Search Results (66)

Klebsiella pneumoniae is commonly known to cause a vast range of community-acquired or nosocomial infections. The isolation of K. pneumoniae has also been noted in diseased food-producing animals, including swine. The main goals of this study were to document clinical manifestation of a septicaemia outbreak in suckling piglets due to K. pneumoniae ST25 and provide molecular characterisation of the isolates. For the purpose of this investigation, 13 dead suckling piglets with cyanosis were selected. All the isolates obtained from affected lungs were susceptible to apramycin, ceftiofur, gentamycin, neomycin, and spectinomycin, presented intermediate susceptibility to florfenicol, and were resistant to other tested antibiotics. Histopathological examination of lungs, kidneys, and livers revealed lesions typical of septicaemia. MLST analysis of the isolates demonstrated a complex metabolic profile of the bacteria with genes attributable to the hypervirulent phenotype. To the best of our knowledge, we documented the first outbreak of K. pneumoniae septicaemia in suckling piglets reared in Poland. Full article

Several studies have demonstrated that methionine supplementation in fish diets enhances immune status, inflammatory response, and resistance to bacterial infections by modulating for DNA methylation, aminopropylation, and transsulfuration pathways. However, the immunomodulatory effects of methionine in viral infections remain unexplored. This study aimed to evaluate the effect of methionine supplementation on immune modulation and resistance to the viral haemorrhagic septicaemia virus (VHSV) in rainbow trout (Oncorhynchus mykiss). Two diets were formulated and fed to juvenile rainbow trout for four weeks: a control diet (CTRL) with all nutritional requirements, including the amino acid profile required for the species, and a methionine-supplemented diet (MET), containing twice the normal requirement of DL-methionine. After feeding, fish were bath-infected with VHSV, while control fish were exposed to a virus-free bath. Samples were collected at 0 (after feeding trial), 24, 72, and 120 h post-infection for the haematological profile, humoral immune response, oxidative stress, viral load, RNAseq, and gene expression analysis. In both diets, results showed a peak in viral activity at 72 h, followed by a reduction in viral load at 120 h, indicating immune recovery. During the peak of infection, leukocytes, thrombocytes, and monocytes migrated to the infection site, while oxidative stress biomarkers (superoxide dismutase glutathione S-transferase, and glutathione redox ratio) suggested a compromised ability to manage cellular imbalance due to intense viral activity. At 120 h, immune recovery and homeostasis were observed due to an increase in the amount of nitric oxide, GSH/GSSG levels, leukocyte replacement, monocyte influx, and a reduction in the viral load. When focusing on the infection peak, gene ontology (GO) analysis showed several exclusively enriched pathways in the skin and gills of MET-fed fish, driven by the upregulation of several key genes. Genes involved in recognition/signalling, inflammatory response, and other genes with direct antiviral activity, such as TLR3, MYD88, TRAF2, NF-κB, STING, IRF3, -7, VIG1, caspases, cathepsins, and TNF, were observed. Notably, VIG1 (viperin), a key antiviral protein, was significantly upregulated in gills, confirming the modulatory role of methionine in inducing its transcription. Viperin, which harbours an S-adenosyl-L-methionine (SAM) radical domain, is directly related to methionine biosynthesis and plays a critical role in the innate immune response to VHSV infection in rainbow trout. In summary, this study suggests that dietary methionine supplementation can enhance a more robust fish immune response to viral infections, with viperin as a crucial mediator. The improved antiviral readiness observed in MET-fed fish underscores the potential of targeted nutritional adjustments to sustain fish health and welfare in aquaculture. Full article

