Systemic Inflammatory Mediators Are Effective Biomarkers for Predicting Adverse Outcomes in Clostridioides difficile Infection

ABSTRACT Clostridioides difficile infection (CDI) can result in severe disease and death, with no accurate models that allow for early prediction of adverse outcomes. To address this need, we sought to develop serum-based biomarker models to predict CDI outcomes. We prospectively collected sera ≤48 h after diagnosis of CDI in two cohorts. Biomarkers were measured with a custom multiplex bead array assay. Patients were classified using IDSA severity criteria and the development of disease-related complications (DRCs), which were defined as ICU admission, colectomy, and/or death attributed to CDI. Unadjusted and adjusted models were built using logistic and elastic net modeling. The best model for severity included procalcitonin (PCT) and hepatocyte growth factor (HGF) with an area (AUC) under the receiver operating characteristic (ROC) curve of 0.74 (95% confidence interval, 0.67 to 0.81). The best model for 30-day mortality included interleukin-8 (IL-8), PCT, CXCL-5, IP-10, and IL-2Rα with an AUC of 0.89 (0.84 to 0.95). The best model for DRCs included IL-8, procalcitonin, HGF, and IL-2Rα with an AUC of 0.84 (0.73 to 0.94). To validate our models, we employed experimental infection of mice with C. difficile. Antibiotic-treated mice were challenged with C. difficile and a similar panel of serum biomarkers was measured. Applying each model to the mouse cohort of severe and nonsevere CDI revealed AUCs of 0.59 (0.44 to 0.74), 0.96 (0.90 to 1.0), and 0.89 (0.81 to 0.97). In both human and murine CDI, models based on serum biomarkers predicted adverse CDI outcomes. Our results support the use of serum-based biomarker panels to inform Clostridioides difficile infection treatment. IMPORTANCE Each year in the United States, Clostridioides difficile causes nearly 500,000 gastrointestinal infections that range from mild diarrhea to severe colitis and death. The ability to identify patients at increased risk for severe disease or mortality at the time of diagnosis of C. difficile infection (CDI) would allow clinicians to effectively allocate disease modifying therapies. In this study, we developed models consisting of only a small number of serum biomarkers that are capable of predicting both 30-day all-cause mortality and adverse outcomes of patients at time of CDI diagnosis. We were able to validate these models through experimental mouse infection. This provides evidence that the biomarkers reflect the underlying pathophysiology and that our mouse model of CDI reflects the pathogenesis of human infection. Predictive models can not only assist clinicians in identifying patients at risk for severe CDI but also be utilized for targeted enrollment in clinical trials aimed at reduction of adverse outcomes from severe CDI.

Download Full-text

Defining the black box: a narrative review of factors associated with adverse outcomes from severe Clostridioides difficile infection

Therapeutic Advances in Gastroenterology ◽

10.1177/17562848211048127 ◽

2021 ◽

Vol 14 ◽

pp. 175628482110481

Author(s):

Adam Ressler ◽

Joyce Wang ◽

Krishna Rao

Keyword(s):

The United States ◽

Adverse Outcomes ◽

Chronic Illnesses ◽

Narrative Review ◽

Healthcare Associated Infection ◽

Clostridioides Difficile ◽

Clostridioides Difficile Infection ◽

Patients At Risk ◽

Hospital Deaths ◽

Healthcare Associated

In the United States, Clostridioides difficile infection (CDI) is the leading cause of healthcare-associated infection, affecting nearly half a million people and resulting in more than 20,000 in-hospital deaths every year. It is therefore imperative to better characterize the intricate interplay between C. difficile microbial factors, host immunologic signatures, and clinical features that are associated with adverse outcomes of severe CDI. In this narrative review, we discuss the implications of C. difficile genetics and virulence factors in the molecular epidemiology of CDI, and the utility of early biomarkers in predicting the clinical trajectory of patients at risk of developing severe CDI. Furthermore, we identify associations between host immune factors and CDI outcomes in both animal models and human studies. Next, we highlight clinical factors including renal dysfunction, aging, blood biomarkers, level of care, and chronic illnesses that can affect severe CDI diagnosis and outcome. Finally, we present our perspectives on two specific treatments pertinent to patient outcomes: metronidazole administration and surgery. Together, this review explores the various venues of CDI research and highlights the importance of integrating microbial, host, and clinical data to help clinicians make optimal treatment decisions based on accurate prediction of disease progression.

