Asymptomatic Clostridium difficile colonization: epidemiology and clinical implications

Clostridioides difficile and Gut Microbiota: From Colonization to Infection and Treatment

Clostridioides difficile is the main causative agent of antibiotic-associated diarrhea (AAD) in hospitals in the developed world. Both infected patients and asymptomatic colonized individuals represent important transmission sources of C. difficile. C. difficile infection (CDI) shows a large range of symptoms, from mild diarrhea to severe manifestations such as pseudomembranous colitis. Epidemiological changes in CDIs have been observed in the last two decades, with the emergence of highly virulent types and more numerous and severe CDI cases in the community. C. difficile interacts with the gut microbiota throughout its entire life cycle, and the C. difficile's role as colonizer or invader largely depends on alterations in the gut microbiota, which C. difficile itself can promote and maintain. The restoration of the gut microbiota to a healthy state is considered potentially effective for the prevention and treatment of CDI. Besides a fecal microbiota transplantation (FMT), many other approaches to re-establishing intestinal eubiosis are currently under investigation. This review aims to explore current data on C. difficile and gut microbiota changes in colonized individuals and infected patients with a consideration of the recent emergence of highly virulent C. difficile types, with an overview of the microbial interventions used to restore the human gut microbiota.

Clostridium perfringens in central Colombia: frequency, toxin genes, and risk factors

Clostridium perfringens is an opportunistic bacterium that causes intestinal diseases in both humans and animals. This study aimed to assess the frequency of C. perfringens and the presence of toxin-encoding genes in fecal samples from individuals with or without gastrointestinal symptoms in the Department of Boyacá, Colombia. Additionally, risk factors associated with carriage and disease development were analyzed. A total of 114 stool samples were analyzed using a molecular test based on specific polymerase chain reaction (PCR) targeting 16S-rRNA and alpha toxin (cpa) genes. For individuals with a positive result for the PCR test, stool samples were cultured on Tryptose Sulfite Cycloserine (TSC) agar. Two to five colonies forming units were selected based on phenotypic characteristics, resulting in 56 bacterial isolates. These isolates were then analyzed for toxin-coding genes associated with gastrointestinal diseases. In addition, sociodemographic and clinical data from 77 individuals were also analyzed. The overall frequency of C. perfringens was 19.3% (n = 22/114). The detection frequency in 77 individuals with clinical data was 16.6% (n = 5/30) among symptomatic individuals and 21.2% (n = 10/47) among asymptomatic individuals. All 56 isolates obtained carried the cpa gene, while cpb2 was present in 10.7% (n = 6/56); cpe and cpb genes were not detected. Notably, diabetes and autoimmune diseases are significantly associated with an increased risk of C. perfringens detection (adjusted OR 8.41: 95% CI 1.32-35.89). This study highlights an elevated frequency of C. perfringens and the presence of the cpb2 gene in asymptomatic individuals compared with their symptomatic counterparts. These findings offer insights into the distribution and virulence factors of C. perfringens at a micro-geographical level. This information supports the need for developing tailored prevention strategies based on local characteristics to promote active surveillance programs based on molecular epidemiology.

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.

Early identification of a ward-based outbreak of Clostridioides difficile using prospective multilocus sequence type-based Oxford Nanopore genomic surveillance

OBJECTIVE

To describe an outbreak of sequence type (ST)2 Clostridioides difficile infection (CDI) detected by a recently implemented multilocus sequence type (MLST)-based prospective genomic surveillance system using Oxford Nanopore Technologies (ONT) sequencing.

SETTING

Hemato-oncology ward of a public tertiary referral centre.

METHODS

From February 2022, we began prospectively sequencing all C. difficile isolated from inpatients at our institution on the ONT MinION device, with the output being an MLST. Bed-movement data are used to construct real-time ST-specific incidence charts based on ward exposures over the preceding three months.

RESULTS

Between February and October 2022, 76 of 118 (64.4%) CDI cases were successfully sequenced. There was wide ST variation across cases and the hospital, with only four different STs being seen in >4 patients. A clear predominance of ST2 CDI cases emerged among patients with exposure to our hemato-oncology ward between May and October 2022, which totalled ten patients. There was no detectable rise in overall CDI incidence for the ward or hospital due to the outbreak. Following a change in cleaning product to an accelerated hydrogen peroxide wipe and several other interventions, no further outbreak-associated ST2 cases were detected. A retrospective phylogenetic analysis using original sequence data showed clustering of the suspected outbreak cases, with the exception of two cases that were retrospectively excluded from the outbreak.

CONCLUSIONS

Prospective genomic surveillance of C. difficile using ONT sequencing permitted the identification of an outbreak of ST2 CDI that would have otherwise gone undetected.

Impact of the Reverse 2-Step Algorithm for Clostridioides difficile Testing in the Microbiology Laboratory on Hospitalized Patients

Background

Multistep laboratory testing is recommended for the diagnosis of Clostridioides difficile infection (CDI). The aim of this study was to present the impact of multistep CDI diagnostic testing in an academic hospital system and evaluate the toxin B gene polymerase chain reaction (PCR) cycle threshold (Ct) values of PCR-positive tests.

Methods

In October 2022, our system began reflex testing all PCR-positive stool samples with the C. DIFF QUIK CHEK COMPLETE (Techlab), an enzyme immunoassay-based test with results for the glutamate dehydrogenase antigen (GDH) and C difficile toxin A/B. Hospital-onset (HO) CDI and CDI antibiotic use before and after testing were tracked. Ct values were obtained from the Infectious Diseases Diagnostic Laboratory. Receiver operating curve analysis was used to examine the sensitivity and specificity for identifying GDH+/toxin+ and GDH-/toxin- at various Ct thresholds.

Results

The HO-CDI rate decreased from 0.352 cases per 1000 patient-days to 0.115 cases per 1000 patient-days post-reflex testing (P < .005). Anti-CDI antibiotics use decreased, but the decrease was not commensurate with CDI rates following reflex testing. PCR+/GDH+/toxin+ samples had a lower mean Ct value than PCR+/GDH-/toxin- samples (23.3 vs 33.5, P < .0001). A Ct value of 28.65 could distinguish between those 2 groups. Fifty-four percent of PCR+/GDH+/toxin- samples had a Ct value below that cut-off, suggesting the possibility of CDI with a negative toxin test.

Conclusions

Reflex testing for a laboratory diagnosis of CDI results in rapid, systemwide decreases in the rate of HO-CDI. Additional research is needed to distinguish CDI from C difficile colonization in patients with discordant testing.

Reviewing the Clostridioides difficile Mouse Model: Insights into Infection Mechanisms

Clostridioides difficile is an anaerobic, spore-forming bacterium associated with intestinal infection, manifesting a broad spectrum of gastrointestinal symptoms, ranging from mild diarrhea to severe colitis. A primary risk factor for the development of C. difficile infection (CDI) is antibiotic exposure. Elderly and immunocompromised individuals are particularly vulnerable to CDI. A pivotal aspect for comprehending the complexities of this infection relies on the utilization of experimental models that mimic human CDI transmission, pathogenesis, and progression. These models offer invaluable insights into host-pathogen interactions and disease dynamics, and serve as essential tools for testing potential therapeutic approaches. In this review, we examine the animal model for CDI and delineate the stages of infection, with a specific focus on mice. Our objective is to offer an updated description of experimental models employed in the study of CDI, emphasizing both their strengths and limitations.

