Search Results (497)

The impact of Oedema Disease produced by Shiga toxigenic Escherichia coli (STEC) in swine is increasing in some production countries due to increasing limitations on treatment with antimicrobials and zinc oxide, either because of the increased prevalence of multi-resistant strains or because of legal restrictions. The main pathological effect of Shiga toxin 2e is represented by damage to the endothelial cells of the blood vessel walls, leading to liquid extravasation and oedema formation in multiple tissues. These oedemas are generally easily identifiable in acute clinical cases. However, disease caused by Shiga toxin can occur without any externally visible oedema in the pigs, as observed in the subclinical presentation of Oedema Disease. It also causes productive losses, so it is important to identify and/or diagnose cases to set up control measures in order to optimize production and health. This article includes a comprehensive review of lesions and signs caused by Shiga toxin toxicosis in pigs, as well as other insights about the aetiology and epidemiology of STEC in pigs, and the effect of Shiga toxin recombinant toxoid vaccines in reducing these clinical and subclinical signs under field conditions. Full article

Background/Objectives: Increasing levels of antimicrobial resistance (AMR) have recently been observed at the human–domestic animal–wildlife interface. Wild birds have been identified as carriers of antimicrobial-resistant bacteria and serve as excellent biomarkers for epidemiological studies. This study assessed the current AMR presence in Eastern Spain’s commensal Escherichia coli isolated from free-ranging Bonelli’s eagles (Aquila fasciata). Methods: Nestlings and their nests were intensively sampled between 2022 and 2024 to determine their AMR profile and characterize E. coli. AMR testing was conducted using the broth microdilution method, following the European Committee on Antimicrobial Susceptibility Testing guidelines. Additionally, the presence of eaeA (intimin gene) and stx-1 and stx-2 (shiga toxins) was analyzed by real-time PCR to classify E. coli strains into enteropathogenic (EPEC) and Shiga-toxigenic (STEC) pathotypes. Results: Of all E. coli isolates, 41.7% were resistant to at least one antimicrobial, and 30% were multidrug-resistant. Only two strains were classified as EPEC and none as STEC. The highest resistance rates were observed for amoxicillin and tetracycline (19.6% each). Alarmingly, resistance to colistin and meropenem, last-resort antibiotics in human medicine, was also detected. Conclusions: Although the mechanisms of resistance acquisition remain unclear, transmission is likely to occur through the food chain, with synanthropic prey acting as intermediary vectors. These results highlight the role of Bonelli’s eagles as essential sentinels of environmental AMR dissemination, even in remote ecosystems. Strengthening One Health-based surveillance is necessary to address AMR’s ecological and public health risks in wildlife. Full article

This study presents a comprehensive comparison of static and SLAM (Simultaneous Localization and Mapping) laser scanners of both new and old generation in a controlled indoor environment of a standard commercial building with long, linear corridors and recesses. The aim was to assess both global and local accuracy, as well as noise characteristics, of each scanner. Methods: A highly accurate static scanner was used to generate a reference point cloud. Five devices were evaluated: two static scanners (Leica RTC 360 and Trimble X7) and three SLAM scanners (GeoSLAM ZEB Horizon RT, Emesent Hovermap ST-X, and FARO Orbis). Accuracy analysis included systematic and random error assessment, axis-specific displacement evaluation, and profile-based local accuracy measurements. Additionally, noise was quantified before and after data smoothing. Static scanners yielded superior accuracies, with the Leica RTC 360 achieving the best performance (absolute accuracy of 1.2 mm). Among SLAM systems, the Emesent Hovermap ST-X and FARO Orbis—both newer-generation devices—demonstrated significant improvements over the older-generation GeoSLAM ZEB Horizon RT. After smoothing, the noise levels of these new-generation SLAM scanners (approx. 2.1–2.2 mm) approached those of static systems. The findings underline the ongoing technological progress in SLAM systems, with the new-generation SLAM scanners becoming increasingly viable alternatives to static scanners, especially when speed, ease of use, and reduced occlusions are prioritized. This makes them well-suited for rapid indoor mapping applications, provided that the slightly lower accuracy is acceptable for the intended use. Full article

