Search Results (1,061)

Lipopolysaccharide (LPS) is widely used to model immune stress in weaned piglets, but it does not fully replicate the pathophysiological alterations induced by live bacterial infection. This study therefore established an oral Salmonella enterica (SE) challenge model and systematically compared its effects with those of LPS to evaluate its potential as a complementary immune stress paradigm. Forty piglets were assigned to five groups: control (saline), LPS (intraperitoneal, 100 μg/kg BW), and three SE groups receiving low-, middle-, or high-dose oral SE (1 × 10⁸ CFU/mL, 2 × 10⁸ CFU/mL, or 3 × 10⁸ CFU/mL in a 10 mL saline volume, respectively). Both LPS and SE significantly reduced average daily gain, while only SE challenge decreased colon length. A transient rectal temperature elevation occurred at 8 h in all challenged groups, persisting at 12 h in the LPS and high-dose SE groups. Serum cytokine analysis revealed that LPS induced early but transient interleukin-12 and tumor necrosis factor-α elevation at 8 h, followed by sustained suppression of interferon-γ, interleukin-6, and interleukin-8. In contrast, the middle-dose SE triggered robust increases in multiple pro-inflammatory cytokines at 24 h. Both challenges significantly reduced the CD4⁺/CD8⁺ T cell ratios in blood and lymphoid organs and decreased intestinal interleukin-10 levels. SE infection produced more severe intestinal pathology, including dose-dependent villus perforations, microvillus disorganization, and mitochondrial cristae vacuolization, beyond the villus shortening and goblet cell reduction observed in both groups. While both LPS and SE induced immune stress and intestinal injury, SE infection caused more severe and comprehensive pathophysiological alterations. Oral administration of 2 × 10⁹ CFU SE for 24 h established a physiologically relevant immune stress model that effectively mimics natural Salmonella infection in weaned piglets, providing a valuable tool for studying enteric diseases and evaluating interventions. Full article

The paper describes a predatory Gram-negative bacterium from the genus Bdellovibrio, which was isolated from water of the Lyubozhikha River. As revealed by electron microscopy, the bacterium is an intracellular predator of Gram-negative microorganisms. Its prey range includes Pseudomonas tolaasii, the phytopathogen responsible for brown spot disease in the cultivated button mushroom (Agaricus bisporus). Based on the results of a 16S rRNA gene sequence analysis, the bacterium was identified as Bdellovibrio bacteriovorus strain LR3. We characterized the predator–prey dynamics between B. bacteriovorus LR3 and P. tolaasii, determining the optimal temperature and pH conditions for this interaction. Our results demonstrate the potential of B. bacteriovorus LR3 as a biocontrol agent against P. tolaasii in mushroom cultivation. The possibility of using B. bacteriovorus LR3 against clinical cases Salmonella and Escherichia infections is also addressed. Full article

Microbial biosurfactants (mBSs) are bioactive molecules with diverse applications, notably as antimicrobial agents against antibiotic-resistant pathogens. Produced by bacteria and yeasts, mBSs are classified as glycolipids, lipopeptides, polymeric, and particulate types. The global rise in multidrug-resistant organisms, such as Escherichia coli, Klebsiella pneumoniae, Salmonella typhimurium, Pseudomonas aeruginosa, and Acinetobacter baumannii, underscores the urgent need for new antimicrobial strategies. mBSs disrupt microbial growth by interacting with the lipid components of pathogens, offering promising alternatives to conventional antibiotics. This review highlights the sources, chemical structures, and properties of mBSs, their antimicrobial activities, synergistic effects with antibiotics, and structure–activity relationships. Special emphasis is placed on surfactant modification, where targeted changes—such as valine substitution in surfactin—significantly lower critical micelle concentrations (CMC) and enhance antimicrobial potency. Such rational engineering demonstrates how biosurfactants can be tailored for improved biomedical performance while minimizing cytotoxicity. In parallel, artificial intelligence (AI) algorithms, including artificial neural networks and genetic algorithms, optimize yields, predict substrate suitability from agricultural residues, and guide microbial strain engineering. AI models can predict interfacial behavior and synchronize fermentation with purification. Advancing the understanding of mBS interactions with microbial membranes, combined with modification strategies and AI-guided optimization, is essential for developing targeted therapies against resistant infections. Future research should integrate these approaches to engineer novel derivatives, reduce costs, and validate clinical potential through comprehensive in vivo studies. Full article

