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Keywords = enterotoxigenic

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16 pages, 2820 KiB  
Article
AiiA Lactonase Suppresses ETEC Pathogenicity Through 3OC12-HSL Quenching in a Murine Model
by Yang Yang, Ji Shao, Zixin Han, Junpeng Li, Qiaoqiao Fang and Guoqiang Zhu
Microbiol. Res. 2025, 16(8), 166; https://doi.org/10.3390/microbiolres16080166 - 31 Jul 2025
Viewed by 113
Abstract
This study elucidates how the quorum-sensing (QS) signal 3OC12-HSL exacerbates enterotoxigenic E. coli (ETEC) pathogenicity and intestinal barrier dysfunction. In vitro, 3OC12-HSL enhanced ETEC C83902 growth (66.7% CFU increase at 8 h) and dysregulated stress/growth genes (e.g., eight-fold rmf upregulation under static conditions). [...] Read more.
This study elucidates how the quorum-sensing (QS) signal 3OC12-HSL exacerbates enterotoxigenic E. coli (ETEC) pathogenicity and intestinal barrier dysfunction. In vitro, 3OC12-HSL enhanced ETEC C83902 growth (66.7% CFU increase at 8 h) and dysregulated stress/growth genes (e.g., eight-fold rmf upregulation under static conditions). In synthetic gut microbiota, 3OC12-HSL selectively augmented E. coli colonization (37.6% 16S rDNA increase at 12 h). Murine studies revealed 3OC12-HSL reduced jejunal villus height (381.5 μm vs. 543.2 μm in controls), elevated serum LPS, D-lactate, and DAO, and altered microbial composition (Firmicutes/Bacteroidetes imbalance). The lactonase AiiA reversed these effects by degrading 3OC12-HSL. It abrogated bacterial growth stimulation (in vitro CFU restored to baseline), normalized microbiota diversity (Shannon index recovered to control levels), suppressed pro-inflammatory cytokines (IL-6/TNF-α reduction), and restored intestinal integrity (villus length: 472.5 μm, 20.5% increase vs. ETEC-infected mice). Our findings establish AiiA as a potent quorum-quenching agent that counteracts ETEC virulence via targeted signal inactivation, highlighting its translational value. Full article
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16 pages, 3054 KiB  
Article
Naringenin Inhibits Enterotoxigenic Escherichia coli-Induced Ferroptosis via Targeting HSP90 in IPEC-J2 Cells
by Pengxin Jiang, Kangping Liu, Yanan Cui, Puyu Liu, Xutao Wang, Zijuan Hou, Jiamei Cui, Ning Chen, Jinghui Fan, Jianguo Li, Yuzhu Zuo and Yan Li
Antioxidants 2025, 14(8), 914; https://doi.org/10.3390/antiox14080914 - 25 Jul 2025
Viewed by 324
Abstract
Enterotoxigenic Escherichia coli (ETEC) leads to severe diarrhea in piglets. Naringenin (Nar), a natural flavonoid compound, is known for its antibacterial and anti-antioxidant properties. However, the protective effects of Nar against ETEC-induced diarrhea have not been reported yet. This study investigated the protective [...] Read more.
Enterotoxigenic Escherichia coli (ETEC) leads to severe diarrhea in piglets. Naringenin (Nar), a natural flavonoid compound, is known for its antibacterial and anti-antioxidant properties. However, the protective effects of Nar against ETEC-induced diarrhea have not been reported yet. This study investigated the protective mechanisms of Nar against ETEC infection in porcine intestinal epithelial cells (IPEC-J2). ETEC infection induced oxidative stress and ferroptosis in IPEC-J2 cells by elevating intracellular iron content and ROS accumulation, increasing MDA levels, downregulating SOD activity and GPX4 expression, and upregulating the transcription of CHAC1 and SLC7A11. In contrast, Nar suppressed ETEC-induced ferroptosis of IPEC-J2 cells by inhibiting the SLC7A11/GPX4 pathway. Specifically, Nar mitigated mitochondrial damage, reduced intracellular iron levels and ROS accumulation, and ultimately reversed the oxidative stress. Network pharmacology and molecular docking identified heat-shock protein 90 (HSP90) as a potential target of Nar. Overexpression and knockdown experiments revealed that ETEC-induced ferroptosis was mediated by upregulation of HSP90, while the protective effects of Nar against ETEC-induced ferroptosis were dependent on the downregulation of HSP90. In conclusion, Nar targets host HSP90 to protect IPEC-J2 cells from ferroptosis caused by ETEC infection. This study demonstrates that Nar is a potent antioxidant natural compound with potential for preventing ETEC-induced intestinal damage. Full article
(This article belongs to the Special Issue Oxidative Stress in Livestock and Poultry—3rd Edition)
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28 pages, 1513 KiB  
Review
The Impact of the Microbiota on the Immune Response Modulation in Colorectal Cancer
by Ana Iulia Neagu, Marinela Bostan, Vlad Alexandru Ionescu, Gina Gheorghe, Camelia Mia Hotnog, Viviana Roman, Mirela Mihaila, Simona Isabelle Stoica, Camelia Cristina Diaconu, Carmen Cristina Diaconu, Simona Maria Ruta and Coralia Bleotu
Biomolecules 2025, 15(7), 1005; https://doi.org/10.3390/biom15071005 - 14 Jul 2025
Viewed by 613
Abstract
Colorectal cancer (CRC) is a multifactorial disease increasingly recognized for its complex interplay with the gut microbiota. The disruption of microbial homeostasis—dysbiosis—has profound implications for intestinal barrier integrity and host immune function. Pathogenic bacterial species such as Fusobacterium nucleatum, Escherichia coli harboring polyketide [...] Read more.
