, A., and Duperthuy, M. (2025). Temperature Influences Antimicrobial Resistance and Virulence of Vibrio parahaemolyticus Clinical Isolates from Quebec, Canada. Pathogens, 14.","DOI":"10.3390\/pathogens14060521"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"109919","DOI":"10.1016\/j.fsi.2024.109919","article-title":"Characterization of Streptococcus agalactiae 1a isolated from farmed Nile tilapia (Oreochromis niloticus) in North America, Central America, and Southeast Asia","volume":"154","author":"Fyrand","year":"2024","journal-title":"Fish. Shellfish. Immunol."},{"key":"ref_21","unstructured":"Rozas-Serri, M. (2025). Characterization of Streptococcus agalactiae serotype 1a, ST7, CC1 isolated from outbreaks in nile tilapia (Oreochromis niloticus) farmed in six Latin American countries. LACQUA 25 Abstr. Book, 326."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"13538","DOI":"10.1038\/s41598-017-13228-z","article-title":"Large-scale genomic analyses reveal the population structure and evolutionary trends of Streptococcus agalactiae strains in Brazilian fish farms","volume":"7","author":"Barony","year":"2017","journal-title":"Sci. Rep."},{"key":"ref_23","unstructured":"Rozas-Serri, M. (2024). Field efficacy results of vaccines for the control of streptococcosis caused by Streptococcus agalactiae serotype 1a ST-7 CC-1 in farmed tilapia in Latin America. LACQUA 24 Abstr. Book, 442."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"101","DOI":"10.14202\/vetworld.2017.101-111","article-title":"Molecular identification and histopathological study of natural Streptococcus agalactiae infection in hybrid tilapia (Oreochromis niloticus)","volume":"10","author":"Laith","year":"2017","journal-title":"Vet. World"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"307","DOI":"10.1016\/j.meegid.2015.10.009","article-title":"Genomic comparison between pathogenic Streptococcus agalactiae isolated from Nile tilapia in Thailand and fish-derived ST7 strains","volume":"36","author":"Kayansamruaj","year":"2015","journal-title":"Infect. Genet. Evol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1497","DOI":"10.1111\/jam.13447","article-title":"Molecular serotyping, virulence gene profiling and pathogenicity of Streptococcus agalactiae isolated from tilapia farms in Thailand by multiplex PCR","volume":"122","author":"Kannika","year":"2017","journal-title":"J. Appl. Microbiol."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Guo, C.-M., Chen, R.-R., Kalhoro, D.H., Wang, Z.-F., Liu, G.-J., Lu, C.-P., and Liu, Y.-J. (2014). Identification of Genes Preferentially Expressed by Highly Virulent Piscine Streptococcus agalactiae upon Interaction with Macrophages. PLoS ONE, 9.","DOI":"10.1371\/journal.pone.0087980"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"627","DOI":"10.1186\/2193-1801-3-627","article-title":"Isolation and molecular identification of the etiological agents of streptococcosis in Nile tilapia (Oreochromis niloticus) cultured in net cages in Lake Sentani, Papua, Indonesia","volume":"3","author":"Anshary","year":"2014","journal-title":"SpringerPlus"},{"key":"ref_29","first-page":"756","article-title":"Characterization of Streptococcus agalactiae bacterium isolated from tilapia (Oreochromis niloticus) culture in Indonesia","volume":"12","author":"Suhermanto","year":"2019","journal-title":"AACL Bioflux"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1","DOI":"10.4102\/koedoe.v58i1.1353","article-title":"Ethical considerations for field research on fishes","volume":"58","author":"Bennett","year":"2016","journal-title":"Koedoe"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1016\/j.diagmicrobio.2017.06.003","article-title":"A novel one-step real-time multiplex PCR assay to detect Streptococcus agalactiae presence and serotypes Ia, Ib, and III","volume":"89","author":"Furfaro","year":"2017","journal-title":"Diagn. Microbiol. Infect. Dis."