Clostridioides difficile Biofilm

Clostridioides difficile infection (CDI), previously Clostridium difficile infection, is a symptomatic infection of the large intestine caused by the spore-forming anaerobic, gram-positive bacterium Clostridioides difficile. CDI is an important healthcare-associated disease worldwide, characterized by high levels of recurrence, morbidity, and mortality. CDI is observed at a higher rate in immunocompromised patients after antimicrobial therapy, with antibiotics disrupting the commensal microbiota and promoting C. difficile colonization of the gastrointestinal tract.A rise in clinical isolates resistant to multiple antibiotics and the reduced susceptibility to the most commonly used antibiotic molecules have made the treatment of CDI more complicated, allowing the persistence of C. difficile in the intestinal environment.Gut colonization and biofilm formation have been suggested to contribute to the pathogenesis and persistence of C. difficile. In fact, biofilm growth is considered as a serious threat because of the related antimicrobial tolerance that makes antibiotic therapy often ineffective. This is the reason why the involvement of C. difficile biofilm in the pathogenesis and recurrence of CDI is attracting more and more interest, and the mechanisms underlying biofilm formation of C. difficile as well as the role of biofilm in CDI are increasingly being studied by researchers in the field.Findings on C. difficile biofilm, possible implications in CDI pathogenesis and treatment, efficacy of currently available antibiotics in treating biofilm-forming C. difficile strains, and some antimicrobial alternatives under investigation will be discussed here.

Animal and In Vitro Models as Powerful Tools to Decipher the Effects of Enteric Pathogens on the Human Gut Microbiota

Examining the interplay between intestinal pathogens and the gut microbiota is crucial to fully comprehend the pathogenic role of enteropathogens and their broader impact on human health. Valid alternatives to human studies have been introduced in laboratory practice to evaluate the effects of infectious agents on the gut microbiota, thereby exploring their translational implications in intestinal functionality and overall health. Different animal species are currently used as valuable models for intestinal infections. In addition, considering the recent advances in bioengineering, futuristic in vitro models resembling the intestinal environment are also available for this purpose. In this review, the impact of the main human enteropathogens (i.e., Clostridioides difficile, Campylobacter jejuni, diarrheagenic Escherichia coli, non-typhoidal Salmonella enterica, Shigella flexneri and Shigella sonnei, Vibrio cholerae, and Bacillus cereus) on intestinal microbial communities is summarized, with specific emphasis on results derived from investigations employing animal and in vitro models.

The opportunistic nature of gut commensal microbiota

The abundance of gut commensals has historically been associated with health-promoting effects despite the fact that the definition of good or bad microbiota remains condition-specific. The beneficial or pathogenic nature of microbiota is generally dictated by the dimensions of host-microbiota and microbe-microbe interactions. With the increasing popularity of gut microbiota in human health and disease, emerging evidence suggests opportunistic infections promoted by those gut bacteria that are generally considered beneficial. Therefore, the current review deals with the opportunistic nature of the gut commensals and aims to summarise the concepts behind the occasional commensal-to-pathogenic transformation of the gut microbes. Specifically, relevant clinical and experimental studies have been discussed on the overgrowth and bacteraemia caused by commensals. Three key processes and their underlying mechanisms have been summarised to be responsible for the opportunistic nature of commensals, viz. improved colonisation fitness that is dictated by commensal-pathogen interactions and availability of preferred nutrients; pathoadaptive mutations that can trigger the commensal-to-pathogen transformation; and evasion of host immune response as a survival and proliferation strategy of the microbes. Collectively, this review provides an updated concept summary on the underlying mechanisms of disease causative events driven by gut commensal bacteria.

Does this patient have Clostridioides difficile infection? A systematic review and meta-analysis

BACKGROUND

The clinical features and predictors of Clostridioides difficile infection overlap with many conditions.

OBJECTIVES

We performed a systematic review to evaluate the diagnostic utility of clinical features (clinical examination, risk factors, laboratory tests, and radiographic findings) associated with C. difficile.

METHODS

Systematic review and meta-analysis of diagnostic features for C. difficile.

DATA SOURCES

MEDLINE, EMBASE, CINAHL, and Cochrane databases were searched up to September 2021.

STUDY ELIGIBILITY CRITERIA

Studies that reported clinical features of C. difficile, a valid reference standard test for confirming diagnosis of C. difficile, and a comparison among patients with a positive and negative test result.

PARTICIPANTS

Adult and paediatric patients across diverse clinical settings.

OUTCOMES

Sensitivity, specificity, likelihood ratios.

REFERENCE STANDARD

Stool nucleic acid amplification tests, enzyme immunoassays, cell cytotoxicity assay, and stool toxigenic culture.

ASSESSMENT OF RISK OF BIAS

Rational Clinical Examination Series and Quality Assessment of Diagnostic Accuracy Studies-2.

METHODS OF DATA SYNTHESIS

Univariate and bivariate analyses.

RESULTS

We screened 11 231 articles of which 40 were included, enabling the evaluation of 66 features for their diagnostic utility for C. difficile (10 clinical examination findings, 4 laboratory tests, 10 radiographic findings, prior exposure to 13 antibiotic types, and 29 clinical risk factors). Of the ten features identified on clinical examination, none were significantly clinically associated with increased likelihood of C. difficile infection. Some features that increased likelihood of C. difficile infection were stool leukocytes (LR+ 5.31, 95% CI 3.29-8.56) and hospital admission in the prior 3 months (LR+ 2.14, 95% CI 1.48-3.11). Several radiographic findings also strongly increased the likelihood of C. difficile infection like ascites (LR+ 2.91, 95% CI 1.89-4.49).

DISCUSSION

There is limited utility of bedside clinical examination alone in detecting C. difficile infection. Accurate diagnosis of C. difficile infection requires thoughtful clinical assessment for interpretation of microbiologic testing in all suspected cases.

Gut Microbiota Associated with Clostridioides difficile Carriage in Three Clinical Groups (Inflammatory Bowel Disease, C. difficile Infection and Healthcare Workers) in Hospital Field

Clostridioides difficile is an anaerobic spore-forming Gram-positive bacterium. C. difficile carriage and 16S rDNA profiling were studied in three clinical groups at three different sampling times: inflammatory bowel disease (IBD) patients, C. difficile infection (CDI) patients and healthcare workers (HCWs). Diversity analysis was realized in the three clinical groups, the positive and negative C. difficile carriage groups and the three analysis periods. Concerning the three clinical groups, β-diversity tests showed significant differences between them, especially between the HCW group and IBD group and between IBD patients and CDI patients. The Simpson index (evenness) showed a significant difference between two clinical groups (HCWs and IBD). Several genera were significantly different in the IBD patient group (Sutterella, Agathobacter) and in the CDI patient group (Enterococcus, Clostridioides). Concerning the positive and negative C. difficile carriage groups, β-diversity tests showed significant differences. Shannon, Simpson and InvSimpson indexes showed significant differences between the two groups. Several genera had significantly different relative prevalences in the negative group (Agathobacter, Sutterella, Anaerostipes, Oscillospira) and the positive group (Enterococcus, Enterobacteriaceae_ge and Enterobacterales_ge). A microbiota footprint was detected in C. difficile-positive carriers. More experiments are needed to test this microbiota footprint to see its impact on C. difficile infection.

Longitudinal genomic surveillance of carriage and transmission of Clostridioides difficile in an intensive care unit

Despite enhanced infection prevention efforts, Clostridioides difficile remains the leading cause of healthcare-associated infections in the United States. Current prevention strategies are limited by their failure to account for patients who carry C. difficile asymptomatically, who may act as hidden reservoirs transmitting infections to other patients. To improve the understanding of asymptomatic carriers' contribution to C. difficile spread, we conducted admission and daily longitudinal culture-based screening for C. difficile in a US-based intensive care unit over nine months and performed whole-genome sequencing on all recovered isolates. Despite a high burden of carriage, with 9.3% of admissions having toxigenic C. difficile detected in at least one sample, only 1% of patients culturing negative on admission to the unit acquired C. difficile via cross-transmission. While patients who carried toxigenic C. difficile on admission posed minimal risk to others, they themselves had a 24-times greater risk for developing a healthcare-onset C. difficile infection than noncarriers. Together, these findings suggest that current infection prevention practices can be effective in preventing nosocomial cross-transmission of C. difficile, and that decreasing C. difficile infections in hospitals further will require interventions targeting the transition from asymptomatic carriage to infection.

