Elevated lactoferrin is associated with moderate to severe Clostridium difficile disease, stool toxin, and 027 infection

Clostridioides difficile infection: history, epidemiology, risk factors, prevention, clinical manifestations, treatment, and future options

SUMMARYClostridioides difficile infection (CDI) is one of the major issues in nosocomial infections. This bacterium is constantly evolving and poses complex challenges for clinicians, often encountered in real-life scenarios. In the face of CDI, we are increasingly equipped with new therapeutic strategies, such as monoclonal antibodies and live biotherapeutic products, which need to be thoroughly understood to fully harness their benefits. Moreover, interesting options are currently under study for the future, including bacteriophages, vaccines, and antibiotic inhibitors. Surveillance and prevention strategies continue to play a pivotal role in limiting the spread of the infection. In this review, we aim to provide the reader with a comprehensive overview of epidemiological aspects, predisposing factors, clinical manifestations, diagnostic tools, and current and future prophylactic and therapeutic options for C. difficile infection.

Association of intestinal inflammation and permeability markers with clinical manifestations of Parkinson's disease

INTRODUCTION

Intestinal inflammation and gut microbiota dysbiosis can stimulate degeneration of dopaminergic neurons and development of Parkinson's disease (PD) via the gut-brain axis in certain patients.

METHODS

In a case-control study, fecal markers of intestinal inflammation and permeability were measured using the ELISA method in PD patients and healthy controls. Motor and nonmotor symptoms were assessed using the Movement Disorder Society (MDS) Unified PD Rating Scale, Hoehn & Yahr scale, MDS Non-Motor Symptom Scale, Scales for Outcomes in PD - Autonomic Dysfunction, PD Sleep Scale - 2, Montreal Cognitive Assessment, Beck Anxiety Inventory, and Beck Depression Inventory-II. A correlation was established between the intestinal inflammation and permeability markers and PD symptoms.

RESULTS

Higher levels of beta-defensin 2, zonulin and lactoferrin were recorded in PD patients compared to controls. Calprotectin and secretory immunoglobulin A showed no significant differences. Regression analysis indicated the roles of beta-defensin 2 and lactoferrin in predicting PD likelihood. Calprotectin yielded positive correlations with disease duration, depression, motor fluctuations, and gastrointestinal symptoms; beta defensin 2 with thermoregulation; and secretory immunoglobulin A with depression. Secretory immunoglobulin A showed negative correlation with age and age at disease onset, while zonulin showed negative correlation with the MDS Unified PD Rating Scale total score.

CONCLUSIONS

Fecal markers differed in PD patients compared to controls and correlated with age, disease duration, and some nonmotor symptoms. Future studies should identify the subgroups of PD patients that are likely to develop intestinal inflammation.

Predictive value of fecal calprotectin and lactoferrin levels for negative outcomes in Clostridioides difficile infection

PURPOSE

We investigated the role of fecal calprotectin (FC) and lactoferrin (FL) as predictive biomarkers in Clostridioides difficile infection (CDI).

METHODS

We assembled a prospective cohort including all patients with a laboratory-confirmed CDI diagnosis between January and December 2017. FL and FC levels were measured at diagnosis by commercial ELISA and EIA kits. We investigated the diagnostic accuracy of FC and FL to predict CDI recurrence and severity (study outcomes) and explored optimal cut-off values in addition to those proposed by the manufacturers (200 µg/g and 7.2 µg/mL, respectively).

RESULTS

We included 170 CDI cases (152 first episodes and 18 recurrences). The rates of recurrence (first episodes only) and severity (entire cohort) were 9.2% (14/152) and 46.5% (79/170). Both FL and FC levels were significantly higher in patients who developed study outcomes. Optimal cut-off values for FC and FL to predict CDI recurrence were 1052 µg/g and 6.0 µg/mL. The optimal cut-off value for FC yielded higher specificity (60.9%) and positive predictive value (PPV) (16.9%) than that proposed by the manufacturer. Regarding CDI severity, the optimal cut-off value for FC (439 µg/g) also provided higher specificity (43.9%) and PPV (54.1%) than that of the manufacturer, whereas the optimal cut-off value for FL (4.6 µg/mL) resulted in an improvement of PPV (57.5%).

CONCLUSION

By modifying the thresholds for assay positivity, the measurement of FC and FL at diagnosis is useful to predict recurrence and severity in CDI. Adding these biomarkers to current clinical scores may help to individualize CDI management.

