Avian diseasesPub Date : 2025-04-01DOI: 10.1637/aviandiseases-D-24-00076
Helena Eriksson, Eva Wattrang, Robert Söderlund, Désirée S Jansson
{"title":"Erysipelas-A Review of an Emerging Disease in Layers.","authors":"Helena Eriksson, Eva Wattrang, Robert Söderlund, Désirée S Jansson","doi":"10.1637/aviandiseases-D-24-00076","DOIUrl":"https://doi.org/10.1637/aviandiseases-D-24-00076","url":null,"abstract":"<p><p>Despite being a disease known to affect poultry for well over 100 years, several aspects of erysipelas, caused by <i>Erysipelothrix rhusiopathiae</i>, are still poorly understood. For many years, erysipelas in poultry was considered a disease of interest primarily in turkeys, with only a few cases reported in chickens and other poultry species. However, since the change of housing systems for layers from conventional battery cages to litter-based systems, sometimes with access to the outdoors, there has been an increase in the number of outbreaks, especially in Europe, and erysipelas is now considered to be an emerging disease in layers. The aim of this review is therefore to provide a summary background on erysipelas in general, as well as in other poultry species, after which the focus is directed to the disease in chickens, with special emphasis on recent advances in knowledge on immune responses.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"68 S1","pages":"506-520"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144057055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Avian diseasesPub Date : 2025-04-01DOI: 10.1637/aviandiseases-D-24-00066
Eman Gadu, Amro Hashish, Mostafa M S Shelkamy, Maria Chaves, Osemeke Onyekachukwu, Mariela E Srednik, Yuko Sato, Mohamed El-Gazzar
{"title":"Development and Validation of TaqMan Real-Time Quantitative PCR Assay for Improved Diagnosis of Spotty Liver Disease.","authors":"Eman Gadu, Amro Hashish, Mostafa M S Shelkamy, Maria Chaves, Osemeke Onyekachukwu, Mariela E Srednik, Yuko Sato, Mohamed El-Gazzar","doi":"10.1637/aviandiseases-D-24-00066","DOIUrl":"https://doi.org/10.1637/aviandiseases-D-24-00066","url":null,"abstract":"<p><p>Spotty liver disease (SLD) is a reemerging infection caused by <i>Campylobacter</i> species that results in increased mortality and reduced egg production, with increased incidence in cage-free commercial layer hens. Recently, <i>Campylobacter hepaticus</i> has been identified as a key pathogen responsible for SLD. The laboratory diagnosis of SLD primarily relies on isolating <i>C. hepaticus</i> colonies, a process hindered by the bacterium's fastidious nature and the requirement for time-consuming and specialized culture conditions. Molecular diagnosis using quantitative real-time PCR (qPCR) overcomes these limitations and offers a more sensitive and specific alternative. However, the existing qPCR assay using a DNA-binding dye chemistry suffers from nonspecific binding to any double-stranded DNA in the sample, which could potentially lead to an increased incidence of false-positive cases. In this study, we present the development of a more specific TaqMan probe-based qPCR assay targeting the glycerol kinase gene of <i>C. hepaticus</i>. This assay demonstrated excellent analytical specificity and sensitivity, with a detection limit of 5 copies/µl and a PCR efficiency of 95.15%. Additionally, it exhibited 100% diagnostic specificity and sensitivity. Furthermore, probe-based PCRs are the most commonly used type of diagnostic PCR assay and are much better suited for routine diagnostics compared to other types of PCRs. In conclusion, the newly developed assay represents a significant advancement in the accurate and efficient diagnosis of SLD caused by <i>C. hepaticus</i> directly from clinical samples.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"68 S1","pages":"499-505"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144061490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Avian diseasesPub Date : 2025-04-01DOI: 10.1637/aviandiseases-D-24-00064
Aaliyah Gore, Grayson K Walker, Mitsu Suyemoto, Mike Petrik, Rocio Crespo