Download Full-text

Type 3 Immunity during Clostridioides difficile Infection: Too Much of a Good Thing?

Infection and Immunity ◽

10.1128/iai.00306-19 ◽

2019 ◽

Vol 88 (1) ◽

Cited By ~ 4

Author(s):

Mahmoud M. Saleh ◽

William A. Petri

Keyword(s):

The United States ◽

Lymphoid Cells ◽

Interleukin 17 ◽

Gastrointestinal Infections ◽

Content Type ◽

Animal Models Of Disease ◽

Interleukin 22 ◽

Inflammatory Conditions ◽

Clostridioides Difficile ◽

Type 3

ABSTRACT Clostridioides (formerly known as Clostridium) difficile is the leading cause of hospital-acquired gastrointestinal infections in the United States and one of three urgent health care threats identified by the Centers for Disease Control and Prevention. C. difficile disease is mediated by the production of toxins that disrupt the epithelial barrier and cause a robust host inflammatory response. Studies in humans as well as animal models of disease have shown that the type of immune response generated against the infection dictates the outcome of disease, often irrespective of bacterial burden. Much of the focus on immunity during C. difficile infection (CDI) has been on type 3 immunity because of the established role for this arm of the immune system in other gastrointestinal inflammatory conditions such as inflammatory bowel disease (IBD). For example, interleukin-22 (IL-22) production by group 3 innate lymphoid cells (ILC3s) protects against pathobionts translocating across the epithelium during CDI. On the other hand, interleukin-17 (IL-17) production by Th17 cells increases CDI-associated mortality. Additionally, neutropenia has been associated with increased susceptibility to CDI in humans, but increased neutrophilia in mouse models correlates with host pathology. Taking the data together, these findings suggest dual roles for type 3 immune responses during infection. Here, we review the complex role of type 3 immunity during CDI and delineate what is known about innate and adaptive cellular immunity as well as the downstream effector cytokines known to be important during this infection.

Download Full-text

Serum Biomarkers of Iron Stores Are Associated with Increased Risk of All-Cause Mortality and Cardiovascular Events in Nondialysis CKD Patients, with or without Anemia

Journal of the American Society of Nephrology ◽

10.1681/asn.2020101531 ◽

2021 ◽

pp. ASN.2020101531

Author(s):

Murilo Guedes ◽

Daniel G. Muenz ◽

Jarcy Zee ◽

Brian Bieber ◽

Benedicte Stengel ◽

...

Keyword(s):

Iron Deficiency ◽

Cardiovascular Events ◽

Transferrin Saturation ◽

The United States ◽

Serum Biomarkers ◽

Major Adverse Cardiovascular Events ◽

Content Type ◽

Iron Stores ◽

Increased Risk ◽

All Cause Mortality

BackgroundApproximately 30%–45% of patients with nondialysis CKD have iron deficiency. Iron therapy in CKD has focused primarily on supporting erythropoiesis. In patients with or without anemia, there has not been a comprehensive approach to estimating the association between serum biomarkers of iron stores, and mortality and cardiovascular event risks.MethodsThe study included 5145 patients from Brazil, France, the United States, and Germany enrolled in the Chronic Kidney Disease Outcomes and Practice Patterns Study, with first available transferrin saturation (TSAT) and ferritin levels as exposure variables. We used Cox models to estimate hazard ratios (HRs) for all-cause mortality and major adverse cardiovascular events (MACE), with progressive adjustment for potentially confounding variables. We also used linear spline models to further evaluate functional forms of the exposure-outcome associations.ResultsCompared with patients with a TSAT of 26%–35%, those with a TSAT ≤15% had the highest adjusted risks for all-cause mortality and MACE. Spline analysis found the lowest risk at TSAT 40% for all-cause mortality and MACE. Risk of all-cause mortality, but not MACE, was also elevated at TSAT ≥46%. Effect estimates were similar after adjustment for hemoglobin. For ferritin, no directional associations were apparent, except for elevated all-cause mortality at ferritin ≥300 ng/ml.ConclusionsIron deficiency, as captured by TSAT, is associated with higher risk of all-cause mortality and MACE in patients with nondialysis CKD, with or without anemia. Interventional studies evaluating the effect on clinical outcomes of iron supplementation and therapies for alternative targets are needed to better inform strategies for administering exogenous iron.