Colorectal cancer (CRC) is a multifactorial disease increasingly recognized for its complex interplay with the gut microbiota. The disruption of microbial homeostasis—dysbiosis—has profound implications for intestinal barrier integrity and host immune function. Pathogenic bacterial species such as Fusobacterium nucleatum, Escherichia coli harboring polyketide synthase (pks) island, and enterotoxigenic Bacteroides fragilis are implicated in CRC through mechanisms involving mucosal inflammation, epithelial barrier disruption, and immune evasion. These pathogens promote pro-tumorigenic inflammation, enhance DNA damage, and suppress effective anti-tumor immunity. Conversely, commensal and probiotic bacteria, notably Lactobacillus and Bifidobacterium species, exert protective effects by preserving epithelial barrier function and priming host immune responses. These beneficial microbes can promote the maturation of dendritic cells, stimulate CD8+ T cell cytotoxicity, and modulate regulatory T cell populations, thereby enhancing anti-tumor immunity. The dichotomous role of the microbiota underscores its potential as both a biomarker and a therapeutic target in CRC. Recent advances in studies have explored microbiota-modulating strategies—ranging from dietary interventions and prebiotics to fecal microbiota transplantation (FMT) and microbial consortia—as adjuncts to conventional therapies. Moreover, the composition of the gut microbiome has been shown to influence the responses to immunotherapy and chemotherapy, raising the possibility of microbiome-informed precision oncology therapy. This review synthesizes the current findings on the pathogenic and protective roles of bacteria in CRC and evaluates the translational potential of microbiome-based interventions in shaping future therapeutic paradigms. Full article
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22 pages, 2242 KiB  
Article
Quercetin Can Alleviate ETECK88-Induced Oxidative Stress in Weaned Piglets by Inhibiting Quorum-Sensing Signal Molecule Autoinducer-2 Production in the Cecum
by Hailiang Wang, Min Yao, Dan Wang, Mingyang Geng, Shanshan Nan, Xiangjian Peng, Yuyang Xue, Wenju Zhang and Cunxi Nie
Antioxidants 2025, 14(7), 852; https://doi.org/10.3390/antiox14070852 - 11 Jul 2025
Viewed by 442
Abstract
This study evaluated the inhibitory activity of quercetin at sub-inhibitory concentrations on quorum-sensing (QS) molecules in vitro and the effects of dietary supplementation with quercetin (for 24 consecutive days) on enterotoxigenic Escherichia coli (ETEC)-induced inflammatory and oxidative stress responses in weaned piglets. The [...] Read more.
This study evaluated the inhibitory activity of quercetin at sub-inhibitory concentrations on quorum-sensing (QS) molecules in vitro and the effects of dietary supplementation with quercetin (for 24 consecutive days) on enterotoxigenic Escherichia coli (ETEC)-induced inflammatory and oxidative stress responses in weaned piglets. The piglets were fed one of three diets: the basal diet (Con), ETEC challenge (K88) after the basal diet, or ETEC challenge (quercetin + K88) after the basal diet supplemented with 0.2% quercetin. In vitro experiments revealed that 5 mg/mL quercetin exhibited the strongest QS inhibitory activity and reduced pigment production by Chromobacterium violaceum ATCC12472 by 67.70%. In vivo experiments revealed that quercetin + K88 significantly increased immunoglobulin A (IgA), immunoglobulin M (IgM), and immunoglobulin G (IgG) levels in the serum, ileum mucosa, and colon mucosa; increased glutathione peroxidase (GSH-Px), catalase (CAT), and superoxide dismutase (SOD) levels in the serum, liver, and colon mucosa; and decreased cluster of differentiation 3 (CD3) and cluster of differentiation 8 (CD8)activity in the serum compared with K88 alone. Quercetin + K88 significantly alleviated pathological damage to the liver and spleen and upregulated antioxidant genes (nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1(HO-1), CAT, SOD, and glutathione s-transferase (GST)). Inducible nitric oxide synthase (iNOS) and kelch-like ech-associated protein 1 (Keap1), which cause oxidative damage to the liver and spleen, were significantly downregulated. The acetic acid content in the cecum was significantly increased, and the E. coli count and QS signal molecule autoinducer-2 (AI-2) yield were significantly reduced. In conclusion, 0.2% dietary quercetin can alleviate ETEC-induced inflammation and oxidative stress in weaned piglets. Full article
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18 pages, 2390 KiB  
Article
Modeling ETBF-Mediated Colorectal Tumorigenesis Using AOM/DSS in Wild-Type Mice
by Soonjae Hwang, Yeram Lee and Ki-Jong Rhee
Int. J. Mol. Sci. 2025, 26(13), 6218; https://doi.org/10.3390/ijms26136218 - 27 Jun 2025
Viewed by 411
Abstract
Enterotoxigenic Bacteroides fragilis (ETBF) promotes colitis-associated cancer through the Bacteroides fragilis toxin (BFT), which induces colonic inflammation that can be exacerbated by external stimuli. We found that BALB/c mice infected with ETBF and treated with azoxymethane and dextran sodium sulfate (DSS) developed numerous [...] Read more.