Environmental approaches to controlling Clostridioides difficile infection in healthcare settings

As today's most prevalent and costly healthcare-associated infection, hospital-onset Clostridioides difficile infection (HO-CDI) represents a major threat to patient safety world-wide. This review will discuss how new insights into the epidemiology of CDI have quantified the prevalence of C. difficile (CD) spore contamination of the patient-zone as well as the role of asymptomatically colonized patients who unavoidable contaminate their near and distant environments with resilient spores. Clarification of the epidemiology of CD in parallel with the development of a new generation of sporicidal agents which can be used on a daily basis without damaging surfaces, equipment, or the environment, led to the research discussed in this review. These advances underscore the potential for significantly mitigating HO-CDI when combined with ongoing programs for optimizing the thoroughness of cleaning as well as disinfection. The consequence of this paradigm-shift in environmental hygiene practice, particularly when combined with advances in hand hygiene practice, has the potential for significantly improving patient safety in hospitals globally by mitigating the acquisition of CD spores and, quite plausibly, other environmentally transmitted healthcare-associated pathogens.

Association of ward-level antibiotic consumption with healthcare-associated Clostridioides difficile infections: an ecological study in five German university hospitals, 2017-2019

OBJECTIVES

To analyse the influence of antibiotic consumption on healthcare-associated healthcare onset (HAHO) Clostridioides difficile infection (CDI) in a German university hospital setting.

METHODS

Monthly ward-level antibiotic consumption measured in DDD/100 patient days (pd) and CDI surveillance data from five university hospitals in the period 2017 through 2019 were analysed. Uni- and multivariable analyses were performed with generalized estimating equation models.

RESULTS

A total of 225 wards with 7347 surveillance months and 4 036 602 pd participated. With 1184 HAHO-CDI cases, there was a median incidence density of 0.17/1000 pd (IQR 0.03-0.43) across all specialties, with substantial differences among specialties. Haematology-oncology wards showed the highest median incidence density (0.67/1000 pd, IQR 0.44-1.01), followed by medical ICUs (0.45/1000 pd, IQR 0.27-0.73) and medical general wards (0.32/1000 pd, IQR 0.18-0.53). Multivariable analysis revealed carbapenem (mostly meropenem) consumption to be the only antibiotic class associated with increased HAHO-CDI incidence density. Each carbapenem DDD/100 pd administered increased the HAHO-CDI incidence density by 1.3% [incidence rate ratio (IRR) 1.013; 95% CI 1.006-1.019]. Specialty-specific analyses showed this influence only to be valid for haematological-oncological wards. Overall, factors like ward specialty (e.g. haematology-oncology ward IRR 2.961, 95% CI 2.203-3.980) or other CDI cases on ward had a stronger influence on HAHO-CDI incidence density (e.g. community-associated CDI or unknown association case in same month IRR 1.476, 95% CI 1.242-1.755) than antibiotic consumption.

CONCLUSIONS

In the German university hospital setting, monthly ward-level carbapenem consumption seems to increase the HAHO-CDI incidence density predominantly on haematological-oncological wards. Furthermore, other patient-specific factors seem to be equally important to control HAHO-CDI.

Clostridioides (Clostridium) difficile: A silent nosocomial pathogen

Clostridioides difficile (C. difficile) infection is still a threat to many healthcare settings worldwide. Clostridioides difficile epidemiology has changed over the last 20 years, largely due to the emergence of hypervirulent and antimicrobial-resistant C. difficile strains. The excessive use of antimicrobials, the absence of optimal antibiotic policies, and suboptimal infection control practices have fueled the development of this pressing health issue. The prudent use of antimicrobials, particularly broad-spectrum agents, and simple infection control measures, such as hand hygiene, can significantly reduce C. difficile infection rates. Moreover, the early detection of these infections and understanding their epidemiological behavior using accurate laboratory methods are the cornerstone to decreasing the incidence of C. difficile infection and preventing further spread. Although there is no consensus on the single best laboratory method for the diagnosis of C. difficile infection, the use of 2 or more techniques can improve diagnostic accuracy, and it is recommended.

Prevalence, Risk Factors, and Sequelae of Asymptomatic Clostridioides difficile Colonization in Children with Cystic Fibrosis

Patients with CF (pwCF) have high antibiotic use and an altered intestinal microbiome, known risk factors for infection with Clostridioides difficile. However, in adults with CF, C. difficile infection (CDI) is uncommon and asymptomatic colonization with C. difficile occurs frequently, for reasons that remain unclear. We investigated the rate, risk factors, and sequelae of asymptomatic C. difficile colonization in children with CF (cwCF). We identified that 32% of cwCF were colonized with C. difficile without acute gastrointestinal symptoms. Higher BMI and exposure to specific antibiotic classes (cephalosporins, fluoroquinolones, and vancomycin) were significantly associated with C. difficile colonization. No children developed symptomatic CDI in 90-days following enrollment.

Gut microbiota diversity of hospitalized older adult patients with and without antibiotic-associated diarrhea

BACKGROUND

The incidence of antibiotic-related diarrhea (AAD) is high in older adults.

AIM

To examine the gut microbiota changes in older adults who received antibiotics to identify the microbial signatures associated with antibiotic use and AAD.

METHODS

A nested prospective observational cohort study was conducted between December 2019 and June 2021 in patients ≥ 65 years old at Huashan Hospital affiliated with Fudan University. The patients were grouped as antibiotic-treated (HA group) and no antibiotics (HC group); the HA group was subdivided as with vs. without AAD. Fecal samples were collected at admission (i.e., before eventual antibiotics) and after 7 days.

RESULT

Thirty-eight and 19 participants were included in the HA and HC groups. There were significant differences in gut microbiota between the HA after antibiotics vs. HC groups, with a higher Firmicutes/Bacteroidetes ratio. Before antibiotics in the HA group, the relative abundances of Akkermansia and Alistipes were lower in the AAD subgroup than the no-AAD subgroup, while the relative abundance of Actinomyces was higher. After antibiotics in the HA group, specific bacterial species were decreased in the AAD subgroup compared with the no-AAD subgroup. Among HA participants without probiotics, the abundance of Akkermansia in the patients without AAD was higher than in the patients with AAD at baseline (P = 0.007).

CONCLUSION

Patients with or without AAD have different gut microbiota compositions before antibiotics. Antibiotics can lead to dysbiosis, with a decrease in beneficial bacteria and an increase in Enterococcus.

Clostridioides difficile Toxin B Induced Senescence: A New Pathologic Player for Colorectal Cancer?

Clostridioides difficile (C. difficile) is responsible for a high percentage of gastrointestinal infections and its pathological activity is due to toxins A and B. C. difficile infection (CDI) is increasing worldwide due to the unstoppable spread of C. difficile in the anthropized environment and the progressive human colonization. The ability of C. difficile toxin B to induce senescent cells and the direct correlation between CDI, irritable bowel syndrome (IBS), and inflammatory bowel diseases (IBD) could cause an accumulation of senescent cells with important functional consequences. Furthermore, these senescent cells characterized by long survival could push pre-neoplastic cells originating in the colon towards the complete neoplastic transformation in colorectal cancer (CRC) by the senescence-associated secretory phenotype (SASP). Pre-neoplastic cells could appear as a result of various pro-carcinogenic events, among which, are infections with bacteria that produce genotoxins that generate cells with high genetic instability. Therefore, subjects who develop IBS and/or IBD after CDI should be monitored, especially if they then have further CDI relapses, waiting for the availability of senolytic and anti-SASP therapies to resolve the pro-carcinogenic risk due to accumulation of senescent cells after CDI followed by IBS and/or IBD.