Download Full-text

The interplay of Clostridioides difficile infection and inflammatory bowel disease

Therapeutic Advances in Gastroenterology ◽

10.1177/17562848211020285 ◽

2021 ◽

Vol 14 ◽

pp. 175628482110202

Author(s):

Kanika Sehgal ◽

Devvrat Yadav ◽

Sahil Khanna

Keyword(s):

Inflammatory Bowel Disease ◽

Bowel Disease ◽

Adverse Outcomes ◽

Molecular Tests ◽

Clostridioides Difficile ◽

Increased Risk ◽

Clostridioides Difficile Infection ◽

Pros And Cons ◽

Inflammatory Bowel ◽

High Index Of Suspicion

Inflammatory bowel disease (IBD) is a chronic disease of the intestinal tract that commonly presents with diarrhea. Clostridioides difficile infection (CDI) is one of the most common complications associated with IBD that lead to flare-ups of underlying IBD. The pathophysiology of CDI includes perturbations of the gut microbiota, which makes IBD a risk factor due to the gut microbial alterations that occur in IBD, predisposing patients CDI even in the absence of antibiotics. Superimposed CDI not only worsens IBD symptoms but also leads to adverse outcomes, including treatment failure and an increased risk of hospitalization, surgery, and mortality. Due to the overlapping symptoms and concerns with false-positive molecular tests for CDI, diagnosing CDI in patients with IBD remains a clinical challenge. It is crucial to have a high index of suspicion for CDI in patients who seem to be experiencing an exacerbation of IBD symptoms. Vancomycin and fidaxomicin are the first-line treatments for the management of CDI in IBD. Microbiota restoration therapies effectively prevent recurrent CDI in IBD patients. Immunosuppression for IBD in IBD patients with CDI should be managed individually, based on a thorough clinical assessment and after weighing the pros and cons of escalation of therapy. This review summarizes the epidemiology, pathophysiology, the diagnosis of CDI in IBD, and outlines the principles of management of both CDI and IBD in IBD patients with CDI.

Download Full-text

Spo0A Suppresses sin Locus Expression in Clostridioides difficile

mSphere ◽

10.1128/msphere.00963-20 ◽

2020 ◽

Vol 5 (6) ◽

Author(s):

Babita Adhikari Dhungel ◽

Revathi Govind

Keyword(s):

Diarrheal Disease ◽

Toxin Production ◽

The United States ◽

Upstream Region ◽

Pcr Analysis ◽

Bacterial Cells ◽

Master Regulator ◽

Content Type ◽

Clostridioides Difficile

ABSTRACT Clostridioides difficile is the leading cause of nosocomial infection and is the causative agent of antibiotic-associated diarrhea. The severity of the disease is directly associated with toxin production, and spores are responsible for the transmission and persistence of the organism. Previously, we characterized sin locus regulators SinR and SinR′ (we renamed it SinI), where SinR is the regulator of toxin production and sporulation. The SinI regulator acts as its antagonist. In Bacillus subtilis, Spo0A, the master regulator of sporulation, controls SinR by regulating the expression of its antagonist, sinI. However, the role of Spo0A in the expression of sinR and sinI in C. difficile had not yet been reported. In this study, we tested spo0A mutants in three different C. difficile strains, R20291, UK1, and JIR8094, to understand the role of Spo0A in sin locus expression. Western blot analysis revealed that spo0A mutants had increased SinR levels. Quantitative reverse transcription-PCR (qRT-PCR) analysis of its expression further supported these data. By carrying out genetic and biochemical assays, we show that Spo0A can bind to the upstream region of this locus to regulates its expression. This study provides vital information that Spo0A regulates the sin locus, which controls critical pathogenic traits such as sporulation, toxin production, and motility in C. difficile. IMPORTANCE Clostridioides difficile is the leading cause of antibiotic-associated diarrheal disease in the United States. During infection, C. difficile spores germinate, and the vegetative bacterial cells produce toxins that damage host tissue. In C. difficile, the sin locus is known to regulate both sporulation and toxin production. In this study, we show that Spo0A, the master regulator of sporulation, controls sin locus expression. Results from our study suggest that Spo0A directly regulates the expression of this locus by binding to its upstream DNA region. This observation adds new detail to the gene regulatory network that connects sporulation and toxin production in this pathogen.

