Avian diseases最新文献

{"title":"Rapid and Visual Detection of <i>Pasteurella multocida</i> and <i>Riemerella anatipestifer</i> Using Recombinase Polymerase Amplification Coupled with Lateral Flow Dipstick Assay.","authors":"Jing Li, Qing-Ling Gu, Si-Mei Xian, Tao-Tao Bao, Qian Liang, Wei-Hao Zheng, You-Ci Long, Qin Wu","doi":"10.1637/aviandiseases-D-24-00099","DOIUrl":"https://doi.org/10.1637/aviandiseases-D-24-00099","url":null,"abstract":"<p><p>To establish a convenient, novel, and visual detection method for on-site diagnosis of <i>Riemerella anatipestife</i>r (RA) and <i>Pasteurella multocida</i> (PM), we used the previously constructed plasmids pMD19-T-ompA and pMD19-T-kmt1 as templates and selected as target sequences the conserved regions of the RA <i>ompA</i> gene sequence and the PM <i>kmt1</i> gene sequence registered in GenBank. Specific basic primers for recombinase polymerase amplification (RPA) were designed and synthesized. Probes (RA-P, PM-P) were designed according to the requirements of the lateral flow dipstick (LFD) assay. After optimizing the reaction conditions, a dual RPA-LFD method for detecting RA and PM was established, and specificity and sensitivity tests were conducted. The developed method was then applied to 64 clinical samples. The established dual RPA-LFD method completed amplification within 15 min at 37 C. Using the nucleic acids of <i>Escherichia coli</i> from ducks, <i>Salmonella enteritidis</i> from ducks, RA and PM from poultry, <i>Staphylococcus</i>, goose parvovirus, duck plague virus, and Muscovy duck parvovirus as templates, and plasmids pMD19-T-ompA and pMD19-T-kmt1 as positive controls, the dual RPA-LFD detection system showed that only the positive controls yielded positive results, indicating good specificity. Plasmid standards pMD19-T-ompA and pMD19-T-kmt1 were diluted tenfold, and the sensitivity was detected to be 10² copies/µl when plasmid standards with concentrations ranging from 10⁷ to 10⁰ copies/µl were used as templates. For the 64 clinical samples, results were observed directly via the test strips, showing an RA detection rate of 10.93% (7/64) and a PM detection rate of 4.68% (3/64), with a 100% concordance rate with PCR results. The dual RPA-LFD method successfully established in this study has the advantages of strong specificity, high sensitivity, rapidity, and visualization, making it suitable for the on-site detection of RA and PM.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"70 2","pages":"189-195"},"PeriodicalIF":1.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148431794","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":"Epidemiology, Antimicrobial Resistance, and Genetic Determinants of Methicillin-Resistant <i>Staphylococcus aureus</i> (MRSA) in Broiler Chickens with Arthritis.","authors":"Hanem El-Sharkawy, Mohamed Marzok, Mohammed Al-Rasheed, Amin Tahoun","doi":"10.1637/aviandiseases-D-25-00060","DOIUrl":"https://doi.org/10.1637/aviandiseases-D-25-00060","url":null,"abstract":"<p><p>Methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) is a serious zoonotic pathogen that poses significant threats to both public health and the poultry industry due to its multidrug resistance and virulence. In broiler chickens, MRSA infections are commonly associated with arthritis, resulting in impaired mobility, reduced productivity, and economic losses. This study aimed to investigate the epidemiology, antimicrobial resistance profiles, and genetic determinants of MRSA in broiler chickens presenting with clinical arthritis in the Kafr El-Sheikh Governorate, northern Egypt. In this study, 100 broiler farms were randomly selected from a list provided by the local veterinary authority in Kafr El-Sheikh Governorate. Of these, 20 medium-sized farms (5000-10,000 birds per cycle) had clinically arthritic chickens. A total of 140 synovial fluid samples (six to eight chickens per farm) were aseptically collected from affected birds. The affected farms represented approximately 4.8% of the total broiler farms in the governorate and were distributed across different districts, indicating that MRSA-associated arthritis was not confined to a single locality. Bacterial isolation was performed using selective culture media and confirmed via biochemical tests and PCR targeting the <i>nuc</i> gene. Antimicrobial susceptibility testing was conducted using the Kirby Bauer disk diffusion method against 16 antibiotics following CLSI 2020 guidelines. Molecular screening for resistance and virulence genes (<i>mecA</i>, <i>vanA</i>, <i>hig</i>) was performed