Nurses’ Knowledge, Attitudes and Practices on the Management of Clostridioides difficile Infection: A Cross-Sectional Study

Clostridioides difficile is, worldwide, the leading cause of hospital-acquired infection. Outbreaks are largely related to antibiotic exposure and contact contamination, but little is known about C. difficle infection (CDI) awareness in the nurse population. We conducted a cross-sectional survey to study Italian nurses, based on CDI guidelines. We recruited 200 nurses working in 14 Italian hospitals. Using a one-way analysis of variance of knowledge scores, female nurses (mean 9.67 (standard deviation ± 1.63), p = 0.03), and nurses with a higher level of university education (mean 9.79 (SD ± 1.67), p = 0.04) were demonstrated to have better knowledge about CDI. In addition, 92.5% (n = 184) of the sample declared that they did not have specific postgraduate training about CDI. Seventy-four percent (n = 149) of the respondents declared that they used procedures, protocols and guidelines about CDI in their workplace, but only 46.5% (n = 93) reported using C. difficile-specific bundles during their daily practice. In conclusion, our study highlights a lack of knowledge concerning CDI clinical guidelines among Italian nurses.

Higher mortality rates associated with Clostridioides difficile infection in hospitalized children with cystic fibrosis

OBJECTIVE(S)

To determine the association of Clostridioides difficile Infection (CDI) with in-hospital mortality, Length of Stay (LOS), and hospital charges among pediatric Cystic Fibrosis (CF) hospitalizations using a large nationally representative pediatric hospital database.

STUDY DESIGN

We identified Cystic Fibrosis-related hospitalizations during the years 1997 to 2016 in the Kids' Inpatient Database (KID) and compared in-hospital mortality, LOS, and hospital charges among hospitalizations with and without a coexisting diagnosis of C. difficile using logistic regression models for mortality and general linear models with gamma distribution and logarithmic transformation for LOS and hospital charges. We also evaluated temporal trends in the proportion of CF hospitalizations with concomitant CDI using data published triennially RESULTS: We analyzed 21,616 pediatric CF hospitalizations between the years 1997 to 2016 and found a total of 240 (1.1%) hospitalizations with concurrent CDI diagnosis. Adjusted analyses demonstrated an association of CDI with increased mortality (OR 5.2, 95% CI 2.5-10.7), longer LOS (46.5% increment, 95% CI 36.0-57.1), and higher charges (65.8% increment, 95% CI 53.5-78.1) for all comparisons. The proportion of CF hospitalizations with CDI increased over time from 0.64% in 1997 to 1.73% in 2016 (p < 0.001).

CONCLUSION(S)

As CDI is associated with excess mortality, LOS, and cost in children hospitalized for CF, a healthy level of suspicion for CDI may be needed in patients with CF in the appropriate clinical context. Efforts to prevent, diagnose, and treat CDI may improve hospital outcomes among children with CF.

Cytotoxic synergism of Clostridioides difficile toxin B with proinflammatory cytokines in subjects with inflammatory bowel diseases

Clostridioides difficile (C. difficile) is progressively colonizing humans and animals living with humans. During this process, hypervirulent strains and mutated toxin A and B of C. difficile (TcdA and TcdB) are originating and developing. While in healthy subjects colonization by C. difficile becomes a risk after the use of antibiotics that alter the microbiome, other categories of people are more susceptible to infection and at risk of relapse, such as those with inflammatory bowel disease (IBD). Recent in vitro studies suggest that this increased susceptibility could be due to the strong cytotoxic synergism between TcdB and proinflammatory cytokines the tumor necrosis factor-alpha and interferon-gamma (CKs). Therefore, in subjects with IBD the presence of an inflammatory state in the colon could be the driver that increases the susceptibility to C. difficile infection and its progression and relapses. TcdB is internalized in the cell via three receptors: chondroitin sulphate proteoglycan 4; poliovirus receptor-like 3; and Wnt receptor frizzled family. Chondroitin sulphate proteoglycan 4 and Wnt receptor frizzled family are involved in cell death by apoptosis or necrosis depending on the concentration of TcdB and cell types, while poliovirus receptor-like 3 induces only necrosis. It is possible that cytokines could also induce a greater expression of receptors for TcdB that are more involved in necrosis than in apoptosis. Therefore, in subjects with IBD there are the conditions: (1) For greater susceptibility to C. difficile infection, such as the inflammatory state, and abnormalities of the microbiome and of the immune system; (2) for the enhancement of the cytotoxic activity of TcdB +Cks; and (3) for a greater expression of TcdB receptors stimulated by cytokines that induce cell death by necrosis rather than apoptosis. The only therapeutic approach currently possible in IBD patients is monitoring of C. difficile colonization for interventions aimed at reducing tumor necrosis factor-alpha and interferon-gamma levels when the infection begins. The future perspective is to generate bacteriophages against C. difficile for targeted therapy.

Pediatric diarrhea patients living in urban areas have a higher incidence of Clostridioides difficile infection

Clostridioides difficile infection (CDI) is a major cause of antibiotic-associated diarrhea and an unappreciated contributor to child mortality in low- and middle-income countries where the diagnosis may be difficult. There is little information about the prevalence of CDI among infants, children, and adolescents in Africa. Using a cross-sectional design, seventy-six samples were collected from pediatric patients presenting with diarrhea, including infants (≤ 2 years old), children (2-12 years), and adolescents (13 ≤17 years) from three hospitals between January and December 2019. Demographic data, medical history, and prior antibiotic use were recorded. Toxigenic culture and PCR were used to detect and validate the presence of C. difficile in the samples. Data obtained were analyzed using descriptive and inferential statistics. A total of 29 (38.7%), 39 (52.0%) and 7 (9.3%) samples were from infants, children, and adolescents, respectively. The average age of the patients was 4.4 years. Of these samples, 31 (41%) were positive for C. difficile by culture and were verified by PCR amplification of C. difficile-specific genes (tcdA and tcdB). The most positive cases were children (53.3%) and infants (40.0%) with the majority of them residing in urban areas. Forty-nine (66.2%) of the patients had no known antibiotics exposure, whereas 29.0% and 29.7% reported the use of over-the-counter antibiotics at 14 and 90 days, prior to the hospital visit, respectively. CDI is relatively common among children with diarrhea in Northern Nigeria. Therefore, for effective management and treatment, more attention should be given to testing for C. difficile as one of the causative agents of diarrhea.

Food for thought-The link between Clostridioides difficile metabolism and pathogenesis

Clostridioides difficile (C. difficile) is an opportunistic pathogen that leads to antibiotic-associated diarrhoea and is a leading cause of morbidity and mortality worldwide. Antibiotic usage is the main risk factor leading to C. difficile infection (CDI), as a dysbiotic gut environment allows colonisation and eventual pathology manifested by toxin production. Although colonisation resistance is mediated by the action of secondary bile acids inhibiting vegetative outgrowth, nutrient competition also plays a role in preventing CDI as the gut microbiota compete for nutrient niches inhibiting C. difficile growth. C. difficile is able to metabolise carbon dioxide, the amino acids proline, hydroxyproline, and ornithine, the cell membrane constituent ethanolamine, and the carbohydrates trehalose, cellobiose, sorbitol, and mucin degradation products as carbon and energy sources through multiple pathways. Zinc sequestration by the host response mediates metabolic adaptation of C. difficile by perhaps signalling an inflamed gut allowing it to acquire abundant nutrients. Persistence within the gut environment is also mediated by the by-products of metabolism through the production of p-cresol, which inhibit gut commensal species growth promoting dysbiosis. This review aims to explore and describe the various metabolic pathways of C. difficile, which facilitate its survival and pathogenesis within the colonised host gut.