Enterotoxigenic Bacteroides fragilis (ETBF) promotes colitis-associated cancer through the Bacteroides fragilis toxin (BFT), which induces colonic inflammation that can be exacerbated by external stimuli. We found that BALB/c mice infected with ETBF and treated with azoxymethane and dextran sodium sulfate (DSS) developed numerous distal colon polyps more rapidly than B6 mice, suggesting strain differences in ETBF-induced tumorigenicity. Using a bft gene-deficient ETBF strain, we confirmed BFT’s crucial role in ETBF-promoted tumorigenesis and inflammation. While both 1% and 2% DSS induced comparable polyp formation, 1% DSS minimized mortality, proving sufficient for maximizing polyp development. Mechanistically, BFT-mediated tumorigenesis involves NF-κB/CXCL1 signaling in colonic epithelial cells exposed to BFT and DSS, a pathway known to be critical for inflammation and cancer progression. This model provides a valuable platform for dissecting ETBF’s colitis-associated cancer-promoting mechanisms, particularly those involving BFT, and for evaluating BFT-targeted therapeutic interventions. Full article
(This article belongs to the Special Issue Advanced Research of Gut Microbiota and Toxins)
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13 pages, 1186 KiB  
Article
Determination of Phylogroups, Pathotypes and Antibiotic Resistance Profiles of E. coli Isolates from Freshwater and Wastewater in the City of Panama
by Gabriela A. Rodríguez Guevara, Emmanuel Michelangelli, Juan R. Medina-Sánchez, Fermín Mejía-Meléndez, Carmen Indira Espino, José E. Moreno P., Alex O. Martínez Torres and Jordi Querol-Audí
Pathogens 2025, 14(7), 617; https://doi.org/10.3390/pathogens14070617 - 20 Jun 2025
Viewed by 689
Abstract
Untreated water bodies are critical ecological niches where environmental conditions can drive the adaptive evolution of bacterial populations, enabling them to acquire new traits such as antibiotic-resistance genes. Escherichia coli is typically a commensal bacterium but can evolve into a pathogenic form, known [...] Read more.
Untreated water bodies are critical ecological niches where environmental conditions can drive the adaptive evolution of bacterial populations, enabling them to acquire new traits such as antibiotic-resistance genes. Escherichia coli is typically a commensal bacterium but can evolve into a pathogenic form, known as Diarrheagenic E. coli, responsible for both intestinal and extraintestinal diseases. This study focuses on the characterization of E. coli isolates from water samples collected from the Matasnillo River and the influence of the Juan Díaz Wastewater Treatment Plant (WWTP). While isolates from the Matasnillo River were classified as commensal, 18% of the isolates from the WWTP belonged to either phylogroups D or B2. Pathotype analysis revealed the presence of Entero-Toxigenic and Entero-Hemorrhagic E. coli in the WWTP. Moreover, Matasnillo River isolates exhibited resistance mainly to the quinolone ciprofloxacin, whereas those from the WWTP influent showed resistance to multiple broad-spectrum antibiotics. Sequencing analysis revealed the prevalence of the transmissible quinolone resistance qnrB19 among the Matasnillo River isolates and mutations conferring resistance to quinolone in gyrA, parC, and parE. These findings highlight the importance of monitoring antibiotic-resistant bacterial contamination in both freshwater and wastewater to mitigate the risk of the spread of resistant pathogens and potential epidemic outbreaks. Full article
(This article belongs to the Special Issue Current Progress on Bacterial Antimicrobial Resistance)
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16 pages, 3286 KiB  
Article
The Impact of Imidacloprid in Dietary Residues on Intestinal Damage and the Increased Risk of Enterotoxigenic Escherichia coli Infection
by Xinlei Yuan, Zihan Wang, Fang Wu, Le Cheng, Yutong Jin, Jianguo Dong, Chenyan Zheng, Yumeng Ma, Yan Jin and Bing Fang
Foods 2025, 14(12), 2119; https://doi.org/10.3390/foods14122119 - 17 Jun 2025
Viewed by 387
Abstract
Pesticide residues in foods can disturb the intestinal barrier and microbiota, even at a very low dose; however, studies on direct consequences on intestinal health are still lacking. Here, we evaluated the damage of imidacloprid (IMI) to the intestine and the resulting defense [...] Read more.