Background: Aeromonas hydrophila is a common bacterial pathogen that causes hemorrhagic septicaemia in several farmed aquaculture species. Phage therapy is considered a promising and feasible alternative to antibiotic treatment. Methods: In this study, an A. hydrophila-infecting jumbo phage Z90 was isolated from an aquaculture pond. The biological characteristics, genomic features, and in vitro and in vivo experiments were investigated to evaluate its application potential. Results: Phage Z90 was a myovirus with distinctive curled tail fibers. Additionally, phylogenetic and genomic analyses found that the phage Z90 was a novel virus belonging to the genus Ferozepurvirus of the family Chimalliviridae. One-step growth curve analysis revealed that the phage Z90 was a lytic phage, exhibiting a short latency period of 20 min and a relatively large burst size of 270 ± 42 PFU/cell. The phage Z90 particles were stable at psychrotrophic and mesophilic temperatures (10–50 °C) and a wide range of pH (pH 3–12). Genomic analysis revealed that the phage Z90 did not contain any genes encoding toxins, virulence factors, or antibiotic resistance factors. In vivo analysis demonstrated that the phage Z90 protected American eels from A. hydrophila infection, greatly increasing eel survival rates and alleviating symptoms caused by bacterial infections. The comparison of different phage administration methods suggested that phage Z90 was better administered through intraperitoneal injection than immersion in aquaculture water. Moreover, the combination of phage Z90 and ampicillin improved the bactericidal effect and reduced the treatment dosage compared to antibiotics or phage alone. Conclusions: Altogether, the findings of this study indicate that the phage Z90 can serve as a promising biocontrol agent for the treatment of A. hydrophila infection in aquaculture. Full article

Vibrio is a genus of ubiquitous aquatic bacteria that includes numerous pathogenic species. Their remarkable genomic plasticity and rapid evolution make them of particular interest from both clinical and ecological perspectives. Successful infection by Vibrio species often relies on multiple virulence factors, including secreted enzymes. Here, we report the characterization of a novel environmental Vibrio strain isolated from a wild octopus that developed fulminant septicaemia accompanied by widespread soft tissue lysis. These severe symptoms prompted a detailed investigation into the bacterium’s identity and enzymatic profile, focused on proteases as potential virulence factors. Multi-locus sequence analysis placed the isolate within the Harveyi clade but revealed no perfect match to known strains, supporting its designation as a novel strain. Biochemical assays demonstrated strong proteolytic—including collagenolytic—activity, which makes this strain a promising source of enzymes for biotechnological applications. Full article

Background/Objectives: Neisseria meningitidis is a human-specific pathogen capable of causing life-threatening illnesses. Occasionally, it is recovered from unusual sites, other than the bloodstream or the central nervous system. Herein, we describe two rare manifestations due to N. meningitidis within a year (2024) in Greece. Methods: Atypical infection due to N. meningitidis was diagnosed in two different patients: Case-1 presented with an inflammatory swelling in the mid-line of the neck, and Case-2 presented with swelling of the left knee. Both patients had high fever and no neurological signs at admission; Case-2 progressed to meningoencephalitis. Phenotypic and genotypic identifications were carried out in both cases. Results: Case-1 and Case-2 isolates were identified as follows: MenX: 18, 25-44, F5-5, ST-823; 198cc and MenB: 7-1, 1, F3-3, ST-7460; 32cc for PorA, FetA and MLST, respectively. MenX was identified for the first time in Greece and finetyping revealed rare genotypic characteristics. Both isolates were susceptible to cefotaxime, ceftriaxone and rifampicin, while Case-2 isolate expressed reduced susceptibility to penicillin and resistance to ciprofloxacin. Both patients recovered fully. Conclusions: Although uncommon, N. meningitidis may be isolated from atypical sites and specimens. Clinicians and microbiologists should remain aware that meningococcus is a potential cause of infections beyond meningitis and septicaemia. Full article