Diagnostic Guidance for C. difficile Infections

Diagnosis of Clostridioides difficile infection (CDI) can be challenging. First of all, there has been debate on which of the two reference assays, cell cytotoxicity neutralization assay (CCNA) or toxigenic culture (TC), should be considered the gold standard for CDI detection. Although the CCNA suffers most from suboptimal storage conditions and subsequent toxin degradation, TC is reported to falsely increase CDI detection rates as it cannot differentiate CDI patients from patients asymptomatically colonised by toxigenic C. difficile. Several rapid assays are available for CDI detection and fall into three broad categories: (1) enzyme immunoassays for glutamate dehydrogenase, (2) enzyme immunoassays or single-molecule array assays for toxins A/B and (3) nucleic acid amplification tests detecting toxin genes. All three categories have their own limitations, being suboptimal specificity and/or sensitivity or the inability to discern colonised patients from CDI patients. In light of these limitations, multi-step algorithmic testing has been advocated by international guidelines (IDSA/SHEA and ESCMID) in order to optimize diagnostic accuracy. As a result, a survey performed in 2018-2019 in Europe revealed that most of all hospital sites reported using more than one test to diagnose CDI. CDI incidence rates are also influenced by sample selection criteria, as several studies have shown that if not all unformed stool samples are tested for CDI, many cases may be missed due to an absence of clinical suspicion. Since methods for diagnosing CDI remain imperfect, there has been a growing interest in alternative testing strategies like faecal microbiota biomarkers, immune modulating interleukins, cytokines and imaging methods. At the moment, these alternative methods might play an adjunctive role, but they are not suitable to replace conventional CDI testing strategies.

Serum/Faecal S100A12, CRP and lactoferrin can be used to distinguish ınfectious and non-ınfectious canine diarrhoea

OBJECTIVES

This study aimed to evaluate the diagnostic efficacies of selected inflammatory and intestinal biomarkers in cases of infectious and non-infectious diarrhoea in dogs.

METHODS

A total of 60 dogs, 12 healthy (Control Group) and 48 with diarrhoea were used. Viral, Bacterial, Parasitic (infectious) and Nutritional diarrhoea (non-infectious) subgroups (n: 12) were formed according to the aetiology, on the basis of clinical and laboratory examinations. Selected inflammatory and intestinal biomarkers (Calgranulin, S100A12; Lactoferrin, LCTF; C-reactive protein, CRP) were measured both in serum and faecal samples.

RESULTS

Compared to the Control and Nutritional Diarrhoea groups, the infectious diarrhoea groups had higher serum S100A12, LCTF, CRP, blood urea nitrogen, creatinine (CR), alanine transaminase and alkaline phosphatase, and lower glucose (GLU), sodium (Na) and potassium (K) concentrations (p < 0.05); Viral and Parasitic Diarrhoea groups had lower serum albumin (ALB) and total protein (TP) concentrations (p < 0.05). Faecal S100A12, LCTF and CRP concentrations were higher in infectious diarrhoea groups compared to the Control and Nutritional Diarrhoea groups (p < 0.05). Faecal LCTF and CRP concentrations were higher in the Bacterial Diarrhoea group than in the Viral and Parasitic Diarrhoea groups (p < 0.05).

CLINICAL SIGNIFICANCE

It was determined that serum (area under curve, AUC: 0.842 and 0.956) and faecal (AUC: 0.975 and 0.786) S100A12 and CRP concentrations in viral diarrhoea; serum (AUC: 0.956) and faecal (AUC: 0.992) LCTF concentrations in bacterial diarrhoea have diagnostic values in the diagnosis of the presence of intestinal inflammation and damage and can be used in the differential diagnosis of infectious and non-infectious diarrhoea.

The unusual properties of lactoferrin during its nascent phase

Lactoferrin, a multifunctional iron-binding protein containing 16 disulfides, is actively studied for its antibacterial and anti-carcinogenic properties. However, scarce information is nowadays available about its oxidative folding starting from the reduced and unfolded status. This study discovers unusual properties when this protein is examined in its reduced molten globule-like conformation. Using kinetic, CD and fluorescence analyses together with mass spectrometry, we found that a few cysteines display astonishing hyper-reactivity toward different thiol reagents. In details, four cysteines (i.e. 668, 64, 512 and 424) display thousands of times higher reactivity toward GSSG but normal against other natural disulfides. The formation of these four mixed-disulfides with glutathione probably represents the first step of its folding in vivo. A widespread low pKa decreases the reactivity of other 14 cysteines toward GSSG limiting their involvement in the early phase of the oxidative folding. The origin of this hyper-reactivity was due to transient lactoferrin-GSSG complex, as supported by fluorescence experiments. Lactoferrin represents another disulfide containing protein in addition to albumin, lysozyme, ribonuclease, chymotrypsinogen, and trypsinogen which shows cysteines with an extraordinary and specific hyper-reactivity toward GSSG confirming the discovery of a fascinating new feature of proteins in their nascent phase.

Binary Toxin Expression by Clostridioides difficile Is Associated With Worse Disease

BACKGROUND

The incidence of Clostridioides difficile infection (CDI) has increased over the past 2 decades and is considered an urgent threat by the Centers for Disease Control and Prevention. Hypervirulent strains such as ribotype 027, which possess genes for the additional toxin C. difficile binary toxin (CDT), are contributing to increased morbidity and mortality.

