Natural Clostridioides difficile Toxin Immunization in Colonized Infants

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.

Understanding the influence of the microbiome on childhood infections

INTRODUCTION

The microbiome is known to have a substantial impact on human health and disease. However, the impacts of the microbiome on immune system development, susceptibility to infectious diseases, and vaccine-elicited immune responses are emerging areas of interest.

AREAS COVERED

In this review, we provide an overview of development of the microbiome during childhood. We highlight available data suggesting that the microbiome is critical to maturation of the immune system and modifies susceptibility to a variety of infections during childhood and adolescence, including respiratory tract infections, Clostridioides difficile infection, and sexually transmitted infections. We discuss currently available and investigational therapeutics that have the potential to modify the microbiome to prevent or treat infections among children. Finally, we review the accumulating evidence that the gut microbiome influences vaccine-elicited immune responses among children.

EXPERT OPINION

Recent advances in sequencing technologies have led to an explosion of studies associating the human microbiome with the risk and severity of infectious diseases. As our knowledge of the extent to which the microbiome influences childhood infections continues to grow, microbiome-based diagnostics and therapeutics will increasingly be incorporated into clinical practice to improve the prevention, diagnosis, and treatment of infectious diseases among children.

Incidence and risk factors for recurrent Clostridioides difficile infection in pediatric at-risk groups in selected Pediatric Investigators Collaborative Network on Infections in Canada (PICNIC) hospitals

OBJECTIVES

Incidence and risk factors for recurrent Clostridioides difficile infection (rCDI) are well established in adults, though data are lacking in pediatrics. We aimed to determine incidence of and risk factors for rCDI in pediatrics.

METHODS

This retrospective cohort study of pediatric patients was conducted at 3 tertiary-care hospitals in Canada with laboratory-confirmed CDI between April 1, 2012, and March 31, 2017. rCDI was defined as an episode of CDI occurring 8 weeks or less from diagnostic test date of the primary episode. We used logistic regression to determine and quantify risk factors significantly associated with rCDI.

RESULTS

In total, 286 patients were included in this study. The incidence proportion for rCDI was 12.9%. Among hospitalized patients, the incidence rate was estimated at 2.6 cases of rCDI per 1,000 hospital days at risk (95% confidence interval [CI], 1.7-3.9). Immunocompromised patients had higher incidence of rCDI (17.5%; P = .03) and higher odds of developing rCDI independently of antibiotic treatment given for the primary episode (odds ratio [OR], 2.31; 95% CI, 1.12-5.09). Treatment with vancomycin monotherapy did not show statistically significant protection from rCDI, independently of immunocompromised status (OR, 0.33; 95% CI, 0.05-1.15]).

CONCLUSIONS

The identification of increased risk of rCDI in immunocompromised pediatric patients warrants further research into alternative therapies, prophylaxis, and prevention strategies to prevent recurrent disease burden within these groups. Treatment of the initial episode with vancomycin did not show statistically significant protection from rCDI.

Clostridioides difficile Infection in Children: Recent Updates on Epidemiology, Diagnosis, Therapy

Clostridioides (formerly Clostridium) difficile is the most important infectious cause of antibiotic-associated diarrhea worldwide and a leading cause of healthcare-associated infection in the United States. The incidence of C. difficile infection (CDI) in children has increased, with 20 000 cases now reported annually, also posing indirect educational and economic consequences. In contrast to infection in adults, CDI in children is more commonly community-associated, accounting for three-quarters of all cases. A wide spectrum of disease severity ranging from asymptomatic carriage to severe diarrhea can occur, varying by age. Fulminant disease, although rare in children, is associated with high morbidity and even fatality. Diagnosis of CDI can be challenging as currently available tests detect either the presence of organism or disease-causing toxin but cannot distinguish colonization from infection. Since colonization can be high in specific pediatric groups, such as infants and young children, biomarkers to aid in accurate diagnosis are urgently needed. Similar to disease in adults, recurrence of CDI in children is common, affecting 20% to 30% of incident cases. Metronidazole has long been considered the mainstay therapy for CDI in children. However, new evidence supports the safety and efficacy of oral vancomycin and fidaxomicin as additional treatment options, whereas fecal microbiota transplantation is gaining popularity for recurrent infection. Recent advancements in our understanding of emerging epidemiologic trends and management of CDI unique to children are highlighted in this review. Despite encouraging therapeutic advancements, there remains a pressing need to optimize CDI therapy in children, particularly as it pertains to severe and recurrent disease.