Download Full-text

Changes in Antigen-Specific Cytokine and Chemokine Responses to Plasmodium falciparum Antigens in a Highland Area of Kenya after a Prolonged Absence of Malaria Exposure

Infection and Immunity ◽

10.1128/iai.01924-14 ◽

2014 ◽

Vol 82 (9) ◽

pp. 3775-3782 ◽

Cited By ~ 6

Author(s):

Lyticia A. Ochola ◽

Cyrus Ayieko ◽

Lily Kisia ◽

Ng'wena G. Magak ◽

Estela Shabani ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Severe Disease ◽

Clinical Malaria ◽

Necrosis Factor Alpha ◽

Content Type ◽

Highland Area ◽

Cytokine Responses ◽

Increased Risk ◽

Tnf Α ◽

Ifn Γ

ABSTRACTIndividuals naturally exposed toPlasmodium falciparumlose clinical immunity after a prolonged lack of exposure.P. falciparumantigen-specific cytokine responses have been associated with protection from clinical malaria, but the longevity ofP. falciparumantigen-specific cytokine responses in the absence of exposure is not well characterized. A highland area of Kenya with low and unstable malaria transmission provided an opportunity to study this question. The levels of antigen-specific cytokines and chemokines associated in previous studies with protection from clinical malaria (gamma interferon [IFN-γ], interleukin-10 [IL-10], and tumor necrosis factor alpha [TNF-α]), with increased risk of clinical malaria (IL-6), or with pathogenesis of severe disease in malaria (IL-5 and RANTES) were assessed by cytometric bead assay in April 2008, October 2008, and April 2009 in 100 children and adults. During the 1-year study period, none had an episode of clinicalP. falciparummalaria. Two patterns of cytokine responses emerged, with some variation by antigen: a decrease at 6 months (IFN-γ and IL-5) or at both 6 and 12 months (IL-10 and TNF-α) or no change over time (IL-6 and RANTES). These findings document thatP. falciparumantigen-specific cytokine responses associated in prior studies with protection from malaria (IFN-γ, TNF-α, and IL-10) decrease significantly in the absence ofP. falciparumexposure, whereas those associated with increased risk of malaria (IL-6) do not. The study findings provide a strong rationale for future studies of antigen-specific IFN-γ, TNF-α, and IL-10 responses as biomarkers of increased population-level susceptibility to malaria after prolonged lack ofP. falciparumexposure.

Download Full-text

Associations of Community Water Lead Concentrations with Hemoglobin Concentrations and Erythropoietin-Stimulating Agent Use among Patients with Advanced CKD

Journal of the American Society of Nephrology ◽

10.1681/asn.2020091281 ◽

2021 ◽

pp. ASN.2020091281

Author(s):

John Danziger ◽

Kenneth J. Mukamal ◽

Eric Weinhandl

Keyword(s):

United States ◽

Drinking Water ◽

Kidney Disease ◽

The United States ◽

Water Systems ◽

Adverse Outcomes ◽

Content Type ◽

Community Water Systems ◽

Community Water ◽

Lead Levels

BackgroundAlthough patients with kidney disease may be particularly susceptible to the adverse health effects associated with lead exposure, whether levels of lead found commonly in drinking water are associated with adverse outcomes in patients with ESKD is not known.MethodsTo investigate associations of lead in community water systems with hemoglobin concentrations and erythropoietin stimulating agent (ESA) use among incident patients with ESKD, we merged data from the Environmental Protection Agency (EPA) Safe Drinking Water Information System (documenting average 90th percentile lead concentrations in community water systems during 5 years before dialysis initiation, according to city of residence) with patient-level data from the United States Renal Data System.ResultsAmong 597,968 patients initiating dialysis in the United States in 2005 through 2017, those in cities with detectable lead levels in community water had significantly lower pre-ESKD hemoglobin concentrations and more ESA use per 0.01 mg/L increase in 90th percentile water lead. Findings were similar for the 208,912 patients with data from the first month of ESKD therapy, with lower hemoglobin and higher ESA use per 0.01 mg/L higher lead concentration. These associations were observed at lead levels below the EPA threshold (0.015 mg/L) that mandates regulatory action. We also observed environmental inequities, finding significantly higher water lead levels and slower declines over time among Black versus White patients.ConclusionsThis first nationwide analysis linking EPA water supply records to patient data shows that even low levels of lead that are commonly encountered in community water systems throughout the United States are associated with lower hemoglobin levels and higher ESA use among patients with advanced kidney disease.