METHODS

We retrospectively tested stool from 215 CDI patients for CDT by enzyme-linked immunosorbent assay (ELISA). Stratifying patients by CDT status, we assessed if disease severity and clinical outcomes correlated with CDT positivity. Additionally, we completed quantitative PCR (PCR) DNA extracted from patient stool to detect cdtB gene. Lastly, we performed 16 S rRNA gene sequencing to examine if CDT-positive samples had an altered fecal microbiota.

RESULTS

We found that patients with CdtB, the pore-forming component of CDT, detected in their stool by ELISA, were more likely to have severe disease with higher 90-day mortality. CDT-positive patients also had higher C. difficile bacterial burden and white blood cell counts. There was no significant difference in gut microbiome diversity between CDT-positive and -negative patients.

CONCLUSIONS

Patients with fecal samples that were positive for CDT had increased disease severity and worse clinical outcomes. Utilization of PCR and testing for C. difficile toxins A and B may not reveal the entire picture when diagnosing CDI; detection of CDT-expressing strains is valuable in identifying patients at risk of more severe disease.

Fecal host biomarkers predicting severity of Clostridioides difficile infection

Clostridioides difficile is a major cause of health care-associated diarrhea. Severity ranges from mild to life-threatening, but this variability remains poorly understood. Microbiologic diagnosis of C. difficile infection (CDI) is straightforward but offers little insight into the patient's prognosis or into pathophysiologic determinants of clinical trajectory. The aim of this study was to discover host-derived, CDI-specific fecal biomarkers involved in disease severity. Subjects without and with CDI diarrhea were recruited. CDI severity was based on Infectious Diseases Society of America/Society for Healthcare Epidemiology of America criteria. We developed a liquid chromatography tandem mass spectrometry approach to identify host-derived protein biomarkers from stool and applied it to diagnostic samples for cohort-wise comparison (CDI-negative vs. nonsevere CDI vs. severe CDI). Selected biomarkers were orthogonally confirmed and subsequently verified in a CDI mouse model. We identified a protein signature from stool, consisting of alpha-2-macroglobulin (A2MG), matrix metalloproteinase-7 (MMP-7), and alpha-1-antitrypsin (A1AT), that not only discriminates CDI-positive samples from non-CDI ones but also is potentially associated with disease severity. In the mouse model, this signature with the murine homologs of the corresponding proteins was also identified. A2MG, MMP-7, and A1AT serve as biomarkers in patients with CDI and define novel components of the host response that may determine disease severity.

Recent advances in the treatment of Clostridioides difficile infection: the ever-changing guidelines

Clostridioides difficile infection (CDI), formerly known as Clostridium difficile, continues to be the most common healthcare-associated infection worldwide. With the shifting epidemiology towards higher a incidence of community-acquired CDI and the continued burden on the healthcare system posed by high rates of CDI recurrence, there has been an impetus to advance the diagnostic testing and treatment strategies. Recent advancements over the past decade have led to rapidly changing guidelines issued by the Infectious Diseases Society of America and European Society of Clinical Microbiology and Infectious Diseases. With our comprehensive review, we aim to summarize the latest advances in diagnosing and treating CDI and thus attempt to help readers guide best practices for patient care. This article also focusses on cost-effectiveness of various therapies currently available on the market and provides an analysis of the current evidence on a relatively new monoclonal antibody therapy, Bezlotoxumab, to treat recurrent CDI.

Clostridioides difficile Infection: The Challenge, Tests, and Guidelines

Clostridioides difficile is a dangerous human pathogen because it can grow to high numbers in the intestine, cause colitis with its potent toxins, and persist as spores. C. difficile infection (CDI) is the primary hospital-acquired infection in North America and Europe, and it now is a global disease. Even with newer laboratory tests, there still is confusion on accurately diagnosing this disease. Three guidelines from three different healthcare-affiliated societies have recently been published. Consensus consolidated recommendations from these guidelines should be recognized by healthcare professionals, who need to understand why this disease continues to be difficult to diagnose and need a clear understanding of the advantages and limitations of current tests. Hopefully, these combined efforts will lead to an improvement in the recognition of this pathogen and a reduction in the suffering and economic loss caused by CDI.

Low glutamate dehydrogenase levels are associated with colonization in Clostridium difficile PCR-only positive patients with inflammatory bowel disease

BACKGROUND/AIMS

Clostridioides difficile infection (CDI) remains a diagnostic challenge in patients with inflammatory bowel disease (IBD). We tested novel biomarkers to differentiate CDI from colonization in patients without (CDI-only) and with IBD (IBD-CDI).