Multidrug resistance (MDR) in Gram-negative bacteria is a global issue and needs to be addressed urgently. MDR can emerge through genetic mutations and horizontal gene transfer and deteriorate under antibiotic selective pressure. The emergence of resistance to last-resort antibiotics, which are used to treat MDR bacteria, is of particular concern. Colistin has been recognized as a last-line antibiotic for the treatment of MDR Gram-negative bacterial infections caused by Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Recently, the increasing reports of colistin resistance pose a significant threat to public health, caused by both acquired and intrinsic mechanisms. The review aimed to elucidate the trends in colistin resistance, the use of colistin in human and veterinary medicine, underlying resistance mechanisms and transmission pathways, and potential mitigation of this emerging threat through novel intervention strategies. Colistin resistance is mediated by plasmid-encoded phosphoethanolamine transferases (mcr-1 to mcr-10) and chromosomal lipid A remodeling pathways. In Escherichia coli, resistance involves mcr-1–10, acrB efflux mutations, pmrA/pmrB, arnBCADTEF, and mgrB inactivation. Klebsiella pneumoniae exhibits mcr-1, mcr-8, mcr-9, mgrB disruption and phoP/phoQ–pmrAB activation. Acinetobacter baumannii harbors mcr-1–4, while Salmonella enterica and Enterobacter spp. carry mcr variants with arnBCADTEF induction. Therapeutic options include adjunct strategies such as antimicrobial peptides, nanomaterials, therapeutic adjuvants, CRISPR-Cas9-based gene editing, probiotics, vaccines, and immune modulators to restore susceptibility. This review identified that specific and wide actions are required to handle the growing colistin resistance, including genomic surveillance, tracing novel resistance mechanisms, and the application of alternative management strategies. The One Health approach is considered a key strategy to address this growing issue. Full article

Background/Objectives: Antimicrobial peptides (AMPs), evolutionarily conserved components of innate immunity characterized by their broad-spectrum efficacy and minimal resistance development, are increasingly recognized as promising therapeutic candidates. This review aims to integrate current knowledge concerning natural and synthetic antimicrobial peptides and their therapeutic effectiveness in addressing gastrointestinal infections. Methods: A literature review was performed, evaluating recent peer-reviewed studies on AMPs. The research concentrated on their molecular mechanisms of action, antimicrobial spectrum, and their interactions with standard antibiotics. More in detail, the peptide classes examined herein included defensins, cathelicidins, histatins, and various natural peptides such as lactoferricin, protamines, RegIII, and hepcidin, along with synthetic analogs like WR12, D-IK8, MSI-78, and IMX942. Results: Natural AMPs demonstrated significant antimicrobial and immunomodulatory effects against Escherichia coli, Klebsiella pneumoniae, Salmonella spp., and Shigella spp. Beyond direct antimicrobial activity, antimicrobial peptides act as integrated anti-infective agents not only by modulating host–microbiota interactions, but also preserving epithelial barrier integrity, and limiting inflammation, thereby offering a multifaceted strategy to control gastrointestinal infections. On the other hand, synthetic peptides showed improved stability, reduced cytotoxicity, and synergistic interactions with antibiotics, which suggests that they could be used either alone or in combination with other treatments. Conclusions: AMPs constitute a promising category endowed with anti-infective activity, especially for therapy of intestinal diseases, which is attributed to their distinctive anti-infective mechanisms, immune-modulating characteristics, and a relatively low propensity for resistance development compared to conventional antibiotics. However, more clinical trials and improvements to their formulation are needed to translate promising in vitro results into reliable patient outcomes. Full article