Pesticide residues in foods can disturb the intestinal barrier and microbiota, even at a very low dose; however, studies on direct consequences on intestinal health are still lacking. Here, we evaluated the damage of imidacloprid (IMI) to the intestine and the resulting defense against enterotoxigenic Escherichia coli (ETEC) in C57BL/6J mice. After 8-week exposure to 0.06 mg /kg bodyweight/day, IMI significantly damaged intestinal structure and intestinal integrity, characterized by an increased permeability to FITC-dextran and decreased mRNA expression of tight junction proteins, as well as more broken villi and lower proportions of goblet cells and paneth cells. These were related to the suppression of the self-renewal of intestinal stem cells (ISCs), as evidenced by significantly decreased Sox9+ ISCs and increased apoptosis. Furthermore, the impaired intestinal integrity in mice exposed to low doses of IMI directly increased the susceptibility to ETEC infection and even caused death. On the other hand, exposure to 0.6 mg IMI/kg bodyweight/day lead to significantly increased contents of IL-1β and TNFα both in the intestine and serum, and significantly decreased Th1 cell and IFN-γ contents in the lamina propria during the ETEC infection. Our study suggested that the intestinal damage induced by pesticide residues would significantly decrease the defense ability of the intestine, which suggests a novel perspective when evaluating the long-term effects of food contaminates on intestinal health at low doses without significant toxicological injuries. Full article
(This article belongs to the Section Food Microbiology)
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14 pages, 832 KiB  
Review
Biological Mechanisms of Enterotoxigenic Bacteroides fragilis Toxin: Linking Inflammation, Colorectal Cancer, and Clinical Implications
by Seyedesomaye Jasemi, Paola Molicotti, Milena Fais, Ilaria Cossu, Elena Rita Simula and Leonardo A. Sechi
Toxins 2025, 17(6), 305; https://doi.org/10.3390/toxins17060305 - 16 Jun 2025
Viewed by 861
Abstract
Enterotoxigenic Bacteroides fragilis (ETBF) has emerged as a gut microbiome pathogen that can promote intestinal inflammation and contribute to colorectal cancer (CRC). Its principal virulence factor, the Bacteroides fragilis toxin (BFT), is a zinc-dependent metalloprotease that disrupts epithelial barrier integrity, initiates inflammatory signaling [...] Read more.
Enterotoxigenic Bacteroides fragilis (ETBF) has emerged as a gut microbiome pathogen that can promote intestinal inflammation and contribute to colorectal cancer (CRC). Its principal virulence factor, the Bacteroides fragilis toxin (BFT), is a zinc-dependent metalloprotease that disrupts epithelial barrier integrity, initiates inflammatory signaling pathways, and enhances epithelial proliferation. Although growing evidence supports a link between ETBF and CRC, some inconsistencies across studies highlight the need for further investigation into the molecular mechanisms underpinning BFT-mediated pathogenesis. This review examines the biological structure and activity of BFT, with a focus on its role in epithelial injury, inflammatory responses, and tumorigenesis. In addition, we discuss current challenges in the detection and characterization of ETBF and BFT, including technical limitations in clinical diagnostics and methodological variability across studies. Recent advances in multi-omics technologies, molecular diagnostics, nanobody-based detection platforms, and probiotic intervention are also highlighted as promising avenues for improving ETBF identification and therapeutic targeting. Future research integrating systematic molecular profiling with clinical data is essential to enhance diagnostic accuracy, elucidate pathophysiological mechanisms, and develop effective interventions against ETBF-associated diseases. Full article
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19 pages, 1601 KiB  
Article
Isolation and Characterization of Lactic Acid Bacteria from an Italian Traditional Raw Milk Cheese: Probiotic Properties and Technological Performance of Selected Strains
by Marianna Roselli, Federica Colafranceschi, Valentina Cipriani, Alessandra Valle, Paola Zinno, Barbara Guantario, Emily Schifano, Daniela Uccelletti and Chiara Devirgiliis
Microorganisms 2025, 13(6), 1368; https://doi.org/10.3390/microorganisms13061368 - 12 Jun 2025
Viewed by 629
Abstract
The increasing interest in fermented foods stems from their health benefits, mediated by foodborne microorganisms. This study aimed to characterize the fermentative microbiota of Pecorino di Picinisco, a traditional Italian cheese made from ovine raw milk, and to evaluate the probiotic and technological [...] Read more.