Validating agent-based simulation model of hospital-associated Clostridioides difficile infection using primary hospital data

As agent-based models (ABMs) are increasingly used for modeling infectious diseases, model validation is becoming more crucial. In this study, we present an alternate approach to validating hospital ABMs that focuses on replicating hospital-specific conditions and proposes a new metric for validating the social-environmental network structure of ABMs. We adapted an established ABM representing Clostridioides difficile infection (CDI) spread in a generic hospital to a 426-bed Midwestern academic hospital. We incorporated hospital-specific layout, agent behaviors, and input parameters estimated from primary hospital data into the model, referred to as H-ABM. We compared the predicted CDI rate against the observed rate from 2013-2018. We used colonization pressure, a measure of nearby infectious agents, to validate the socio-environmental agent networks in the ABM. Finally, we conducted additional experiments to compare the performance of individual infection control interventions in the H-ABM and the generic model. We find that the H-ABM is able to replicate CDI trends during 2013-2018, including a roughly 46% drop during a period of greater infection control investment. High CDI burden in socio-environmental networks was associated with a significantly increased risk of C. difficile colonization or infection (Risk ratio: 1.37; 95% CI: [1.17, 1.59]). Finally, we found that several high-impact infection control interventions have diminished impact in the H-ABM. This study presents an alternate approach to validation of ABMs when large-scale calibration is not appropriate for specific settings and proposes a new metric for validating socio-environmental network structure of ABMs. Our findings also demonstrate the utility of hospital-specific modeling.

Clostridioides difficile Infection in Hospitalized Pediatric Patients: Comparisons of Epidemiology, Testing, and Treatment from 2013 to 2019

OBJECTIVES

To compare the incidence, epidemiology, testing patterns, treatment, and outcomes of Clostridioides difficile infection (CDI) among hospitalized pediatric patients from 2013 to 2019.

STUDY DESIGN

The Pediatric Health Information System database was queried for patient admissions (age 0-17 years) with International Classification of Diseases, 9th and 10th edition, codes for diagnoses of CDI with a billing code for a CDI-related antibiotic treatment.

RESULTS

We identified 17 142 pediatric patients, representing 23 052 admissions, with CDI. The adjusted annual CDI incidence decreased over the study period from 7.09 cases per 10 000 patient-days (95% CI, 6.15-8.18) in 2013 to 4.89 cases per 10 000 patient-days (95% CI, 4.03-5.93) in 2019 (P < .001). C difficile-specific testing also decreased during the study period (P < .001). Chronic gastrointestinal conditions (36%) and malignancy (32%) were the most common comorbidities in CDI encounters. Oral metronidazole use decreased during the study period (P < .01) and oral vancomycin use increased (P < .001).

CONCLUSIONS

Our study demonstrates a decrease in CDI incidence in hospitalized pediatric patients, a notable change from prior studies, although this may have been influenced by altered testing patterns. We found a high incidence of CDI in patients with cancer and gastrointestinal conditions: groups that warrant targeted evaluation of CDI prevention and treatment.

Application of Procalcitonin for the Rapid Diagnosis of Clostridioides difficile Infection in Patients with Inflammatory Bowel Disease

Background: The incidence of Clostridioides difficile infection (CDI) has increased in recent years in patients with inflammatory bowel disease (IBD). C. difficile is a toxin-producing bacterium, and CDI results in the worsening of underlying IBD, increasing the risk of IBD treatment failure, surgery, and hospitalization. Because the symptoms of CDI overlap with those of IBD, it is challenging to make a differential diagnosis. Therefore, early, rapid, and reliable diagnostic tools that can identify CDI in IBD patients would be valuable to clinicians. Methods: This study retrospectively collected 135 patients with IBD. Among them, 44 patients were diagnosed with CDI, and 42 patients were diagnosed with viral or fungal infections. A total of 49 patients without infections were defined as the control group. The diagnostic values of procalcitonin (PCT), C-reactive protein (CRP), and white blood cell (WBC) count in the peripheral blood were examined. Results: In this study, PCT levels were significantly higher in patients with CDI than in non-CDI patients (including patients with viral/fungal infections and the control group; p < 0.001 and p < 0.05, respectively). CRP levels were significantly higher in patients with CDI than in non-CDI patients (p < 0.05). The area under the curve (AUC) of PCT and WBC count were compared using DeLong’s test: the AUCs of PCT vs. CRP for the detection of the IBD−CDI group and the control group was 0.826 [95% confidence interval (CI) 0.743−0.909] vs. 0.663 [95% confidence interval (CI) 0.551−0.774] (p < 0.05), respectively. WBC count was inferior as a diagnostic tool for CDI. The sensitivity was 59.09% (95% CI: 43.2% to 73.7%), the specificity was 89.80% (95% CI: 77.8% to 96.6%), and the positive likelihood ratio LR (+) was 5.79 for PCT for the diagnosis of CDI. Conclusions: The present study demonstrates the superiority of PCT over CRP and WBC count for the rapid diagnosis of CDI in IBD patients.

Rapid-format recombinant antibody-based methods for the diagnosis of Clostridioides difficile infection: Recent advances and perspectives

Clostridioides difficile, the most common cause of nosocomial diarrhea, has been continuously reported as a worldwide problem in healthcare settings. Additionally, the emergence of hypervirulent strains of C. difficile has always been a critical concern and led to continuous efforts to develop more accurate diagnostic methods for detection of this recalcitrant pathogen. Currently, the diagnosis of C. difficile infection (CDI) is based on clinical manifestations and laboratory tests for detecting the bacterium and/or its toxins, which exhibit varied sensitivity and specificity. In this regard, development of rapid diagnostic techniques based on antibodies has demonstrated promising results in both research and clinical environments. Recently, application of recombinant antibody (rAb) technologies like phage display has provided a faster and more cost-effective approach for antibody production. The application of rAbs for developing ultrasensitive diagnostic tools ranging from immunoassays to immunosensors, has allowed the researchers to introduce new platforms with high sensitivity and specificity. Additionally, DNA encoding antibodies are directly accessible in these approaches, which enables the application of antibody engineering to increase their sensitivity and specificity. Here, we review the latest studies about the antibody-based ultrasensitive diagnostic platforms for detection of C. difficile bacteria, with an emphasis on rAb technologies.

Toxic Megacolon Burdened with COVID-19 Coinfection-Worsening of an Unfavorable Diagnosis: A Single-Center Retrospective Study

INTRODUCTION

This study primarily sought to evaluate the risk factors for toxic megacolon development and treatment outcomes in Clostridium difficile-positive COVID-19 patients, secondarily to determining predictors of survival.

METHODS

During the second COVID-19 wave (May 2020 to May 2021), we identified 645 patients with confirmed COVID-19 infection, including 160 patients with a severe course in the intensive care unit. We selected patients with Clostridium difficile infection (CDI) (31 patients) and patients with toxic megacolon (9 patients) and analyzed possible risk factors.

RESULTS

Patients who developed toxic megacolon had a higher incidence (without statistical significance, due to small sample size) of cancer and chronic obstructive pulmonary disease, a higher proportion of them required antibiotic treatment using cephalosporins or penicillins, and there was a higher rate of extracorporeal circulation usage. C-reactive protein (CRP) and interleukin-6 values showed significant differences between the groups (CRP [median 126 mg/L in the non-toxic megacolon cohort and 237 mg/L in the toxic megacolon cohort; p = 0.037] and interleukin-6 [median 252 ng/L in the group without toxic megacolon and 1127 ng/L in those with toxic megacolon; p = 0.016]). As possible predictors of survival, age, presence of chronic venous insufficiency, cardiac disease, mechanical ventilation, and infection with Candida species were significant for increasing the risk of death, while corticosteroid and cephalosporin treatment and current Klebsiella infection decreased this risk.