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1177\/104063871102300102","article-title":"Selection of a cutoff value for real-time polymerase chain reaction results to fit a diagnostic purpose: Analytical and epidemiologic approaches","volume":"23","author":"Caraguel","year":"2011","journal-title":"J. Vet. Diagn. Investig."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1111\/jam.14556","article-title":"Development and evaluation of a quantitative polymerase chain reaction for aquatic Streptococcus agalactiae based on the groEL gene","volume":"129","author":"Leigh","year":"2020","journal-title":"J. Appl. Microbiol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"183","DOI":"10.1016\/j.gene.2013.06.013","article-title":"Evaluation of reference genes for quantitative real-time RT-PCR analysis of gene expression in Nile tilapia (Oreochromis niloticus)","volume":"527","author":"Yang","year":"2013","journal-title":"Gene"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"2530","DOI":"10.1128\/JCM.41.6.2530-2536.2003","article-title":"Multilocus sequence typing system for group B streptococcus","volume":"41","author":"Jones","year":"2003","journal-title":"J. Clin. Microbiol."},{"key":"ref_36","unstructured":"Hall, T.A. (1999, January 1\u20135). BioEdit: A user-friendly biological sequence alignment editor and analysis program for Windows 95\/98\/NT. Proceedings of the Nucleic Acids Symposium Series, London, UK."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"11030","DOI":"10.1073\/pnas.0404206101","article-title":"Prospects for inferring very large phylogenies by using the neighbor-joining method","volume":"101","author":"Tamura","year":"2004","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"3022","DOI":"10.1093\/molbev\/msab120","article-title":"MEGA11: Molecular Evolutionary Genetics Analysis Version 11","volume":"38","author":"Tamura","year":"2021","journal-title":"Mol. Biol. Evol."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"26319","DOI":"10.1038\/srep26319","article-title":"Inapparent Streptococcus agalactiae infection in adult\/commercial tilapia","volume":"6","author":"Sun","year":"2016","journal-title":"Sci. Rep."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"734543","DOI":"10.1016\/j.aquaculture.2019.734543","article-title":"Molecular characterization and pathogenicity of Streptococcus agalactiae serotypes Ia ST7 and III ST283 isolated from cultured red hybrid tilapia in Malaysia","volume":"515","author":"Syuhada","year":"2020","journal-title":"Aquaculture"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"107664","DOI":"10.1016\/j.micpath.2025.107664","article-title":"Genetic diversity, virulence genes, antimicrobial resistance genes, and antimicrobial susceptibility of group B Streptococcus (GBS) associated with mass mortalities of cultured Nile tilapia in Brazil","volume":"205","author":"Assane","year":"2025","journal-title":"Microb. Pathog."},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Mudzana, R., Mavenyengwa, R.T., and Gudza-Mugabe, M. (2021). Analysis of virulence factors and antibiotic resistance genes in group B streptococcus from clinical samples. BMC Infect. Dis., 21.","DOI":"10.1186\/s12879-021-05820-6"},{"key":"ref_43","unstructured":"(2025). Performance Standards for Antimicrobial Susceptibility Testing, 35th Ed. CLSI Supplement M100 (Standard No. CLSI M100:2025)."