Gut Pathogens最新文献

Background: Helicobacter pylori infection is a major global health issue associated with chronic gastritis, peptic ulcers, and gastric cancer. Due to the increasing resistance of H. pylori to conventional antibiotics, there is growing interest in researching alternative therapeutic agents, particularly those from medicinal plants.

Methods: Preparation and purification of extracts from two plant species, Plectranthus asirensis and Premna resinosa, were performed by cold maceration. The anti-microbial activity of two extracts was then evaluated against H. pylori to determine the minimum inhibitory concentration (MIC). The activity of the extracts was further analyzed by electron microscopy, bacterial cell lysis and Western blotting. The effects on AGS gastric epithelial cells upon infection were monitored by cell scattering, cell vacuolization, DNA damage analysis, NF-κB reporter assay and chemokine ELISA.

Results: We determined the MIC of P. asirensis and P. resinosa extracts on treated H. pylori as 200 µg/mL and 35 µg/mL, respectively. Electron microscopy showed severe deformation of the bacterial cells. We obtained no bacterial cell lysis and only minimal changes in protein expression levels of the virulence factors CagA, CagY, HopQ, urease, and flagellin. However, we found that cleavage of the vacuolating cytotoxin VacA p98 pro-form to the p88 active form was significantly downregulated. The enzymatic urease activity was also impaired by the addition of both extracts, while the proteolytic activity of serine protease HtrA was not affected. Infection of AGS cells in the presence of both extracts revealed that type IV secretion system (T4SS)-dependent CagA injection, cell scattering and motility, as well as VacA-dependent cellular vacuolation were completely inhibited. Furthermore, H. pylori-induced pro-inflammatory transcription factor NF-κB and interleukin-8 release were also significantly downregulated. Finally, both extracts prevented T4SS-induced DNA double-strand breaks (DSBs) and chromosomal fragmentation in the nuclei of host cells.

Conclusions: Taken together, we have discovered natural compounds of P. asirensis and P. resinosa that exhibit potent anti-H. pylori activities, not only inhibiting bacterial growth, but also suppressing key virulence mechanisms involved in epithelial cell damage, inflammation and genomic instability. These extracts are promising candidates for future therapeutic applications in patients, which could help minimizing H. pylori infections and gastric cancer development.

Fecal calprotectin is widely used as a non-invasive biomarker for intestinal inflammation, particularly in inflammatory bowel disease (IBD), the most common clinical context for its use, where misinterpretation can lead to unnecessary invasive procedures or inappropriate therapy escalation. However, its specificity has been questioned due to elevated levels observed in non-intestinal conditions. Here, we investigated whether nasopharyngeal viral infections contribute to elevated fecal calprotectin, thereby confounding its diagnostic interpretation. Bioinformatic analysis revealed high constitutive expression of calprotectin subunits (S100A8/A9) in squamous epithelia of the upper aerodigestive tract compared with distal gut mucosa. To assess gastrointestinal stability of epithelial-derived calprotectin, healthy volunteers ingested porcine calprotectin, which was subsequently detected in feces, demonstrating resistance to intestinal degradation. In a retrospective cohort, patients with non-SARS-CoV-2 respiratory viral infections displayed significantly higher fecal calprotectin levels than SARS-CoV-2 patients (447 µg/g vs. 82 µg/g, p < 0.001), despite limited gastrointestinal involvement. Nasopharyngeal calprotectin levels did not differ significantly between viral etiologies, but in COVID-19 patients, fecal calprotectin positively correlated with nasopharyngeal calprotectin (R = 0.43, p = 0.008) and viral load (R = 0.13, p = 0.026). These findings suggest that calprotectin released from proximal epithelial tissues during viral infection can persist through the gastrointestinal tract and influence fecal calprotectin levels, underscoring the importance of contextual interpretation of this biomarker and the value of incorporating virological assessment into diagnostic workflows.

