The Role of Toll-Like Receptor-2 in Clostridioides difficile Infection: Evidence From a Mouse Model and Clinical Patients

AgeAnnoMO: a knowledgebase of multi-omics annotation for animal aging

Aging entails gradual functional decline influenced by interconnected factors. Multiple hallmarks proposed as common and conserved underlying denominators of aging on the molecular, cellular and systemic levels across multiple species. Thus, understanding the function of aging hallmarks and their relationships across species can facilitate the translation of anti-aging drug development from model organisms to humans. Here, we built AgeAnnoMO (https://relab.xidian.edu.cn/AgeAnnoMO/#/), a knowledgebase of multi-omics annotation for animal aging. AgeAnnoMO encompasses an extensive collection of 136 datasets from eight modalities, encompassing 8596 samples from 50 representative species, making it a comprehensive resource for aging and longevity research. AgeAnnoMO characterizes multiple aging regulators across species via multi-omics data, comprehensively annotating aging-related genes, proteins, metabolites, mitochondrial genes, microbiotas and age-specific TCR and BCR sequences tied to aging hallmarks for these species and tissues. AgeAnnoMO not only facilitates a deeper and more generalizable understanding of aging mechanisms, but also provides potential insights of the specificity across tissues and species in aging process, which is important to develop the effective anti-aging interventions for diverse populations. We anticipate that AgeAnnoMO will provide a valuable resource for comprehending and integrating the conserved driving hallmarks in aging biology and identifying the targetable biomarkers for aging research.

Association of Single Nucleotide Polymorphisms in Nucleotide-Binding Domain Leucine-Rich Repeat Protein 1 with Clostridioides difficile Colonization or Infection

Introduction

Nucleotide-binding domain leucine-rich repeat protein (NLRP) is critical in the inflammasome-activation pathway, which is important for host survival and the clearance of Clostridioides difficile. Therefore, the influence of NLRP1 polymorphisms on C. difficile colonization (CdC) or infection (CDI) was analyzed.

Materials and Methods

A prospective cohort study consisted of hospitalized adults was conducted from January 2011 to January 2013. Single nucleotide polymorphisms (SNPs) of NLRP1, including rs12150220, rs2670660, rs6502867, rs878329, rs8182352, rs3744717, and rs11078571, were incorporating in analyses. The episodes of CdC and CDI were the primary and secondary outcome, respectively.

Results

Of the total of 509 eligible patients, 376 (73.9%) had neither CdC nor CDI, 104 (21.8%) had CdC without developing CDI, and 29 (4.3%) developed CDI during the study period. Through multivariate analyses, comorbid diabetes mellitus (adjusted odds ratio [AOR] 1.59, P=0.04) and CC genotype in NLRP1 rs3744717 (AOR 1.70, P=0.02) were recognized as the risk factor of CdC. After adjusting the independent predictors of CDI, in terms of comorbid diabetes mellitus (AOR 3.18, P=0.005) and prior exposure to ceftazidime/ceftriaxone (AOR 2.87, P=0.04) or proton pump inhibitors (AOR 3.86, P=0.001), patients with CC+GC genotype in NLRP1, rs878329 (AOR 2.39, P=0.03) remained a higher risk of CDI.

Conclusion

For hospitalized adults, the association of CC genotype in NLRP1 rs3744717 and CdC as well as the CC+GC genotype in NLRP1 rs878329 and CDI was respectively evidenced. We believed the prompt identification of patients having specific genotype in NLRP1 would prevent and improve the quality of care in CDI.

Mouse models for bacterial enteropathogen infections: insights into the role of colonization resistance

Globally, enteropathogenic bacteria are a major cause of morbidity and mortality.1-3 Campylobacter, Salmonella, Shiga-toxin-producing Escherichia coli, and Listeria are among the top five most commonly reported zoonotic pathogens in the European Union.4 However, not all individuals naturally exposed to enteropathogens go on to develop disease. This protection is attributable to colonization resistance (CR) conferred by the gut microbiota, as well as an array of physical, chemical, and immunological barriers that limit infection. Despite their importance for human health, a detailed understanding of gastrointestinal barriers to infection is lacking, and further research is required to investigate the mechanisms that underpin inter-individual differences in resistance to gastrointestinal infection. Here, we discuss the current mouse models available to study infections by non-typhoidal Salmonella strains, Citrobacter rodentium (as a model for enteropathogenic and enterohemorrhagic E. coli), Listeria monocytogenes, and Campylobacter jejuni. Clostridioides difficile is included as another important cause of enteric disease in which resistance is dependent upon CR. We outline which parameters of human infection are recapitulated in these mouse models, including the impact of CR, disease pathology, disease progression, and mucosal immune response. This will showcase common virulence strategies, highlight mechanistic differences, and help researchers from microbiology, infectiology, microbiome research, and mucosal immunology to select the optimal mouse model.