{"title":"Characterization of <i>Enterococcus faecalis</i> Isolated from Pullet Layers with Growth Depression and Amyloid Arthropathy.","authors":"Aaliyah Gore, Grayson K Walker, Mitsu Suyemoto, Mike Petrik, Rocio Crespo","doi":"10.1637/aviandiseases-D-24-00064","DOIUrl":"https://doi.org/10.1637/aviandiseases-D-24-00064","url":null,"abstract":"<p><p><i>Enterococcus faecalis</i> is a commensal bacterium that colonizes the intestines of mammals and birds. It is characterized as an opportunistic pathogen and has been commonly associated with late-stage embryonic mortality, omphalitis, growth depression, sepsis, and amyloid arthropathy in poultry. In this study, <i>E. faecalis</i> isolates recovered from a flock of 6200 layer pullets located in Canada exhibited impaired growth, poor uniformity, and sporadic lameness that started at 1 wk of age and extended throughout the rearing phase. <i>Enterococcus faecalis</i> was isolated from swollen tarsometatarsal joints of lame pullets that contained yellow-orange material and from the house environment. Two sequence types (STs) known to be pathogenic to chickens, ST82 and ST49, were identified among the joint isolates. Seventeen known <i>E. faecalis</i> virulence genes were detected in these strains, including <i>gelE</i> for gelatinase production and the <i>fsrB</i> quorum-sensing signaling peptide gene required for virulence regulation. Phylogenetic analysis revealed that an ST82 strain isolated from an environmental sample was clonally related to the joint isolate. Furthermore, both sequence types, ST82 and ST49, had antimicrobial-resistance genes against tetracyclines, lincosamide, and streptogramin antimicrobials. ST49 had additional resistance genes to common ionophores used in poultry production. An embryo lethality assay was conducted to determine the pathogenicity of isolates. Inoculation with ST82 resulted in significantly lower survivability of embryos compared to ST49. To date, cases of amyloid arthropathy caused by <i>E. faecalis</i> are reported in European countries, but rarely from North American poultry operations. Further characterization of these <i>E. faecalis</i> strains is needed to elucidate transmission routes, uncover environmental reservoirs, and identify specific virulence genes in the development of amyloid arthropathy in poultry.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"68 S1","pages":"435-442"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144061586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Avian diseasesPub Date : 2025-04-01DOI: 10.1637/aviandiseases-D-24-00090
Ben Wade, Silke Rautenschlein, T T Hao Van, Robert J Moore
{"title":"<i>Campylobacter hepaticus</i> and Spotty Liver Disease in Poultry.","authors":"Ben Wade, Silke Rautenschlein, T T Hao Van, Robert J Moore","doi":"10.1637/aviandiseases-D-24-00090","DOIUrl":"https://doi.org/10.1637/aviandiseases-D-24-00090","url":null,"abstract":"<p><p>Spotty liver disease is an economically important, emerging disease that primarily impacts the cage-free poultry layer industry. While this disease remains understudied, several important findings have been reported in the last 5 yr that warrant an updated review of the field. These include updated cost estimates of disease, insights into the molecular biology of the causative agent, the identification of a second bacterium responsible for disease production, insights into disease epidemiology and interventions, and the generation of new molecular tools for further study.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"68 S1","pages":"481-489"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144049389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ornithobacterium rhinotracheale in Moroccan Poultry: Antimicrobial Susceptibility Profiles, Characterization of Recent Isolates, and Retrospective Study (2019-23) of Its Occurrence in Different Poultry Production Systems.","authors":"Yassmina Bidoudan, Siham Fellahi, Ouafaa Fassi Fihri, Enrico Bollo, Mounir Khayli, Mohamed Mouahid, Noursaid Tligui","doi":"10.1637/aviandiseases-D-24-00078","DOIUrl":"https://doi.org/10.1637/aviandiseases-D-24-00078","url":null,"abstract":"<p><p><i>Ornithobacterium rhinotracheale</i> (ORT) is one of the most important respiratory pathogens of poultry, notably in turkeys, while <i>Riemerella anatipestifer</i> (RA) is the etiologic agent of infectious serositis, the most economically significant disease of domestic ducks and, to a lesser extent, geese and turkeys. Currently, little is known about ORT and RA infections in Moroccan poultry. Thus, the main aim of this study was to describe ORT incidence in Moroccan poultry flocks during the period from 2019 to 2023 and gain better insights into genetic characteristics in combination with assessment of antimicrobial susceptibility of Moroccan ORT isolates during 2023 outbreaks. In addition, we report the first detection of RA in Moroccan turkeys and caged layer chickens. For this purpose, poultry flocks exhibiting elevated mortality rates along with respiratory clinical signs were necropsied. Additionally, the birds presenting fibrinous