},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Sleight, S.C., Wigginton, N.S., and Lenski, R.E. (2006). Increased susceptibility to repeated freeze-thaw cycles in Escherichia coli following long-term evolution in a benign environment. BMC Evol. Biol., 6.","DOI":"10.1186\/1471-2148-6-104"},{"key":"ref_45","unstructured":"(2024). Performance Standards for Antimicrobial Disk and Dilution Susceptibility Tests for Bacteria Isolated from Animals, 6th Ed (Standard No. CLSI standard VET01)."},{"key":"ref_46","unstructured":"(2024). Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria That Grow Aerobically (Standard No. CLSI M07 Standard (12th edition))."},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Algammal, A.M., Mabrok, M., Almessiry, B.K., Atwah, B., Al-otaibi, A.S., Mohamed, Y.S., Steele, S., Enany, M., Dayrit, G.B., and Yousseff, F.M. (2025). Unraveling the pathogenic potential, virulence traits, and antibiotic resistance genes of multidrug-resistant Streptococcus agalactiae strains retrieved from Nile tilapia. BMC Microbiol., 25.","DOI":"10.1186\/s12866-025-04405-6"},{"key":"ref_48","first-page":"4","article-title":"From drawing board to dining table: The success story of the GIFT project","volume":"27","author":"Gupta","year":"2004","journal-title":"Naga"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"15458","DOI":"10.1038\/srep15458","article-title":"Disparate developmental patterns of immune responses to bacterial and viral infections in fish","volume":"5","author":"Castro","year":"2015","journal-title":"Sci. Rep."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"1682047","DOI":"10.1155\/2023\/1682047","article-title":"Streptococcus agalactiae Serotype VII, an Emerging Pathogen Affecting Snakeskin Gourami (Trichogaster pectoralis) in Intensive Farming","volume":"2023","author":"Pulpipat","year":"2023","journal-title":"Transbound. Emerg. Dis."},{"key":"ref_51","doi-asserted-by":"crossref","unstructured":"Ferrari, N.A., Favero, L.M., Facimoto, C.T., Dall Agnol, A.M., Gaeta, M.L., de Oliveira, T.E.S., Gon\u00e7alves, D.D., Lopera-Barrero, N.M., Pereira, U.d.P., and Di Santis, G.W. (2024). Clinical and Histopathological Evolution of Acute Intraperitoneal Infection by Streptococcus agalactiae Serotypes Ib and III in Nile Tilapia. Fishes, 9.","DOI":"10.3390\/fishes9070279"},{"key":"ref_52","doi-asserted-by":"crossref","unstructured":"Van Doan, H., Soltani, M., Leit\u00e3o, A., Shafiei, S., Asadi, S., Lymbery, A.J., and Ring\u00f8, E. (2022). Streptococcosis a Re-Emerging Disease in Aquaculture: Significance and Phytotherapy. Animals, 12.","DOI":"10.3390\/ani12182443"},{"key":"ref_53","doi-asserted-by":"crossref","unstructured":"Abdallah, E.S.H., Metwally, W.G.M., Abdel-Rahman, M.A.M., Albano, M., and Mahmoud, M.M. (2024). Streptococcus agalactiae Infection in Nile Tilapia (Oreochromis niloticus): A Review. Biology, 13.","DOI":"10.3390\/biology13110914"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"58","DOI":"10.1016\/j.aqrep.2015.12.002","article-title":"Evidence of vertical transmission and tissue tropism of Streptococcosis from naturally infected red tilapia (Oreochromis spp.)","volume":"3","author":"Pradeep","year":"2016","journal-title":"Aquac. Rep."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"1431","DOI":"10.1111\/jfd.13247","article-title":"Isolation and molecular characterization of streptococcal species recovered from clinical infections in farmed Nile tilapia (Oreochromis niloticus) in the Philippines","volume":"43","author":"Legario","year":"2020","journal-title":"J. Fish Dis."},{"key":"ref_56","first-page":"119","article-title":"Report on Intussusception in Channel Catfish Ictalurus Punctatus (Rafinesque, 1818) from Commercial Farms in Mexico: A Case Study","volume":"65","year":"2018","journal-title":"Indian J. Fish."