C. difficile Infection: Changing Epidemiology and Management Paradigms

Core-genome-mediated promising alternative drug and multi-epitope vaccine targets prioritization against infectious Clostridium difficile

Prevention of Clostridium difficile infection is challenging worldwide owing to its high morbidity and mortality rates. C. difficile is currently being classified as an urgent threat by the CDC. Devising a new therapeutic strategy become indispensable against C. difficile infection due to its high rates of reinfection and increasing antimicrobial resistance. The current study is based on core proteome data of C. difficile to identify promising vaccine and drug candidates. Immunoinformatics and vaccinomics approaches were employed to construct multi-epitope-based chimeric vaccine constructs from top-ranked T- and B-cell epitopes. The efficacy of the designed vaccine was assessed by immunological analysis, immune receptor binding potential and immune simulation analyses. Additionally, subtractive proteomics and druggability analyses prioritized several promising and alternative drug targets against C. difficile. These include FMN-dependent nitroreductase which was prioritized for pharmacophore-based virtual screening of druggable molecule databases to predict potent inhibitors. A MolPort-001-785-965 druggable molecule was found to exhibit significant binding affinity with the conserved residues of FMN-dependent nitroreductase. The experimental validation of the therapeutic targets prioritized in the current study may worthy to identify new strategies to combat the drug-resistant C. difficile infection.

Automated Detection of Patient Harm: Implementation and Prospective Evaluation of a Real-Time Broad-Spectrum Surveillance Application in a Hospital With Limited Resources

OBJECTIVES

This study aimed to prospectively validate an application that automates the detection of broad categories of hospital adverse events (AEs) extracted from a basic hospital information system, and to efficiently mobilize resources to reduce the level of acquired patient harm.

METHODS

Data were collected from an internally designed software, extracting results from 14 triggers indicative of patient harm, querying clinical and administrative databases including all inpatient admissions (n = 8760) from October 2019 to June 2020. Representative samples of the triggered cases were clinically validated using chart review by a consensus expert panel. The positive predictive value (PPV) of each trigger was evaluated, and the detection sensitivity of the surveillance system was estimated relative to incidence ranges in the literature.

RESULTS

The system identified 394 AEs among 946 triggered cases, associated with 291 patients, yielding an overall PPV of 42%. Variability was observed among the trigger PPVs and among the estimated detection sensitivities across the harm categories, the highest being for the healthcare-associated infections. The median length of stay of patients with an AE showed to be significantly higher than the median for the overall patient population.

CONCLUSIONS

This application was able to identify AEs across a broad spectrum of harm categories, in a real-time manner, while reducing the use of resources required by other harm detection methods. Such a system could serve as a promising patient safety tool for AE surveillance, allowing for timely, targeted, and resource-efficient interventions, even for hospitals with limited resources.

Comparison between Symptomatic and Asymptomatic Mice after Clostridioides difficile Infection Reveals Novel Inflammatory Pathways and Contributing Microbiota

Clostridioides difficile causes the highest number of nosocomial infections. Currently, treatment options for C. difficile infection (CDI) are very limited, resulting in poor treatment outcomes and high recurrence rates. Although the disease caused by CDI is inflammatory in nature, the role of inflammation in the development of CDI symptoms is contradictory and not completely understood. Hence, the use of anti-inflammatory medication is debatable in CDI. In the current study, we evaluated the genetic and microbiome profiles of mice after infection with C. difficile. These mice were categorized based on the severity of CDI and the results were viewed accordingly. Our results indicate that certain genes are upregulated in severe CDI more than in the moderate case. These include oncostatin-M (OSM), matrix metalloprotease 8 (MMP8), triggering receptor expressed on myeloid cells 1 (Trem-1), and dual oxidase 2 (Duox2). We also investigated the microbiome composition of CDI mice before and after infecting with C. difficile. The results show that C. difficile abundance is not indicative of diseases severity. Certain bacterial species (e.g., Citrobacter) were enriched while others (e.g., Turicibacter) were absent in severe CDI. This study identifies novel inflammatory pathways and bacterial species with a potential role in determining the severity of CDI.