Background: Diabetic foot ulcers (DFUs) are a severe complication of diabetes and are characterized by impaired wound healing and a high amputation risk. Exosomes—which are nanovesicles carrying proteins, RNAs, and lipids—mediate intercellular communication in wound microenvironments, yet their biomarker potential in DFUs remains underexplored. Methods: We analyzed transcriptomic data from GSE134431 (13 DFU vs. 8 controls) as a training set and validated findings in GSE80178 (6 DFU vs. 3 controls). A sum of 7901 differentially expressed genes (DEGs) of DFUs were detected and intersected with 125 literature-curated exosome-related genes (ERGs) to yield 51 candidates. This was followed by GO/KEGG analyses and a PPI network construction. Support vector machine–recursive feature elimination (SVM-RFE) and the Boruta random forest algorithm distilled five biomarkers (DIS3L, EXOSC7, SDC1, STX11, SYT17). Expression trends were confirmed in both datasets. Analyses included nomogram construction, functional and correlation analyses, immune infiltration, GSEA, gene co-expression and regulatory network construction, drug prediction, molecular docking, and RT-qPCR validation in clinical samples. Results: A nomogram combining these markers achieved an acceptable calibration (Hosmer–Lemeshow p = 0.0718, MAE = 0.044). Immune cell infiltration (CIBERSORT) revealed associations between biomarker levels and NK cell and neutrophil subsets. Gene set enrichment analysis (GSEA) implicated IL-17 signaling, proteasome function, and microbial infection pathways. A GeneMANIA network highlighted RNA processing and vesicle trafficking. Transcription factor and miRNA predictions uncovered regulatory circuits, and DGIdb-driven drug repurposing followed by molecular docking identified Indatuximab ravtansine and heparin as high-affinity SDC1 binders. Finally, RT-qPCR validation in clinical DFU tissues (n = 5) recapitulated the bioinformatic expression patterns. Conclusions: We present five exosome-associated genes as novel DFU biomarkers with diagnostic potential and mechanistic links to immune modulation and vesicular transport. These findings lay the groundwork for exosome-based diagnostics and therapeutic targeting in DFU management. Full article

A single domain antibody (SDAb) targeting canine PD-1 was developed as a potential immunotherapeutic for canine cancer. An alpaca was immunized with canine PD-1 protein, and a phage-display library was constructed using mRNA isolated from peripheral lymphocytes. Screening of the library yielded multiple SDAb candidates capable of nanomolar binding to canine PD-1. Among these, clone STX-1b5 demonstrated high expression in a yeast-based recombinant system and was selected for further characterization. Binding and competition assays using ELISA confirmed its ability to bind canine PD-1 and block PDL-1 interaction. In silico structural modeling supported the interaction of STX-1b5 with key PD-1 residues implicated in ligand binding. These findings support the feasibility of using SDAbs and cost-effective yeast expression systems to generate immunotherapeutics for veterinary use, with STX-1b5 representing a promising lead candidate for future clinical development. Full article

Subclinical mastitis (SCM) is a stealthy but devastating challenge in the dairy industry, leading to economic losses and hindering efforts to achieve milk self-sufficiency. This study investigated the prevalence of SCM, antimicrobial resistance, and virulence profiles of Escherichia coli. A total of 174 milk samples were analyzed using the California mastitis test (CMT), somatic cell counts (SCCs), bacteriological culture, MALDI-TOF MS, and polymerase chain reaction (PCR). The findings revealed that the SCM prevalence was 68/174 (39.08%) based on CMT and SCC. Among SCM-positive samples, 60/68 (88.23%) were identified as E. coli, confirmed by MALDI-TOF MS and PCR assay. The most frequently detected serogroups were 0113 (11.6%) and 0113 (3.3%). Additionally, the genes for Stx1 and Stx2 were also detected in nine (15%) and one (1.7%), respectively. Antimicrobial susceptibility tests showed widespread resistance, with E. coli isolates demonstrating resistance to penicillin in 43 (71.6%), followed by ciprofloxacin in 42 (70%) and gentamicin in 18 (30%). A larger proportion of the E. coli strains (100%) harbored the bla_VIM gene, while 23 (38.3%), 20%, 20%, and 1.47% contained bla_KPC, bla_NMD, suli1, and msrA. Thirty (50%) isolates were considered multidrug-resistant (MDR). These findings underscore the urgent need for enhanced surveillance and antibiotic stewardship in dairy farming. The presence of MDR E. coli in SCM poses a dual threat of potential transmission to humans and treatment failures in mastitis management. This study highlights the importance of proactive control strategies to mitigate the spread of antimicrobial resistance in livestock and beyond. Full article