Background: Non-typhoidal Salmonella (NTS) is a major foodborne pathogen, with poultry products, especially eggs, being the primary source of human infections. Current serovar-specific poultry vaccines effectively reduce targeted Salmonella serovars but may inadvertently promote the emergence of untargeted serovars within poultry flocks. Therefore, novel vaccine candidates providing broad cross-serovar protection are needed to improve overall effectiveness of Salmonella control programs. Objectives: This study evaluated the immunogenicity of the novel subunit vaccine candidate InvG and assessed its ability to reduce Salmonella colonization in vaccinated laying hens and their progeny through maternally derived antibodies transferred via egg yolk. Methodology: Three experiments were performed. Experiment I evaluated the immunogenicity of purified recombinant InvG by (a) measuring anti-InvG antibodies using an enzyme-linked immunosorbent assay (ELISA) and (b) completing transcriptomic profiling of immune responses in vaccinated chickens. Vaccinated chickens were subsequently challenged with Salmonella Enteritidis to assess the efficacy of anti InvG antibodies in reducing intestinal colonization of Salmonella. Experiment II involved immunizing hens with InvG, to evaluate passive transfer of antibodies via egg yolk and the protective efficacy of maternally derived antibodies against Salmonella challenge. Passive transfer was assessed by measuring IgY antibodies in hen serum, egg yolk, and progeny serum, as well as secretory IgA (sIgA) antibodies in progeny intestinal washings using ELISA. Protective efficacy was evaluated by orally challenging one-day-old chicks with three different Salmonella serovars. Experiment III assessed the persistence of anti-InvG antibodies in the serum of vaccinated hens and their transfer into eggs following two doses of InvG. Results: InvG vaccination induced robust IgY antibody responses in hens, with efficient maternal antibody transfer to progeny via egg yolk. A statistically significant reduction in Salmonella colonization was observed in both vaccinated hens and their progeny. Conclusions: These findings demonstrate that InvG represents a promising subunit vaccine candidate for Salmonella control in poultry and warrants further investigation towards development as a broadly protective commercial poultry vaccine against Salmonella. Full article

Salmonella typhimurium (S.T) infection of the central nervous system (CNS) induces severe inflammation, leading to elevated expression of inducible nitric oxide synthase (iNOS) in microglia. This process catalyzes excessive production of nitric oxide (NO), resulting in irreversible damage to neuronal mitochondria. Asiatic acid (AA) is a small molecule with neuroprotective potential; however, its ability to counteract nerve injury induced by S.T and the underlying mechanisms remain unclear. In this study, we established an S.T-infected mouse model (in vivo) and an S.T-stimulated microglial model using BV-2 cells (in vitro) and employed techniques including immunofluorescence (IF), Western blot, co-immunoprecipitation (Co-IP), and RNA extraction and quantitative reverse transcription PCR (RT-qPCR) to systematically evaluate the protective effects and mechanisms of AA. The results showed that pre-treatment with AA significantly reduced the expression of iNOS and the production of NO caused by S.T infection in mouse hippocampal tissue and BV-2 cells. Mechanistically, AA exerts its effects by inhibiting the upstream Toll-like receptor 2 (TLR2)/Notch and nuclear factor-κB (NF-κB) signaling axis. It interferes with the nuclear translocation of Notch and p65 proteins and their complex formation under S.T stimulation, thereby blocking downstream expression of iNOS and production of NO. This study reveals a novel mechanism by which AA alleviates infection-related neuroinflammation through targeting Notch-p65 interactions, providing a new theoretical basis for its clinical application. Full article