Download Full-text

Dual Reporting of Clostridioides difficile PCR and Predicted Toxin Result Based on PCR Cycle Threshold Reduces Treatment of Toxin-Negative Patients without Increases in Adverse Outcomes

Journal of Clinical Microbiology ◽

10.1128/jcm.01288-19 ◽

2019 ◽

Vol 57 (11) ◽

Cited By ~ 1

Author(s):

Matthew M. Hitchcock ◽

Marisa Holubar ◽

Catherine A. Hogan ◽

Lucy S. Tompkins ◽

Niaz Banaei

Keyword(s):

Nucleic Acid ◽

Chart Review ◽

Patient Characteristics ◽

Adverse Outcomes ◽

Nucleic Acid Amplification ◽

Content Type ◽

Cycle Threshold ◽

Clostridioides Difficile ◽

All Cause Mortality ◽

High Negative Predictive Value

ABSTRACT Nucleic acid amplification tests are commonly used to diagnose Clostridioides difficile infection (CDI). Two-step testing with a toxin enzyme immunoassay is recommended to discriminate between infection and colonization but requires additional resources. Prior studies showed that PCR cycle threshold (CT) can predict toxin positivity with high negative predictive value. Starting in October 2016, the predicted toxin result (CT-toxin) based on a validated cutoff was routinely reported at our facility. To evaluate the clinical efficacy of this reporting, all adult patients with positive GeneXpert PCR results from October 2016 through October 2017 underwent a chart review to measure the recurrence of or conversion to a CT-toxin+ result and 30-day all-cause mortality. There were 482 positive PCR tests in 430 unique patients, 282 CT-toxin+ and 200 CT-toxin−. Patient characteristics were similar at testing, though CT-toxin+ patients had higher white blood cell (WBC) counts (12.5 × 103 versus 9.3 × 103 cells/μl; P = 0.001). All cases (n = 21) of fulminant CDI had a CT-toxin+ result. Index CT-toxin+ patients were significantly more likely to have a CT-toxin+ result within 90 days than CT-toxin− patients (17.4% [n = 49] versus 8.0% [n = 16], respectively; P = 0.003). Thirty-day all-cause mortality was higher in CT-toxin− patients (11.1% versus 6.8%; P = 0.1), though no deaths in CT-toxin− patients were directly attributable to CDI. Of the 200 CT-toxin− patients, 51.5% (n = 103) were treated for CDI. The rates of conversion to a CT-toxin+ result (8.8% versus 7.2%; P = 0.8) and all-cause mortality (8.8% versus 13.4%; P = 0.3) were similar between treated and untreated CT-toxin− patients, respectively. CT-based toxin prediction may identify patients at higher risk for CDI-related complications and reduce treatment among CT-toxin− patients.

Download Full-text

An Observational Cohort Study ofClostridium difficileRibotype 027 and Recurrent Infection

mSphere ◽

10.1128/msphere.00033-18 ◽

2018 ◽

Vol 3 (3) ◽

Cited By ~ 10

Author(s):

Krishna Rao ◽

Peter D. R. Higgins ◽

Vincent B. Young

Keyword(s):