The increasing interest in fermented foods stems from their health benefits, mediated by foodborne microorganisms. This study aimed to characterize the fermentative microbiota of Pecorino di Picinisco, a traditional Italian cheese made from ovine raw milk, and to evaluate the probiotic and technological potential of selected lactic acid bacteria strains. Three strains representative of the different species found (Lactococcus lactis, Lactiplantibacillus plantarum and Latilactobacillus curvatus) were chosen and analyzed. All three strains were able to adhere to human intestinal Caco-2 cells, were resistant to simulated in vitro digestion and significantly prolonged the lifespan of Caenorhabditis elegans, used as a simplified in vivo model, with respect to the commercial probiotic strain Lacticaseibacillus rhamnosus GG. The L. plantarum Pic37.4 strain was particularly promising; therefore, its cell-free supernatant was employed to evaluate the antimicrobial activity against indicator strains of foodborne and intestinal pathogens or spoilage bacteria. The results demonstrated the effectiveness of the supernatant against all strains tested, with the strongest effect on the intestinal pathogen enterotoxigenic Escherichia coli K88. In addition, the inhibitory effect on pathogen adhesion to intestinal mucosa was investigated on Caco-2 cells, resulting in a significant reduction in adhesion mediated by the L. plantarum Pic37.4 supernatant. The antimicrobial properties of the L. plantarum strain were confirmed in vivo in C. elegans. These promising results lay the ground for further investigations aimed at substantiating the probiotic and technological potential of the L. plantarum Pic37.4 investigated in this work. Full article
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11 pages, 257 KiB  
Article
Antibiotic Resistance Profiles of Diarrhoeagenic Enterobacterales in Bioko Island, Equatorial Guinea
by Úrsula-Eva Eñeso Efuá, Silvia Herrera-León, Fátima Patabobe, Pascual Erasmo Owono and Agustín Benito
Acta Microbiol. Hell. 2025, 70(2), 24; https://doi.org/10.3390/amh70020024 - 10 Jun 2025
Viewed by 940
Abstract
Acute diarrhoeal disease caused by antibiotic-resistant diarrhoeagenic bacteria is a significant global public health issue, particularly in low- and middle-income countries. This study provides the first molecular characterisation of antimicrobial resistance profiles, including the detection of CTX-M-15 and CTX-M-55 extended-spectrum beta-lactamases (ESBLs), among [...] Read more.
Acute diarrhoeal disease caused by antibiotic-resistant diarrhoeagenic bacteria is a significant global public health issue, particularly in low- and middle-income countries. This study provides the first molecular characterisation of antimicrobial resistance profiles, including the detection of CTX-M-15 and CTX-M-55 extended-spectrum beta-lactamases (ESBLs), among diarrhoeagenic Enterobacterales in Bioko Island, Equatorial Guinea, offering novel epidemiological insights into an understudied region. This study investigated the antibiotic resistance profiles of pathogenic bacteria isolated from diarrhoeal samples on Bioko Island. A total of 153 clinical isolates were collected between 1 February and 30 May 2014, and antimicrobial susceptibility testing was performed at Loeri Comba Polyclinic (Malabo) using the Kirby–Bauer method. The molecular characterisation of β-lactamase-associated genes was performed on different isolates of diarrhoeagenic pathotypes—144 Escherichia coli, 7 Salmonella enterica, and 2 Shigella flexneri—at the National Centre for Microbiology (Majadahonda, Spain). High resistance rates were detected against ampicillin (98%), tetracycline (93.5%), sulfonamides (94.8%), sulfamethoxazole–trimethoprim (88.2%), and cefotaxime (78.8%), while moderate rates of resistance were noted for ciprofloxacin (26.7%), and all isolates remained susceptible to imipenem. Of the isolates, 107 (69.9%) produced either single or multiple β-lactamases. Among these, 73 (68.2%) harbored classical β-lactamases, specifically TEM and OXA-1 types, representing 47.7% of the total sample. Additionally, 34 (31.8%) of the isolates were identified as producers of extended-spectrum β-lactamases (ESBLs), specifically CTX-M enzymes. Sequencing identified CTX-M-15 and CTX-M-55 variants. The predominant ESBL-producing bacteria were enteroaggregative Escherichia coli (56.2%), followed by enteropathogenic and enterotoxigenic E. coli. These findings confirm the circulation of multidrug-resistant diarrhoeagenic Enterobacterales in Equatorial Guinea, raising concerns about limited treatment options due to widespread resistance to multiple antibiotic classes, including third-generation cephalosporins and quinolones. The most important conclusion drawn from this study is that a high percentage of diarrhoeagenic bacteria have an antibiotic resistance and multi-resistance profile, especially to beta-lactams and other groups of antibiotics such as tetracyclines and sulphonamides. There is also a moderate prevalence of isolates carrying ESBLs on Bioko Island, Equatorial Guinea, which could indicate the inappropriate use of antimicrobials. Full article
19 pages, 2148 KiB  
Article
Evaluation of Probiotic Bacillus velezensis for the Control of Pathogens That Cause Post-Weaning Diarrhea in Piglets—Results from In Vitro Testing and an In Vivo Model Using Caenorhabditis elegans
by Pia Bilde Rasmussen, Josh Walker, Stacey Robida Stubbs, Andreea Cornelia Udrea and Chong Shen
Microorganisms 2025, 13(6), 1247; https://doi.org/10.3390/microorganisms13061247 - 28 May 2025
Viewed by 566
Abstract
We investigated the effect of probiotic Bacillus velezensis strains (LSSA01, 15AP4 and 2084) on pathogens causing post-weaning diarrhea in piglets (Enterotoxigenic Escherichia coli, Clostridium perfringens, Salmonella spp.). We studied the effect of B. velezensis and its cell-free supernatant on (1) pathogen [...] Read more.
