Search Results (332)

Avian infective endocarditis is an uncommon but severe disease that is typically diagnosed postmortem because of nonspecific clinical signs and rapid progression. In the present study, five broiler chickens (n = 5) from a commercial flock were examined with septicemia and lesions suggestive of endocarditis. This study reports the first molecularly confirmed and characterized case of valvular endocarditis associated with multidrug-resistant Vagococcus fluvialis in poultry and provides a comprehensive review of bacterial endocarditis in avian species. The case involved a broiler chicken that presented with sudden death and septicemic lesions, including vegetative valvular endocarditis, pericarditis, and multiorgan involvement. Bacterial isolates recovered from cardiac lesions were identified as V. fluvialis using MALDI-TOF mass spectrometry and confirmed by 16S rRNA gene sequencing. Antimicrobial susceptibility testing revealed a multidrug resistance profile, with resistance to several antimicrobial classes commonly used in poultry production. The literature review identified published studies describing avian infective endocarditis, which predominantly affects poultry and is caused mainly by Gram-positive bacteria, with clinical signs and necropsy findings largely overlapping across etiologies. These findings highlight the novelty of V. fluvialis as a potential etiological agent of avian infective endocarditis and underscores the diagnostic challenges associated with avian endocarditis, particularly when uncommon pathogens are involved, and underscore the importance of advanced identification methods for an accurate etiological determination. Collectively, the results of this study expand the spectrum of bacterial species associated with avian infective endocarditis and emphasize the relevance of antimicrobial resistance and improved diagnostic strategies in poultry health and disease surveillance. Full article

Lactococcosis caused by Lactococcus garvieae is an emerging threat to warmwater aquaculture, yet evidence integrating field outbreaks with robust molecular confirmation and controlled virulence testing remains limited for Thailand’s cage-cultured tilapia. From May to October 2025, acute mortality events were investigated in cage-cultured Nile tilapia (Oreochromis niloticus) in a reservoir in Ubon Ratchathani Province, Thailand. Suspected outbreaks were defined by abrupt daily mortality exceeding 5% accompanied by septicemia-like clinical signs. Water quality during sampling covered the following ranges: temperature 28.6–31.9 °C, pH 6.5–7.0, salinity 0.02–0.03 ppt, electrical conductivity 0.036–0.046 mS/cm, TDS 22.20–26.50 mg/L, total alkalinity 17.0–34.0 mg/L as CaCO₃, total hardness 12.0–60.0 mg/L as CaCO₃, dissolved oxygen 6.5–7.0 mg/L, and NH₃ were below the limit of detection. Full-length 16S rRNA tissue profiling revealed strong tissue partitioning: blood microbiomes were consistently dominated by Lactococcus and L. garvieae at the species level, whereas gills showed higher richness and mixed communities with multiple opportunistic taxa. Culture isolation was more reliable from blood than gills, yielding 16 Gram-positive, catalase-negative isolates (AAHM-LG2501–AAHM-LG2516) that clustered within the L. garvieae clade in near full-length 16S rRNA phylogenetic analysis and were separated from closely related Lactococcus lineages. A representative blood isolate (AAHM-LG2501) showed dose-dependent virulence in controlled challenges, with an LD₅₀ of ~1.05 × 10⁵ CFU/fish by intraperitoneal injection and an LC₅₀ of ~1.20 × 10⁶ CFU/mL by immersion. Histopathology supported systemic dissemination, with injection producing more consistent multi-organ lesions than immersion, particularly in head kidney, liver, and spleen, while gills exhibited route-associated epithelial and vascular alterations. Together, these findings confirm L. garvieae as a major etiological agent of septicemic outbreaks in cage-cultured tilapia in Thailand and support a practical surveillance framework prioritizing blood sampling, molecular confirmation, and risk-based monitoring to guide biosecurity and vaccine-oriented prevention. Full article