pleuropneumonia were investigated for ORT infection during the period from January to December 2023. Samples of the lungs, air sacs, and tracheas were collected for bacteriology testing, and the antimicrobial susceptibility testing was conducted on the isolates. Furthermore, trachea and lung samples were subjected to real-time quantitative polymerase chain reaction (qPCR), and positive qPCR samples were then selected for further amplification of the <i>rpoB</i> gene, followed by sequencing. Moreover, a retrospective study of the incidence of ORT from 2019 to 2023 was carried out. The results showed a significant increase of ORT cases (<i>p</i> , 0.001); additionally, age was identified as the sole significant risk factor associated with ORT diagnosis in the multivariable logistic regression analysis (odds ratio = 4.87, 95% confidence interval = 2.54-9.37, <i>p</i> , 0.001). Bacteriology confirmed 10 ORT isolates. Additionally, antimicrobial susceptibility testing revealed complete resistance to several antibiotics, with varying levels of resistance and sensitivity across isolates, including 100% sensitivity to florfenicol in broilers and turkeys. Sequencing of the <i>rpoB</i> gene revealed that 10 ORT isolates had nucleotide similarity ranging from 98% to 100% with other known ORT isolates from chickens and turkeys reported in the U.K., Chile, China, Portugal, and the United States. On the other hand, two ORT isolates were found to be genetically very close to known RA strains, despite testing positive for ORT by real-time qPCR. Amino acid sequence comparisons for these isolates reached 83.10% similarity with <i>Riemerella</i> sp. strain WJ4 isolated in China and 98.79% similarity with strain IPDH 98/90 isolated in Germany. In conclusion, the prevalence of ORT in Moroccan poultry flocks increased over the 5-yr period covered by this retrospective study, contributing significantly to recent respiratory disease outbreaks. Additionally, RA may also contribute to polyserositis in poultry; however, further stu","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"68 S1","pages":"469-480"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144061492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Avian diseasesPub Date : 2025-04-01DOI: 10.1637/aviandiseases-D-24-00009
Meghann Pierdon, Rowan Prown, Sherrill Davison, Donna Kelly, Laurel Redding
{"title":"A Case Control Survey of Farm Characteristics, Biosecurity Measures, and Risk Events in Flocks With and Without Infectious Coryza.","authors":"Meghann Pierdon, Rowan Prown, Sherrill Davison, Donna Kelly, Laurel Redding","doi":"10.1637/aviandiseases-D-24-00009","DOIUrl":"https://doi.org/10.1637/aviandiseases-D-24-00009","url":null,"abstract":"<p><p>The Pennsylvania poultry industry experienced an outbreak of infectious coryza (IC) starting at the end of 2018. Since the disease had not previously been found routinely in Pennsylvania, many questions emerged about the source of the infection and routes of transmission. To better understand the factors related to farm characteristics, risk events, and biosecurity that could influence the risk for the occurrence of IC, a case control study was undertaken to survey those flocks affected and a matched set of controls. Several factors were identified that increased the odds of being a case, including multiple vehicle entrances and having multiple categories of visitors. Other factors, such as bench entry, were found to be protective. This study indicates that fomites are a likely route of transmission for IC and that improvements in biosecurity can mitigate the risk of IC introduction.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"68 S1","pages":"398-403"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144047619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Avian diseasesPub Date : 2025-04-01DOI: 10.1637/aviandiseases-D-24-00022
Veronica Nguyen, Simone Stoute, Shayne Ramsubeik, Ian Miller, Carmen Jerry, Charles Corsiglia, Rodrigo A Gallardo