Giardia lamblia is a globally distributed fecal-oral transmitted enteroparasite. G. lamblia is phylogenetically divided into assemblages A to H. Assemblages A and B have high zoonotic potential, as reported in humans and other animals, including dogs and cats. Currently, G. lamblia genotyping is performed using gene sequencing, which is an expensive technique, especially in developing countries where higher frequencies of the protozoan have been reported. Real-time PCR with High Resolution Melting (qPCR-HRM) is a sensitive method for detecting polymorphisms and is used for differentiate species, subspecies, and assemblages. This study aimed to standardize and validate the qPCR-HRM technique for genotyping G. lamblia in human fecal samples, regardless of the parasite load. qPCR-HRM was standardized using the β-giardin target, and validation was performed using DNA extracted from fecal samples (n = 76). Sanger sequencing of the same genetic target was used the gold standard. Genotyping of the samples (assemblages A and B) was performed using both techniques, and qPCR-HRM demonstrated 98.08% concordance with the sequencing results. Only one sample showed a discrepancy in the assemblage determination between the techniques. DNA sequencing failed to characterize 24 samples from patients with low or moderate parasite loads. Thus, qPCR-HRM successfully differentiate 23 samples into assemblage A and one as assemblage B. In this context, when compared to sequencing, the qPCR-HRM technique proved to be effective for genotyping G. lamblia, even in samples with a low parasite load, with the potential to significantly reduce execution time and financial investment required to identify G. lamblia assemblages. This tool can be strategic for strengthening public health policies for the surveillance and control of giardiasis.

Background: The incidence of an infection with Helicobacter pylori, or H. pylori rises with age, mostly affecting children.The infection rate of Helicobacter pylori increases with age, primarily affecting children. The rate of cases of disease of the hands, feet, and mouth (HFMD), an infectious illness that mostly affects newborns and young children and is ubiquitous throughout the Asia-Pacific area, declines with age. Asthma, shigellosis, TB, anaphylactic disease, and other diarrheal illnesses are all prevented by H. pylori. It also has a strong correlation with infectious disorders brought on by infection with pathogens including Orientia tsutsugamushi, HIV, HCV, and Brucella abortus. Nonetheless, the status of infection with H. pylori in individuals already infected with HFMD and the clinical implications of CagA⁺ H. pylori strains remain unreported.

Methods: From October 2020 to October 2023, 130 children clinically diagnosed with HFMD enrolled in the observation group at the Affiliated Hospital of Youjiang Medical University for Nationalities Affiliated Hospital of Youjiang Medical College of Nationalities and the People's Hospital of Beihai. With respect to gender, age, and location of residence, 150 chronologically matched healthy children made up the control group. Serum H. pylori antibodies in patients were measured, and the strain was identified through the Western blot technique.

Results: 1. The frequency of infections with H. pylori with the prevalence of CagA + strains were found to be 16.2% and 8.5%, respectively, in patients with HFMD. These figures are lower than the 29.3% and 18.0% that are seen in healthy children, respectively (P-value < 0.05 for both). 2. The infection rate of the bacteria H. pylori and CagA + strains was found to be 18.5% and 9.3% in HFMD patients over 5 years of age, which is lower than the 41.5% and 26.2% observed in healthy children over 5 years, respectively (P-value < 0.05). In contrast, the rate of H. pylori and CagA + strains in HFMD patients aged 5 years and below was comparable to that of healthy children in the same age group, with both results showing no statistically significant differences. 3. H. pylori and CagA + strain prevalence were similar in primary and subsequent HFMV infections, although neither was statistically significant. 4.The findings of the univariate and multivariate analyses indicated that vaccination against HFMD and infection with H. pylori CagA + were protective factors against HFMD (0.203; 0.069-0.593; 0.004).

Conclusion: When compared to children in good health, individuals with HFMD had much lower levels of Helicobacter pylori infection. Additionally, H. pylori that carries the CagA gene could be able to prevent the development of HFMD.