Background/Objectives: Multidrug-resistant (MDR) Escherichia coli has increasingly been recognized as a pathogen capable of causing severe systemic infections in various animal species. However, reports describing respiratory and septicemic infections caused by MDR E. coli in guinea pigs remain scarce. The objective of this report was to describe the clinical, pathological, and microbiological findings associated with a fatal infection in a domestic guinea pig. Case Study: A 10-month-old female guinea pig (Cavia porcellus), kept as a companion animal in a household environment, presented with acute respiratory distress, lethargy, and anorexia, progressing rapidly to death within approximately 36 h of onset. Post-mortem examination revealed severe pulmonary congestion, diffuse inflammatory lesions in the trachea, and generalized vascular congestion in multiple organs. Bacteriological cultures obtained from lung and bone marrow samples yielded pure growth of Escherichia coli. Identification was confirmed using MALDI-TOF mass spectrometry. Antimicrobial susceptibility testing demonstrated resistance to several antibiotic classes, including β-lactams, fluoroquinolones, tetracyclines, sulfonamides, and phenicols, while susceptibility was retained only to aminoglycosides. Molecular analysis revealed the presence of virulence genes involved in adhesion and iron acquisition, supporting the pathogenic potential of the isolate. Conclusions: This report highlights the ability of MDR E. coli to cause severe respiratory and systemic infections in guinea pigs. The findings underline the importance of early diagnosis, appropriate antimicrobial stewardship, and improved husbandry conditions in preventing such infections. From a One Health perspective, the circulation of resistant strains in companion animals may represent a potential risk for both environmental and human health. Full article

The number of confiscated CITES-listed animals has increased dramatically worldwide, creating significant health, logistical, and resource challenges for responsible authorities. Rescue centers represent a scientific and humanitarian response to this challenge, providing solutions through rehabilitation, research, and environmental education. This postmortem survey provides information on disease and mortality during a four-year period, in confiscated CITES-listed birds and reptiles housed in an authorized rescue center. A total of 29 animals (17 birds and 12 reptiles) were examined by necropsy and histopathology. Infectious disease accounted for the mortality of 58.8% of birds and 49.8% of reptiles, with overrepresentation of bacterial disease in both groups. Lesions consisted mainly of granulomas in multiple organs. Suspected viral disease occurred in 23.3% of birds, and protozoal infections were found in 17.3% of birds. Systemic disease caused by an unknown haemosporozoan was the cause of death in a Lonchura oryzivora. An unknown infectious agent was associated with renal disease in a Ctenosaura sp. Gout secondary to dehydration was overrepresented in reptiles (33.3%). This study highlights the complexity of disease processes affecting confiscated birds and reptiles in CITES rescue settings and provides invaluable information for other rescue centers that may impact the success of conservation strategies. Full article

The scientific understanding of cetacean pathology has advanced significantly in recent decades. However, data concerning the health status of members of the family Kogiidae remains scarce. This study presents a comprehensive pathological assessment and determination of causes of death in 45 stranded kogiids, comprising 35 Kogia breviceps and 10 K. sima, along the coasts of the Canary Islands between 1999 and 2018. Causes of death (CD) were classified as natural (30/45; 66.6%) or anthropogenic (11/45; 24.4%), while the cause remained undetermined in four cases (9%). Among natural causes, the most prevalent etiologies included trauma (13/30; 43.3%), infectious (7/30; 23.3%), parasitic (5/30; 16.6%), cardiomyopathy (3/30; 10%), malnutrition (1/30; 3.3%), and fetal distress (1/30; 3.3%). Anthropogenic causes were vessel collisions (7/11; 63.6%), interactions with fishing activities (2/11; 18.2%), and foreign body-associated pathology (2/11; 18.2%). Notably, intra- and interspecific traumatic interactions were frequently identified in this cohort, and variable degrees of gross and histologic cardiomyopathic changes were observed in 68.9% of individuals (31/45) without evident sex bias. Septicemia caused by Clostridium perfringens and C. tertium was confirmed in three cases. Additionally, cervical gill slit adenitis by Crassicauda sp. (15/45; 33%) and parasitic gastritis by Anisakis sp. (27/45; 60%) were frequent findings. These findings provide novel insights into the pathologic spectrum affecting kogiids and enhance the current understanding of their health status, with implications for diagnostic protocols, stranding response, and conservation strategies. Full article