CONCLUSIONS

More than ever, the COVID-19 pandemic required strong up-to-date treatment recommendations to decrease the rate of serious in-hospital complications. Further studies are required to evaluate the interplay between COVID-19 and CDI/toxic megacolon.

A High-Carbohydrate Diet Prolongs Dysbiosis and Clostridioides difficile Carriage and Increases Delayed Mortality in a Hamster Model of Infection

Studies using mouse models of Clostridioides difficile infection (CDI) have demonstrated a variety of relationships between dietary macronutrients on antibiotic-associated CDI; however, few of these effects have been examined in more susceptible hamster models of CDI. In this study, we investigated the effect of a high-carbohydrate diet previously shown to protect mice from CDI on the progression and resolution of CDI in a hamster disease model, with 10 animals per group. Hamsters fed the high-carbohydrate diet developed distinct diet-specific microbiomes during antibiotic treatment and CDI, with lower diversity, persistent C. difficile carriage, and delayed microbiome restoration. In contrast to CDI protection in mice, most hamsters fed a high-carbohydrate diet developed fulminant CDI including several cases of late-onset CDI, that were not observed in hamsters fed a standard lab diet. We speculate that prolonged high-carbohydrate diet-specific dysbiosis in these animals allowed C. difficile to persist in the gut of the animals where they could proliferate postvancomycin treatment, leading to delayed CDI onset. This study, along with similar studies in mouse models of CDI, suggests some high-carbohydrate diets may promote antibiotic-associated dysbiosis and long-term C. difficile carriage, which may later convert to symptomatic CDI. IMPORTANCE The effects of diet on CDI are not completely known. Here, we used a high-carbohydrate diet previously shown to protect mice against CDI to assess its effect on a hamster model of CDI and paradoxically found that it promoted dysbiosis, C. difficile carriage, and higher mortality. A common thread in both mouse and hamster experimental models was that the high-carbohydrate diet promoted dysbiosis and long-term carriage of C. difficile, which may have converted to fulminant CDI only in the highly susceptible hamster model system. If diets high in carbohydrates also promote dysbiosis and C. difficile carriage in humans, then these diets might paradoxically increase chances of CDI relapse despite their protective effects against primary CDI.

The Current Knowledge on Clostridioides difficile Infection in Patients with Inflammatory Bowel Diseases

Clostridioides difficile (C. difficile) represents a major health burden with substantial economic and clinical impact. Patients with inflammatory bowel diseases (IBD) were identified as a risk category for Clostridioides difficile infection (CDI). In addition to traditional risk factors for C. difficile acquisition, IBD-specific risk factors such as immunosuppression, severity and extension of the inflammatory disease were identified. C. difficile virulence factors, represented by both toxins A and B, induce the damage of the intestinal mucosa and vascular changes, and promote the inflammatory host response. Given the potential life-threatening complications, early diagnostic and therapeutic interventions are required. The screening for CDI is recommended in IBD exacerbations, and the diagnostic algorithm consists of clinical evaluation, enzyme immunoassays (EIAs) or nucleic acid amplification tests (NAATs). An increased length of hospitalization, increased colectomy rate and mortality are the consequences of concurrent CDI in IBD patients. Selection of CD strains of higher virulence, antibiotic resistance, and the increasing rate of recurrent infections make the management of CDI in IBD more challenging. An individualized therapeutic approach is recommended to control CDI as well as IBD flare. Novel therapeutic strategies have been developed in recent years in order to manage severe, refractory or recurrent CDI. In this article, we aim to review the current evidence in the field of CDI in patients with underlying IBD, pointing to pathogenic mechanisms, risk factors for infection, diagnostic steps, clinical impact and outcomes, and specific management.

Gut associated metabolites and their roles in Clostridioides difficile pathogenesis

The nosocomial pathogen Clostridioides difficile is a burden to the healthcare system. Gut microbiome disruption, most commonly by broad-spectrum antibiotic treatment, is well established to generate a state that is susceptible to CDI. A variety of metabolites produced by the host and/or gut microbiota have been shown to interact with C. difficile. Certain bile acids promote/inhibit germination while other cholesterol-derived compounds and amino acids used in the Stickland metabolic pathway affect growth and CDI colonization. Short chain fatty acids maintain intestinal barrier integrity and a myriad of other metabolic compounds are used as nutritional sources or used by C. difficile to inhibit or outcompete other bacteria in the gut. As the move toward non-antibiotic CDI treatment takes place, a deeper understanding of interactions between C. difficile and the host's gut microbiome and metabolites becomes more relevant.

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.

Our experience with 80 cases of SARS-CoV-2-Clostridioides difficile co-infection: An observational study

Beside the changes in the gut microbiota in context of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, the increased use of high-risk broad-spectrum antibiotics during the actual pandemic raises concerns about a possible increase of Clostridioides difficile infections (CDIs). We retrospectively analyzed 80 consecutive patients, with SARS-CoV-2 pneumonia and CDI. The mean length of hospitalization was 19.63 days. The mean time of the onset of the digestive symptoms related to CDI was 5.16 days. Patients with an onset of the digestive symptoms from hospital admission have a significantly lower median length in hospital stay. The recovered patients present a statistically significant decreased median age. coronavirus disease 2019 (COVID-19) cured patients present CDI symptoms much earlier than the deceased patients, when comparing the median days before the occurrence of any digestive symptoms regarding CDI. Among the patients that prior to their hospitalization for COVID-19 were exposed to antibiotics, 54.7% presented CDI digestive symptoms during their hospitalization and 65.6% had a severe or critical COVID-19 form. Although the incidence of CDI in the pandemic is lower compared to the period before the pandemic, the severity of cases and the death rate increased. In the actual setting clinicians need to be aware of possible CDI and SARS-CoV-2 co-infection.

Novel structural insights for a pair of monoclonal antibodies recognizing non-overlapping epitopes of the glucosyltransferase domain of Clostridium difficile toxin B

Clostridium difficile toxins are the primary causative agents for hospital-acquired diarrhea and pseudomembranous colitis. Numerous monoclonal antibodies (mAbs) targeting different domains of Clostridium difficile toxin have been reported. Here we report the crystal structures of two mAbs, B1 and B2, in complex with the glycosyltransferase domain (GTD) of the Clostridium difficile toxin B (TcdB). B2 bound to the N-terminal 4 helix bundle of the GTD, a conserved membrane localization domain (MLD) found in the large clostridial glycosylating toxin family implicated in targeting plasma membrane. B1 bound to a distinct epitope at the hinge region between the MLD and the catalytic subdomain of the GTD. Functional studies revealed the potency of these mAbs in vitro and in vivo to be synergistic when given in combination.

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Identified 2 novel potent mAbs B1 and B2 targeting the TcdB GTD domain and synergistic effects were observed when combined.

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Novel non-overlapped epitopes were identified for B1 and B2 through X-ray crystallography.

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B2 epitope belongs to a conserved MLD (membrane localization domain) in the large clostridial glycosylating toxin family.

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B2 was shown to target the key regions (Loop 1 and Loop 3) of MLD proposed to be essential for membrane localization.

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B1 epitope was found to be at the hinge region between the GTD catalytic domain and the MLD of GTD.