Clostridioides difficile infection in infants: a case report and literature review

BACKGROUND

Clostridioides difficile (C. difficile) is the major pathogen causing antibiotic-associated diarrhea. There are a variety of symptoms associated with C. difficile infection (CDI) in adults, including self-limiting diarrhea, pseudomembranous colitis, toxic megacolon, septic shock, and even death from the infection. However, the infant's intestine appears to be completely resistant to the effects of C. difficile toxins A and B with rare development of clinical symptoms.

CASE PRESENTATION

In this study, we reported a 1-month-old girl with CDI who was born with neonatal hypoglycemia and necrotizing enterocolitis. Her symptom of diarrhea occurred after extensive use of broad-spectrum antibiotics during hospitalization and was accompanied by elevated white blood cell, platelet, and C-reactive protein levels, and repeated routine stool examinations were abnormal. She was recovered by norvancomycin (an analogue of vancomycin) and probiotic treatment. The results of 16 S rRNA gene sequencing also demonstrated the recovery of intestinal microbiota with the enrichment of Firmicutes and Lactobacillus.

CONCLUSIONS

Based on the literature review and this case report, clinicians should also pay attention to diarrhea caused by C. difficile in infants and young children. More strong evidence is needed to explain the true prevalence of CDI in this population and to better understand the C. difficile-associated diarrhea in infants.

Intestinal bile acids provide a surmountable barrier against C. difficile TcdB-induced disease pathogenesis

Intestinal bile acids play an essential role in the Clostridioides difficile lifecycle having been shown in vitro to modulate various aspects of pathogenesis, including spore germination, vegetative growth, and more recently the action of the primary virulence determinant, TcdB. Here, we investigated whether physiological levels of the total pool of intestinal bile acids in mice and humans protect against TcdB action. Small molecules extracted from the lumenal contents of the small intestine, cecum, colon, and feces were found to inhibit TcdB in accordance with the differential amounts of total bile acids in each compartment. Extracts from antibiotic-treated and germ-free mice, despite harboring dramatically altered bile acid profiles, unexpectedly also prevented TcdB-induced cell rounding to similar extents. We show that protection, however, is surmountable and can be overcome at higher doses of TcdB-typical to those seen during severe C. difficile infection-suggesting that the protective properties of intestinal bile acids are operant primarily under low to moderate toxin levels. Taken together, these findings demonstrate a role for intestinal bile acids in attenuating virulence, provide insights into asymptomatic carriage of toxigenic C. difficile, and inform strategies to manipulate bile acid levels for therapeutic benefit.

Stool Interleukin-1β Differentiates Clostridioides difficile Infection (CDI) From Asymptomatic Carriage and Non-CDI Diarrhea

BACKGROUND

Despite advances in the understanding and diagnosis of Clostridioides difficile infection (CDI), clinical distinction within the colonization-infection continuum remains an unmet need.

METHODS

By measuring stool cytokines and antitoxin antibodies in well-characterized cohorts of CDI (diarrhea, nucleic acid amplification test [NAAT] positive), non-CDI diarrhea (NCD; diarrhea, NAAT negative), asymptomatic carriers (ASC; no diarrhea, NAAT positive) and hospital controls (CON; no diarrhea, NAAT negative), we aim to discover novel biological markers to distinguish between these cohorts. We also explore the relationship of these stool cytokines and antitoxin antibody with stool toxin concentrations and disease severity.