METHODS

Samples were enzyme immunoassay (EIA)-tested for glutamate dehydrogenase (GDH) and toxin, followed by reflex PCR. Quantitative GDH [(qGDH) - a novel indicator of Clostridium difficile load] and stool lactoferrin were tested at days 0, 3 and 10 during antibiotic treatment. Samples were also analyzed for toxin B cytotoxicity neutralization assay (CNA) and toxigenic culture, gold standards to detect free toxin and virulent bacteria, respectively.

RESULTS

Forty-five symptomatic patients (28 CDI-only, 13 with Crohn's disease, 4 with ulcerative colitis) were recruited with 3 sequential samples available for 36 (21 CDI-only, 15 IBD-CDI). Thirty-nine of 45 (87%) cases were toxigenic culture-positive. In the CDI-only group, 78.6% were positive for EIA-toxin, 21.4% were PCR-positive while 82.1% were CNA-positive. In the IBD-CDI group, only one patient (6%) was EIA-toxin positive and 17.6% CNA-positive. The median qGDH level at day 0 was higher in CNA-positive patients compared to CNA-negative patients (1111 vs. 146 ng/g, P = 0.004) and dropped together with lactoferrin from day 0 to 10. CDI eradication improved symptoms in 72.2% of patients with CDI-only. In 60% of patients with IBD-CDI, eradication was ineffective, with symptoms improving in 89% of them after IBD therapy intensification.

CONCLUSION

In patients with IBD-CDI, PCR-only positivity might mainly reflect colonization rather than disease. C. difficile load by qGDH correlates with CNA-detected toxin and together with stool lactoferrin might differentiate CDI from colonization in patients with IBD.

Detection of Clostridioides difficile by Real-time PCR in Young Children Does Not Predict Disease

OBJECTIVES

Diagnosing Clostridioides difficile infections in young children with high asymptomatic colonization is challenging. We compared the frequency of C difficile detection by polymerase chain reaction (PCR) in healthy control (HC) children with those with acute gastroenteritis (AGE) and evaluated fecal-lactoferrin and organism load as possible indicators of true C difficile infection disease.

METHODS

Stool was collected from children <2 years old with AGE and from HCs. C difficile was detected by real-time PCR, and lactoferrin was measured by enzyme-linked immunosorbent assay. Clinical data were obtained via interviews and chart review. Mann-Whitney U test and χ² tests were used for group comparisons.

RESULTS

Of 524 stools collected from 524 children (250 with AGE, 274 HCs), C difficile was detected less in children with AGE (14%, 36 of 250) than in HCs (28%, 76 of 274) stools (P < .0001). Among infants <1 year old (n = 297), C difficile was detected in 18% of children with AGE versus 32% of HCs (P < .005), and among children 1 to 2 years old (n = 227), C difficile was detected in 10% of children with AGE versus 21% of HCs (P < .02). There was no significant difference in C difficile PCR cycle threshold values between children with AGE and HCs or lactoferrin levels in C difficile PCR-positive versus -negative stools.

CONCLUSIONS

HC children <2 years of age had higher rates of C difficile detection by PCR than children with AGE; C difficile detection by real-time PCR alone is not a reliable means to diagnose C difficile disease in children <2 years old.

The gut microbiome diversity of Clostridioides difficile-inoculated mice treated with vancomycin and fidaxomicin

OBJECTIVE

To investigate the effect of vancomycin and fidaxomicin on the diversity of intestinal microbiota in a mouse model of Clostridioides difficile infection.

METHODS

Mice were divided into 11 models (4 mice per model): 6 uninoculated models and 5 models inoculated with C. difficile BI/NAP1/027. Inoculated models were prepared using intraperitoneal clindamycin followed by inoculation with C. difficile BI/NAP1/027. Uninoculated and C. difficile-inoculated mice received 2 or 7 days' vancomycin or fidaxomicin. Clostridium butyricum MIYAIRI 588 probiotic and lactoferrin prebiotic were administered for 10 days to uninoculated mice. Intestinal microbiome composition was investigated by sequence analyses of bacterial 16S rRNA genes from faeces, and microbiota diversity estimated.

RESULTS

In uninoculated, untreated ('normal') mice, Clostridia (57.8%) and Bacteroidia (32.4%) accounted for the largest proportions of gut microbiota. The proportion of Clostridia was numerically reduced in C. difficile-inoculated versus normal mice. Administration of vancomycin to C. difficile-inoculated mice reduced the proportions of Bacteroidia and Clostridia, and increased that of Proteobacteria. Administration of fidaxomicin to C. difficile-inoculated mice reduced the proportion of Clostridia to a lesser extent, but increased that of Bacteroidia. Microbiota diversity was lower in C. difficile-inoculated versus normal mice (164.5 versus 349.1 operational taxonomic units (OTUs), respectively); treatment of C. difficile-inoculated mice with 7 days' vancomycin reduced diversity to a greater extent than did 7 days' fidaxomicin treatment (26.2 versus 134.2 OTUs, respectively).