Pain killers: the interplay between nonsteroidal anti-inflammatory drugs and Clostridioides difficile infection

Clostridioides difficile is one of the leading causes of nosocomial infections worldwide. Increases in incidence, severity, and healthcare cost associated with C. difficile infection (CDI) have made this pathogen an urgent public health threat worldwide. The factors shaping the evolving epidemiology of CDI and impacting clinical outcomes of infection are not well understood, but involve tripartite interactions between the host, microbiota, and C. difficile. In addition to this, emerging data suggests an underappreciated role for environmental factors, such as diet and pharmaceutical drugs, in CDI. In this review, we discuss the role of nonsteroidal anti-inflammatory drugs (NSAIDs) and eicosanoids in CDI.

Some issues of safety of antimicrobial therapy in COVID-19 patients

Currently, there is a lack of evidence for empiric use of antimicrobial agents in most patients with COVID-19 in outpatient and hospital settings as the overall proportion of secondary bacterial infections in COVID-19 is quite low. This literature review summarizes data on changes in antimicrobial resistance over the course of COVID-19 pandemic, especially in nosocomial ESKAPE pathogens. The other significant consequences of excessive and unnecessary administration of antibiotics to COVID-19 patients including risk of Clostridioides difficile infection and adverse effects of antimicrobial agents are also discussed.

Oxidative ornithine metabolism supports non-inflammatory C. difficile colonization

The enteric pathogen Clostridioides difficile (Cd) is responsible for a toxin-mediated infection that causes more than 200,000 recorded hospitalizations and 13,000 deaths in the United States every year1. However, Cd can colonize the gut in the absence of disease symptoms. Prevalence of asymptomatic colonization by toxigenic Cd in healthy populations is high; asymptomatic carriers are at increased risk of infection compared to noncolonized individuals and may be a reservoir for transmission of Cd infection2,3. Elucidating the molecular mechanisms by which Cd persists in the absence of disease is necessary for understanding pathogenesis and developing refined therapeutic strategies. Here, we show with gut microbiome metatranscriptomic analysis that mice recalcitrant to Cd infection and inflammation exhibit increased community-wide expression of arginine and ornithine metabolic pathways. To query Cd metabolism specifically, we leverage RNA sequencing in gnotobiotic mice infected with two wild-type strains (630 and R20291) and isogenic toxin-deficient mutants of these strains to differentiate inflammation-dependent versus -independent transcriptional states. A single operon encoding oxidative ornithine degradation is consistently upregulated across non-toxigenic Cd strains. Combining untargeted and targeted metabolomics with bacterial and host genetics, we demonstrate that both diet- and host-derived sources of ornithine provide a competitive advantage to Cd, suggesting a mechanism for Cd persistence within a non-inflammatory, healthy gut.

Detection of potential enteric pathogens in children with severe acute gastroenteritis using the filmarray: Results from a three - years hospital-based survey in Northern Italy

Acute gastroenteritis (AGE) are leading causes of morbidity and mortality in children. Therefore, rapid pathogens identification is needed. The AGE aetiology was investigated from 2018 to 2020 in 2,066 children in Parma (Italy) by FilmArray Gastrointestinal Panel and Enterovirus-targeting RT-PCR. Pathogens were detected in 1,162 (56.2%) stool samples from as many children; 798 (68.7%) were single and 364 (31.3%) mixed infections (68.7% vs 31.3%, P < 0.0001). Children aged 0-5 years showed the highest infection incidence (66.1%). The most frequent pathogens were Enteropathogenic Escherichia coli (EPEC; 19.14%), Clostridioides difficile (10.42%), Norovirus (10.36%), Enterovirus (9.44%), and Campylobacter (9.21%). EPEC, Campylobacter, enteroaggregative E. coli, Norovirus, and Rotavirus showed seasonality. The incidence of pathogens detected decreased between 2018 and 2020 (42.7% vs 20.8%, P < 0.0001), seemingly for the preventive measures imposed by the severe acute respiratory syndrome coronavirus-2 pandemic. A putative aetiology in half the children examined and an estimate of enteric pathogens epidemiology were assessed.

Clostridioides difficile infection induces a rapid influx of bile acids into the gut during colonization of the host

Clostridioides difficile is the leading cause of nosocomial intestinal infections in the United States. Ingested C. difficile spores encounter host bile acids and other cues that are necessary for germinating into toxin-producing vegetative cells. While gut microbiota disruption (often by antibiotics) is a prerequisite for C. difficile infection (CDI), the mechanisms C. difficile employs for colonization remain unclear. Here, we pioneered the application of imaging mass spectrometry to study how enteric infection changes gut metabolites. We find that CDI induces an influx of bile acids into the gut within 24 h of the host ingesting spores. In response, the host reduces bile acid biosynthesis gene expression. These bile acids drive C. difficile outgrowth, as mice receiving the bile acid sequestrant cholestyramine display delayed colonization and reduced germination. Our findings indicate that C. difficile may facilitate germination upon infection and suggest that altering flux through bile acid pathways can modulate C. difficile outgrowth in CDI-prone patients.

Health Care Environmental Hygiene: New Insights and Centers for Disease Control and Prevention Guidance

Recent research has significantly clarified the impact of optimizing patient-zone environmental hygiene. New insights into the environmental microbial epidemiology of many hospital-associated pathogens, especially Clostridioides difficile, have clarified and quantified the role of ongoing occult pathogen transmission from the near-patient environment. The recent development of safe, broadly effective surface chemical disinfectants has led to new opportunities to broadly enhance environmental hygiene in all health care settings. The Centers for Disease Control and Prevention has recently developed a detailed guidance to assist all health care settings in implementing optimized programs to mitigate health care-associated pathogen transmission from the near-patient surfaces.

Invisible steps for a global endemy: molecular strategies adopted by Clostridioides difficile

Clostridioides difficile infection (CDI) is on the rise worldwide and is associated with an increase in deaths and socio-health burden. C. difficile has become ubiquitous in anthropized environments because of the extreme resistance of its spores. Based on the epidemiological data and knowledge of molecular pathogenesis of C. difficile, it is possible to predict its progressive colonization of the human population for the following reasons: first, its global spread is unstoppable; second, the toxins (Tcds) produced by C. difficile, TcdA and TcdB, mainly cause cell death by apoptosis, but the surviving cells acquire a senescence state that favours persistence of C. difficile in the intestine; third, proinflammatory cytokines, tumour necrosis factor-α and interferon-γ, induced during CDI, enhance the cytotoxicity of Tcds and can increase the survival of senescent cells; fourth, Tcds block mobility and induce apoptosis in immune cells recruited at the infection site; and finally, after remission from primary infection or relapse, C. difficile causes functional abnormalities in the enteric glial cell (EGC) network that can result in irritable bowel syndrome, characterized by a latent inflammatory response that contributes to C. difficile survival and enhances the cytotoxic activity of low doses of TcdB, thus favouring further relapses. Since a 'global endemy' of C. difficile seems inevitable, it is necessary to develop an effective vaccine against Tcds for at-risk individuals, and to perform a prophylaxis/selective therapy with bacteriophages highly specific for C. difficile. We must be aware that CDI will become a global health problem in the forthcoming years, and we must be prepared to face this menace.

Descriptive Study of Gut Microbiota in Infected and Colonized Subjects by Clostridiodes difficile

Clostridiodes difficile can lead to a range of situations from the absence of symptoms (colonization) to severe diarrhea (infection). Disruption of gut microbiota provides an ideal environment for infection to occur. Comparison of gut microbiota of infected and colonized subjects could provide relevant information on susceptible groups or protectors to the development of infection, since the presence of certain genera could be related to the inhibition of transition from a state of colonization to infection. Through high-throughput sequencing of 16S rDNA gene, we performed alpha and beta diversity and composition studies on 15 infected patients (Group CDI), 15 colonized subjects (Group P), and 15 healthy controls (Group CTLR). A loss of alpha diversity and richness and a different structure have been evidenced in the CDI and P groups with respect to the CTRL group, but without significant differences between the first two. In CDI and P groups, there was a strong decrease in phylum Firmicutes and an expansion of potential pathogens. Likewise, there was a loss of inhibitory genus of C. difficile germination in infected patients that were partially conserved in colonized subjects. Therefore, infected and colonized subjects presented a gut microbiota that was completely different from that of healthy controls, although similar to each other. It is in composition where we found that colonized subjects, especially in minority genera, presented differences with respect to those infected.