RESULTS

Stool interleukin (IL) 1β, stool immunoglobulin A (IgA), and immunoglobulin G (IgG) anti-toxin A had higher (P < .0001) concentrations in CDI (n = 120) vs ASC (n = 43), whereas toxins A, B, and fecal calprotectin did not. Areas under the receiver operating characteristic curve (ROC-AUCs) for IL-1β, IgA, and IgG anti-toxin A were 0.88, 0.83, and 0.83, respectively. A multipredictor model including IL-1β and IgA anti-toxin A achieved an ROC-AUC of 0.93. Stool IL-1β concentrations were higher in CDI compared to NCD (n = 75) (P < .0001) and NCD + ASC+ CON (CON, n = 75) (P < .0001), with ROC-AUCs of 0.83 and 0.86, respectively. Stool IL-1β had positive correlations with toxins A (ρA = +0.55) and B (ρB = +0.49) in CDI (P < .0001) but not in ASC (P > .05).

CONCLUSIONS

Stool concentrations of the inflammasome pathway, proinflammatory cytokine IL-1β, can accurately differentiate CDI from asymptomatic carriage and NCD, making it a promising biomarker for CDI diagnosis. Significant positive correlations exist between stool toxins and stool IL-1β in CDI but not in asymptomatic carriers.

Epidemiological and microbiome associations of Clostridioides difficile carriage in infancy and early childhood

There has been an increase in the prevalence of Clostridioides difficile (C. diff) causing significant economic impact on the health care system. Although toxigenic C. diff carriage is recognized in infancy, there is limited data regarding its longitudinal trends, associated epidemiolocal risk factors and intestinal microbiome characteristics. The objectives of our longitudinal cohort study were to investigate temporal changes in the prevalence of toxigenic C.diff colonization in children up to 2 years, associated epidemiological and intestinal microbiome characteristics. Pregnant mothers were enrolled prenatally, and serial stool samples were collected from their children for 2 years. 2608 serial stool samples were collected from 817 children. 411/817 (50%) were males, and 738/817 (90%) were born full term. Toxigenic C.diff was detected in 7/569 (1%) of meconium samples, 116/624 (19%) of 2 m (month), 221/606 (37%) of 6 m, 227/574 (40%) of 12 m and 18/235 (8%) of 24 m samples. Infants receiving any breast milk at 6 m were less likely to be carriers at 2 m, 6 m and 12 m than those not receiving it. (p = 0.002 at 2 m, p < 0.0001 at 6 m, p = 0.022 at 12 m). There were no robust differences in the underlying alpha or beta diversity between those with and without toxigenic C. diff carriage at any timepoint, although small differences in the relative abundance of certain taxa were found. In this largest longitudinal cohort study to date, a high prevalence of toxigenic C. diff carrier state was noted. Toxigenic C. diff carrier state in children is most likely a transient component of the dynamic infant microbiome.

Gut Microbiota Composition Associated with Clostridioides difficile Colonization and Infection

Clostridioides difficile is an anaerobic Gram-positive and spore-forming bacterium. The majority of C. difficile strains produce two toxins, A and B, associated with the development of acute diarrhea and/or colitis. In this review, two situations are distinguished: C. difficile infection (CDI) and asymptomatic colonization (AC). The main objective of this review is to explore the available data related to the link between the gut microbiota and the development of CDI. The secondary aim is to provide more information on why some people colonized with toxigenic C. difficile develop an infection while others show no signs of disease. Several factors, such as the use of antibiotics and proton pump inhibitors, hospitalization, and age, predispose individuals to C. difficile colonization and/or C. difficile infection. The gut microbiota of people with AC showed decreased abundances of Prevotella, Alistipes, Bacteroides, Bifidobacterium, Dorea, Coprococcus, and Roseburia. The gut microbiota of people suffering from CDI showed reductions in the abundances of Lachnospiraceae, Ruminococcaceae, Blautia spp., Prevotella spp., Dialister spp., Bifidobacterium spp., Roseburia spp., Anaerostipes spp., Faecalibacterium spp. and Coprococcus spp., in comparison with healthy people. Furthermore, increases in the abundances of Enterococcaceae and Enterococcus were associated with C. difficile infection.