Streptococcus suis type 2 (SS2) is a pathogen causing diseases like meningitis and septicaemia worldwide. While microRNAs (miRNAs) are acknowledged for their role in post-transcriptional regulation of gene expression and influence on immune responses, their exact functions in hosts during SS2 infection remain elusive. This study aims to explore the role of miR-7a-5p in macrophages during SS2 infection. Our findings reveal that SS2 infection in J774A.1 cells triggers upregulation of the NLRP3 inflammasome signaling pathways, evidenced by enhanced mRNA expression of pro-inflammatory cytokines (IL-6, IL-18, IL-23, TNF-α) and elevated protein levels of NLRP3, caspase-1, and IL-1β. Concurrently, SS2 infection reduces miR-7a-5p expression. Dual-luciferase reporter assays confirm that miR-7a-5p directly targets the 3′UTR of NLRP3 mRNA. Notably, miR-7a-5p overexpression in SS2-infected J774A.1 cells suppresses NLRP3 inflammasome activation and downstream signaling, as demonstrated by reduced mRNA levels of inflammatory mediators and decreased protein levels of NLRP3, caspase-1, IL-1β, and IL-18. Conversely, miR-7a-5p inhibition produces effects opposite to those of overexpression. In mice, administration of miR-7a-5p mimics mitigates SS2-induced lung, liver, and spleen damage, reducing histological scores in these organs. Collectively, these results show that miR-7a-5p alleviates SS2-induced inflammation by inhibiting the NLRP3 inflammasome, underscoring its potential as a therapeutic target for SS2-associated diseases. Full article

Streptococcus equi subsp. zooepidemicus (SEZ) is a major problem in equine veterinary medicine. Typically, a commensal in horses, SEZ can cause severe disease including respiratory infections, septicaemia and reproductive tract infections under certain conditions. Recent evidence suggests that humans can also develop severe disease infection through direct contact with infected animals or the consumption of contaminated unpasteurised milk and milk products. This study investigates SEZ strains isolated from nasal swabs of equidae in central Italy in 2023 to describe the epidemiology and genomic characteristics of circulating strains. A sampling plan was implemented to randomly collect nasal swabs from equid farms in the Abruzzo and Molise regions. In addition, a sampling form was designed to collect information on risk factors related to the presence of the bacterium and the potential development of respiratory disease. Relative risk was used to measure the association between the presence of SEZ in the samples and various variables. The swabs were analysed by real-time PCR and isolation. To confirm the identification and characterise the strains, the isolates were fully sequenced by next-generation sequencing (NGS) using the Illumina platform. A total of 478 animals from 99 farms were sampled and 30% of the animals tested positive for SEZ (79% horses, 20% donkeys, 1% mules). Forty-five percent of the farms tested positive for SEZ. Monitoring the clonal spread of SEZ is essential to understand the ecology of this emerging zoonotic pathogen, to assess the risk, and to implement effective control measures. In addition, genomic assessments are recommended to investigate the pathogenicity of circulating strains. This study provides a comprehensive understanding of the epidemiology and genomic diversity of SEZ strains isolated in central Italy. Full article

Objectives of the study: The aim of this study was to assess the impact of the COVID-19 pandemic on the epidemiology and clinical course of chickenpox in children based on 6 years of self-reported observations. MATERIAL AND METHODS: The medical records of 350 patients under 18 years of age hospitalised in the Department of Paediatrics, Infectious Diseases, and Hepatology between 1 January 2018 to 31 December 2023 were analysed retrospectively. RESULTS: During the analysed period, 350 children were hospitalised due to chickenpox, the fewest in the pandemic period, the greatest number in 2023. Complications of chickenpox were diagnosed in 297 children (84.86%). The most commonly diagnosed complications were bacterial dermatitis (168, 48%) and lower respiratory tract infections (13.42%). After the pandemic period, a generalised inflammatory reaction was observed significantly more often (p ≤ 0.01069). Among children hospitalised in 2023, 5.90% of patients with bacterial dermatitis required surgical intervention due to skin abscess or fasciitis. In 2023, 41.46% of cultures from swabs taken from skin lesions grew Streptococcus pyogenes. After the pandemic, children with chickenpox and gastrointestinal symptoms were hospitalised significantly less frequently (p ≤ 0.00001). CONCLUSIONS: In the post-pandemic period, there were more hospitalisations of patients with chickenpox complicated by bacterial skin infection progressing to a generalised inflammatory reaction or septicaemia, related to the increase in invasive group A streptococcal infections observed in Europe. On the other hand, thanks to the widespread adaption of hygiene practices and infection prevention measures, the number of patients with gastrointestinal symptoms significantly decreased. Full article

