{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,13]],"date-time":"2026-10-13T04:39:41Z","timestamp":1791866381391,"version":"4.3.4"},"reference-count":31,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2023,4,22]],"date-time":"2023-04-22T00:00:00Z","timestamp":1682121600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"United States Department of Agriculture National Institute of Food and Agriculture (USDA-NIFA) Animal Health CACALV-AH-408"},{"name":"California Department of Fish and Wildlife\u2014Statewide Fish Disease Research Program"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pathogens"],"abstract":"<jats:p>Lactococcus petauri is an important emergent bacterial pathogen of salmonids in the USA. The purpose of this study was to evaluate the protection conferred to rainbow trout (Oncorhynchus mykiss) against L. petauri by formalin-killed vaccines in immersion and injectable forms, as well as the enhanced protection afforded by booster vaccination. In the first challenge, fish were immunized via intracoelomic injection (IC) or immersion (Imm) routes alone. Approximately 418 degree days (Temperature in degree Celsius \u00d7 days post-immunization) (dd) Imm, or 622 dd IC post-vaccination, fish were challenged via IC with wild-type L. petauri. In the second experiment, initial Imm vaccination was followed by booster vaccination via Imm or IC routes 273 dd post-immunization along with appropriate PBS controls. The various vaccination protocol efficacies were evaluated by challenging fish with L. petauri by cohabitation with diseased fish 399 dd post-booster administration. A relative percent survival (RPS) of 89.5% and 28% was recorded in the IC and Imm single immunization treatments, respectively. In the second study, an RPS of 97.5%, 10.2%, 2.6% and \u221210.1% plus approximately 0%, 50%, 20%, and 30% bacterial persistence was recorded in the Imm immunized + IC boosted, Imm immunized + mock IC boosted, Imm immunized + Imm boosted, and Imm immunized + mock Imm boosted treatments, respectively. Only the Imm immunized + IC injection boosted treatments provided significant protection when compared to unvaccinated and challenged treatments (p &lt; 0.05). In conclusion, although both Imm and IC vaccines appear safe for trout, the inactivated Imm vaccines seem to provide only mild and temporary protection against lactococcosis; whereas IC immunized trout develop a significantly stronger protective response in both challenges.<\/jats:p>","DOI":"10.3390\/pathogens12050632","type":"journal-article","created":{"date-parts":[[2023,4,24]],"date-time":"2023-04-24T03:38:07Z","timestamp":1682307487000},"page":"632","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":18,"title":["Comparative Evaluation of Booster Vaccine Efficacy by Intracoelomic Injection and Immersion with a Whole-Cell Killed Vaccine against Lactococcus petauri Infection in Rainbow Trout (Oncorhynchus mykiss)"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4636-6270","authenticated-orcid":false,"given":"Tryssa","family":"de Ruyter","sequence":"first","affiliation":[{"name":"Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California\u2013Davis, Davis, CA 95616, USA"},{"name":"School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eric","family":"Littman","sequence":"additional","affiliation":[{"name":"Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California\u2013Davis, Davis, CA 95616, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zeinab","family":"Yazdi","sequence":"additional","affiliation":[{"name":"Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California\u2013Davis, Davis, CA 95616, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mark","family":"Adkison","sequence":"additional","affiliation":[{"name":"California Department of Fish and Wildlife, Rancho Cordova, CA 95670, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alvin","family":"Camus","sequence":"additional","affiliation":[{"name":"Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Susan","family":"Yun","sequence":"additional","affiliation":[{"name":"Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California\u2013Davis, Davis, CA 95616, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Timothy J.","family":"Welch","sequence":"additional","affiliation":[{"name":"National Center for Cool and Coldwater Aquaculture, Kearneysville, WV 25430, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"William R.","family":"Keleher","sequence":"additional","affiliation":[{"name":"Kennebec River Biosciences, Richmond, ME 04357, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Esteban","family":"Soto","sequence":"additional","affiliation":[{"name":"Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California\u2013Davis, Davis, CA 95616, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,4,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1089","DOI":"10.1007\/s00284-020-01905-8","article-title":"First Report of Isolation and Genome Sequence of L. petauri Strain from a Rainbow Trout Lactococcosis Outbreak","volume":"77","author":"Kotzamanidis","year":"2020","journal-title":"Curr. Microbiol."