Pathobionts: mechanisms of survival, expansion, and interaction with host with a focus on Clostridioides difficile

Pathobionts are opportunistic microbes that emerge as a result of perturbations in the healthy microbiome due to complex interactions of various genetic, exposomal, microbial, and host factors that lead to their selection and expansion. Their proliferations can aggravate inflammatory manifestations, trigger autoimmune diseases, and lead to severe life-threatening conditions. Current surge in microbiome research is unwinding these complex interplays between disease development and protection against pathobionts. This review summarizes the current knowledge of pathobiont emergence with a focus on Clostridioides difficile and the recent findings on the roles of immune cells such as iTreg cells, Th17 cells, innate lymphoid cells, and cytokines in protection against pathobionts. The review calls for adoption of innovative tools and cutting-edge technologies in clinical diagnostics and therapeutics to provide insights in identification and quantification of pathobionts.

Clostridioides difficile and the Microbiota Early in Life

Clostridioides difficile is a spore-forming, obligate anaerobe, and ubiquitous nosocomial pathogen. While C. difficile infection in adults causes a spectrum of disease, including pseudomembranous colitis and toxic megacolon, healthy infants are asymptomatically colonized at high rates. The mechanisms leading to high colonization rates and infant protection from C. difficile are currently unknown; however, the ecology and metabolic state of the intestinal microbiome are factors known to influence C. difficile pathogenesis. In this review, we will examine the aspects of the early-life microbiome that may contribute to the incidence of C. difficile and protection from disease manifestation in infants. We will also discuss whether features of the adult microbiota that enable and restrict C. difficile are prevalent during early-life colonization.

Translational Aspects of the Immunology of Clostridioides difficile Infection: Implications for Pediatric Populations

Clostridioides difficile has become the most common healthcare-associated pathogen in the United States, leading the US Centers for Disease Control and Prevention (CDC) to classify C. difficile as an "urgent" public health threat that requires "urgent and aggressive action." This call to action has led to new discoveries that have advanced our understanding of Clostridioides difficile infection (CDI) immunology and clinical development of immunologic-based therapies for CDI prevention. However, CDI immunology research has been limited in pediatric populations, and several unanswered questions remain regarding the function of host immune response in pediatric CDI pathogenesis and the potential role of immunologic-based therapies in children. This review summarizes the innate and adaptive immune responses previously characterized in animals and humans and provides a current update on clinical development of immunologic-based therapies for CDI prevention in adults and children. These data inform the future research needs for children.

Prevalence of Detection of Clostridioides difficile Among Asymptomatic Children: A Systematic Review and Meta-analysis

IMPORTANCE

Detection of Clostridioides difficile has frequently been described in asymptomatic infants and children, but accurate estimates across the age spectrum are unavailable.

OBJECTIVE

To assess the prevalence of C difficile detection among asymptomatic children across the age spectrum.

DATA SOURCES

This systematic review and meta-analysis included a search of the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, CINAHL, Scopus, and Web of Science for articles published from January 1, 1990, to December 31, 2020. Search terms included Clostridium difficile, Peptoclostridium difficile, Clostridioides difficile, CDF OR CDI OR c diff OR c difficile, Clostridium infections OR cd positive diarrhea OR cd positive diarrhea OR Clostridium difficile OR Peptoclostridium difficile OR pseudomembranous colitis OR pseudomembranous enterocolitis, enterocolitis, and pseudomembranous. These were combined with the following terms: bacterial colonization and colonization OR colonized OR colonizing OR epidemiology OR prevalence OR seroprevalence.

STUDY SELECTION

Studies were screened independently by 2 authors. Studies were included if they reported testing for C difficile among asymptomatic children (ie, children without diarrhea) younger than 18 years.

DATA EXTRACTION AND SYNTHESIS

Data were extracted independently and in duplicate by 2 reviewers. Preferred Reporting Items for a Systematic Review and Meta-analysis (PRISMA) guidelines were used. Data were pooled using a random-effects model.

MAIN OUTCOMES AND MEASURES

The primary outcome was prevalence of C difficile detection among asymptomatic children. Secondary outcomes included prevalence of toxigenic vs nontoxigenic strains of C difficile and prevalence of C difficile detection stratified by geographic region, income status, testing method, and year of testing.