Harbour seals (Phoca vitulina) are the most common pinniped species in the Wadden Sea of Schleswig-Holstein, Hamburg and Lower Saxony, Germany. Their numbers have recovered after significant depletion due to viral outbreaks and effects of anthropogenic activities like pollution and habitat disturbance. Within the Wadden Sea National Park of Lower Saxony the harbour seal is protected. As a top predator in the Wadden Sea ecosystem, the harbour seal is a sentinel species for the state of the environment. Between 2015 and 2017, a total of 80 stranded dead harbour seals were collected along the coastline of Lower Saxony and submitted for pathological investigations. Of these, 70 seals were born in the same year (0–7 months, age group 1) and eight in the previous year (8–19 months, age group 2), due to high mortality rates in these age groups. However, two perennial animals were also available for examination during this period, one of which was in good nutritional condition. Many of the seals that had been mercy-killed and found dead were in poor nutritional status. Histopathological, microbiological, parasitological and virological examinations were conducted on 69 individuals (86% (69/80)) in a suitable state of preservation. Respiratory tract parasitosis, cachexia, and bronchopneumonia were the most common causes of death or disease. Overall, there was no evidence of a relapse of a viral disease outbreak. Macrowaste, such as plastic waste or fishery-related debris, were not found in any gastrointestinal tract of the animals examined. There was also no evidence of grey seal predation. Weakness and cachexia were prominent causes of disease and death in harbour seals found within a few weeks after birth, but bronchopneumonia and septicaemia also developed in slightly older animals. Frequently found microbial pathogens in seals from Lower Saxony were similar to those found in other studies on seals from the Wadden Sea region in Schleswig-Holstein, for example streptococci and Escherichia coli/v. haemolytica, Brucella spp. and Erysipelothrix rhusiopathiae, potentially human pathogenic germs. The results of the examinations of dead harbour seals from Lower Saxony show that pathological investigations on a representative number of animals deliver urgently needed information on the health status of the population. The results represent an important contribution to the state of the top predators of the Wadden Sea as part of the obligations within the Trilateral Wadden Sea Agreement, Oslo and Paris Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR) and the Marine Framework Directive. The investigations should be continued as a matter of urgency and the stranding network should be expanded. Full article

Background: Intravascular stent infections are often associated with high risks of morbidity and mortality. We report here a case of a patient with an arterial stent and recurrent Pseudomonas septicaemias successfully treated with phage–meropenem combination therapy. Methods: A 75-year-old female with arteriosclerosis and comorbidities went through a femoropopliteal bypass with prosthesis in the right inguinal area. After the bypass, she developed a recurring Pseudomonas aeruginosa infection and also neutropenia during different antibiotics. A rapidly growing pseudoaneurysm in the right inguinal area led to an emergency intra-arterial stent placement during blood stream infection, later suspected to host a P. aeruginosa biofilm. Removing the stent was deemed precarious, and phage therapy was considered as a compassionate treatment option. A three-phage cocktail infecting the P. aeruginosa strain was prepared and administered intravenously together with meropenem for two weeks, after which, a ten-month follow-up was carried out. Results: No adverse reactions occurred during the phage therapy treatment, while infection markers were normalized. In addition, recovery was seen in a PET-CT scan. During the 10-month follow-up, no further P. aeruginosa septicaemias occurred. Conclusions: Phage–meropenem combination therapy was thus found safe and effective in the treatment of recurrent Pseudomonas septicaemia in a patient with an arterial stent. Full article