Background: The prognostic value of preoperative hemoglobin A1c (HbA1c) in patients undergoing cardiac surgery remains uncertain. This study investigated the association between preoperative HbA1c levels and the risk of postoperative low cardiac output syndrome (LCOS) and in-hospital mortality in patients undergoing elective cardiac and/or thoracic aortic surgery. Methods: This single-center retrospective cohort study included consecutive adult patients who underwent elective cardiac and/or thoracic aortic surgery between 1 November 2019 and 30 June 2021. Patients younger than 18 years, pregnant, or lacking a preoperative HbA1c measurement within one week before surgery were excluded. A total of 728 patients were analyzed. Baseline clinical characteristics, operative variables, and postoperative outcomes were collected. Associations between HbA1c and perioperative parameters were assessed using univariate analyses, and independent predictors of LCOS and in-hospital mortality were identified using multivariate logistic regression. Results: Higher HbA1c levels were associated with greater body mass index (BMI; r = 0.08, p = 0.025), higher New York Heart Association (NYHA) functional class (III vs. I–II: 6.86 ± 1.60% vs. 6.15 ± 1.13%, p = 0.001), postoperative LCOS (7.05 ± 1.72% vs. 6.15 ± 1.13%, p = 0.013), and in-hospital mortality (6.79 ± 1.50% vs. 6.15 ± 1.13%, p = 0.011). In multivariate analysis, HbA1c independently predicted LCOS (odds ratio [OR] 1.52; 95% confidence interval [CI] 1.09–2.12; p = 0.015), together with reduced left ventricular ejection fraction and postoperative atrial fibrillation. Independent predictors of in-hospital mortality included BMI, HbA1c (OR 1.81; 95% CI 1.19–2.74; p = 0.005), EuroScore II, prolonged cardiopulmonary bypass time, impaired glomerular filtration rate, postoperative septicemia, continuous renal replacement therapy, re-intubation, and prolonged mechanical ventilation. Conclusions: Higher preoperative HbA1c levels were independently associated with an increased risk of postoperative LCOS and in-hospital mortality in patients undergoing elective cardiac and/or thoracic aortic surgery. These findings support the role of HbA1c as a prognostic biomarker and its potential integration into preoperative risk stratification models for cardiac surgery. Full article

Klebsiella pneumoniae is a prominent pathogen implicated in a wide range of infections, including pneumonia, urinary tract infections, and septicemia. Its ability to acquire and disseminate antibiotic resistance, coupled with the rising prevalence of hypervirulent strains, represents a significant public health threat. Understanding the molecular basis of drug resistance can guide the design and development of effective treatment strategies. Antimicrobial resistance (AMR) in these bacteria is a complicated process and cannot be attributed to a single resistance mechanism. K. pneumoniae develops resistance to antibiotics through a variety of mechanisms, ranging from single molecular mechanisms to complex interactions, where molecular synergy exacerbates resistance. This review summarizes the current understanding of the molecular mechanisms that contribute to the drug resistance and virulence of this pathogen. Key antibiotic resistance mechanisms include drug inactivation via B-lactamases and carbapenemases, membrane remodeling, efflux pump systems, such as AcrAB-TolC and OqxAB, and biofilm formation facilitated by quorum sensing. Additionally, the role of ribosomal changes in resistance is highlighted. This review also examines the mechanisms of virulence, emphasizing fimbriae, iron acquisition systems, and immune evasion strategies. Understanding these mechanisms of drug resistance and virulence is crucial for remodeling existing antibiotics and developing new therapeutic strategies. Full article