Peroxisome proliferator-activated receptor-γ as the gatekeeper of tight junction in Clostridioides difficile infection

Clostridioides difficile is a major causative pathogen of nosocomial antibiotic-associated diarrhea and severe colitis. Despite the use of vancomycin and fidaxomicin as standard drugs for the treatment of C. difficile infection (CDI), clinical relapse rates remain high. Therefore, new alternative therapeutics to treat CDI are urgently required. The nuclear receptor, peroxisome proliferator-activated receptor-γ (PPAR-γ), is mainly expressed in the adipose tissue and modulates lipid metabolism and insulin sensitization. Previous studies have shown that PPAR-γ is highly expressed in colonic tissues and regulates tight junction function in epithelial cells. However, the role of PPAR-γ in CDI pathogenesis remains unclear. In this study, we used a mouse model of CDI and found that both expression levels of PPAR-γ and the tight junction protein, occludin, were decreased in colonic tissues. Furthermore, to investigate the role of PPAR-γ in CDI, we used PPAR-γ defective mice and found that intestinal permeability and bacterial dissemination in these mice were significantly higher than those in wild-type mice during CDI. Administration of the PPAR-γ agonist, pioglitazone, to activate PPAR-γ activity improved the phenotypes of CDI, including bodyweight loss, inflammation, and intestinal integrity. Taken together, these results demonstrate that PPAR-γ is a potential therapeutic target in CDI, as it modulates colonic inflammation and integrity.

Risk Factors and Clinical Impact of Carbapenem-Resistant Enterobacterales Coinfections Among Hospitalized Patients with Clostridioides difficile Infection

Introduction

The risk factors and clinical impact of carbapenem-resistant Enterobacterales (CRE) coinfection among hospitalized patients with Clostridioides difficile infection (CDI) were analyzed in this study.

Materials and Methods

A clinical study was performed at the medical wards of Tainan Hospital, Ministry of Health and Welfare in southern Taiwan. Patients with CDI between January 2013 and April 2020 were included.

Results

Among 238 patients included for analysis, 22 (9.2%) patients developed CRE coinfections within 14 days before or after the onset of CDI. CDI patients with CRE coinfection had longer hospitalization stays (103.0 ± 97.0 days vs 42.5 ± 109.6 days, P = 0.01) than those without CRE coinfection. In the multivariate analysis, age (odds ratio [OR] 1.05, 95% confidence interval [CI] 1.01–1.10, P = 0.02) was independently associated with CRE coinfection. In contrast, underlying old stroke (OR 0.15, 95% CI 0.03–0.70, P = 0.02) was negatively linked to CRE coinfection.

Conclusion

Among patients with CDI, CRE coinfections were associated with prolonged hospitalization for CDI. Age was an independent risk factor for CRE coinfection among patients with CDI.

Impacts of Corticosteroid Therapy at Acute Stage of Hospital-Onset Clostridioides difficile Infections

Introduction

The influence of corticosteroid therapy before or after the onset of Clostridioides difficile infections (CDIs) on the clinical outcomes of adults with hospital-onset CDIs was investigated.

Materials and Methods

A clinical study was conducted on the medical wards of a teaching hospital between January 2013 and April 2020. Adults (aged ≥ 20 years) with hospital-onset CDIs (ie, symptom onset at least 48 hours after hospitalization) were included. "Corticosteroid therapy during acute CDIs" was defined as the receipt of a corticosteroid at the prednisolone equivalent (PE) dose of ≥10 mg for at least 48 hours within one week after the CDI diagnosis. "Prior corticosteroid exposure" was defined as the receipt of a corticosteroid at the PE dose of ≥5 mg PE for at least 48 hours within one month before the CDI diagnosis.