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"154","DOI":"10.1111\/raq.12743","article-title":"Bacterial diseases of tilapia, their zoonotic potential and risk of antimicrobial resistance","volume":"15","author":"Haenen","year":"2023","journal-title":"Rev. Aquac."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"737370","DOI":"10.1016\/j.aquaculture.2021.737370","article-title":"Distribution and localization of Streptococcus agalactiae in different tissues of artificially infected tilapia (Oreochromis niloticus)","volume":"546","author":"Cao","year":"2022","journal-title":"Aquaculture"},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"8945","DOI":"10.12681\/jhvms.36285","article-title":"Ocular Ailments Doctrine (Ophthalmology) in Fish: Exophthalmia Scenario as Forzando and Eyes-Brain Connection","volume":"76","author":"Filik","year":"2025","journal-title":"J. Hell. Vet. Med. Soc."},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1016\/j.micpath.2015.01.007","article-title":"Streptococcus agalactiae infection in zebrafish larvae","volume":"79","author":"Kim","year":"2015","journal-title":"Microb. Pathog."},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"6","DOI":"10.2174\/1874318809003010006","article-title":"Fecal strings associated with Streptococcus agalactiae infection in Nile tilapia, Oreochromis niloticus","volume":"3","author":"Pasnik","year":"2009","journal-title":"Open Vet. Sci. J."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"735387","DOI":"10.1016\/j.aquaculture.2020.735387","article-title":"Anatomopathological characterization and etiology of lesions on Nile tilapia fillets (Oreochromis niloticus) caused by bacterial pathogens","volume":"526","author":"Ferreira","year":"2020","journal-title":"Aquaculture"},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"4185","DOI":"10.1038\/s41598-022-08097-0","article-title":"Genomic epidemiology of Streptococcus agalactiae ST283 in Southeast Asia","volume":"12","author":"Aiewsakun","year":"2022","journal-title":"Sci. Rep."},{"key":"ref_64","doi-asserted-by":"crossref","unstructured":"Barkham, T., Zadoks, R.N., Azmai, M.N.A., Baker, S., Bich, V.T.N., Chalker, V., Chau, M.L., Dance, D., Deepak, R.N., and van Doorn, H.R. (2019). One hypervirulent clone, sequence type 283, accounts for a large proportion of invasive Streptococcus agalactiae isolated from humans and diseased tilapia in Southeast Asia. PLoS Negl. Trop. Dis., 13.","DOI":"10.1371\/journal.pntd.0007421"},{"key":"ref_65","doi-asserted-by":"crossref","first-page":"2276","DOI":"10.1128\/IAI.01559-13","article-title":"Identification of a Group B Streptococcal Fibronectin Binding Protein, SfbA, That Contributes to Invasion of Brain Endothelium and Development of Meningitis","volume":"82","author":"Mu","year":"2014","journal-title":"Infect. Immun."},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"1479","DOI":"10.1086\/598217","article-title":"The group B streptococcal serine-rich repeat 1 glycoprotein mediates penetration of the blood-brain barrier","volume":"199","author":"Quach","year":"2009","journal-title":"J. Infect. Dis."},{"key":"ref_67","doi-asserted-by":"crossref","first-page":"2499","DOI":"10.1172\/JCI23829","article-title":"Blood-brain barrier invasion by group B Streptococcus depends upon proper cell-surface anchoring of lipoteichoic acid","volume":"115","author":"Doran","year":"2005","journal-title":"J. Clin. Investig."