Recent genomic characterisation of translocating Escherichia coli HMLN-1 isolated from mesenteric lymph nodes (MLNs) and blood of a patient with a fatal case of pancreatitis revealed the presence of a type 6 secretion system (T6SS) that was not present in non-translocating E. coli strains. This strain was also genomically similar to adherent-invasive E. coli (AIEC) LF82 pathotype. We aimed to identify the role of T6SS-1 in the pathogenesis of this strain and other pathogenic E. coli. The HMLN-1 strain was initially tested for the presence of six virulence genes (VGs) associated with AIEC strains and an iron sequestering system. Additionally, HMLN-1’s interaction with a co-culture of Caco-2:HT29-MTX cells and its intra-macrophagic survival was evaluated. We subsequently screened a collection of 319 pathogenic E. coli strains isolated from patients with urinary tract infection (UTI), diarrhoea, inflammatory bowel disease (IBD) and septicaemia for the presence of T6SS-1 and its expression related to adhesion, invasion and translocation via the above co-culture of the intestinal cell lines. The results showed that HMLN-1 harboured four of the AIEC-associated VGs (dsbA, htrA, ompC and afaC). Screening of the pathogenic E. coli collection detected the presence of the T6SS-1 genes in septicaemic and UTI E. coli strains at a significantly higher level than diarrhoea and IBD strains (p < 0.0001). The high expression of T6SS-1 in E. coli HMLN-1 upon adhesion and invasion, as well as its high prevalence among extra-intestinal E. coli strains, suggests a role for T6SS-1 in the pathogenesis of translocating E. coli. Full article

The lessons learned from reviewing national risk assessments to modernise the Australian Standard for the post-mortem inspection and disposition judgement of beef, sheep, goat, and pig carcases are discussed. The initial risk profiles identified priorities for quantitative assessments. Broadly, the main difficulty encountered was the paucity of quantified performance for the current inspection. Resolving this involved acquiring gross abnormality data representing regional production/proportional abattoir volumes, the range of gross abnormalities appearing nationally, proportional occurrence at carcase sites, and seasonality to enable the comparison of procedures. The methodologies followed the Codex Alimentarius Commission’s risk assessment guidelines and are fully documented in the associated publications. The evidence and discussion are provided for the associated challenges experienced, including preventing contamination, the use of food chain information to support amendment, inspection as a part of industry Quality Assurance programmes, and opportunities to improve inspector training. The criteria considered by the Competent Authority for the determination of the equivalence of alternative post-mortem inspection techniques included comparisons of public health risk, non-detection rates for gross abnormalities, and microbial contamination resulting from inspection activities, as appropriate. Most of the gross abnormalities detected arose from animal health and welfare conditions affecting wholesomeness and did not present as food safety hazards. The non-detection rates between the current and alternative inspection (observation) were negligible. A quantitative risk assessment for Cysticercus bovis was conducted. Carcases with multiple gross abnormalities predominantly reflected historic infections (prior septicaemia), where trimming achieved wholesomeness unless they were cachexic. Full article