{"title":"A Retrospective Analysis to Identify Epidemiologic Patterns of the Infectious Coryza Outbreak in California 2016-22.","authors":"Veronica Nguyen, Simone Stoute, Shayne Ramsubeik, Ian Miller, Carmen Jerry, Charles Corsiglia, Rodrigo A Gallardo","doi":"10.1637/aviandiseases-D-24-00022","DOIUrl":"https://doi.org/10.1637/aviandiseases-D-24-00022","url":null,"abstract":"<p><p>Infectious coryza (IC) is a poultry respiratory disease caused by the bacterium <i>Avibacterium paragallinarum</i>. IC has major economic impacts in both the layer and broiler industries because this disease can cause increased mortality in affected flocks, an increase in condemnations at the processing plants, and decreased egg production in laying hens. In 2017, an increased number of IC-positive cases was seen in the Turlock Branch of the California Animal Health and Food Safety (CAHFS) Laboratory System. The objective of this study was to assess the epidemiologic patterns of IC before, during, and after this outbreak, as the number of positive cases remained elevated from 2017 to the end of 2022. Necropsy cases positive for IC in the CAHFS electronic database were analyzed from January 1, 2016, a year prior to the outbreak, to December 31, 2022. Out of 1935 submissions tested for IC during this period, the 674 cases found to be positive were then categorized by age, poultry type, season, and spatial distribution to investigate risk factors for IC. Raw data trends showed that most of the cases were from backyard poultry flocks (50.5%, 341/674), which appeared to be mainly localized to Los Angeles County and San Joaquin County. Commercial layers made up the second greatest number of cases (31.4%, 212/674) and were mostly localized to Merced County and Stanislaus County. Last, most of the commercial broiler cases (18.0%, 121/674) were in Merced County. Statistical analysis of this raw data was also performed and demonstrated that poultry in commercial egg layer operations located in the Central Valley and southern regions of California were at an increased risk for IC (odds ratio = 1.3, 95% confidence interval: 1.01-1.65, <i>p</i> = 0.039). Ultimately, this study provides updated information on IC trends in California and the risk factors associated with the outbreak.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"68 S1","pages":"391-397"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144048832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Avian diseasesPub Date : 2025-04-01DOI: 10.1637/aviandiseases-D-24-00105
Mohamed El-Gazzar, Rodrigo Gallardo, Robert Bragg, Amro Hashish, Hui-Ling Sun, Sherrill Davison, Anneke Feberwee, Yosef Huberman, T Skein, Azil Coertzen, Donna Kelly, Edgardo Soriano-Vargas, Vladimir Morales-Erasto, Ana Da Silva, Meng-Jiao Guo, Brian Ladman, Remco Dijkman, Mostafa Ghanem
{"title":"<i>Avibacterium paragallinarum</i>, the Causative Agent of Infectious Coryza: A Comprehensive Review.","authors":"Mohamed El-Gazzar, Rodrigo Gallardo, Robert Bragg, Amro Hashish, Hui-Ling Sun, Sherrill Davison, Anneke Feberwee, Yosef Huberman, T Skein, Azil Coertzen, Donna Kelly, Edgardo Soriano-Vargas, Vladimir Morales-Erasto, Ana Da Silva, Meng-Jiao Guo, Brian Ladman, Remco Dijkman, Mostafa Ghanem","doi":"10.1637/aviandiseases-D-24-00105","DOIUrl":"https://doi.org/10.1637/aviandiseases-D-24-00105","url":null,"abstract":"<p><p>Infectious coryza (IC) caused by <i>Avibacterium paragallinarum</i> (AP) has risen in importance as a poultry disease over the past several years because of its increased incidence in commercial poultry in both Europe and the United States. Because of this rise in importance, more attention has been focused on diagnosis, isolation, and surveillance of this bacterial pathogen. As a result, new knowledge has been produced and published. This review was compiled with the main purpose of summarizing and presenting the updated knowledge available about AP. However, the new knowledge can only be understood in the context of previously known facts about the disease. Therefore, this review has been organized in two major parts. The first part is a review of the established knowledge about AP, followed by recent updates. In the first part, we summarize the established well-known as well as some of the less-known facts and literature about AP. The second section focuses on specifics of the latest IC outbreaks in commercial poultry in northern latitudes, particularly in Europe and in North America. Additionally, we reviewed the current geographical distribution of the disease in Asia, South America, and Africa. The crises created by emerging or re-emerging disease outbreaks ignite interest in understanding the disease and pathogen in order to combat it properly. This results in new knowledge that improves the understanding of the disease features, leading to improved disease prevention, control, and eradication. Although knowledge about AP has advanced, knowledge gaps about the disease still persist. Therefore, this review concludes with summarizing the current knowledge gaps as well as potential areas for future research.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"68 S1","pages":"362-379"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144016387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Avian diseasesPub Date : 2025-04-01DOI: 10.1637/aviandiseases-D-24-00084