by uniplex PCR. Phylogenetic analysis of 16S rRNA sequences was carried out using the Maximum Likelihood method. Clinical signs included joint swelling, deformity, and impaired locomotion. Epidemiological analysis revealed that MRSA-associated arthritis was detected in (3/20) 15% of infected farms, with 7.67 ± 1.53% of birds affected within infected flocks. <i>Staphylococcus aureus</i> was isolated from 60% of footpad abscesses and 65% of hock joint swellings. All isolates were resistant to multiple β-lactam antibiotics, including oxacillin, cefoxitin, penicillin G, and piperacillin. High resistance was also observed to clindamycin, cephradine, and cephalexin. The most effective agents were ampicillin-sulbactam and vancomycin. The <i>mecA</i> and <i>nuc</i> genes were detected in all isolates, and <i>vanA</i> and <i>hig</i> genes were detected in 5% and 25% of isolates, respectively. Phylogenetic analysis confirmed the close genetic relatedness of the local isolate (PQ879639.1) to global <i>S. aureus</i> strains. MRSA is an emerging pathogen in broiler flocks with a marked capacity for antimicrobial resistance and zoonotic transmission. The detection of multidrug-resistant strains carrying key resistance genes highlights the urgent need for enhanced biosecurity, prudent antimicrobial use, and routine monitoring programs to mitigate its impact on poultry and public health.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"70 2","pages":"196-203"},"PeriodicalIF":1.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148431757","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":"Facilitated Molting as a Management Strategy During a Low-Pathogenic H1N2 Avian Influenza Outbreak in a Breeder Turkey Flock.","authors":"Oluwatimileyin Abolarin","doi":"10.1637/aviandiseases-D-26-00006","DOIUrl":"10.1637/aviandiseases-D-26-00006","url":null,"abstract":"<p><p>Low-pathogenic avian influenza (LPAI) outbreaks in turkey breeder flocks can significantly impair egg production and impact economic viability, particularly in regions densely populated with swine production. In December 2024, after an egg production drop in one barn of an otherwise normal four-barn, 54 wk-of-age turkey breeder flock in southwestern Ontario, Canada, an H1N2 LPAI strain was detected. Following PCR confirmation, a controlled nonfasted molt was initiated across the four barns to mitigate production losses and facilitate a relatively uniform viral clearance. Diagnostic monitoring included serial PCR and ELISA testing during and after molt. Results indicated rapid horizontal transmission during the molt, with all barns seroconverted by 56 wk of age. The flock achieved negative PCR status by week 60, and subsequent testing confirmed clearance of the pathogen. Postmolt production resumed at acceptable levels, suggesting that facilitated molting may serve as a viable management strategy for LPAI outbreaks in high-value breeder operations. This case highlights the potential role of molting as an adjunct to biosecurity and regulatory measures, though controlled studies are needed to further validate efficacy and further consider welfare implications.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"70 2","pages":"224-227"},"PeriodicalIF":1.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148431749","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":"Effect of Different Concentrations of Deoxynivalenol-Contaminated Diets on Proventriculus Injury in Broiler Chickens.","authors":"Jiaxu Liu, Qian Han, Xin You, Huajie Yang, Sitao Guo, Zhaoquan Chen, Xueqiao Qian, Yongqiang Wang","doi":"10.1637/aviandiseases-D-25-00046","DOIUrl":"https://doi.org/10.1637/aviandiseases-D-25-00046","url":null,"abstract":"<p><p>Deoxynivalenol (DON, also known as vomitoxin), a prevalent mycotoxin in contaminated feed, poses significant threats the poultry industry, yet its effects on proventriculus injury in broilers remain insufficiently explored. This study evaluates the effects of DON at different levels (5, 10, and 15 mg/kg feed) on broilers during different trial periods (9 and 14 days). Eighty-one-day-old male broilers were randomly allocated to control (basal diet) and DON-exposed (L, M, H) groups. Results demonstrated dose- and time-dependent proventriculus and gizzard injuries, with histopathological lesions (mucosal necrosis and shedding) prominent at ≥10 mg/kg and 14 days. Tight junction proteins (claudins, occludin, ZO-1) were disrupted, notably via claudin-15 downregulation at 10-15 mg/kg (<i>P</i> < 0.05), suggesting impaired nutrient absorption. Pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) surged at higher doses (<i>P</i> < 0.05), while antioxidant enzymes (SOD, CAT, Nrf2, HO-1, GPx) initially increased but declined with prolonged exposure, exacerbating oxidative stress (<i>P</i> < 0.05). Apoptosis transiently spiked without sustained effects over 14 days, partially explaining avian DON resistance. In conclusion, DON at concentrations of 5-15 mg/kg temporarily enhanced antioxidant capacity but induced glandular inflammation (≥5 mg/kg), with cumulative oxidative damage outweighing transient apoptotic responses. These findings highlight critical thresholds for DON tolerance in poultry diets.