Results

Of the 243 adults with hospital-onset CDIs, patients (44, 18.1%) who received corticosteroid therapy during acute CDIs were more likely to have prior corticosteroid exposure (86.4% vs 11.9%, P <0.001) and CDI episodes in intensive care units (31.8% vs 10.8%, P =0.001). Of note, a crucial association between corticosteroid therapy during acute CDIs and CDI recurrence was evidenced (13.6% vs 1.5%, P =0.002). Prior corticosteroid exposure was not associated with favorable CDI outcomes in terms of successful treatment (78.3% vs 74.9%, P =0.89), in-hospital crude mortality (17.4% vs 24.0%, P =0.61), or CDI recurrence (4.3% vs 5.3%, P = 1.00). However, for 177 patients without prior corticosteroid exposure, corticosteroid therapy during acute CDIs was linked to a higher proportion of CDI recurrence (33.3% vs 5.3%, P =0.046).

Conclusion

Corticosteroid therapy during acute CDIs might impact the recurrence of CDIs, particularly in those with a lack of prior corticosteroid exposure.

Neutrophil Ratio of White Blood Cells as a Prognostic Predictor of Clostridioides difficile Infection

Introduction

A leukocyte count ≥15,000 cells/mL and serum creatinine of >1.5 mg/dL have been reported as two important predictors of severe CDI. However, the association of the differential ratios of blood leukocytes, and the prognosis of Clostridioides difficile infection (CDI) is not clear.

Materials and Methods

A clinical study was conducted at medical wards of Tainan Hospital, Ministry of Health and Welfare in southern Taiwan between January 2013 and April 2020. Hospitalized adults (aged ≥20 years) with hospital-onset CDI (ie, symptom onset after at least 48 hours of admission) were included.

Results

A total of 235 adults with an average age of 75.7 years and female predominance (51.5%), including 146 (62%) adults with non-severe CDI and 87 (38%) severe CDI, were included for analysis. Patients with severe CDI had a higher crude in-hospital mortality rate than patients with non-severe CDI (35.6% vs 18.5%, P = 0.005). Multivariate analysis revealed no association between a leukocyte count >15,000 cell/mL at the onset of CDI and in-hospital mortality (odds ratio [OR] 1.66, P = 0.21). In contrast, a neutrophil ratio >75% (OR 2.65, P = 0.02), serum creatinine >1.5 mg/L (OR 3.42, P = 0.03), and CDI caused by isolates harboring the tcdC gene (OR 3.54, P = 0.02) were independently associated with in-hospital mortality. Patients with a neutrophil ratio >85%, 80–85%, or 75–80% of serum leukocytes had a higher mortality rate (34.8%, 30.3%, or 34.4%, respectively) than patients with a neutrophil ratio of 70–75% or ≤75% (12.5% or 13.9%, respectively).

Conclusion

Serum creatinine >1.5 mg/L, a high neutrophil ratio of blood leukocytes (>75%), and the causative C. difficile harboring the tcdC gene was independent prognostic predictors in hospitalized adults with CDI.

Avian Macrophage Responses to Virulent and Avirulent Clostridium perfringens

The present study evaluated the avian macrophage responses against Clostridium perfringens that varied in their ability to cause necrotic enteritis in chickens. Strains CP5 (avirulent-netB+), CP1 (virulent-netB+), and CP26 (highly virulent-netB+tpeL+) were used to evaluate their effect on macrophages (MQ-NCSU cells) and primary splenic and cecal tonsil mononuclear cells. The bacilli (whole cells) or their secretory products from all three strains induced a significant increase in the macrophage transcription of Toll-like receptor (TLR)21, TLR2, interleukin (IL)-1β, inducible nitric oxide synthase (iNOS), and CD80 genes as well as their nitric oxide (NO) production and major histocompatibility complex (MHC)-II surface expression compared to an unstimulated control. The CP1 and CP26-induced expression of interferon (IFN)γ, IL-6, CD40 genes, MHC-II upregulation, and NO production was significantly higher than that of CP5 and control groups. Furthermore, splenocytes and cecal tonsillocytes stimulated with bacilli or secretory products from all the strains showed a significant increase in the frequency of macrophages, their surface expression of MHC-II and NO production, while CP26-induced responses were significantly higher for the rest of the groups. In summary, macrophage interaction with C. perfringens can lead to cellular activation and, the ability of this pathogen to induce macrophage responses may depend on its level of virulence.