CONCLUSIONS

Both C. difficile inoculation and treatment with vancomycin or fidaxomicin reduced microbiota diversity; however, dysbiosis associated with fidaxomicin was milder than with vancomycin.

The Effect of Lactoferrin and Pepsin-Treated Lactoferrin on IEC-6 Cell Damage Induced by Clostridium Difficile Toxin B

Clostridium difficile infections (CDI) have recently increased worldwide. Some CDI progress to fulminant and recurrent CDI and are associated with high mortality and morbidity. CD produces toxins A and B, which cause intestinal mucosal damage, although toxin B exhibits greater cytotoxicity. Pepsin-treated lactoferrin (PLF) is the decomposed product of lactoferrin (LF), a multifunctional glycoprotein with anti-inflammatory properties. Here, we investigate the effects of LF and PLF in toxin B-stimulated rat intestinal epithelial (IEC-6) cells. Different toxin B concentrations were added to IEC-6 cells with or without LF or PLF. Mitochondrial function and cell cytotoxicity were assessed by measuring WST-1 and LDH levels, respectively. WST-1 levels were higher in IEC-6 cells treated with toxin B and LF or PLF than in the toxin B-only control (P < 0.05). Compared with the toxin B-only control, LDH levels significantly decreased after toxin B and LF or PLF addition (P < 0.05). Wound restitution measurement using microscopy demonstrated significantly greater levels of wound restitution in cells treated with toxin B and LF or PLF than in those treated with toxin B alone after 12 h (P < 0.001). Furthermore, changes in IEC-6 cell tight junctions (TJs) were evaluated by immunofluorescence microscopy and zonula occludens-1 (ZO-1) protein expression. When LF or PLF were added to IEC-6 cells, TJ structures were maintained, and ZO-1 and occludin expression was upregulated. Taken together, these results demonstrate that LF and PLF prevent the cytotoxicity of toxin B and might have the potential to control CDI.

Novel therapies and preventative strategies for primary and recurrent Clostridium difficile infections

Clostridium difficile is the leading infectious cause of antibiotic-associated diarrhea and colitis. C. difficile infection (CDI) places a heavy burden on the healthcare system, with nearly half a million infections yearly and an approximate 20% recurrence risk after successful initial therapy. The high incidence has driven new research on improved prevention such as the emerging use of probiotics, intestinal microbiome manipulation during antibiotic therapies, vaccinations, and newer antibiotics that reduce the disruption of the intestinal microbiome. While the treatment of acute C. difficile is effective in most patients, it can be further optimized by adjuvant therapies that improve the initial treatment success and decrease the risk of subsequent recurrence. Finally, the high risk of recurrence has led to multiple emerging therapies that target toxin activity, recovery of the intestinal microbial community, and elimination of latent C. difficile in the intestine. In summary, CDIs illustrate the complex interaction among host physiology, microbial community, and pathogen that requires specific therapies to address each of the factors leading to primary infection and recurrence.

Clostridioides (Clostridium) difficile infection: current and alternative therapeutic strategies

Clostridioides difficile (C. difficile) has become a pathogen of worldwide importance considering that epidemic strains are disseminated in hospitals of several countries, where community-acquired infections act as a constant source of new C. difficile strains into hospitals. Despite the advances in the treatment of infections, more effective therapies against C. difficile are needed but, at the same time, these therapies should be less harmful to the resident gastrointestinal microbiota. The purpose of this review is to present a description of issues associated to C. difficile infection, a summary of current therapies and those in developmental stage, and a discussion of potential combinations that may lead to an increased efficacy of C. difficile infection treatment.

Diagnostic Guidance for C. difficile Infections

Diagnosis of Clostridium difficile infection (CDI) can be challenging. First of all, there has been debate on which of the two reference assays, cell cytotoxicity neutralization assay (CCNA) or toxigenic culture (TC) should be considered the gold standard for CDI detection. Although the CCNA suffers most from suboptimal storage conditions and subsequent toxin degradation, TC is reported to falsely increase CDI detection rates as it cannot differentiate CDI patients from patients asymptomatically colonised by toxigenic C. difficile. Several rapid assays are available for CDI detection and fall into three broad categories: (1) enzyme immunoassays for glutamate dehydrogenase, (2) enzyme immunoassays for toxins A/B and (3) nucleic acid amplification tests detecting toxin genes. All three categories have their own limitations, being suboptimal specificity and/or sensitivity or the inability to discern colonised patients from CDI patients. In light of these limitations, multi-step algorithmic testing has now been advocated by international guidelines in order to optimize diagnostic accuracy. Despite these recommendations, testing methods between hospitals vary widely, which impacts CDI incidence rates. CDI incidence rates are also influenced by sample selection criteria, as several studies have shown that if not all unformed stool samples are tested for CDI, many cases may be missed due to an absence of clinical suspicion. Since methods for diagnosing CDI remain imperfect, there has been a growing interest in alternative testing strategies like faecal biomarkers, immune modulating interleukins, cytokines and imaging methods. At the moment, these alternative methods might play an adjunctive role, but they are not suitable to replace conventional CDI testing strategies.