Immunocompromised inflammatory bowel disease (IBD) patients may develop life-threatening pneumonia and bronchiolitis upon HCoV-NL63 infection. However, little is known whether these patients will be more susceptible to HCoV-NL63 infection. We compared the expression of ACE2 in different tissues and cell lines. Besides, the susceptibility of colonic cells to HCoV-NL63 was assessed. We then examined the expression of ACE2 in the colonic mucosa from IBD patients and animal models, and in the inflammatory colonic cells. The susceptibility of inflammatory colonic cells to HCoV-NL63 was detected using a pseudovirus-based system. Pseudovirus based neutralization assay was used to quantify the neutralizing antibodies to HCoV-NL63 in patients with IBD and healthy controls. ACE2 was abundantly expressed in the colonic tissue and cells. And colonic cells were susceptible to pseudotyped HCoV-NL63. The expression of ACE2 was increased in the colonic mucosa from IBD patients and animal models, and in inflammatory colonic cells. Inflammatory colonic cells were more susceptible to pseudotyped HCoV-NL63. Besides, reduced protective neutralizing antibody titers were seen in patients with IBD, especially for male or older IBD patients. These results suggest IBD patients may be particularly susceptible to infection with HCoV-NL63 and thus extra precautions should be taken to prevent them from infection. Further mechanistic studies are needed to support our findings.

Fusobacterium nucleatum (Fn), a gram-negative anaerobic bacterium,, transitions from oral commensal to systemic pathogen in colorectal cancer (CRC), inflammatory bowel disease (IBD), arthritis, and preterm birth. This review synthesizes Fn's subspecies-specific pathogenic mechanisms. Its virulence factors enable immune evasion, inflammation modulation, and tumor progression. In the gastrointestinal tract, Fn disrupts intestinal barrier integrity through paracellular and apoptotic pathways, activates Th17/ T regulatory (Treg) immune balance alterations, and induces macrophage polarization. Moreover, Fn's role in tumorigenesis involves biofilm formation and metabolic regulation. Within microbial networks, Fn exhibits both synergistic and antagonistic interactions. It collaborates with pathogens like Clostridioides difficile and Pseudomonas aeruginosa to enhance infection, while being inhibited by probiotics such as Lactobacillus rhamnosus and Akkermansia muciniphila. Notably, microbial metabolites like butyrate and hydrogen sulfide display context-dependent roles-some may drive disease progression, while others may suppress it. This comprehensive review highlights Fn's pathogenicity and its complex interactions within microbial communities, offering novel interventions for microbiota-driven pathologies.

Background: Biliary atresia (BA) is the leading cause of pediatric liver transplantation. It is characterized by progressive extrahepatic bile duct obstruction in young infants. Inspired by the success of antifungal treatment in a newborn with BA-related obstructive cholangitis, we explored a potential link between BA and fungi, particularly Aspergillus. Fecal DNA was analyzed using 18S ribosomal sequencing and validated with a published fecal metagenomic dataset. Epidemiological data from the UK, Taiwan, and Japan were also examined.

Results: Gut Aspergillus was exclusively detected in BA cases, suggesting it may be a potential trigger. Independent fecal metagenomic data from China and epidemiological correlations further supported this hypothesis. In the UK, BA presentations strongly correlated (r = 0.98, 95% CI [0.36, 1.0], p = 0.02) with Aspergillosis, but not with Candidiasis, during the COVID-19 lockdown. In Taiwan, a decade of data showed BA incidence was significantly associated (r = 0.78, 95% CI [0.29, 0.94], p = 0.01) with yearly Aspergillus-positive isolates among cancer-adjusted hospital admissions. In Japan, BA cases over 25 years correlated significantly (r = 0.85, 95% CI [0.37, 0.97], p = 0.01) with visceral Aspergillus burdens in autopsied cases, but not with other fungal infections.

Conclusions: The resolution of obstructive cholangitis in the antifungal-treated index case, together with multi-modal, cross-country evidence, highlights a potential link between gut Aspergillus and BA. Although limited by small sample size, retrospective design, and lack of mechanistic validation, the study may still be interpreted as hypothesis-generating and underscores the need for prospective studies to validate and extend these observations.

Background: Staphylococcus aureus is an opportunistic pathogen that can both colonize the gastrointestinal tract and cause antibiotic associated diarrhea.

Methods: To develop a robust murine model for S. aureus gastrointestinal infection (SAGII) and colonization, mice were (a) treated with varying antibiotic regimes prior to infection, (b) infected with either a methicillin-sensitive S. aureus (MSSA) or a methicillin-resistant S. aureus (MRSA) strain, (c) challenged with different bacterial inocula (d) tested for sexual dimorphism of SAGII virulence, and (e) tested for macronutrient effects on SAGII onset and virulence.