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"70 2","pages":"164-173"},"PeriodicalIF":1.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148431673","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":"Association of Different Diagnostic Methods Used to Identify Coccidiosis in Broiler Chickens and Potentially Associated Bacterial Lesions.","authors":"Renata Assis Casagrande, Fábio Santiani, Anna Laura de Oliveira Cunha, Sandra Maria Ferraz, Ricardo Antônio Sfaciotte, Gustavo Willian Pandolfo, Maria Augusta Fornara, Andreas Lazaros Chryssafidis","doi":"10.1637/aviandiseases-D-25-00091","DOIUrl":"https://doi.org/10.1637/aviandiseases-D-25-00091","url":null,"abstract":"<p><p>Coccidiosis is a major avian enteropathy caused by <i>Eimeria</i> spp., and mixed infections can hinder diagnosis due to overlapping lesions. This study aimed to evaluate the occurrence of coccidiosis in broiler chickens through characterization of gross and histopathologic lesions, parasitologic identification, and investigation of potentially associated bacterial infections. A cross-sectional study was conducted on 28 flocks housed in positive-pressure ventilated poultry houses, with a sample of 280 broilers collected at two time points: sampling 1 (21 to 28 days of age) and sampling 2 (35 to 42 days of age). Analyses included scoring of gross and histopathologic lesions, morphometric and morphologic assessment of <i>Eimeria</i> oocysts, <i>Salmonella</i> testing in feces and litter, and aerobic bacterial culture of organs with lesions. <i>Eimeria</i> spp. positivity was 82.14% in sampling 1 and 100% in sampling 2. Oocysts morphologically consistent with <i>Eimeria acervulina</i> predominated initially, while <i>Eimeria tenella</i> was most frequent later. Due to morphometric overlap among species, identification was based solely on morphology and not confirmed molecularly. Mixed infections were frequent. Histopathology showed higher diagnostic sensitivity, with a 28.5% increase in positive case detection compared to gross evaluation. Grade 1 lesions were predominant at both time points, except in sampling 2, where <i>E. tenella</i> was responsible for a higher frequency of grade 3 lesions. No flocks tested positive for <i>Salmonella</i>. Opportunistic bacteria (<i>Escherichia coli</i>, coagulase-negative <i>Staphylococcus</i>) were isolated in broilers with septic extraintestinal lesions, including airsacculitis, perihepatitis, pericarditis, hepatitis, and splenitis, with no significant association with coccidiosis. The results reinforce the importance of integrating diagnostic methods to increase the accuracy of disease detection and suggest that the low incidence of bacterial infections may reflect appropriate biosecurity practices on the evaluated farms.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"70 2","pages":"153-163"},"PeriodicalIF":1.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148431666","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":"Comprehensive Pathologic Evaluation of <i>Histomonas meleagridis</i> Field Isolates in Target (Cecum and Liver) and Primary Lymphoid (Bursa and Thymus) Organs in Turkeys.","authors":"Vijay Durairaj, Frederic J Hoerr, Ryan Vander Veen","doi":"10.1637/aviandiseases-D-25-00096","DOIUrl":"https://doi.org/10.1637/aviandiseases-D-25-00096","url":null,"abstract":"<p><p>Histomoniasis (blackhead disease) is caused by an anaerobic protozoan, <i>Histomonas meleagridis.