Current knowledge on the laboratory diagnosis of Clostridium difficile infection

Clostridium difficile (C. difficile) is a spore-forming, toxin-producing, gram-positive anaerobic bacterium that is the principal etiologic agent of antibiotic-associated diarrhea. Infection with C. difficile (CDI) is characterized by diarrhea in clinical syndromes that vary from self-limited to mild or severe. Since its initial recognition as the causative agent of pseudomembranous colitis, C. difficile has spread around the world. CDI is one of the most common healthcare-associated infections and a significant cause of morbidity and mortality among older adult hospitalized patients. Due to extensive antibiotic usage, the number of CDIs has increased. Diagnosis of CDI is often difficult and has a substantial impact on the management of patients with the disease, mainly with regards to antibiotic management. The diagnosis of CDI is primarily based on the clinical signs and symptoms and is only confirmed by laboratory testing. Despite the high burden of CDI and the increasing interest in the disease, episodes of CDI are often misdiagnosed. The reasons for misdiagnosis are the lack of clinical suspicion or the use of inappropriate tests. The proper diagnosis of CDI reduces transmission, prevents inadequate or unnecessary treatments, and assures best antibiotic treatment. We review the options for the laboratory diagnosis of CDI within the settings of the most accepted guidelines for CDI diagnosis, treatment, and prevention of CDI.

A Review of Experimental and Off-Label Therapies for Clostridium difficile Infection

In spite of increased awareness and the efforts taken to optimize Clostridium difficile infection (CDI) management, with the limited number of currently available antibiotics for C. difficile the halt of this increasing epidemic remains out of reach. There are, however, close to 80 alternative treatment methods with controversial anti-clostridial efficacy or in experimental phase today. Indeed, some of these therapies are expected to become acknowledged members of the recommended anti-CDI arsenal within the next few years. None of these alternative treatment methods can respond in itself to all the major challenges of CDI management, which are primary prophylaxis in the susceptible population, clinical cure of severe cases, prevention of recurrences, and forestallment of asymptomatic C. difficile carriage and in-hospital spread. Yet, the greater the variety of treatment choices on hand, the better combination strategies can be developed to reach these goals in the future. The aim of this article is to provide a comprehensive summary of these experimental and currently off-label therapeutic options.

Occurrence of Clostridium difficile ribotype 027 in hospitals of Silesia, Poland

Clostridium difficile is an important healthcare-associated pathogen, responsible for a broad spectrum of diarrheal diseases. The aim of this prospective study was to determine the occurrence of C. difficile infection (CDI), to characterize cultured C. difficile strains and to investigate the association of fecal lactoferrin with CDI. Between January 2013 and June 2014, 148 stool samples were obtained from adult diarrheal patients (C. difficile as a suspected pathogen) hospitalized in different healthcare facilities of 15 Silesian hospitals. Out of 134 isolated C. difficile strains, 108 were ribotyped: 82.4% belonged to Type 027, 2.8% to Type 176, 2.8% to Type 014, 1.9% to Type 010 and 0.9% to Types 001, 018, 020 and 046 each. In total, 6.5% non-typable strains were identified. All Type 027 isolates contained both toxin genes tcdA & tcdB, and binary toxin genes (cdtA &cdtB). Susceptibility testing revealed that all Type 027 isolates were sensitive to metronidazole and vancomycin and resistant to moxifloxacin, ciprofloxacin, imipenem and erythromycin. Of 89 Type 027 strains, 16 had a ermB (688 bp) gene coinciding with high levels of erythromycin resistance (MIC >256 μg/mL). Of 16 ermB positive strains, 14 demonstrated also high level of resistance to clindamycin (>256 μg/mL). A significant difference (p = 0.004) in lactoferrin level was found between C. difficile toxin-positive (n = 123; median 185.9 μg/mL; IQR 238.8) and toxin-negative (n = 25; median 22.4 μg/mL; IQR 141.7) fecal samples. Stool samples from n = 89 patients with CDI caused by Type 027 demonstrated significantly higher (p = 0.03) lactoferrin level (median 173.0 μg/mL; IQR 237.3) than from patients with CDI caused by other ribotypes and non-typable C. difficile strains (median 189.4 μg/mL; IQR 190.8).