Hemorrhagic septicemia (HS) is a highly contagious and fatal disease of cattle and buffaloes caused by P. multocida. Both conventional and molecular methods are applied in parallel for rapid diagnosis of HS outbreaks and the periodical surveillance strategy to identify risk areas for HS is ignored. The current cross-sectional study aimed to estimate sero-prevalence and associated risk factors for HS in cattle and buffaloes in non-vaccinated regions of two Indian states. HS surveillance was carried out through the multi-stage random sampling technique at different strata. The study employed a questionnaire incorporating host factors (species, breed, sex, age, and lactation) and demographic parameters (state, district, block/cluster and village/epiunits, and household). First, two Indian states known for high milk production were selected followed by two districts within each state, subsequently four clusters within each district, finally 5–10 epiunits within clusters and 5–8 households within clusters were randomly selected to collect cattle and buffalo samples. The chi-square/p values and maps were prepared to represent disease prevalence and to correlate disease risk factors at different strata. A total of 692 cattle and buffalo serum samples were sourced from two states of the country (Karnataka-285 and Gujarat-407). In the first strata, antibodies to P. multocida were high in Gujarat (14.49%, CI: 11.22–18.30) compared to Karnataka (3.85%, CI: 1.94–6.80) with significant (p < 0.0001) association between the states. In the second strata, one of the four districts investigated revealed the highest sero-prevalence (18.61%, CI: 13.81–24.24) with statistical significance (p = 0.01) between the districts. Among clusters, one out of eight clusters showed the highest sero-prevalence (23.02%, CI: 16.59–30.54) with statistical significance (p = 0.03) between the clusters in the third strata. At epiunit level (fourth strata), 9 out of 27 epiunits (33.33%) visited in Karnataka and 24 out of 29 epiunits sampled in Gujarat were sero-positive (82.75%) in iELISA. At the household level, out of 306 HH visited, 40 HH had at least one positive animal (13.07%) and the p value between HH in the two states was highly significant (p = 0.0002). Chi-square analysis did not find any association of HS sero-prevalence to species, age, and lactation. However, significantly higher (p < 0.05) sero-prevalence was recorded in indigenous cattle breeds (16.56%) compared to crossbreeds (6.59%). Various immunoprophylactics and antibiotic therapies are effective against HS, but inappropriate disease reporting and failure to implement adequate vaccination control measures are the gaps identified. The present study highlights the current scenario of HS sero-prevalence in two of the high milk-producing states of India, which will be useful for stakeholders for undertaking the implementation of surveillance and control strategies for the regions. Full article

Aeromonas dhakensis is increasingly recognised to be an important pathogen responsible for disease losses in warm-water aquaculture and, similar to several other Aeromonas species, it can infect humans. Knowledge of A. dhakensis is accumulating, but this species remains relatively under-investigated compared to its close relative, Aeromonas hydrophila. The significance of A. dhakensis may have been overlooked in disease events of aquatic animals due to issues with reliable identification. Critical to appreciating the importance of this pathogen is the application of dependable molecular tools that enable accurate identification and discrimination from A. hydrophila and other motile aeromonads. This review aims to synthesise the key literature on A. dhakensis, particularly with relevance to aquaculture, including knowledge of the bacterium derived from disease case studies in aquatic hosts. Identification methods and strain phylogeny are discussed, with accurate detection important for prompt diagnosis and for distinguishing strains with heightened virulence. Increasing evidence suggests that A. dhakensis may be more virulent than A. hydrophila and correct identification is required to determine the zoonotic risks posed, which includes concerns for antibiotic-resistant strains. This review provides an impetus to improve species identification in the future and screen strain collections of presumptive Aeromonas spp. retrospectively to reveal the true prevalence and impact of A. dhakensis in aquaculture, the environment, and healthcare settings. Full article

In aquaculture, Lactococcus garvieae is a common fish pathogen that can cause significant economic losses in several fresh and saltwater species. Despite the extensive range of hosts, L. garvieae infection in sea bass (Dicentrarchus labrax) has rarely been reported. During the summer of 2023, an outbreak occurred in an inland farm in the Gulf of Follonica (Tuscany, Italy). Fish of various sizes were affected, showing apathy, inappetence, erratic swimming and eye lesions, while the mortality was low (2–3% per month). Anatomopathological examinations suggested a septicaemic infection characterised by melanosis, diffuse redness (skin and fins), paleness (gills and internal organs), haemorrhages and splenomegaly. Seventy swabs from the viscera of 14 subjects were collected and colonies similar to Streptococcus spp. grew from all the samples. Lactococcus garvieae was identified via the biochemical tests, API20STREP, MALDI-TOF, 16S rDNA and whole genome sequencing. Genetical characterisation revealed remarkable differences between this isolate and the strains previously isolated in Italian fish farms. Feed treatments with flumequine and erythromycin were ineffective. Considering the limited effects of antimicrobials, preventive measures, such as vaccination and biosecurity, should be implemented. Full article