Results: Antibiotic-treated male mice (but not female mice) were highly susceptible to both an MSSA and an MRSA strains. Interestingly, male mice challenged with the laboratory MSSA strain showed more severe and more prolonged SAGII symptomatology than animals challenged with the clinical MRSA strain. Diet composition significantly influenced disease outcome: a high-carbohydrate diet and a high-fat diet led to asymptomatic intestinal colonization followed by delayed SAGII sign onset in male mice. In contrast, a high-protein diet led to an early onset of SAGII signs followed by severe SAGII signs two weeks post-challenge. Furthermore, only the high-protein diet sensitized female mice to SAGII, but their symptomatology remained less severe than in male mice.

Conclusions: We developed a robust murine model for antibiotic-associated S. aureus gastrointestinal infection and colonization. This model shows both sexual dimorphism and macronutrient preference for SAGII signs severity. Diet manipulation can also be used to establish S. aureus colonization of the GI tract. Furthermore, the SAGII murine model demonstrates essential features of S. aureus pathogenesis which could provide understanding about human gastrointestinal colonization and infection mechanisms.

Background: Inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), are chronic conditions characterized by periods of clinical remission and relapse. Pediatric cases (pIBD) often have a more complicated disease course, where approximately 30% will develop a relapse within a year of diagnosis. Identifying prognostic markers for pIBD is important to optimize treatment and improve long-term outcomes. Our aim was to analyze the tissue microbiome, identify microbial prognostic markers, and validate their predictive power in non-invasive fecal samples.

Results: Tissue and fecal microbiome were characterized from a prospective cohort comprising 33 therapeutically naïve pCD and 23 pUC patients, and 26 non-IBD pediatric controls, using amplicon 16S rRNA gene sequencing. Disease relapse was monitored for one year. At diagnosis, relapsing pCD patients exhibited a significantly decreased alpha diversity and altered beta diversity in tissue compared to non-relapsing pCD patients. Specific taxa were differentially abundant in relapsing pCD, with Barnesiella being the most depleted genus in tissue samples. Receiver Operating Characteristic (ROC) analysis identified Barnesiella (AUC = 0.818), Butyricimonas, and Collinsella as individual microbial tissue markers discriminating pCD relapse. Combining Barnesiella with the weighted Pediatric Crohn's Disease Activity Index (wPCDAI) further enhanced the specificity and sensitivity of the ROC analysis (AUC = 0.872 in tissue, 0.852 in feces), suggesting potential for non-invasive prognostic markers from stool.

Conclusions: Tissue and fecal microbial markers can predict relapse in pCD patients with high prognostic power, providing a basis for precision medicine and personalized treatment strategies in pIBD.

Trichinella spiralis (T. spiralis) infection dynamically modulates macrophage polarization. It promotes M1 macrophage polarization, enhancing the pro-inflammatory pathways. This study investigates how ivermectin nanoparticles (IVM-NP) and Moringa oleifera leaf extract (MOL-NP) regulate these pathways to improve the pathophysiological outcomes of trichinosis. Thirty Swiss albino mice were infected with T. spiralis and divided equally into five groups of six mice each: healthy controls, infected untreated, IVM-NP-treated, MOL-NP-treated, and combined IVM-NP and MOL-NP-treated. IVM-NP were administered as a single oral dose of 200 µg/kg at the beginning of the experiment. MOL-NP were delivered orally at a dose of 400 mg/kg/day for 5 consecutive days starting from experiment initiation. Parasitological examination to detect the parasitic burden in addition to histopathological, immunohistochemical and quantitative histomorphometric assessment of intestinal tissue for nuclear factor kappa B (NF-κB) and inducible nitric oxide synthase (iNOS) were done. Furthermore, RT-PCR was performed to evaluate the relative gene expression of Arginase-1, TNF-α, and IL-10. Treatment with nanoparticle formulations of IVM and MOL modulated macrophage-related immune responses by reducing the pro-inflammatory markers iNOS, TNF-α and NF-κB, while increasing the relative gene expression of the anti-inflammatory cytokine IL-10. Combination therapy exhibited superior efficacy in decreasing parasite burden and mitigating intestinal pathology compared to monotherapy.