Saxitoxin (STX) is a potent toxin produced by marine dinoflagellates and freshwater or brackish water cyanobacteria, and is a member of the paralytic shellfish toxins (PSTs). As a highly specific blocker of voltage-gated sodium channels (NaVs), STX blocks sodium ion influx, thereby inhibiting nerve impulse transmission and leading to systemic physiological dysfunctions in the nervous, respiratory, cardiovascular, and digestive systems. Severe exposure can lead to paralysis, respiratory failure, and mortality. STX primarily enters the human body through the consumption of contaminated shellfish, posing a significant public health risk as the causative agent of paralytic shellfish poisoning (PSP). Beyond its acute toxicity, STX exerts cascading impacts on food safety, marine ecosystem integrity, and economic stability, particularly in regions affected by harmful algal blooms (HABs). Moreover, the complex molecular structure of STX—tricyclic skeleton and biguanide group—and its diverse analogs (more than 50 derivatives) have made it the focus of research on natural toxins. In this review, we traced the discovery history, chemical structure, molecular biosynthesis, biological enrichment mechanisms, and toxicological actions of STX. Moreover, we highlighted recent advancements in the potential for detection and treatment strategies of STX. By integrating multidisciplinary insights, this review aims to provide a holistic understanding of STX and to guide future research directions for its prevention, management, and potential applications. Full article

In the past two decades, Shiga toxin-producing Escherichia coli (STEC) has been responsible for multiple large-scale outbreaks worldwide, affecting thousands of individuals. While surveillance systems in developed countries such as the United States, the United Kingdom, Europe, Australia, Japan, and Canada are well-established, data on STEC prevalence in developing nations remain sparse, partly due to the absence of well-structured molecular diagnostic networks or surveillance systems. This review analyzed 250 studies published between 2014 and 2024 across 39 developing countries in Africa, Asia, Latin America, and the Caribbean, yielding 8986 STEC isolates. Detailed serogroup and serotype data were available for 55.9% of these, with O111, O157, and O26 being most common in humans. In animals, O157:H7 was most frequent, while food isolates mirrored global trends with O157 and O111 dominance. Notably, O145, a serogroup frequently reported in the U.S. and Europe, was absent from the ‘’Top Seven’’ serogroups. Shiga toxin subtypes stx1a and stx2a were most prevalent in human cases. In animal isolates, stx2e was the most prevalent subtype, while stx2c was most commonly found in food samples. We recommend establishing reference laboratories in these regions to improve data quality, strengthen monitoring efforts, and reduce the burden of STEC infections globally. Full article

Paralytic shellfish poisoning toxins (PSPTs) are a class of neurotoxins most known for causing illness from consuming contaminated shellfish. These toxins are also present in freshwater systems with the concern that they contaminate drinking and recreational waters. This review provides (1) a complete list of the 84+ known PSPTs and important chemical features; (2) a complete list of all environmental freshwater PSPT detections; (3) an outline of the certified PSPT methods and their inherent weaknesses; and (4) a discussion of PSPT toxicology, the weaknesses in existing data, and existing freshwater regulatory limits. We show ample evidence of production of freshwater PSPTs by cyanobacteria worldwide, but data and method uncertainties limit a proper risk assessment. One impediment is the poor understanding of freshwater PSPT profiles and lack of commercially available standards needed to identify and quantify freshwater PSPTs. Further constraints are the limitations of toxicological data derived from human and animal model exposures. Unassessed mouse toxicity data from 1978 allowed us to calculate and propose toxicity equivalency factors (TEF) for 11-hydroxysaxitoxin (11-OH STX; M2) and 11-OH dcSTX (dcM2). TEFs for the 11-OH STX epimers were calculated to be 0.4 and 0.6 for 11α-OH STX (M2α) and 11β-OH STX (M2β), while we estimate that TEFs for 11α-OH dcSTX (dcM2α) and 11β-OH dcSTX (dcM2β) congeners would be 0.16 and 0.23, respectively. Future needs for freshwater PSPTs include increasing the number of reference materials for environmental detection and toxicity evaluation, developing a better understanding of PSPT profiles and important environmental drivers, incorporating safety factors into exposure guidelines, and evaluating the accuracy of the established no-observed-adverse-effect level. Full article