We investigated the effect of probiotic Bacillus velezensis strains (LSSA01, 15AP4 and 2084) on pathogens causing post-weaning diarrhea in piglets (Enterotoxigenic Escherichia coli, Clostridium perfringens, Salmonella spp.). We studied the effect of B. velezensis and its cell-free supernatant on (1) pathogen growth; (2) IPEC-J2 cell cytokine and tight junction protein expression; (3) IPEC-J2 cell ‘wound’ recovery; (4) adhesion to IPEC-J2 cells and pathogen exclusion; and (5) Caenorhabditis elegans survival following pathogen exposure. Cell-free supernatant (CFS) from all strains inhibited the growth of ETEC F4 and F18 (by 36.9–53.2%; p < 0.05). One or more strains inhibited C. perfringens and Salmonella spp. (p < 0.05). Strain 2084 CFS increased IL-8 expression (+12.0% vs. control; p < 0.05; 6 h incubation), whereas LSSA01 CFS increased the expression of tight junction proteins (p < 0.05 vs. control; 6 h incubation) and accelerated 96 h ‘wound’ healing. Colony-forming units (CFUs) of all strains displayed a higher binding affinity to IPEC-J2 cells than 12 ETEC isolates, reduced adhesion of ETEC F4 and F18 and extended C. elegans survival over 30 d. The results indicate that probiotic B. velezensis strains have potential for use in the control of PWD pathogens. Full article
(This article belongs to the Special Issue Microbial Infections and Host Immunity)
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15 pages, 755 KiB  
Article
Vaccination with a Live Avirulent E. coli Vaccine Resulted in Improved Production Performance Combined with a Significant Reduction in Antimicrobial Use
by Frédéric Vangroenweghe, Thomas Matthijs and Marnix Sinnaeve
Antibiotics 2025, 14(6), 547; https://doi.org/10.3390/antibiotics14060547 - 27 May 2025
Viewed by 468
Abstract
Background/Objectives: In swine production, the post-weaning period has been identified as one of the most challenging and stressful periods in the life of a piglet due to changes in its environment and feeding regimen. During this period, piglets might undergo infectious challenges with [...] Read more.
Background/Objectives: In swine production, the post-weaning period has been identified as one of the most challenging and stressful periods in the life of a piglet due to changes in its environment and feeding regimen. During this period, piglets might undergo infectious challenges with enterotoxigenic Escherichia coli (ETEC) resulting in post-weaning diarrhea (PWD), and meningitis due to Streptococcus suis. Therefore, metaphylactic and curative antimicrobial therapy is frequently applied, which leads to an increased treatment incidence per 100 days at risk (TI100). Methods: Here, we report the results of an antimicrobial coaching trajectory in a 1000-sow farm with high antimicrobial use during the post-weaning period. For a period of 21 weeks, we evaluated the effect of an oral live avirulent E. coli F4F18 vaccine (Coliprotec® F4F18; Elanco AH) for the active immunization of piglets against PWD caused by F4- and F18-ETEC on the reduction in antimicrobial use during the post-weaning period. A 1000-sow farm with PIC sows operating in a 1-week BMS was rated as an ‘attention farm’ at the level of the post-weaning period according to the Antimicrobial Consumption and Resistance in Animals (AMCRA) benchmark reporting tool. To analyze the specific approach towards antimicrobial use and the related post-weaning pathology, a farm visit including a biosecurity check was carried out together with all associated stakeholders. Subsequently, an antimicrobial coaching trajectory was utilized to follow-up on the improvement of the reduction in antimicrobial use after implementation of the various pieces of advice. Results: For analytical purposes, we compared the results obtained in period 1 (P1; vaccination week 1–6) to period 2 (P2; vaccination week 7–21), since practical field experience has demonstrated that a ‘stabilization period’ of about 6 weeks is necessary to obtain the maximal effect of vaccination. There was a significant reduction in mortality (5.7% to 2.0%) and improvement in the average daily weight gain (366 g/d to 392 g/d) following vaccination, with a simultaneous reduction in the number of days in nursery (45 days to 38 days). Meanwhile, the weight at the end of nursery remained at a similar level. There was a clinically relevant though non-significant decrease in the TI100 (32.8 days to 20.6 days). Overall, the implementation of all measures resulted in a positive ROI of 2.72 per piglet. Conclusions: The implementation of several biosecurity measures in combination with the use of an oral live avirulent E. coli F4F18 vaccine (Coliprotec F4F18) could improve performance parameters and reduce mortality, while reducing the number of days in nursery and the TI100. Overall, a positive return on investment of 2.72 could be obtained per piglet produced under these improved conditions. Full article
(This article belongs to the Section Antibiotics Use and Antimicrobial Stewardship)
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13 pages, 1186 KiB  
Article
Potential for a Combined Oral Inactivated Whole-Cell Vaccine Against ETEC and Shigella: Preclinical Studies Supporting Feasibility
by Manuela Terrinoni, Jan Holmgren, Kevin Ross Turbyfill, Lillian Van De Verg, Nicole Maier and Richard Walker
Vaccines 2025, 13(5), 513; https://doi.org/10.3390/vaccines13050513 - 13 May 2025
Viewed by 863
Abstract
Background: Enteric disease caused by Shigella, Campylobacter, and enterotoxigenic Escherichia coli (ETEC) represents a significant global health burden, particularly among children in low-resource settings. However, no licensed vaccines are currently available for these bacterial pathogens. Given the wide range of enteric [...] Read more.