},{"key":"ref_68","doi-asserted-by":"crossref","first-page":"736","DOI":"10.1172\/JCI200317335","article-title":"Group B streptococcal beta-hemolysin\/cytolysin activates neutrophil signaling pathways in brain endothelium and contributes to development of meningitis","volume":"112","author":"Doran","year":"2003","journal-title":"J. Clin. Investig."},{"key":"ref_69","doi-asserted-by":"crossref","first-page":"13529","DOI":"10.1038\/s41598-017-13234-1","article-title":"Quantitative assessment of the blood-brain barrier opening caused by Streptococcus agalactiae hyaluronidase in a BALB\/c mouse model","volume":"7","author":"Luo","year":"2017","journal-title":"Sci. Rep."},{"key":"ref_70","doi-asserted-by":"crossref","unstructured":"Magalh\u00e3es, V., Andrade, E.B., Alves, J., Ribeiro, A., Kim, K.S., Lima, M., Trieu-Cuot, P., and Ferreira, P. (2013). Group B Streptococcus Hijacks the Host Plasminogen System to Promote Brain Endothelial Cell Invasion. PLoS ONE, 8.","DOI":"10.1371\/journal.pone.0063244"},{"key":"ref_71","doi-asserted-by":"crossref","unstructured":"Ravishankar, S., Tuohey, S.M., Ramos, N.O., Uchiyama, S., Hayes, M.I., Kang, K., Nizet, V., and Madigan, C.A. (2025). Group B Streptococci lyse endothelial cells to infect the brain in a zebrafish meningitis model. PLoS Biol., 23.","DOI":"10.1371\/journal.pbio.3003236"},{"key":"ref_72","doi-asserted-by":"crossref","first-page":"309","DOI":"10.56808\/2985-1130.2314","article-title":"Effect of water temperature on susceptibility to Streptococcus agalactiae serotype Ia infection in Nile tilapia (Oreochromis niloticus)","volume":"41","author":"Rodkhum","year":"2011","journal-title":"Thai J. Vet. Med."},{"key":"ref_73","doi-asserted-by":"crossref","unstructured":"Barr\u00eda, A., Benzie, J.A.H., Houston, R.D., De Koning, D.-J., and de Verdal, H. (2021). Genomic Selection and Genome-wide Association Study for Feed-Efficiency Traits in a Farmed Nile Tilapia (Oreochromis niloticus) Population. Front. Genet., 12.","DOI":"10.3389\/fgene.2021.737906"},{"key":"ref_74","doi-asserted-by":"crossref","first-page":"27","DOI":"10.1111\/j.1753-5131.2010.01041.x","article-title":"Genetic improvement of Nile tilapia (Oreochromis niloticus) with special reference to the work conducted by the WorldFish Center with the GIFT strain","volume":"3","author":"Ponzoni","year":"2011","journal-title":"Rev. Aquac."},{"key":"ref_75","doi-asserted-by":"crossref","first-page":"3697","DOI":"10.3390\/su6063697","article-title":"Genetically-Improved Tilapia Strains in Africa: Potential Benefits and Negative Impacts","volume":"6","author":"Ansah","year":"2014","journal-title":"Sustainability"},{"key":"ref_76","doi-asserted-by":"crossref","first-page":"741666","DOI":"10.1016\/j.aquaculture.2024.741666","article-title":"A long-term high temperature on young Nile tilapia females affects its urogenital papilla morphology and future reproductive performance","volume":"595","author":"Bezerra","year":"2025","journal-title":"Aquaculture"},{"key":"ref_77","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1007\/s44154-023-00099-w","article-title":"Acute hyperthermia and hypoxia tolerance of two improved strains of nile tilapia (Oreochromis niloticus)","volume":"3","author":"Obirikorang","year":"2023","journal-title":"Stress Biol."