Donald L Reynolds, Matthew M Hille, Beibei Jia
{"title":"Review of <i>Enterococcus faecalis</i> Infections of Poultry.","authors":"Donald L Reynolds, Matthew M Hille, Beibei Jia","doi":"10.1637/aviandiseases-D-24-00084","DOIUrl":"https://doi.org/10.1637/aviandiseases-D-24-00084","url":null,"abstract":"<p><p><i>Enterococcus faecalis</i> organisms are Gram-positive cocci that are ubiquitous in the environment, occurring in water and soil, and are commensal inhabitants of the intestinal tracts of both vertebrate and invertebrate animals. They are considered opportunists and possess many virulence-encoding traits, including the formation of biofilms and toxins. <i>Enterococcus faecalis</i> produces cytolysin, which is a unique toxin having activity against both eukaryotic and prokaryotic cells. Cytolysin causes hemolysis of red blood cells and has also been termed hemolysin. <i>Enterococcus faecalis</i> organisms are intrinsically resistant to some antibiotics and can transmit antimicrobial resistance to other microorganisms. In poultry, there is ample evidence to indicate that <i>E. faecalis</i> can be egg transmitted, causing decreased hatchability of eggs. <i>Enterococcus faecalis</i> has been found to rapidly spread among hatchlings that are exposed in the hatcher. In older birds, some <i>E. faecalis</i> isolates cause amyloid arthropathy. Various methods have been developed to assess <i>E. faecalis</i> isolates for virulence-encoding traits, including Multilocus sequence typing and embryo lethality assays. However, much variability occurs in interpreting the results of these methods and the correlation between genotypes, phenotypes, and virulence has not been well established. The virulence traits and pathogenesis of <i>E. faecalis</i> in poultry need to be elucidated further.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"68 S1","pages":"412-420"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144039757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Avian diseasesPub Date : 2025-04-01DOI: 10.1637/aviandiseases-D-24-00081
Nicolas Deslauriers, Martine Boulianne
{"title":"Genetic Comparison of <i>Enterococcus</i> Species Isolated from Osteomyelitis Lesions and the Barn Environment of Successive Broiler Chicken Flocks.","authors":"Nicolas Deslauriers, Martine Boulianne","doi":"10.1637/aviandiseases-D-24-00081","DOIUrl":"https://doi.org/10.1637/aviandiseases-D-24-00081","url":null,"abstract":"<p><p>Osteomyelitis caused by <i>Enterococcus cecorum</i> is an emerging disease in broiler chickens in Canada. Other <i>Enterococcus</i> species have been reported as causative agents in certain outbreaks. The epidemiology of this disease is unknown, but contaminated barns are affected by recurring episodes. A broiler chicken flock located in Quebec, Canada, exhibited osteomyelitis lesions positive for <i>E. cecorum</i> and <i>Enterococcus faecalis</i>. Surprisingly, the following lot, in the same barn, revealed the presence of <i>E. faecalis</i>- and <i>Enterococcus raffinosus</i>-positive lesions but no <i>E. cecorum.</i> To better understand the epidemiology of these two outbreaks, verify the persistence of pathogenic isolates in the barn, and identify the possible transfer of genetic material between the <i>Enterococcus</i> species isolated from both events, 16 isolates (1 <i>E. cecorum</i>, 13 <i>E. faecalis</i>, and 2 <i>E. raffinosus</i> isolates) were sequenced, and their genomes were compared. Interestingly, more than one <i>Enterococcus</i> species could be isolated from the same lesion, while other lesions also revealed several nonclonal isolates from the same species. This might suggest the opportunistic nature of <i>Enterococcus</i> spp. as there was no predominant isolate in the lesions. The number of virulence genes varied from 1 to 34 across three <i>Enterococcus</i> species with no common virulence gene. The number and nature of antimicrobial resistance genes among those isolates were worrisome because they indicate the presence of multidrug resistance on the farm. Both plasmids and phages were shared by different <i>Enterococcus</i> species, which suggests potential horizontal gene transfer of mobile genetic elements within this enterococci population.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"68 S1","pages":"421-426"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144060501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}