Fecal Calprotectin Level Reflects the Severity of Clostridium difficile Infection

Clostridium difficile is a significant nosocomial and community-acquired pathogen, and is the leading cause of antibiotic-induced diarrhea associated with high morbidity and mortality. Given that the treatment outcome depends on the severity of C. difficile infection (CDI), we aimed to establish an efficient method of assessing severity, and focused on the stool biomarker fecal calprotectin (FC). FC directly reflects the intestinal inflammation status of a patient, and can aid in interpreting the current guidelines, which requires the integration of indirect laboratory parameters. The distinction of 80 patients with CDI versus 71 healthy controls and 30 severe infection cases versus 50 mild cases was possible using FC as a marker. The area under the receiver operating characteristic curves were 0.821 and 0.746 with a sensitivity of 75% and 70% and specificity of 79% and 80%, for severe versus mild cases, respectively. We suggest FC as a predictive marker for assessing CDI severity, which is expected to improve the clinical management of CDI.

Potential of lactoferrin to prevent antibiotic-induced Clostridium difficile infection

Objectives

Clostridium difficile infection (CDI) is a global healthcare problem. Recent evidence suggests that the availability of iron may be important for C. difficile growth. This study evaluated the comparative effects of iron-depleted (1% Fe³⁺ saturated) bovine apo-lactoferrin (apo-bLf) and iron-saturated (85% Fe³⁺ saturated) bovine holo-lactoferrin (holo-bLf) in a human in vitro gut model that simulates CDI.

Methods

Two parallel triple-stage chemostat gut models were inoculated with pooled human faeces and spiked with C. difficile spores (strain 027 210, PCR ribotype 027). Holo- or apo-bLf was instilled (5 mg/mL, once daily) for 35 days. After 7 days, clindamycin was instilled (33.9 mg/L, four times daily) to induce simulated CDI. Indigenous microflora populations, C. difficile total counts and spores, cytotoxin titres, short chain fatty acid concentrations, biometal concentrations, lactoferrin concentration and iron content of lactoferrin were monitored daily.

Results

In the apo-bLf model, germination of C. difficile spores occurred 6 days post instillation of clindamycin, followed by rapid vegetative cell proliferation and detectable toxin production. By contrast, in the holo-bLf model, only a modest vegetative cell population was observed until 16 days post antibiotic administration. Notably, no toxin was detected in this model. In separate batch culture experiments, holo-bLf prevented C. difficile vegetative cell growth and toxin production, whereas apo-bLf and iron alone did not.

Conclusions

Holo-bLf, but not apo-bLf, delayed C. difficile growth and prevented toxin production in a human gut model of CDI. This inhibitory effect may be iron independent. These observations suggest that bLf in its iron-saturated state could be used as a novel preventative or treatment strategy for CDI.

The contribution of strains and hosts to outcomes in Clostridium difficile infection

Acquisition of Clostridium difficile spores can be followed by a spectrum of clinical outcomes ranging from asymptomatic transit through the bowel to severe colitis and death. This clinical variability is a product of bacterial virulence and host susceptibility to the pathogen. It is important to identify patients at high risk of poor outcome so that increased monitoring and optimal treatment strategies can be instigated. This article discusses the evidence linking strain type to clinical outcome, including the importance of toxin and nontoxin virulence factors. It reviews host factors and their relationship with C difficile infection susceptibility, recurrence, and mortality.

The molecular basis of Clostridium difficile disease and host response

PURPOSE OF REVIEW

Clostridium difficile infection (CDI) ranges from asymptomatic colonization to severe colitis and death. The physiologic and molecular mechanisms determining disease outcome are thus far poorly understood. Here, we review recent advances in the relationship between host response to infection and disease outcome. Furthermore, we review recent studies on the relationship between intestinal microbial ecology and pathogenesis of CDI.

RECENT FINDINGS

Severe CDI is characterized by toxin-induced epithelial injury and marked intestinal inflammation. Recent studies demonstrate that systemic markers of inflammation correlate with disease outcome. Peripheral neutrophil count, C-reactive protein, and proinflammatory cytokines are elevated in patients with severe disease as compared with asymptomatic controls. Furthermore, fecal inflammatory biomarkers are better predictors of disease severity and diarrhea persistence than C. difficile abundance. A landmark study reported higher than 80% success rate of fecal microbiota transplantation for treatment of recurrent CDI. The commensal microbes responsible for C. difficile protection, and the molecular basis by which microbial ecology impacts disease outcome, are under active investigation.

SUMMARY

Under conditions of altered microbial ecology, C. difficile incites epithelial injury and marked intestinal inflammation, the primary determinant of disease outcome. Restoration of a diverse intestinal microbial population by fecal microbiota transplantation attenuates disease and prevents recurrence by mechanisms that are yet to be fully elucidated.