Background: Antimicrobial resistance is a major global challenge that is exacerbated by extensive antibiotic use in livestock farming. Identifying effective alternatives to widely used human antibiotics in animal production is vital to safeguard vital human medicines and ensure sustainable food systems. Here we describe studies identifying nitroxoline (NTX) as a promising antimicrobial candidate for use in poultry production. Methods: The antibacterial activity and resistance potential of NTX were assessed in vitro. In vivo studies in chickens evaluated tolerance, therapeutic efficacy in Salmonella-infected birds, pharmacokinetics, tissue residue depletion, growth performance, and effects on caecal microbiota. NTX was administered in-feed at different dose levels. Pharmacokinetic parameters and withdrawal periods were determined, and caecal microbiota composition was analysed using ribosomal RNA 16S sequencing. Results: NTX exhibits potent broad-spectrum antibacterial activity in vitro and low levels of resistance. NTX is well-tolerated in chickens at 500 mg/kg in-feed for 7 days and substantially reduces liver bacterial loads at 100 mg/kg in Salmonella-infected chickens. Pharmacokinetic and residue analyses reveal NTX manifests rapid absorption and distribution, high oral bioavailability (86%), and efficient tissue clearance with a 17-day withdrawal period required for skin-plus-fat clearance. NTX supplementation is associated with increased weight gain and improved feed efficiency compared to the control group, with performance comparable to chlortetracycline. Microbiota analysis indicates modulation of caecal bacterial communities, including increased Faecalibacterium and Lactobacillus. Conclusions: These results indicate that NTX is a viable alternative to important human antibiotics widely deployed in poultry production, offering a potential approach to minimise antimicrobial resistance whilst maintaining animal health and food biosafety. Full article

Copper has become more important owing to its eco-friendliness and persistent efficacy against infections. Furthermore, copper has benefits such as safety in use and durability. This study aimed to develop and assess the antibacterial efficacy of stainless steel coated with a composite layer, which is nanostructured and incorporates copper, to create antibacterial surfaces with good adherence and good corrosion resistance. The composite coating was produced using anodic oxidation, with an external copper layer applied via pulse electroplating. The homogenous cauliflower-like covering showed important characteristics, like increased surface roughness, boosted surface free energy, reduced contact angle, and higher hardness. Additionally, the adherence between the composite covering and the substrate was exceptional. Electrochemical experiments indicated aggressive corrosion behavior in chloride-containing settings. Antibacterial tests were conducted on four prevalent bacterial strains: Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhimurium—microorganisms often linked to healthcare and environmental pollution. The coating exhibited enhanced antibacterial efficacy relative to untreated steel and anodized steel. Results indicated that the composite coating is an effective and possibly cost-efficient method for controlling the surface proliferation of the mentioned pathogens. Full article

Migratory birds have been implicated in the spread of diverse emerging infectious pathogens, including West Nile virus, Usutu virus, Avian influenza viruses, Salmonella, Campylobacter, antimicrobial-resistant (AMR) bacteria, and antibiotic resistance genes (ARGs). Beyond their roles as vectors and reservoirs, migratory birds are also susceptible hosts whose own health may be compromised by these infections, reflecting their dual position in the ecology of pathogens. As facilitators of pathogen transmission during their long-distance migrations, often spanning thousands of kilometres and connecting ecosystems across continents, these birds can easily cross-national borders and circumvent traditional biosecurity measures, thereby acting as primary or secondary vectors in the transmission of cross-species diseases among wildlife, livestock, and humans. Africa occupies a pivotal position in global migratory bird networks, yet comprehensive data on pathogen carriage remain limited. Gaps in knowledge of pathogen diversity constrain current surveillance systems, resulting in insufficient genomic monitoring of pathogen evolution and a weak integration of avian ecology with veterinary and human health. These limitations hinder early detection of novel pathogens and reduce the continent’s preparedness to manage outbreaks. Therefore, this review provides a holistic assessment of these challenges by consolidating existing knowledge concerning the pathogens transmitted by migratory birds in Africa, while recognizing the adverse effect of pathogens, which potentiates population decline, extinction, and ecological imbalance. It further advocates for the adoption of a comprehensive One Health-omics approach that not only strengthens surveillance and technological capacity but also prioritizes the protection of avian health as an integral component of ecosystem and public health. Full article