RESULTS

A total of 95 studies with 19 186 participants were included. Rates of detection of toxigenic or nontoxigenic C difficile were greatest among infants aged 6 to 12 months (41%; 95% CI, 32%-50%) and decreased to 12% (95% CI, 7%-18%) among children aged 5 to 18 years. The prevalence of toxigenic C difficile colonization was lower, peaking at 14% (95% CI, 8%-21%) among infants aged 6 to 12 months and decreasing to 6% (95% CI, 2%-11%) among children older than 5 years. Although prevalence differed by geographic region (ie, North and South America vs Europe: β, -0.151, P = .001; North and South America vs Western Pacific: β, 0.136, P = .007), there was no difference by testing method (ie, culture vs polymerase chain reaction: β, 0.069, P = .052; culture vs enzyme immunoassay: β, -0.178, P = .051), income class (low-middle income vs high income: β, -0.144, P = .23; upper-middle vs high income: β, -0.020, P = .64), or period (before 1990 vs 2010-2020: β, -0.125, P = .19; 1990-1999 vs 2010-2020: β, -0.037, P = .42; 2000-2009 vs 2010-2020: β, -0.006, P = .86).

CONCLUSIONS AND RELEVANCE

In this systematic review and meta-analysis, C difficile colonization rates among children were greatest at 6 to 12 months of age and decreased thereafter. These estimates may provide context for interpreting C difficile test results among young children.

Recent advances in Clostridioides difficile infection epidemiology, diagnosis and treatment in children

PURPOSE OF REVIEW

The US Centers for Disease Control and Prevention (CDC) classified Clostridioides difficile as an 'urgent' public health threat that requires 'urgent and aggressive action'. This call to action has led to new discoveries that have advanced C. difficile infection (CDI) epidemiology, diagnosis and treatment, albeit predominantly in adults. In 2017, the Infectious Diseases Society of America and Society for Healthcare Epidemiology of America published clinical practice guidelines for both adults and children. At that time, recommendations in children were generally limited to relatively low-quality evidence.

RECENT FINDINGS

Since publication of this guidance, there have been many advancements in the understanding of CDI in children. These include better understanding of healthcare settings as uncommon sources of C. difficile acquisition in children; risk factors for recurrent and community-associated CDI; performance of diagnostic tests in children and strategies for optimizing their use; and a more rigorous evidence base for CDI treatment in children, including the first-ever randomized controlled trial of CDI treatment in children and the largest study of fecal microbiota transplantation in children.

SUMMARY

This review highlights the most recent salient advancements in paediatric CDI knowledge and practice that supplement published clinical guidance provided prior to these advancements.

Humoral Immune Response to Clostridioides difficile Toxins A and B in Hospitalized Immunocompromised Patients With C difficile Infection

Background

The humoral immune response to Clostridioides difficile toxins in C difficile infection (CDI) is incompletely characterized in immunocompromised hosts (ICHs).

Methods

We conducted a prospective study of hospitalized adults with CDI, with and without immunosuppression (hematologic malignancy, active solid tumor, solid organ or stem cell transplant, inflammatory bowel disease, autoimmune disease, congenital or acquired immunodeficiency, asplenia, chronic receipt of high-dose steroids, or receipt of immunosuppressing medications within 12 months). Serum and stool antibody concentrations of immunoglobulin (Ig)M, IgG, and IgA to C difficile toxins A and B at treatment days 0, 3, and 10–14 were compared.

Results

Ninety-eight subjects (47 ICH; 51 non-ICH) were enrolled. Baseline serum antitoxin A and B antibody levels were similar. At day 3, ICHs demonstrated lower serum levels of antitoxin A IgG, antitoxin A IgA, and antitoxin B IgA (all P < .05). At day 10–14, lower antitoxin A IgG concentrations were observed in ICHs (ICH, 21 enzyme-linked immunosorbent assay [ELISA] units; interquartile range [IQR], 16.4–44.6) compared with non-ICH subjects (49.0 ELISA units; IQR, 21.5–103; P = .045). In stool, we observed lower concentrations of antitoxin B IgA antibodies at baseline and at day 3 for ICH subjects, with a notable difference in concentrations of antitoxin B IgA at day 3 (ICH, 6.7 ELISA units [IQR, 1.9–13.9] compared with non-ICH, 18.1 ELISA units [IQR, 4.9–31.7]; P = .003).