This study examines the formation of the clay mineral simonkolleite (Skl) in bentonites contaminated with zinc(II) chloride (ZnCl₂), a process that has been little documented in heterogeneous systems such as contaminated bentonites. We explain the contamination mechanisms and provide new insights into the mineralogical, structural, and physicochemical transformations occurring within these materials. The objective, explored for the first time, was to assess how the ZnCl₂-induced mineral phase formation influences the properties of bentonites used as sealing materials, particularly regarding changes in specific surface area and porosity. Three bentonites were analyzed: Ca-bentonite from Texas (STx-1b), Na-bentonite from Wyoming (SWy-3), and Ca-bentonite from Jelsovy Potok, Slovakia (BSvk). Treatment with ZnCl₂ solution led to ion exchange and the formation of up to ~30% simonkolleite, accompanied by a concurrent decrease in montmorillonite content by 9–30%. A suite of analytical techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray fluorescence (XRF), and energy-dispersive X-ray spectroscopy (EDS), was employed to characterize these transformations. The contamination mechanism of ZnCl₂ involves an ion exchange of Zn²⁺ within the montmorillonite structure, the partial degradation of specific montmorillonite phases, and the formation of a secondary phase, simonkolleite. These transformations caused a ~50% decrease in specific surface area and porosity as measured by the Brunauer–Emmett–Teller (BET) nitrogen adsorption and Barrett–Joyner–Halenda (BJH) methods. The findings raise concerns regarding the long-term performance of bentonite-based barriers. Further research should evaluate hydraulic conductivity, mechanical strength, and the design of modified bentonite materials with improved resistance to Zn-induced alterations. Full article

Hemolytic uremic syndrome (HUS) is a thrombotic microangiopathy characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury (AKI). Shiga toxin (Stx)-producing Escherichia coli-associated HUS (STEC-HUS) is one of the leading causes of AKI in children. Approximately 1.5 to 3% of children die during the acute phase, and about 30% experience long-term renal sequelae. Argentina has the highest incidence of STEC-HUS globally. Given the prominent role of Stx in its pathophysiology, STEC-HUS is considered more of a toxemia than a bacterial disease. Stx transport occurs before and after the STEC-HUS onset, allowing for the distinction between an early toxemia phase and an advanced toxemia phase. In this review, we present our efforts to develop INM004, an anti-Stx treatment aimed at ameliorating or preventing the clinical consequences of STEC-HUS. We describe the protein engineering that facilitated this development and the clinical path to demonstrate the safety and efficacy of INM004. This immunotherapy could represent a new step in the treatment of STEC-HUS, which could potentially prevent long-term damage. If phase 3 trials are successful, earlier and broader use of INM004 is envisioned. We also discuss the potential impact of INM004 therapy, targeted vaccination strategies, and new diagnostic tools for this disease. Full article

Irrigation water can serve as a reservoir and transmission route for pathogenic Escherichia coli, posing a threat to food safety and public health. This study builds upon a previous survey conducted in Hermosillo, Sonora (Mexico), where 445 samples were collected from a local Honeydew melon farm and associated packing facilities. Among the 32 E. coli strains recovered, two strains, A34 and A51, were isolated from irrigation water and selected for further molecular characterization by PCR, due to their high pathogenic potential. Both strains were identified as hybrid aEPEC/STEC pathotypes carrying bfpA and stx1 virulence genes. Adhesion assays in HeLa cells revealed aggregative and diffuse patterns, suggesting enhanced colonization capacity. Phylogenetic analysis classified A34 within group B2 as associated with extraintestinal pathogenicity and antimicrobial resistance, while A51 was unassigned to any known phylogroup. Serotyping revealed somatic antigens shared with Shigella boydii 16, suggesting possible horizontal gene transfer or antigenic convergence. Antibiotic susceptibility testing showed resistance to multiple β-lactam antibiotics, including cephalosporins, linked to the presence of bla_CTX-M-151 and bla_CTX-M-9. Although no plasmid-mediated quinolone resistance genes were detected, resistance may involve efflux pumps or mutations in gyrA and parC. These findings are consistent with previous reports of E. coli adaptability in agricultural environments, suggesting potential genetic adaptability. While our data support the presence of virulence and resistance markers, further studies would be required to demonstrate mechanisms such as horizontal gene transfer or adaptive evolution. Full article