Background: Enteric disease caused by Shigella, Campylobacter, and enterotoxigenic Escherichia coli (ETEC) represents a significant global health burden, particularly among children in low-resource settings. However, no licensed vaccines are currently available for these bacterial pathogens. Given the wide range of enteric pathogens and the constraints posed by an increasingly crowded infant immunization schedule, the development of combination vaccines or combined administration of individual oral vaccines may offer a practical approach to address this unmet need. Objectives: In this study, we evaluated the combined administration of two multicomponent oral vaccine candidates: ETVAX, targeting ETEC, and a trivalent whole-cell vaccine targeting Shigella. Methods: The vaccine candidates were administered orally in mice, both individually and in combination, with and without the inclusion of the double-mutant heat-labile toxin (dmLT) adjuvant. Results: The results demonstrated systemic and intestinal-mucosal immune responses to the key protective antigens following both individual and combined vaccine administration. Importantly, the combination of the two vaccines did not compromise the elicitation of specific antibody responses. The inclusion of dmLT as an adjuvant significantly enhanced immune responses to several antigens, highlighting its potential to improve vaccine efficacy. Conclusions: These findings underscore the feasibility of combining ETEC and Shigella vaccine candidates into a single formulation without compromising immunogenicity. This combined approach has the potential to provide broad protective coverage, thereby mitigating the global impact of enteric diseases and streamlining vaccine delivery within existing childhood immunization programs. Our results support further development of this combination vaccine strategy as a promising tool in combating enteric infections and improving health outcomes, particularly among young children in endemic regions who are vulnerable to enteric disease. Full article
(This article belongs to the Special Issue Recent Scientific Advances in Vaccines for Shigella)
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18 pages, 3792 KiB  
Article
Porcine β-Defensin 2 Expressed in Pichia pastoris Alleviates Enterotoxigenic Escherichia coli-Induced Intestinal Injury and Inflammatory Response in Mice
by Shuaiyang Wang, Huaixia Li, Yaxue Huang, Wenxiao Zhuo, Tingting Li, Tingting Jiang, Qi Huang and Rui Zhou
Animals 2025, 15(10), 1389; https://doi.org/10.3390/ani15101389 - 11 May 2025
Viewed by 729
Abstract
Enterotoxigenic Escherichia coli (ETEC), a common intestinal pathogen, can colonize the intestines and induce diarrhea in piglets, which brings great economic losses to the swine industry. Antibiotics are recommended to the treatment for diarrhea caused by ETEC in weaned piglets. However, with the [...] Read more.