Conclusions

The ICHs with CDI demonstrated lower levels of C difficile antitoxin antibodies in serum and stool during early CDI therapy compared with non-ICHs. These data provide insight into the humoral response to CDI in ICHs.

Review and Commentary on the Importance of Bile Acids in the Life Cycle of Clostridioides difficile in Children and Adults

Clostridioides difficile, a spore-forming anaerobe, resides in the intestine. The life cycle of C. difficile illustrates an interdependent relationship between bile acids, commensal microbiota, and C. difficile. Primary bile acids are critical for the germination of C. difficile spores in the small intestine, while secondary bile acids serve as a counterbalance to inhibit the growth of the organism in the colon. Many commensal bacteria especially Clostridium spp. are responsible for transforming primary bile acids into secondary bile acids. Antibiotics eliminate bacteria that convert primary bile acids into secondary bile acids and, thus, allow C. difficile to flourish and cause diarrhea. In children younger than 2 years of age, who normally only produce primary bile acids, colonization with toxin-producing C. difficile is exceedingly common. The reason for the absence of C. difficile diarrhea in the children remains unexplained.

Transmission of Clostridioides difficile infection (CDI) from patients less than 3 years of age in a pediatric oncology setting

Clostridioides difficile infection (CDI) is prevalent in pediatric oncology patients, but the transmission risk to peers is unknown. In 224 children with CDI, multilocus sequence typing (MLST) identified only 7 alleged transmission events (18%) originating from children <3 years old. None of these events were corroborated by WGS.

Carriage of Clostridioides difficile in healthy infants in the community of Handan, China: A 1-year follow-up study

OBJECTIVE

Clostridioides difficile may colonize healthy infants and young children asymptomatically and for the long-term. C. difficile genotypes and the rate and determinants of colonization differ substantially and vary among countries and regions. A 1-year follow-up study was performed to determine the incidence, kinetics and influencing factors of C. difficile intestinal colonization.

METHODS

Twenty-nine healthy infants (14 girls and 15 boys) living at home with their parents in Handan City were followed by survey from birth to 1 year of age, specifically from October 2014 through December 2015. C. difficile isolates were typed by PCR ribotyping and analyzed for the presence of toxin genes.

RESULTS

During the follow-up study period in the first year of life, 20 of the 29 total enrolled infants acquired C. difficile. A total of 437 fecal samples were obtained, and 111 (25.4%) samples contained C. difficile, including 79 (71.2%) toxigenic strains. The toxigenic isolates comprised six PCR ribotypes, and two PCR ribotypes were identified as nontoxigenic strains.

CONCLUSION

Our study showed that C. difficile colonization increase with age during the 12-month period, and the dominant toxigenic types of C. difficile isolates in infants were those involved in long-term colonization. Feeding patterns may affect the dynamic progress of C. difficile colonization.

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.

Antimicrobial Resistance Patterns in Clostridioides difficile Strains Isolated from Neonates in Germany

Young children are frequently colonized with Clostridioides (C.) difficile. Depending on their resistance patterns, antibiotic treatment can facilitate gastrointestinal spreading in colonized individuals, potentially leading to transmission to others. C. difficile was isolated from stool samples from infants born in two hospitals in Göttingen and Darmstadt, Germany. All isolates were subjected to phenotypic antimicrobial resistance testing, PCR-based screening for toxin genes and mass spectrometry-based exclusion of ribotypes 027 and 176. Within an initial cohort of 324 neonates with a longitudinal survey of C. difficile, 137 strains were isolated from 48 individuals. Antimicrobial resistance was recorded against metronidazole in one (0.7%), erythromycin in 16 (11.7%) and moxifloxacin in 2 (1.5%) of the strains, whereas no resistance was observed against vancomycin (0.0%) or rifampicin (0.0%). Newly observed resistance against erythromycin in children with detection of previously completely sensitive isolates was reported for C. difficile isolates from 2 out of 48 children. In 20 children (42%), non-toxigenic strains were detected, and from 27 children (56%), toxigenic strains were isolated, while both toxigenic and non-toxigenic strains were recorded for 1 child (2%). Ribotypes 027 or 176 were not observed. In conclusion, the German C. difficile strains isolated from the children showed mild to moderate resistance with predominance of macrolide resistance, a substance class which is frequently applied in children. The observed switches to the dominance of macrolide-resistant isolates suggests likely selection of resistant C. difficile strains already in children.