Background: Shiga toxin-producing E. coli (STEC) are important foodborne pathogens that cause serious public health consequences worldwide. This study conducted a systematic review and meta-analysis of the global prevalence of antibiotic resistance and STEC in chickens. Methods: The assessment of previous study records was carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Heterogeneity between studies was assessed using Cochrane’s Q test and I² test statistics based on the random effects model, and comprehensive meta-analysis (CMA) software v4.0 was used to analyse the pooled prevalence estimate (PPE) of antibiotic resistance and STEC in chickens. Results: A total of 61 studies comprising 823 STEC from 18 countries were included in this study. The overall pooled prevalence of STEC was 8.9% (95% CI: 0.620–0.126). m-PCR assay showed the highest PPE of 21.0% (95%: 0.088–0.420). stx1 had the higher PPE of 12.9% (95%: 0.081–0.199), while stx2 had a PPE of 11.8% (95%: 0.077–0.176). Furthermore, the serotype O157 had the higher PPE of 80.5% (95%: 0.520–0.940). The isolates were resistant to the following antibiotics: amoxicillin and clavulanic acid, chloramphenicol, tetracycline, ciprofloxacin, gentamycin, ampicillin, neomycin, and amoxicillin. Conclusions: These findings may assist in the prevention and control of STEC in chickens globally. To minimise the spread of STEC and antibiotic resistance, future foodborne pathogen prevention and control programmes should prioritise increasing laboratory capacity for the early identification of antibiotic resistance. Full article

Butter clams (Saxidomus gigantea) are a staple in the subsistence diets of Alaskan Native communities and are also harvested recreationally. This filter–feeding species can accumulate saxitoxins (STXs), potent neurotoxins produced by late spring and summer blooms of the microalga Alexandrium catenella. The consumption of tainted clams can cause paralytic shellfish poisoning (PSP). Traditional beliefs and early reports on the efficacy of removing clam siphons have created the impression that cleaning butter clams by removing certain tissues makes them safe to eat. However, the toxin distribution within clams can vary over time, making the practice of cleaning butter clams unreliable. This study tested the effectiveness of the cleaning methods practiced by harvesters on Kodiak Island, Alaska. Specifically, butter clams were cleaned by removing different tissues to produce samples of “edible” tissues that were tested for STX content. The results were compared to historical data from a study conducted in Southeast Alaska from 1948 to 1949. Using these data, the risk for an average–sized man and woman consuming 200 g of edible tissue was calculated. The results showed that for clams containing >200 µg STX–equivalents 100 g edible tissue⁻¹, no cleaning method reduced the concentration of STXs in the remaining tissue below the regulatory limit. Meals containing >900 µg STX–equivalents 100 g edible tissue⁻¹ posed a substantial risk of moderate or severe symptoms. No cleaning method assured that untested butter clams are safe to eat. Full article

Early determination of the Shiga toxin type of Shiga toxin-producing Escherichia coli (STEC) is crucial for guiding STEC-infected patients for proper and timely treatment and patient care. Most diagnostic microbiology laboratories rely on PCR assays to detect the presence of stx1 and/or stx2 and enzymatic immunoassays (EIA) to detect the presence of the Shiga toxins 1 and/or 2 in STEC-positive stool samples. Occasionally, the stool samples test positive for STEC by PCR assays but test negative for the presence of Shiga toxins. Insufficient toxin production under laboratory conditions is the main culprit of this discordance. To test whether EIA-based STEC detection could be improved, various clinical STEC strains were treated with mitomycin C, which is a commonly used inducer of Shiga toxin production. A dose-dependent increase in Shiga toxin production, in response to mitomycin C doses of up to 500 ng/mL, was observed without any bactericidal effects. Depending on the serotype, 5–50 times more Shiga toxin 2 was produced than Shiga toxin 1. Shiga toxin production was not induced by the mitomycin C treatment in certain STEC serotypes carrying the toxin subtypes stx1a, stx2a, 2b, 2f, or 2h. This diversity in toxin production indicates that other factors may determine toxin expression in certain STEC strains, which warrant further exploration. Full article