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Austin, B., and Austin, D.A. (2016). Bacterial Fish Pathogens: Disease of Farmed and Wild Fish, Springer International Publishing AG.","DOI":"10.1007\/978-3-319-32674-0"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"67","DOI":"10.3354\/dao03083","article-title":"Lactococcus garvieae: An Emerging Bacterial Pathogen of Fish","volume":"123","author":"Meyburgh","year":"2017","journal-title":"Dis. Aquat. Organ."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"4397","DOI":"10.1099\/ijsem.0.002303","article-title":"Lactococcus petauri sp. Nov., Isolated from an Abscess of a Sugar Glider","volume":"67","author":"Goodman","year":"2017","journal-title":"Int. J. Syst. Evol. Microbiol."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Ortega, C., Irgang, R., Valladares-Carranza, B., Collarte, C., and Avenda\u00f1o-Herrera, R. (2020). First Identification and Characterization of Lactococcus garvieae Isolated from Rainbow Trout (Oncorhynchus mykiss) Cultured in Mexico. Animals, 10.","DOI":"10.3390\/ani10091609"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1016\/j.cimid.2006.06.003","article-title":"Lactococcus garvieae in Fish: A Review","volume":"29","author":"Vendrell","year":"2006","journal-title":"Comp. Immunol. Microbiol. Infect. Dis."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"e0054621","DOI":"10.1128\/MRA.00546-21","article-title":"Genome Sequences of Lactococcus garvieae and Lactococcus petauri Strains Isolated from Traditional Montenegrin Brine Cheeses","volume":"10","author":"Martinovic","year":"2021","journal-title":"Microbiol. Resour. Announc."},{"key":"ref_8","first-page":"3427","article-title":"Streptococcus garvieae sp. Nov. and Streptococcus plantarum sp. Nov","volume":"129","author":"Collins","year":"1983","journal-title":"J. Gen. Microbiol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"e00781-16","DOI":"10.1128\/genomeA.00781-16","article-title":"Draft Genome Sequence of Lactococcus garvieae Strain PAQ102015-99, an Outbreak Strain Isolated from a Commercial Trout Farm in the Northwestern United States","volume":"4","author":"Nelson","year":"2016","journal-title":"Genome Announc."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"2326","DOI":"10.1111\/tbed.14250","article-title":"Isolation and Characterization of Lactococcus garvieae from Rainbow Trout, Onchorhyncus mykiss, from California, USA","volume":"69","author":"Shahin","year":"2021","journal-title":"Transbound. Emerg. Dis."},{"key":"ref_11","unstructured":"Heckman, T.I., Yazdi, Z., Griffin, M.J., Waldbieser, G.C., Welch, T.J., Abraham, T., Littman, E.M., Chow, A.M., Shahin, K., and Mukkatira, K. (2022, January 5\u20138). For Lac of a Better Name: Redefining Piscine Lactococcosis. Proceedings of the 9th International Symposium on Aquatic Animal Health; Santiago, Chile."},{"key":"ref_12","unstructured":"California Department of Fish and Wildlife (CDFW) (2022, June 27). CDFW to Supplement Fish Stocks for Anglers as Bacterial Outbreak Leads to Further Losses at Two Eastern Sierra Trout Hatcheries, Available online: https:\/\/wildlife.ca.gov\/News\/cdfw-to-supplement-fish-stocks-for-anglers-as-bacterial-outbreak-leads-to-further-losses-at-two-eastern-sierra-trout-hatcheries#gsc.tab=0."},{"key":"ref_13","first-page":"19","article-title":"Veterinary Autogenous Vaccines","volume":"117","author":"Hera","year":"2004","journal-title":"Dev. Biol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1759","DOI":"10.1016\/j.fsi.2013.05.029","article-title":"Status and Future Perspectives of Vaccines for Industrialised Fin-Fish Farming","volume":"35","author":"Brudeseth","year":"2013","journal-title":"Fish Shellfish Immunol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"184","DOI":"10.1080\/23308249.2016.1261277","article-title":"Advances in Aquaculture Vaccines Against Fish Pathogens: Global Status and Current Trends","volume":"25","author":"Dadar","year":"2016","journal-title":"Rev. Fish. Sci. Aquac."},{"key":"ref_16","unstructured":"Soto, E., Griffin, M.J., and Tobar, J.A. (2015). Mucosal Health in Aquaculture, Academic Press."},{"key":"ref_17","first-page":"447","article-title":"Potency Testing of Fish Vaccines","volume":"49","author":"Amend","year":"1981","journal-title":"Dev. Biol. Stand."