Background/Objectives: This study aimed to determine the antimicrobial susceptibility patterns of multidrug resistant (MDR) and extensively resistant (XDR) Salmonella enterica serovar Typhi (S. Typhi) strains among children, along with the associated behavioral and environmental risk factors across different population groups in multiple districts of Punjab, Pakistan. Methods: A cross-sectional study was conducted across 20 districts in Punjab, Pakistan. Structured questionnaires were used to assess sociodemographic and behavioral determinants. Blood cultures from febrile children were obtained for the isolation and identification of S. Typhi, followed by antimicrobial susceptibility testing and screening for the resistance genes. Results: A total of 900 blood samples were collected and 41.5% were positive for S. Typhi. The proportion of culture-positive cases were higher among children aged 6–12 years (34.8%). Sociodemographic and behavioral analysis revealed that children from low-income households (PKR < 20,000 showed significantly higher infection rate (67.1%, p < 0.001). Antimicrobial susceptibility testing revealed high resistance rates against several antibiotics: Ciprofloxacin (88.8%), Trimethoprim/sulfamethoxazole (83.7%), Ampicillin (73.8%) and Chloramphenicol (72.7%). However, all isolates remained susceptible to carbapenems and azithromycin. The prevalence of MDR and XDR S. Typhi in urban areas was 28.1% and 60.8%, respectively, while rural areas showed 22.6% MDR and 20.6% XDR. In contrast, nomadic populations exhibited a higher rate of MDR (49.3%) but a lower XDR prevalence of 18.6% with significant geographic variations in resistance patterns. Molecular analysis revealed a high prevalence of resistance genes, including sul1 (83.7%), sul2 (79.7%), followed by dfrA7 (81.3%), catA1 (64.9%) and bla_TEM (60.5%), bla_CTX-M-1 (12.5%), bla_CTX-M-15 (25.9%) and qnrS (88.8%), respectively. Conclusions: The study underscores a persistent typhoid burden and widespread antimicrobial resistance among children in Punjab. Targeted vaccination, antibiotic stewardship, public health education are urgently needed, especially among the nomadic population, where healthcare access and hygiene awareness are limited. Full article

Background: Wildlife is increasingly recognized as an important component in the epidemiology of zoonotic pathogens. Salmonella spp., a leading cause of foodborne disease worldwide, can circulate across human, domestic animal, and environmental interfaces. European hedgehogs (Erinaceus europaeus), a synanthropic species frequently inhabiting urban and peri-urban areas, may act as reservoirs or sentinels for Salmonella. Objectives: The aim of this study was to investigate the prevalence, serotype distribution, and antimicrobial susceptibility profiles of Salmonella spp. isolated from European hedgehogs admitted to wildlife rehabilitation centers in Italy. Methods: Fecal samples were collected from 100 European hedgehogs housed in five wildlife rehabilitation centers located in four Italian regions. Salmonella spp. were isolated using standard bacteriological methods, serotyped according to the Kaufmann–White–Le Minor scheme, and tested for antimicrobial susceptibility by broth microdilution for ampicillin, enrofloxacin, and sulfamethoxazole-trimethoprim. Minimum inhibitory concentrations (MICs) were interpreted following CLSI guidelines. Results: Salmonella spp. was isolated from 30% of the animals sampled. Four serovars were identified, with S. Enteritidis (50%) and S. Typhimurium (36.7%) being the most prevalent, followed by S. Agona (10%) and S. Chester (3.3%). Antimicrobial susceptibility testing revealed a high level of susceptibility, with 90% of isolates sensitive to all tested antibiotics. One S. enteritidis strain showed resistance to enrofloxacin and sulfamethoxazole–trimethoprim, while two isolates exhibited intermediate susceptibility to enrofloxacin. Conclusions: The detection of Salmonella serovars commonly associated with human infections in European hedgehogs highlights the potential role of this species in the ecology of zoonotic Salmonella. Although antimicrobial resistance levels were low, the presence of resistant and intermediate strains underscores the importance of continued surveillance. Despite some limitations related to the study design and sample representativeness, these results support the need for further large-scale investigations, reinforcing the need for integrated One Health surveillance strategies. Full article