Calprotectin and lactoferrin faecal levels in patients with Clostridium difficile infection (CDI): a prospective cohort study

Measurement of both calprotectin and lactoferrin in faeces has successfully been used to discriminate between functional and inflammatory bowel conditions, but evidence is limited for Clostridium difficile infection (CDI). We prospectively recruited a cohort of 164 CDI cases and 52 controls with antibiotic-associated diarrhoea (AAD). Information on disease severity, duration of symptoms, 30-day mortality and 90-day recurrence as markers of complicated CDI were recorded. Specimens were subject to microbiological culture and PCR-ribotyping. Levels of faecal calprotectin (FC) and lactoferrin (FL) were measured by ELISA. Statistical analysis was conducted using percentile categorisation. ROC curve analysis was employed to determine optimal cut-off values. Both markers were highly correlated with each other (r² = 0.74) and elevated in cases compared to controls (p<0.0001; ROC>0.85), although we observed a large amount of variability across both groups. The optimal case-control cut-off point was 148 mg/kg for FC and 8.1 ng/µl for FL. Median values for FL in CDI cases were significantly greater in patients suffering from severe disease compared to non-severe disease (104.6 vs. 40.1 ng/µl, p = 0.02), but were not significant for FC (969.3 vs. 512.7 mg/kg, p = 0.09). Neither marker was associated with 90-day recurrence, prolonged CDI symptoms, positive culture results and colonisation by ribotype 027. Both FC and FL distinguished between CDI cases and AAD controls. Although FL was associated with disease severity in CDI patients, this showed high inter-individual variability and was an isolated finding. Thus, FC and FL are unlikely to be useful as biomarkers of complicated CDI disease.

Ribotype 027 Clostridium difficile infections with measurable stool toxin have increased lactoferrin and are associated with a higher mortality

We evaluated clinical and diagnostic indicators of severe C. difficile infection (CDI) and their association with poor clinical outcome. A total of 210 patients positive according to PCR (toxin B: tcdB) were included, with patients having a median age of 62 years and a Charlson co-morbidity index (CI) score of 5. Ninety-one percent (n = 191) were positive by toxigenic culture and 61 % (n = 129) had stool toxin. Toxin-positive patients had significantly higher fecal lactoferrin (mean 316 μg/g versus 106 μg/g stool; p < 0.0001). Forty percent of patients (n = 85) were infected with ribotype 027 and significantly more of these patients had measurable stool toxin (79 % vs. 50 %; p < 0.0001). The mean fecal lactoferrin was significantly higher for toxin-positive 027 CDI compared with the 027 toxin-negative group (317 vs 60 μg/g; p = 0.0014). Ribotype 027 CDI with stool toxin showed a higher all-cause, 100-day mortality compared with non-027 with stool toxin (36 % vs 18 %; p = 0.017). Logistic regression univariate analysis for odds ratio (OR) and p values revealed that age (OR = 1.1), intensive care unit treatment (OR = 2.7), CI (OR = 1.2), 027 CDI (OR = 2.1), white blood cell count (OR = 1.0), albumin level (OR = 0.1), and stool toxin-positive 027 CDI (OR = 2.5) were significantly associated with 100-day mortality (p < 0.05). In conclusion, CDI PCR-positive patients with 027 infection and stool toxin have increased lactoferrin and are at an increased risk of death.

Quantitative Fecal Lactoferrin as a Biomarker for Severe Clostridium difficile Infection in Hospitalized Patients

BACKGROUND

The incidence and severity of Clostridium difficile infection (CDI) have increased over the past decade, especially among hospitalized patients. In this study, we determined the value of published criteria for severe CDI in predicting 3 month mortality, as well as the utility of fecal lactoferrin as a biomarker for severe CDI.

METHODS

Pilot Year 1 of IRB approved (HSR-IRB# 13630) prospective cohort study of hospitalized patients with CDI at US academic medical center (10/08-4/10). Medical records of hospitalized patients with clinically diagnosed CDI, via toxin assay, were evaluated to objectively define severe CDI based on current guidelines. A stool sample from CDI diagnosis was analyzed for amount of fecal lactoferrin (IBD-SCAN, TechLab, Inc.). Data was analyzed using SPSS for student's t-test and chi-squared, significance p ≤ 0.05.

RESULTS

79 subjects consented and enrolled, mean age was 64 years (standard deviation, sd, 17.2), 48 (61%) female, and average Charlson co-morbidity score was 5.8 (sd 3.8). Subjects with severe CDI were 5 times more likely to die within 3 months of diagnosis (Odds Ratio 5.66 (95% Confidence Interval 2.03-15.79), p=0.001) and had significantly more fecal lactoferrin (580.0 (sd 989.0) vs. 181.7 (sd 244.2) µg/mL, p=0.018), compared to those that did not meet severe CDI criteria.

CONCLUSION

In this pilot study, subjects who meet defined criteria for severe CDI had higher mortality and more intestinal inflammation. These preliminary results were, however, underpowered to show a direct association of lactoferrin with mortality. Larger cohort studies are needed to optimize a criterion for severe CDI and evaluate a direct association of lactoferrin and mortality in hospitalized patients with CDI.