Escherichia coli is a major pathogen responsible for urinary tract infections, septicemia, and other clinically relevant conditions, with increasing multidrug resistance (MDR) limiting available treatment options. In this context, bacteriophages represent a valuable resource for exploring novel antimicrobial and biotechnological tools. Here, we report the isolation and genomic characterization of BorMax, a novel lytic phage infecting multiple MDR E. coli. Transmission electron microscopy revealed a tailed morphology consistent with Dhillonvirus. Whole genome sequencing and de novo assembly showed a linear double-stranded DNA genome of 45,502 bp, encoding 70 predicted coding sequences (CDSs) and lacking tRNAs. Bioinformatic analyses confirmed the absence of lysogeny-associated genes, as well as virulence and antimicrobial resistance determinants. Comparative genomics using classified BorMax within the genus Dhillonvirus as a new species, sharing <77% intergenomic similarity with known members. Notably, predictions using PaCRISPR and AcRanker identified four CDSs with strong anti-CRISPR (Acr) potential, representing previously undescribed Acr candidates in this group. These genomic features highlight the novelty, safety, and potential biotechnological relevance of BorMax and contribute to the expanding genomic and functional diversity of Dhillonvirus and E. coli-infecting phages. Full article

RNA viruses are major pathogens in fish, causing high mortality and substantial economic losses in aquaculture. To uncover conserved antiviral mechanisms, we investigated the response of turbot (Scophthalmus maximus) to viral hemorrhagic septicemia virus (VHSV), infectious pancreatic necrosis virus (IPNV), and red-spotted grouper nervous necrosis virus (RGNNV) using a comparative proteomic approach complemented by in vivo and in vitro functional assays. Proteomic analyses revealed the central, conserved role of proteins involved in reactive oxygen species (ROS) production and redox homeostasis during early infection. Functional assays using head kidney-derived leukocytes identified neutrophils and macrophages as the primary ROS producers and showed that the modulation of cytoplasmic and mitochondrial ROS, as well as ROS-dependent DNA release, follows virus-specific patterns. The pharmacological inhibition of NADPH oxidase and mitochondrial ROS significantly affected viral replication, demonstrating the direct role of ROS in viral pathogenicity. Collectively, these findings highlight redox modulation as a conserved host response in teleost fish during RNA virus infection, linking oxidative stress regulation to viral progression. This knowledge provides a foundation for developing broad-spectrum therapeutic or preventive strategies to enhance disease resistance and promote sustainable aquaculture. Full article

S. suis is a prominent zoonotic pathogen responsible for diseases such as arthritis in piglets, swine septicemia, and meningitis. The emergence of multi-drug resistance (MDR) underscores the urgent need for the development of novel antibacterial strategies. In this context, a systematic evaluation of the antibacterial potential of the bacteriophage lytic enzyme Ply900 was conducted in this study, along with an analysis of its domain functions and an in vivo study of its therapeutic dynamics. Ply900 exhibits potent in vitro lytic activity against multiple bacteria, including Streptococcus suis, Streptococcus agalactiae, and Staphylococcus aureus. Notably, it possesses broad biochemical stability, with tolerance to diverse environmental conditions. In a mouse model of S. suis serotype 2 SC19 infection, both the direct Ply900 treatment group and the triple therapy group achieved effective eradication of S. suis, with markedly improved survival rates. The remaining bacteria remained susceptible to Ply900, with no evidence of induced resistance development. Mechanistic analysis revealed that the SH3B domain of Ply900 enhances targeted cleavage efficiency by binding synergistically to peptidoglycan with the CHAP domain, with CYS-34, HIS-59, and ASP-28 serving as key amino acid sites for Ply900’s cleavage activity. Collectively, these findings lay the foundation for the potential dual applications of the lysin Ply900, both in the clinical treatment of S. suis infections and in the prevention and control of these pathogenic bacteria in livestock farming. Full article