},{"key":"ref_78","doi-asserted-by":"crossref","unstructured":"de Verdal, H., Vandeputte, M., Mekkawy, W., Chatain, B., and Benzie, J.A.H. (2018). Quantifying the genetic parameters of feed efficiency in juvenile Nile tilapia Oreochromis niloticus. BMC Genet., 19.","DOI":"10.1186\/s12863-018-0691-y"},{"key":"ref_79","doi-asserted-by":"crossref","first-page":"489","DOI":"10.1016\/j.aquaculture.2016.11.015","article-title":"Measuring individual feed efficiency and its correlations with performance traits in Nile tilapia, Oreochromis niloticus","volume":"468","author":"Mekkawy","year":"2017","journal-title":"Aquaculture"},{"key":"ref_80","doi-asserted-by":"crossref","unstructured":"Nivelle, R., Gennotte, V., Kalala, E.J.K., Ngoc, N.B., Muller, M., M\u00e9lard, C., and Rougeot, C. (2019). Temperature preference of Nile tilapia (Oreochromis niloticus) juveniles induces spontaneous sex reversal. PLoS ONE, 14.","DOI":"10.1371\/journal.pone.0214689"},{"key":"ref_81","doi-asserted-by":"crossref","first-page":"741017","DOI":"10.1016\/j.aquaculture.2024.741017","article-title":"Effect of increasing ambient temperature on physiological changes, oxidative stress, nitric oxide, total antioxidant power, and mitochondrial activity of Nile tilapia (Oreochromis niloticus Linn.)","volume":"589","author":"Jinagool","year":"2024","journal-title":"Aquaculture"},{"key":"ref_82","doi-asserted-by":"crossref","first-page":"42","DOI":"10.1016\/j.aquaculture.2010.02.009","article-title":"Inbreeding and effective population size in the Malaysian nucleus of the GIFT strain of Nile tilapia (Oreochromis niloticus)","volume":"302","author":"Ponzoni","year":"2010","journal-title":"Aquaculture"},{"key":"ref_83","doi-asserted-by":"crossref","unstructured":"Nguyen, N.H., Hamzah, A., and Thoa, N.P. (2017). Effects of Genotype by Environment Interaction on Genetic Gain and Genetic Parameter Estimates in Red Tilapia (Oreochromis spp.). Front. Genet., 8.","DOI":"10.3389\/fgene.2017.00082"},{"key":"ref_84","doi-asserted-by":"crossref","unstructured":"Nitzan, T., Kokou, F., Doron-Faigenboim, A., Slosman, T., Biran, J., Mizrahi, I., Zak, T., Benet, A., and Cnaani, A. (2019). Transcriptome Analysis Reveals Common and Differential Response to Low Temperature Exposure Between Tolerant and Sensitive Blue Tilapia (Oreochromis aureus). Front. Genet., 10.","DOI":"10.3389\/fgene.2019.00100"},{"key":"ref_85","doi-asserted-by":"crossref","first-page":"172","DOI":"10.1038\/s41598-017-18512-6","article-title":"Physiological response and microRNA expression profiles in head kidney of genetically improved farmed tilapia (GIFT, Oreochromis niloticus) exposed to acute cold stress","volume":"8","author":"Qiang","year":"2018","journal-title":"Sci. Rep."},{"key":"ref_86","first-page":"135","article-title":"Environmental and Genetic Factors Shaping the Global Expansion of Tilapia Aquaculture","volume":"15","author":"Wang","year":"2025","journal-title":"Int. J. Aquac."},{"key":"ref_87","doi-asserted-by":"crossref","unstructured":"Liao, P.-C., Tsai, Y.-L., Chen, Y.-C., Wang, P.-C., Liu, S.-C., and Chen, S.-C. (2020). Analysis of streptococcal infection and correlation with climatic factors in cultured tilapia Oreochromis spp. in Taiwan. Appl. Sci., 10.","DOI":"10.3390\/app10114018"},{"key":"ref_88","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1111\/raq.12776","article-title":"Improving tilapia biosecurity through a value chain approach","volume":"15","author":"MacKinnon","year":"2023","journal-title":"Rev. Aquac."},{"key":"ref_89","doi-asserted-by":"crossref","first-page":"467","DOI":"10.1038\/d41586-024-00816-z","article-title":"Climate models can\u2019t explain 2023\u2019s huge heat anomaly\u2014We could be in uncharted territory","volume":"627","author":"Schmidt","year":"2024","journal-title":"Nature"},{"key":"ref_90","doi-asserted-by":"crossref","unstructured":"Sirimanapong, W., Ph\u01b0\u1edbc, N.N., Crestani, C., Chen, S., and Zadoks, R.N. (2023). Geographical, Temporal and Host-Species Distribution of Potentially Human-Pathogenic Group B Streptococcus in Aquaculture Species in Southeast Asia. Pathogens, 12.","DOI":"10.3390\/pathogens12040525"},{"key":"ref_91","doi-asserted-by":"crossref","first-page":"e00859-00818","DOI":"10.1128\/AEM.00859-18","article-title":"Microevolution of Streptococcus agalactiae ST-261 from Australia Indicates Dissemination via Imported Tilapia and Ongoing Adaptation to Marine Hosts or Environment","volume":"84","author":"Kawasaki","year":"2018","journal-title":"Appl. Environ. Microbiol."