Fidaxomicin for the treatment of Clostridioides difficile in children

Fidaxomicin is an oral narrow-spectrum novel 18-membered macrocyclic antibiotic that was initially approved in 2011 by the US FDA for the treatment of Clostridioides difficile infections (CDI) in adults. In February 2020, the FDA approved fidaxomicin for the treatment of CDI in children age >6 months. In adults, fidaxomicin is as efficacious as vancomycin in treating CDI and reduces the risk of recurrent CDI. An investigator-blinded, randomized, multicenter, multinational clinical trial comparing the efficacy and safety of fidaxomicin with vancomycin in children was recently published confirming similar findings as previously reported in adults. Fidaxomicin is the first FDA-approved treatment for CDI in children and offers a promising option for reducing recurrent CDI in this population.

From Nursery to Nursing Home: Emerging Concepts in Clostridioides difficile Pathogenesis

Clostridioides difficile is a Gram-positive, spore-forming, anaerobic bacterium that infects the human gastrointestinal tract, causing a wide range of disorders that vary in severity from mild diarrhea to toxic megacolon and/or death. Over the past decade, incidence, severity, and costs associated with C. difficile infection (CDI) have increased dramatically in both the pediatric and adult populations. The factors driving this rapidly evolving epidemiology remain largely unknown but are likely due in part to previously unappreciated host, microbiota, and environmental factors. In this review, we will cover the risks and challenges of CDI in adult and pediatric populations and examine asymptomatic colonization in infants. We will also discuss the emerging role of diet, pharmaceutical drugs, and pathogen-microbiota interactions in C. difficile pathogenesis, as well as the impact of host-microbiota interactions in the manifestation of C. difficile-associated disease. Finally, we highlight new areas of research and novel strategies that may shed light on this complex infection and provide insights into the future of microbiota-based therapeutics for CDI.

Porcine Colostrum Protects the IPEC-J2 Cells and Piglet Colon Epithelium against Clostridioides (syn. Clostridium) difficile Toxin-Induced Effects

Clostridioides difficile toxins are one of the main causative agents for the clinical symptoms observed during C. difficile infection in piglets. Porcine milk has been shown to strengthen the epithelial barrier function in the piglet’s intestine and may have the potential to neutralise clostridial toxins. We hypothesised that porcine colostrum exerts protective effects against those toxins in the IPEC-J2 cells and in the colon epithelium of healthy piglets. The IPEC-J2 cells were treated with either the toxins or porcine colostrum or their combination. Analyses included measurement of trans-epithelial electrical resistance (TEER), cell viability using propidium iodide by flow cytometry, gene expression of tight junction (TJ) proteins and immune markers, immunofluorescence (IF) histology of the cytoskeleton and a TJ protein assessment. Colon tissue explants from one- and two-week-old suckling piglets and from five-week-old weaned piglets were treated with C. difficile toxins in Ussing chamber assays to assess the permeability to macromolecules (FITC-dextran, HRP), followed by analysis of gene expression of TJ proteins and immune markers. Toxins decreased viability and integrity of IPEC-J2 cells in a time-dependent manner. Porcine colostrum exerted a protective effect against toxins as indicated by TEER and IF in IPEC-J2 cells. Toxins tended to increase paracellular permeability to macromolecules in colon tissues of two-week-old piglets and downregulated gene expression of occludin in colon tissues of five-week-old piglets (p = 0.05). Porcine milk including colostrum, besides other maternal factors, may be one of the important determinants of early immune programming towards protection from C. difficile infections in the offspring.