</i> The pathogen affects all the gallinaceous birds, while turkeys are highly susceptible. The severity of infection and associated mortality rates of histomoniasis in turkeys vary considerably, and the virulence of <i>H. meleagridis</i> field isolates likely plays a critical role in determining disease outcome. Therefore, characterization of the virulence of field isolates is essential for understanding this disease. The virulence of two <i>H. meleagridis</i> field isolates (HMA and HMB) from the United States was evaluated in independent studies. Tissue samples of ceca, liver, bursa of Fabricius, and thymus were collected for pathologic evaluation. At necropsy, characteristic gross lesions of histomoniasis were noted in the ceca and liver of the infected birds. Histopathologic liver lesions varied from acute to subacute multifocal necrotizing hepatitis to a more chronic lymphohistiocytic hepatitis. Cecal lesions ranged from multifocal to diffuse typhlitis. Furthermore, lymphocyte depletion was documented in the bursa of Fabricius and thymus of infected birds. These findings suggest that <i>H. meleagridis</i> infection may impact both humoral and cellular immunity, warranting further investigation into the immunopathogenesis of the disease.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"70 2","pages":"204-213"},"PeriodicalIF":1.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148431678","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":"High Mortality in Commercial Chukar Partridges (<i>Alectoris chukar</i>) Infected with <i>Salmonella arizonae</i>.","authors":"Ian Miller, Carmen Jerry, Heather Fritz, Veronica Nguyen, Mark Bland, Simone Stoute","doi":"10.1637/aviandiseases-D-25-00062","DOIUrl":"10.1637/aviandiseases-D-25-00062","url":null,"abstract":"<p><p>Arizonosis is a bacterial septicemic disease caused by <i>Salmonella enterica</i> subspecies <i>arizonae</i>. This case report describes <i>S. arizonae</i> septicemia in commercial chukar partridge (<i>Alectoris chukar</i>) chicks that resulted in a 7-day flock mortality of 30% (2100/7000), with mortality rapidly progressing to 99.3% (6950/7000) by 3 wk of age. To our knowledge, this is the first documented case of <i>S. arizonae</i> acute septicemia in chukars. Gross and histopathologic findings in the chukars included hepatosplenomegaly, omphalitis, and multiorgan inflammation. <i>Salmonella arizonae</i> was isolated from the liver, spleen, and yolk sac cultures, and the isolate was serotyped as <i>Salmonella arizonae</i> serovar 18:z4,z23. Minimum inhibitory concentration antimicrobial susceptibility testing performed on <i>S. arizonae</i> classified the isolate as resistant to erythromycin, gentamicin, neomycin, and sulfadimethoxine and not susceptible to amoxicillin and penicillin; the isolate was classified as susceptible to oxytetracycline, tetracycline, ceftiofur, and spectinomycin. In addition to the arizonosis case report, a retrospective analysis of poultry arizonosis cases diagnosed at the California Animal Health and Food Safety laboratories from January 2005 to December 2024 identified 79 poultry cases of <i>S. arizonae</i>, predominantly in turkeys (69/79). A sharp decline in annual <i>S. arizona</i>e poultry cases was noted after 2009. The most common site of isolation was the yolk sac (45/79 cases), suggesting that vertical transmission plays a significant role in the dissemination of the disease. This case report highlights the susceptibility of chukar partridges to <i>S. arizonae</i> infection and disease and underscores the importance of early diagnosis, antimicrobial susceptibility testing, and stringent biosecurity practices to mitigate transmission and economic loss in commercial game bird operations.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"70 2","pages":"228-234"},"PeriodicalIF":1.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148431707","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":"Synergistic Effect of Adding Calcium Hydroxide and a Quaternary Ammonium Compound on the Degradation of Coccidia Oocysts by an Ortho-phenylphenol-Based Disinfectant.","authors":"Kazuaki Takehara, Shotaro Maehana, Hiroki Izawa, Makoto Kubo, Shunsuke Yamaguchi, Hiroki Matsumoto","doi":"10.1637/aviandiseases-D-26-00001","DOIUrl":"https://doi.org/10.1637/aviandiseases-D-26-00001","url":null,"abstract":"<p><p>Only a limited number of disinfectants are capable of inactivating coccidia oocysts, and in Japan, ortho-phenylphenol-based disinfectants (a combination of cresol and 1,2-dichlorobenzene) are mainly used. However, resistance of oocysts to ortho disinfectants has been reported. Previously, we demonstrated a synergistic enhancement of microbicidal activity by adding food-additive-grade calcium hydroxide with a mean particle size of 10 µm to a quaternary ammonium compound. In the present study, we found that the addition of calcium hydroxide and a quaternary ammonium compound to the ortho disinfectant synergistically and significantly enhanced its oocysticidal effect.