Pasteurella multocida serotype B:2 is a primary agent of hemorrhagic septicemia (HS) in livestock, and the strain NQ01 isolated from yaks highlights its cross-species impact. In this study, a murine intranasal infection model was established using P. multocida NQ01 to assess how acute respiratory infection perturbs gut homeostasis. Mice were intranasally inoculated with NQ01, and at 36 h post-infection, ileal tissues and cecal contents were collected for histopathological examination, 16S rRNA gene sequencing, and untargeted metabolomic analysis. Histopathology revealed obvious acute bronchopneumonia but no overt ileal damage. However, 16S rRNA sequencing of cecal microbiota showed significant dysbiosis: microbial diversity was reduced and community composition shifted, including decreased short-chain fatty-acid-producing taxa and increased opportunistic genera. Metabolomic profiling detected 1444 significantly altered cecal metabolites, and pathway analysis indicated marked disruption of amino acid metabolism, notably the tyrosine metabolism pathway. Key tyrosine pathway metabolites were dysregulated (e.g., elevated L-tyrosine and dopamine with reduced L-DOPA), indicating a breakdown of this metabolic pathway. These findings demonstrate that acute respiratory P. multocida infection profoundly disturbs gut microbiota and metabolism, underscoring disruption of the gut–lung axis. This study provides new insight into the systemic consequences of HS-associated P. multocida infection and offers a basis for exploring the gut–lung interaction in hemorrhagic septicemia pathogenesis. Full article

Background: Chromobacterium violaceum is an emerging multidrug-resistant (MDR) Gram-negative bacterium associated with severe septicemia, abscess formation, and high mortality, particularly in immunocompromised individuals. Increasing antimicrobial resistance and the absence of approved vaccines underscore the urgent need for alternative preventive strategies. Traditional vaccine approaches are often inadequate against genetically diverse MDR pathogens, prompting the use of computational immunology and reverse vaccinology for vaccine design. Objectives: This study aimed to design and characterize a novel multi-epitope subunit vaccine (MEV) candidate against C. violaceum using a comprehensive pangenome-guided subtractive proteomics and immunoinformatics pipeline to identify conserved antigenic targets capable of eliciting strong immune responses. Methods: Comparative genomic analysis across eight C. violaceum strains identified 3144 core genes. Subtractive proteomics filtering yielded two essential, non-homologous, surface-accessible, and antigenic proteins—penicillin-binding protein 1A (Pbp1A) and organic solvent tolerance protein (LptD)—as vaccine targets. Cytotoxic T-lymphocyte (CTL), helper T-lymphocyte (HTL), and B-cell epitopes were predicted and integrated into a 272-amino-acid MEV construct adjuvanted with human β-defensin-4A using optimal linkers. The construct was evaluated through structural modeling, molecular docking with TLR4, molecular dynamics simulation, immune simulation, and in silico cloning into the pET-28a(+) vector. Results: The MEV construct exhibited strong antigenicity, non-allergenicity, and non-toxicity, with stable tertiary structure and favorable physicochemical properties. Docking and dynamics simulations demonstrated high binding affinity and stability with TLR4 (ΔG = −16.2 kcal/mol), while immune simulations predicted durable humoral and cellular immune responses with broad population coverage (≈89%). Codon optimization confirmed high expression potential in E. coli K12. Conclusions: The pangenome-guided immunoinformatics approach enabled the identification of conserved antigenic proteins and rational design of a promising multi-epitope vaccine candidate against MDR C. violaceum. The construct exhibits favorable immunogenic and structural features, supporting its potential for experimental validation and future development as a preventive immunotherapeutic against emerging MDR pathogens. Full article

Outbreaks of hemorrhagic septicemia (HS) caused by Pasteurella multocida serogroup B are endemic in Kazakhstan. These outbreaks have repeatedly led to mass mortality events among wild saigas and economic losses to farms. The aim of this study was to conduct the first whole-genome sequencing (WGS) and analysis of P. multocida genomes associated with HS cases in saigas and livestock in Kazakhstan. In this study, WGS was performed on 22 P. multocida isolates obtained from saigas and livestock. A comparative genomic analysis of P. multocida isolates from Kazakhstan and publicly available genomes was performed. All isolates belonged to the B:2:ST122 genotype and formed distinct phylogenetic clusters based on outbreaks in saiga populations and livestock. Clustering also corresponded to identified mutations in virulence genes. Isolates recovered from the 2015 mass mortality of saigas in the Betpak-Dala population were found to have a deletion of the flp1 gene. This observation emphasizes the study of the role of Flp pili in HS pathogenesis. Comparison of the P. multocida B:L2:ST122 genomes revealed low virulence gene diversity and an open pangenome. Prophage annotation did not identify virulence or pathogenicity genes. The obtained results will be useful for future studies of HS pathogenesis. Full article