Non-typhoidal Salmonella (NTS) are globally distributed zoonotic pathogens of major concern within the One Health–One Biofilm framework. Fluoroquinolone-resistant Salmonella strains are included by the World Health Organization (WHO) in the Bacterial Priority Pathogens List as high-risk agents. A key virulence determinant of Salmonella is its ability to form biofilms, which may display multidrug-resistant (MDR) characteristics and contribute to bacterial persistence and treatment failure. Animals, particularly poultry and reptiles, represent important reservoirs of Salmonella, and reptile-associated salmonellosis (RAS) may manifest as extraintestinal infections in humans. In the post-antibiotic era, there is an urgent need to identify effective alternatives to conventional therapies. This review summarizes current knowledge on Salmonella biofilms, with particular attention to their MDR potential, and discusses possible strategies for their prevention and eradication, including specific immunoprophylaxis, bacteriophage therapy, and alternative antimicrobials. The promising antimicrobials include plant-based compounds/extracts, bacteriocins, fatty acids, and synthetic/semi-synthetic substances. The integration of vaccination, phage therapy, and novel anti-biofilm compounds may provide a sustainable alternative to antibiotics in controlling Salmonella infections and aligns with the principles of the One Health approach. Full article

Central nervous system (CNS) infections caused by Salmonella species (spp.) are exceptionally rare in adults but are associated with significant morbidity and mortality, particularly in immunocompromised individuals. Clinical presentation is often nonspecific, including fever, headache, or altered mental status, while imaging may demonstrate meningeal enhancement, abscesses, or cytotoxic lesions. We present a systematic review of non-typhoidal Salmonella spp. infections involving the CNS across various immunosuppressive contexts, illustrated by the case of a 38-year-old HIV-positive man with well-controlled infection. He developed disseminated Salmonella enterica infection, with bacteremia, septic arthritis, and ultimately corpus callosum involvement, following chronic self-administration of corticosteroids for cluster headaches. This case underscores that corticosteroid exposure can precipitate systemic dissemination even in patients with preserved CD4 counts. Although this condition carries a high risk of mortality, early recognition, targeted antibiotic therapy, and careful multidisciplinary management of underlying immunosuppression are critical to improving survival and minimizing neurological sequelae. Full article

In this study, the effects of pediocin (PP) on intestinal barrier function, renal injury, and immune regulation were evaluated in Salmonella pullorum-infected chickens. Forty-five 7-day-old specific-pathogen-free (SPF) chickens were randomly assigned to three groups: control (CON), S. pullorum infection (SP), and S. pullorum infection + PP treatment (SPA). The results showed that S. pullorum infection significantly elevated (p < 0.05) the renal (CREA, UREA), hepatic (ALT, AST), immunological (IgG, IgM), and inflammatory (TNF-α, IL-6, SAA, CRP) parameters, as well as the expression of trefoil factor 3, Toll-like receptor 2, TNF-α, IL-1β, and IL-6. In contrast, the jejunal villus height and the villus-to-crypt ratio, and the expression of intestinal tight junction proteins (occludin, claudin-1, and Zonula occludens-1), mucin-2, and transforming growth factor-β1 were significantly decreased in both the SP and SPA groups. In the SP group, the parameter alterations observed at 6 DPI compared to the CON group persisted until 12 DPI. In contrast, in the SPA group, these parameters returned to levels comparable to those of the CON group after 6 days of PP treatment. Moreover, S. pullorum infection markedly reduced the α-diversity of the gut microbiota, and this reduction could be partially restored following PP treatment. At the phylum level, S. pullorum infection significantly reduced the relative abundances of Proteobacteria and Verrucomicrobia. PP treatment increased the abundances of Firmicutes and Actinobacteria, while also restoring the abundances of Proteobacteria and Verrucomicrobia to some extent. At the genus level, PP treatment significantly increased the abundance of Faecalibacterium and Lactobacillus. Additionally, Faecalibacterium and Butyricicoccus were significantly more abundant in the SPA group. Thus, PP could alleviate S. pullorum infection induced intestinal barrier damage, reduce immune stress responses, and exert a protective effect by modulating the composition of the intestinal microbiota of chickens. Full article