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"70 2","pages":"214-218"},"PeriodicalIF":1.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148431804","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":"Necrotic Hepatitis Associated with <i>Phasianus Chaphamaparvovirus 1</i> and Coccidiosis Coinfection in Pheasant Chicks (<i>Phasianus colchicus</i>) in Bosnia and Herzegovina.","authors":"Ajla Hodžíć Boríć, Jovana Dervovíć, Alma Šeho-Alíć, Adis Softíć, Šejla Goletíć Imamovíć, Teufik Goletíć, Amer Alíć","doi":"10.1637/aviandiseases-D-25-00111","DOIUrl":"10.1637/aviandiseases-D-25-00111","url":null,"abstract":"<p><p><i>Phasianus chaphamaparvovirus 1</i> is a newly recognized pathogen associated with high mortality in young pheasant chicks with significant losses for pheasant breeders. Here we present an outbreak of necrotizing hepatitis with high mortality in a flock of young pheasant chicks in Bosnia and Herzegovina associated with <i>Phasianus chaphamaparvovirus 1</i> and coccidiosis coinfection. Severe necrotizing hepatitis with characteristic intranuclear inclusion bodies in affected hepatocytes was observed on microscopic examination. In addition, multifocal areas of intestinal mucosal necrosis with numerous developing stages (meronts) of coccidia were present. <i>Phasianus chaphamaparvovirus 1</i> was detected with qPCR from the livers of diseased birds. Our report represents the first data on the presence of this new virus in pheasant flocks in the Balkan region and suggests that the virus is widespread across Europe. It further supports the inclusion of <i>Chaphamaparvovirus</i> as a differential diagnosis of pheasant mortality outbreaks both in breeding facilities and in the wild.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"70 2","pages":"235-239"},"PeriodicalIF":1.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148431820","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":"Differentiation of Pathogenic from Nonpathogenic <i>Enterococcus cecorum</i> Field Isolates Based on the Detection of the <i>cpsO</i> Gene and Its Association with Macroscopic Lesions.","authors":"Marcela Arango, Rebecca Mackey, Jay Kay Thornton, Natalie Manginsay, Martha Pulido-Landinez","doi":"10.1637/aviandiseases-D-25-00001","DOIUrl":"https://doi.org/10.1637/aviandiseases-D-25-00001","url":null,"abstract":"<p><p>The clinical presentation of <i>Enterococcus cecorum</i> (EC)-associated systemic disease in broiler chickens is characterized by septicemia, lameness, and sometimes paralysis, typically affecting birds older than 4 wk of age. During the past few years, the incidence of this disease has increased worldwide. The detection of the <i>cpsO</i> gene was recently reported to successfully differentiate between pathogenic and commensal EC strains. This study aimed to evaluate the use of <i>cpsO</i> gene detection to differentiate pathogenic and nonpathogenic EC field isolates and to assess its association with macroscopic lesions observed in affected birds. <i>Enterococcus</i> spp. isolates (<i>n</i> = 348) recovered from necropsy cases submitted to the Mississippi State University's Poultry Research and Diagnostic Laboratory during 2023 were analyzed. Isolates originating from broiler breeders, layer breeders, hatcheries, and broiler chickens were included in this study. One hundred EC isolates were selected for phenotypic characterization and <i>cpsO</i> gene detection by PCR. EC was recovered from samples of the heart, joints, ovary, testicles, midgut, and ceca. The <i>cpsO</i> gene was detected in a high percentage (65%) of EC isolates recovered from broiler chickens, mainly from heart and femoral head lesions. In contrast, <i>cpsO</i> was detected infrequently in isolates from broiler breeders (10%) and was not detected in isolates recovered from intestinal samples or hatchery submissions. The presence of this gene was significantly associated with EC isolated from lesions observed in clinical disease cases, providing support for the pathogenic classification of these isolates. According to multiple literature reports, EC has been reported as a multidrug-resistant bacterium. However, in this study only a small percentage of isolates (3.4%) showed resistance to three or more classes of antimicrobials, and a high percentage of isolates (57%) were susceptible to all antimicrobials tested.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"70 2","pages":"183-188"},"PeriodicalIF":1.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148431759","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}