Cystic Echinococcosis (CE) is a rare but serious parasitic disease caused by Echinococcus granulosus sensu lato, representing only 1–2% of all hydatid disease cases. Due to its nonspecific clinical presentation, its diagnosis and management pose significant challenges. This study aimed to provide a comprehensive overview of intracranial CE cases reported globally over the past 35 years, focusing on demographic characteristics, clinical presentation, diagnostic approaches, treatment modalities, and outcomes. Methods: A systematic review was conducted in accordance with PRISMA guidelines and was registered in PROSPERO (CRD 42024608624). Relevant studies published between 1990 and 2024 were identified from PubMed, Scopus, and Web of Science databases. Results: After screening and eligibility assessment, 392 studies involving 718 intracranial CE cases were included. The majority of patients were children (65%) and male (59.2%). The most frequent presenting symptoms were signs of increased intracranial pressure (79.4%), followed by motor deficits (37.9%) and visual disturbances (23.2%). Most cysts were located in the supratentorial region (88.9%), predominantly in the parietal lobe, and were solitary (88.4%). Surgical intervention was performed in 95.8% of cases, often combined with albendazole therapy. Complete recovery was observed in 85.5% of patients, while 8.7% died—primarily due to cyst rupture-related complications such as septicemia and anaphylaxis. Recurrence was reported in 26% of cases with follow-up. Conclusions: This review presents one of the most extensive analyses of intracranial CE to date. Despite being a rare manifestation, intracranial CE should be considered in the differential diagnosis of space-occupying brain lesions in endemic areas, particularly in paediatric patients. Full article

Hemorrhagic septicemia (HS) is a fulminant bovine disease across Asia and Africa, yet Pasteurella multocida (P. multocida) isolated from yak is poorly reported. We isolated strain NQ01 from a fatal HS case in Xizang, China and identified it as P. multocida B:2 by morphology, Gram stain, and PCR (kmt1⁺, bcbD⁺, LPS L2). NQO1 formed smooth, non-hemolytic colonies. After Gram staining, the cells appeared as red rods with bipolar staining. Antimicrobial testing showed broad susceptibility to β-lactams, aminoglycosides, tetracyclines, fluoroquinolones, midecamycin, florfenicol, polymyxin, and vancomycin, with resistance to metronidazole, trimethoprim sulfamethoxazole, and clindamycin. Streptomycin and ofloxacin had intermediate activity. In mice, the intraperitoneal and intranasal LD₅₀ values were 40.64 CFU/mL and 9.53 × 10⁶ CFU/mL, respectively. The intranasal fatal cases were characterized by bacteremia with multifocal disseminated intravascular coagulation involving lung, liver, and spleen. The complete genome comprises a single 2.33 Mb chromosome (40.47% GC, 2115 CDS, no plasmids) with only one resistance gene (Eco_EFTu_PLV) and 28 virulence genes spanning adhesion (tadA, rcpA, ppdD, pilB, tuf/tufA, htpB, PM_RS00430, PM_RS00425, PM_RS08640), immune modulation (lpxB/C/D, msbB, manB, rfaE/F, gmhA/lpcA, kdsA, pgi, wecA, galE, bexD’, ABZJ_RS06285, ABD1_RS00310), and nutritional/metabolic factor (hgbA, hemR, hemN), plus a YadA-like factor. Phylogenetically, NQ01 clusters with regional B:2 bovine/yak isolates. Collectively, these data define NQ01 as a highly virulent, low-resistance yak isolate and a practical model for natural-route HS pathogenesis and targeted control in high-altitude pastoral settings yaks. Full article