Logistic Regression ◽

Independent Predictor ◽

The United States ◽

Public Health Issue ◽

Clinical Microbiology Laboratory ◽

Clinical Predictors ◽

Content Type ◽

Ribotype 027 ◽

Increased Risk ◽

Wide Range

ABSTRACTRecurrentClostridium difficileinfection (rCDI) frequently complicates recovery from CDI. Accurately predicting rCDI would allow judicious allocation of limited resources, but published models have met with limited success. Thus, biomarkers predictive of recurrence have been sought. This study tested whether PCR ribotype independently predicted rCDI. Stool samples from nonpregnant inpatients ≥18 years of age with diarrhea were included from October 2010 to January 2013 after the patients tested positive forC. difficilein the clinical microbiology laboratory. Per guidelines, the rCDI was defined as a positive test forC. difficileat >2 weeks but ≤8 weeks from the index episode. For each sample, a single colony ofC. difficilewas isolated by anaerobic culture, confirmed to be toxigenic by PCR, and ribotyped. Simple logistic regression and multiple logistic regression were used to model the primary outcome of rCDI, incorporating a wide range of clinical parameters. In total, 927 patients with 968 index episodes of CDI were included, with 110 (11.4%) developing rCDI. Age and use of proton pump inhibitors or concurrent antibiotics did not increase the risk of rCDI. Low serum bilirubin levels and ribotype 027 were associated with increased risk of rCDI on unadjusted analysis, with health care-associated CDI being inversely associated. In the final multivariable model, ribotype 027 was the strongest independent predictor of rCDI (odds ratio, 2.17; 95% confidence interval, 1.33 to 3.56;P= 0.002). Ribotype 027 is an independent predictor of rCDI.IMPORTANCECDI is a major public health issue, with over 400,000 cases per year in the United States alone. Recurrent CDI is common, occurring in approximately one in five individuals after a primary episode. Although interventions exist that could reduce the risk of recurrence, deployment in all patients is limited by cost, invasiveness, and/or an undetermined long-term safety profile. Thus, clinicians need risk stratification tools to properly allocate treatments. Because prior research on clinical predictors has failed to yield a reliable, reproducible, and effective predictive model to assist treatment decisions, accurate biomarkers of recurrence would be of great value. This study tested whether PCR ribotype independently predicted rCDI, and the data build upon prior research in showing that ribotype 027 is associated with rCDI.

Download Full-text

Homologous Recombination in Clostridioides difficile Mediates Diversification of Cell Surface Features and Transport Systems

mSphere ◽

10.1128/msphere.00799-20 ◽

2020 ◽

Vol 5 (6) ◽

Author(s):

Hannah D. Steinberg ◽

Evan S. Snitkin

Keyword(s):

Cell Wall ◽

Homologous Recombination ◽

Sugar Transport ◽

The United States ◽

Strain Typing ◽

Cell Wall Proteins ◽

Genetic Loci ◽

Content Type ◽

Clostridioides Difficile ◽

Host Pathogen

ABSTRACT Illness caused by the pathogen Clostridioides difficile is widespread and can range in severity from mild diarrhea to sepsis and death. Strains of C. difficile isolated from human infections exhibit great genetic diversity, leading to the hypothesis that the genetic background of the infecting strain at least partially determines a patient’s clinical course. However, although certain strains of C. difficile have been suggested to be associated with increased severity, strain typing alone has proved insufficient to explain infection severity. The limited explanatory power of strain typing has been hypothesized to be due to genetic variation within strain types, as well as genetic elements shared between strain types. Homologous recombination is an evolutionary mechanism that can result in large genetic differences between two otherwise clonal isolates, and also lead to convergent genotypes in distantly related strains. More than 400 C. difficile genomes were analyzed here to assess the effect of homologous recombination within and between C. difficile clades. Almost three-quarters of single nucleotide variants in the C. difficile phylogeny are predicted to be due to homologous recombination events. Furthermore, recombination events were enriched in genes previously reported to be important to virulence and host-pathogen interactions, such as flagella, cell wall proteins, and sugar transport and metabolism. Thus, by exploring the landscape of homologous recombination in C. difficile, we identified genetic loci whose elevated rates of recombination mediated diversification, making them strong candidates for being mediators of host-pathogen interaction in diverse strains of C. difficile. IMPORTANCE Infections with C. difficile result in up to half a million illnesses and tens of thousands of deaths annually in the United States. The severity of C. difficile illness is dependent on both host and bacterial factors. Studying the evolutionary history of C. difficile pathogens is important for understanding the variation in pathogenicity of these bacteria. This study examines the extent and targets of homologous recombination, a mechanism by which distant strains of bacteria can share genetic material, in hundreds of C. difficile strains and identifies hot spots of realized recombination events. The results of this analysis reveal the importance of homologous recombination in the diversification of genetic loci in C. difficile that are significant in its pathogenicity and host interactions, such as flagellar construction, cell wall proteins, and sugar transport and metabolism.

Download Full-text