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"132","DOI":"10.1016\/j.fsi.2018.03.060","article-title":"Correlates of Protective Immunity for Fish Vaccines","volume":"85","author":"Evensen","year":"2019","journal-title":"Fish Shellfish Immunol."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"B\u00f8gwald, J., and Dalmo, R.A. (2019). Review on Immersion Vaccines for Fish: An Update 2019. Microorganisms, 7.","DOI":"10.3390\/microorganisms7120627"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"331","DOI":"10.1111\/j.1365-2761.1983.tb00084.x","article-title":"Comparison of Efficacy of Several Delivery Methods Using Yersinia ruckeri Bacterin on Rainbow Trout, Salmo gairdneri Richardson","volume":"6","author":"Johnson","year":"1983","journal-title":"J. Fish Dis."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"119","DOI":"10.1016\/j.aquaculture.2004.02.028","article-title":"Oral Immunization Using Alginate Microparticles as a Useful Strategy for Booster Vaccination against Fish Lactoccocosis","volume":"236","author":"Romalde","year":"2004","journal-title":"Aquaculture"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"505","DOI":"10.1016\/j.fsi.2020.02.033","article-title":"High Efficacy and Economical Procedure of Oral Vaccination against Lactococcus garvieae \/Streptococcus iniae in Rainbow Trout (Oncorhynchus mykiss)","volume":"99","author":"Halimi","year":"2020","journal-title":"Fish Shellfish Immunol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1016\/j.aquaculture.2005.05.027","article-title":"Use of Adjuvanted Vaccines to Lengthen the Protection against Lactococcosis in Rainbow Trout (Oncorhynchus mykiss)","volume":"251","author":"Ravelo","year":"2006","journal-title":"Aquaculture"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"222","DOI":"10.1016\/j.prevetmed.2007.02.008","article-title":"Safety and Efficacy of an Inactivated Vaccine against Lactococcus garvieae in Rainbow Trout (Oncorhynchus mykiss)","volume":"80","author":"Vendrell","year":"2007","journal-title":"Prev. Vet. Med."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"756","DOI":"10.1016\/j.fsi.2012.01.028","article-title":"Effectiveness of Bivalent Vaccines against Aeromonas hydrophila and Lactococcus garvieae Infections in Rainbow Trout Oncorhynchus mykiss (Walbaum)","volume":"32","author":"Bastardo","year":"2012","journal-title":"Fish Shellfish Immunol."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Bwalya, P., Hang\u2019ombe, B.M., Gamil, A.A., Munang\u2019andu, H.M., Evensen, \u00d8., and Mutoloki, S. (2020). A Whole-Cell Lactococcus garvieae Autovaccine Protects Nile Tilapia against Infection. PLoS ONE, 15.","DOI":"10.1371\/journal.pone.0230739"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1579","DOI":"10.1111\/jfd.13260","article-title":"Efficacy of a Formalin-Inactivated Lactococcus garvieae Vaccine in Farmed Grey Mullet (Mugil Cephalus)","volume":"43","author":"Rao","year":"2020","journal-title":"J. Fish Dis."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"263","DOI":"10.1111\/jfd.12509","article-title":"Lactococcus garvieae Outbreaks in Brazilian Farms Lactococcosis in Pseudoplatystoma sp.\u2014Development of an Autogenous Vaccine as a Control Strategy","volume":"40","author":"Fukushima","year":"2017","journal-title":"J. Fish Dis."},{"key":"ref_29","first-page":"85","article-title":"Vaccination Strategies to Prevent Emerging Diseases for Spanish Aquaculture","volume":"121","author":"Romalde","year":"2005","journal-title":"Dev. Biol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"519","DOI":"10.3389\/fimmu.2015.00519","article-title":"Oral Vaccination of Fish\u2014Antigen Preparations, Uptake, and Immune Induction","volume":"6","author":"Mutoloki","year":"2015","journal-title":"Front. Immunol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"16","DOI":"10.1016\/j.fsi.2020.06.049","article-title":"Primary Immunization Using Low Antigen Dosages and Immunological Tolerance in Rainbow Trout","volume":"105","author":"Marana","year":"2020","journal-title":"Fish Shellfish Immunol."}],"container-title":["Pathogens"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-0817\/12\/5\/632\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T19:21:23Z","timestamp":1760124083000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-0817\/12\/5\/632"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,4,22]]},"references-count":31,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2023,5]]}},"alternative-id":["pathogens12050632"],"URL":"https:\/\/doi.org\/10.3390\/pathogens12050632","relation":{},"ISSN":["2076-0817"],"issn-type":[{"value":"2076-0817","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,4,22]]}}}