},{"key":"ref_92","doi-asserted-by":"crossref","first-page":"104195","DOI":"10.1016\/j.meegid.2020.104195","article-title":"Comparative genomic analysis and identification of pathogenicity islands of hypervirulent ST-17 Streptococcus agalactiae Brazilian strain","volume":"80","author":"Ramos","year":"2020","journal-title":"Infect. Genet. Evol."},{"key":"ref_93","doi-asserted-by":"crossref","unstructured":"He, Y., Huang, J.-L., Wang, K.-Y., Chen, D.-F., Geng, Y., Huang, X.-L., Ou-Yang, P., Zhou, Y., Wang, J., and Min, J. (2017). Pathogenicity of Streptococcus agalactiae in Oreochromis niloticus. Oncotarget, 5.","DOI":"10.18632\/oncotarget.23551"},{"key":"ref_94","doi-asserted-by":"crossref","first-page":"119","DOI":"10.15578\/iaj.16.2.2021.119-125","article-title":"Virulence gene profiling and pathogenicity of Streptococcus agalactiae isolated from tilapia, Oreochromis niloticus farms in Indonesia","volume":"16","author":"Sukenda","year":"2021","journal-title":"Indones. Aquac. J."},{"key":"ref_95","doi-asserted-by":"crossref","first-page":"fnz154","DOI":"10.1093\/femsle\/fnz154","article-title":"Molecular typing of Streptococcus agalactiae isolates of serotype la from tilapia in southern China","volume":"366","author":"Su","year":"2019","journal-title":"FEMS Microbiol. Lett."},{"key":"ref_96","doi-asserted-by":"crossref","first-page":"95","DOI":"10.5455\/javar.2022.i573","article-title":"Prevalence, antimicrobial susceptibility, and genotyping of Streptococcus agalactiae in Tilapia fish (Oreochromis niloticus) in Egypt","volume":"9","author":"Alazab","year":"2022","journal-title":"J. Adv. Vet. Anim. Res."},{"key":"ref_97","doi-asserted-by":"crossref","first-page":"27","DOI":"10.3354\/dao03780","article-title":"Serotype distribution, virulence and antibiotic resistance of Streptococcus agalactiae isolated from cultured tilapia Oreochromis niloticus in Lake Volta, Ghana","volume":"158","author":"Duodu","year":"2024","journal-title":"Dis. Aquat. Organ."},{"key":"ref_98","doi-asserted-by":"crossref","unstructured":"Hsu, C.Y., Moradkasani, S., Suliman, M., Uthirapathy, S., Zwamel, A.H., Hjazi, A., Vashishth, R., and Beig, M. (2025). Global patterns of antibiotic resistance in group B Streptococcus: A systematic review and meta-analysis. Front. Microbiol., 16.","DOI":"10.3389\/fmicb.2025.1541524"},{"key":"ref_99","doi-asserted-by":"crossref","unstructured":"Mohammadi, A., Amini, C., Bagheri, P., Salehi, Z., and Goudarzi, M. (2024). Unveiling the genetic landscape of Streptococcus agalactiae bacteremia: Emergence of hypervirulent CC1 strains and new CC283 strains in Tehran, Iran. BMC Microbiol., 24.","DOI":"10.1186\/s12866-024-03521-z"}],"container-title":["Pathogens"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-0817\/15\/5\/545\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,19]],"date-time":"2026-05-19T16:26:44Z","timestamp":1779208004000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-0817\/15\/5\/545"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,5,18]]},"references-count":99,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2026,5]]}},"alternative-id":["pathogens15050545"],"URL":"https:\/\/doi.org\/10.3390\/pathogens15050545","relation":{},"ISSN":["2076-0817"],"issn-type":[{"value":"2076-0817","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,5,18]]}}}