Opportunities for Nanomedicine in Clostridioides difficile Infection

Clostridioides difficile, a spore-forming bacterium, is a nosocomial infectious pathogen which can be found in animals as well. Although various antibiotics and disinfectants were developed, C. difficile infection (CDI) remains a serious health problem. C. difficile spores have complex structures and dormant characteristics that contribute to their resistance to harsh environments, successful transmission and recurrence. C. difficile spores can germinate quickly after being exposed to bile acid and co-germinant in a suitable environment. The vegetative cells produce endospores, and the mature spores are released from the hosts for dissemination of the pathogen. Therefore, concurrent elimination of C. difficile vegetative cells and inhibition of spore germination is essential for effective control of CDI. This review focused on the molecular pathogenesis of CDI and new trends in targeting both spores and vegetative cells of this pathogen, as well as the potential contribution of nanotechnologies for the effective management of CDI.

Caloric restriction disrupts the microbiota and colonization resistance

Diet is a major factor that shapes the gut microbiome1, but the consequences of diet-induced changes in the microbiome for host pathophysiology remain poorly understood. We conducted a randomized human intervention study using a very-low-calorie diet (NCT01105143). Although metabolic health was improved, severe calorie restriction led to a decrease in bacterial abundance and restructuring of the gut microbiome. Transplantation of post-diet microbiota to mice decreased their body weight and adiposity relative to mice that received pre-diet microbiota. Weight loss was associated with impaired nutrient absorption and enrichment in Clostridioides difficile, which was consistent with a decrease in bile acids and was sufficient to replicate metabolic phenotypes in mice in a toxin-dependent manner. These results emphasize the importance of diet-microbiome interactions in modulating host energy balance and the need to understand the role of diet in the interplay between pathogenic and beneficial symbionts.

Prevalence of Clostridium difficile and its toxins in hospital patients with diarrhoeal diseases in Lusaka, Zambia

BACKGROUND

Clostridium difficile infection (CDI) has emerged as an important nosocomial and antibiotic-associated diarrhoeal problem leading to increasing morbidity and mortality, especially in resource-privileged regions. CDI varies in incidence, pathogenicity and risk factors across geographical locations, yet little information is available on CDI in sub-Saharan Africa. This study aimed to determine the prevalence of Clostridium difficile and related toxin expression in stool specimens from patients with diarrhoeal disease at the University Teaching Hospital, Lusaka, Zambia.

METHODS

Between June and September 2017, patients presenting with acute or persistent diarrhoea provided stool samples that were cultured anaerobically on cycloserine cefoxitin fructose agar. Isolates were identified by Gram staining, C. difficile latex agglutination and confirmed by PCR targeting of the tpi housekeeping gene. Toxins A or B were detected by ELISA.

RESULTS

Of 135 participants enrolled, 13 (10%) were C. difficile positive, of which four (31%) were toxigenic by ELISA. Among HIV-positive and HIV-negative participants, the frequency of culturable C. difficile (19% vs 12%; p=0.17) and of toxigenic isolates (15% vs 0%, p=0.19) did not differ.

CONCLUSIONS

We can now revise previous research and confirm that CDI contributes to diarrhoea among hospitalised adult patients irrespective of HIV status.

Alternative Diagnoses in Pediatric Fecal Microbiota Transplant Referral Patients

The incidence of Clostridioides difficile infection (CDI) has been increasing in the United States. About 10-20% recur after initial treatment, with increasing recurrence following subsequent treatment courses. This sequence can lead to recurrent CDI (rCDI), refractory to conventional therapeutics resulting in the most common indication for fecal microbiota transplantation (FMT). FMT is the most effective microbial therapeutic to date and can cure rCDI in 80-90% of cases. There is growing concern, however, for pathogen transmission through FMT, underscoring the importance of careful recipient selection. In adults referred for FMT with a tentative diagnosis of rCDI, alternative diagnoses were recognized in 25% of patients, but such observation in children is lacking. In this single-center retrospective study, alternative diagnoses (eg, constipation/overflow diarrhea, inflammatory bowel disease) were found in 13 (22.4%) of 58 children who were referred for FMT evaluation for rCDI. Of the patients who were diagnosed with rCDI, 16 (27.6%) did not require FMT.

Rapid Classification of Clostridioides difficile Strains Using MALDI-TOF MS Peak-Based Assay in Comparison with PCR-Ribotyping

Typing methods are needed for epidemiological tracking of new emerging and hypervirulent strains because of the growing incidence, severity and mortality of Clostridioides difficile infections (CDI). The aim of this study was the evaluation of a typing Matrix-Assisted Desorption/Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS (T-MALDI)) method for the rapid classification of the circulating C. difficile strains in comparison with polymerase chain reaction (PCR)-ribotyping results. Among 95 C. difficile strains, 10 ribotypes (PR1-PR10) were identified by PCR-ribotyping. In particular, 93.7% of the isolates (89/95) were grouped in five ribotypes (PR1-PR5). For T-MALDI, two classifying algorithm models (CAM) were tested: the first CAM involved all 10 ribotypes whereas the second one only the PR1-PR5 ribotypes. Better performance was obtained using the second CAM: recognition capability of 100%, cross-validation of 96.6% and agreement of 98.4% (60 correctly typed strains, limited to PR1-PR5 classification, out of 61 examined strains) with PCR-ribotyping results. T-MALDI seems to represent an alternative to PCR-ribotyping in terms of reproducibility, set up time and costs, as well as a useful tool in epidemiological investigation for the detection of C. difficile clusters (either among CAM included ribotypes or out-of-CAM ribotypes) involved in outbreaks.

Two-step Testing for Clostridioides Difficile is Inadequate in Differentiating Infection From Colonization in Children

OBJECTIVES

Recent Infectious Disease Society of America guidelines recommend multistep testing algorithms to diagnose Clostridioides difficile infection (CDI), including a combination of nucleic acid amplification-based testing (NAAT) and toxin enzyme immunoassay (EIA). The use of these algorithms in children, including the ability to differentiate between C. difficile colonization and CDI, however, has not been evaluated.

METHODS

We prospectively enrolled asymptomatic pediatric patients with cancer, cystic fibrosis (CF), or inflammatory bowel disease (IBD) and obtained a stool sample for NAAT testing. If positive by NAAT (colonized), EIA was performed. In addition, children with symptomatic CDI who tested positive by NAAT via the clinical laboratory were enrolled, and EIA was performed on residual stool. A functional cell cytotoxicity neutralization assay (CCNA) was also applied to stool samples from both the colonized and symptomatic cohorts.

RESULTS

Of the 225 asymptomatic children enrolled in the study, 47 (21%) were colonized with C. difficile including 9/59 (15.5%) with cancer, 30/92 (32.6%) with CF, and 8/74 (10.8%) with IBD. An additional 41 children with symptomatic CDI were enrolled. When symptomatic and colonized children were compared, neither EIA positivity (44% vs 26%, P = 0.07) nor CCNA positivity (49% vs 45%, P = 0.70) differed significantly or were able to predict disease severity in the symptomatic cohort.

CONCLUSIONS

Use of a multistep testing algorithm with NAAT followed by EIA failed to differentiate symptomatic CDI from asymptomatic colonization in our pediatric cohort. As multistep algorithms are moved into clinical care, the pediatric provider will need to be aware of their limitations.