Enterotoxigenic Escherichia coli (ETEC), a common intestinal pathogen, can colonize the intestines and induce diarrhea in piglets, which brings great economic losses to the swine industry. Antibiotics are recommended to the treatment for diarrhea caused by ETEC in weaned piglets. However, with the emergence and spread of multidrug-resistant ETEC, there is an urgent need to develop alternatives to antibiotics. Due to the unique antibacterial mechanism of targeting bacterial membranes, antimicrobial peptides (AMPs) are promising candidates. In this study, the activity of crude recombinant porcine β-defensin 2 (rPBD2) expressed in Pichia pastoris (P. pastoris) was measured in vitro. Mice infected with ETEC were orally administered 16, 8, and 4 AU crude rPBD2 for 7 consecutive days to evaluate its anti-infective activity in vivo. The results showed that in addition to broad antibacterial activity against Gram-positive and -negative bacteria, crude rPBD2 displayed high tolerance to temperatures ranging from 20 to 60 °C, a broad range of pH, trypsin, pepsin, and physiological concentrations of salts. In an ETEC-induced mouse model, the oral administration of crude rPBD2 decreased diarrhea scores and the intestinal/carcass ratio and alleviated body weight loss. Additionally, crude rPBD2 decreased bacterial loads in stools and the colon (HP group), and the levels of serum pro-inflammatory cytokines IL-6 (HP group) and TNF-α (HP and MP groups), and increased the villus height and the ratio of villus height to crypt depth (VH/CD) in the ileum (HP and MP groups). Our study provides a cost-effective way for PBD2 production and identifies it as a promising candidate to combat ETEC-induced infection. Full article
(This article belongs to the Section Pigs)
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11 pages, 1028 KiB  
Article
Potential for Misinterpretation in the Laboratory Diagnosis of Clostridioides difficile Infections
by Alexandra Kalacheva, Metodi Popov, Valeri Velev, Rositsa Stoyanova, Yordanka Mitova-Mineva, Tsvetelina Velikova and Maria Pavlova
Diagnostics 2025, 15(9), 1166; https://doi.org/10.3390/diagnostics15091166 - 3 May 2025
Viewed by 601
Abstract
Background/Objective. Toxin-producing strains of Clostridioides difficile (C. diff) are the most commonly identified cause of healthcare-associated infection in the elderly. Risk factors include advanced age, hospitalization, prior or concomitant systemic antibacterial therapy, chemotherapy, and gastrointestinal surgery. Patients with unspecified and [...] Read more.
Background/Objective. Toxin-producing strains of Clostridioides difficile (C. diff) are the most commonly identified cause of healthcare-associated infection in the elderly. Risk factors include advanced age, hospitalization, prior or concomitant systemic antibacterial therapy, chemotherapy, and gastrointestinal surgery. Patients with unspecified and new-onset diarrhea with ≥3 unformed stools in 24 h are the target population for C. diff infection (CDI) testing. To present data on the risks of laboratory misdiagnosis in managing CDI. Materials. In two general hospitals, we examined 116 clinical stool specimens from hospitalized patients with acute diarrhea suspected of nosocomial or antibiotic-associated diarrhea (AAD) due to C. diff. Enzyme immunoassay (EIA) tests for the detection of C. diff toxins A (cdtA) and B (cdtB) in stool, automated CLIA assay for the detection of C. diff GDH antigen and qualitative determination of cdtA and B in human feces and anaerobic stool culture were applied for CDI laboratory diagnosis. MALDI-TOF (Bruker) was used to identify the presumptive anaerobic bacterial colonies. The following methods were used as confirmatory diagnostics: the LAMP method for the detection of Salmonella spp. and simultaneous detection of C. jejuni and C. coli, an E. coli Typing RT-PCR detection kit (ETEC, EHEC, STEC, EPEC, and EIEC), API 20E and aerobic stool culture methods. Results. A total of 40 toxigenic strains of C. diff were isolated from all 116 tested diarrheal stool samples, of which 38/40 produced toxin B and 2/40 strains were positive for both cdtA and cdtB. Of the stool samples positive for cdtA (6/50) and/or cdtB (44/50) by EIA, 33 were negative for C. diff culture but positive for the following diarrheal agents: Salmonella enterica subsp. arizonae (1/33, LAMP, culture, API 20E); C. jejuni (2/33, LAMP, culture, MALDI TOF); ETEC O142 (1/33), STEC O145 and O138 (2/33, E. coli RT-PCR detection kit, culture); C. perfringens (2/33, anaerobic culture, MALDI TOF); hypermycotic enterotoxigenic K. pneumonia (2/33) and enterotoxigenic P. mirabilis (2/33, culture; PCR encoding LT-toxin). Two of the sixty-six cdtB-positive samples (2/66) showed a similar misdiagnosis when analyzed using the CLIA method. However, the PCR analysis showed that they were cdtB-negative. In contrast, the LAMP method identified a positive result for C. jejuni in one sample, and another was STEC positive (stx1+/stx2+) by RT-PCR. We found an additional discrepancy in the CDI test results: EPEC O86 (RT-PCR eae+) was isolated from a fecal sample positive for GHA enzyme (CLIA) and negative for cdtA and cdtB (CLIA and PCR). However, the culture of C. diff was negative. These findings support the hypothesis that certain human bacterial pathogens that produce enterotoxins other than C. diff, as well as intestinal commensal microorganisms, including Klebsiella sp. and Proteus sp., contribute to false-positive EIA card tests for C. diff toxins A and B, which are the most widely used laboratory tests for CDI. Conclusions. CDI presents a significant challenge to clinical practice in terms of laboratory diagnostic management. It is recommended that toxin-only EIA tests should not be used as the sole diagnostic tool for CDI but should be limited to detecting toxins A and B. Accurate diagnosis of CDI requires a combination of laboratory diagnostic methods on which proper infection management depends. Full article
(This article belongs to the Section Diagnostic Microbiology and Infectious Disease)
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