In Silico Characterization of Uncharacterized Proteins From Multiple Strains of Clostridium Difficile

Clostridium difficile (C. difficile) is a multi-strain, spore-forming, Gram-positive, opportunistic enteropathogen bacteria, majorly associated with nosocomial infections, resulting in severe diarrhoea and colon inflammation. Several antibiotics including penicillin, tetracycline, and clindamycin have been employed to control C. difficile infection, but studies have suggested that injudicious use of antibiotics has led to the development of resistance in C. difficile strains. However, many proteins from its genome are still considered uncharacterized proteins that might serve crucial functions and assist in the biological understanding of the organism. In this study, we aimed to annotate and characterise the 6 C. difficile strains using in silico approaches. We first analysed the complete genome of 6 C. difficile strains using standardised approaches and analysed hypothetical proteins (HPs) employing various bioinformatics approaches coalescing, including identifying contigs, coding sequences, phage sequences, CRISPR-Cas9 systems, antimicrobial resistance determination, membrane helices, instability index, secretory nature, conserved domain, and vaccine target properties like comparative homology analysis, allergenicity, antigenicity determination along with structure prediction and binding-site analysis. This study provides crucial supporting information about the functional characterization of the HPs involved in the pathophysiology of the disease. Moreover, this information also aims to assist in mechanisms associated with bacterial pathogenesis and further design candidate inhibitors and bona fide pharmaceutical targets.

Incidence, Attributable Mortality, and Healthcare and Out-of-Pocket Costs of Clostridioides difficile Infection in US Medicare Advantage Enrollees

BACKGROUND

US attributable Clostridioides difficile infection (CDI) mortality and cost data are primarily from Medicare fee-for-service populations, and little is known about Medicare Advantage Enrollees (MAEs). This study evaluated CDI incidence among MAEs from 2012 to 2019 and determined attributable mortality and costs by comparing MAEs with and without CDI occurring in 2018.

METHODS

This retrospective cohort study assessed CDI incidence and associated mortality and costs for eligible MAEs ≥65 years of age using the de-identified Optum Clinformatics Data Mart database (Optum; Eden Prairie, Minnesota, USA). Outcomes included mortality, healthcare utilization, and costs, which were assessed via a propensity score-matched cohort using 2018 as the index year. Outcome analyses were stratified by infection acquisition and hospitalization status.

RESULTS

From 2012 to 2019, overall annual CDI incidence declined from 609 to 442 per 100 000 person-years. Although the incidence of healthcare-associated CDI declined overall (2012, 53.2%; 2019, 47.2%), community-associated CDI increased (2012, 46.8%; 2019, 52.8%). The 1-year attributable mortality was 7.9% (CDI cases, 26.3%; non-CDI controls, 18.4%). At the 2-month follow-up, CDI-associated excess mean total healthcare and out-of-pocket costs were $13 476 and $396, respectively. Total excess mean healthcare costs were greater among hospitalized (healthcare-associated, $28 762; community-associated, $28 330) than nonhospitalized CDI patients ($5704 and $2320, respectively), whereas total excess mean out-of-pocket cost was highest among community-associated hospitalized CDI patients ($970).

CONCLUSIONS

CDI represents an important public health burden in the MAE population. Preventive strategies and treatments are needed to improve outcomes and reduce costs for healthcare systems and this growing population of older US adults.

Risk Factors of Patients With Diarrhea for Having Clostridioides (Clostridium) difficile Infection

Nosocomial infections with Clostridioides (Clostridium) difficile have become an emergent health threat. We sought to define risk factors for a C. difficile infection (CDI) beyond the widely known ones, such as antibiotic use and prior hospital stay. We therefore focused on a group of patients with diarrhea in order to identify risk factors for C. difficile infection among this symptomatic cohort. A total of 121 hospitalized patients from Seesen/Germany with diarrhea were included who submitted a stool sample and were interviewed about their socio-demographic background, lifestyle and state of health using a standardized questionnaire. Antibiotic potential of diuretics was examined by agar diffusion test. C. difficile was identified in 29 patients resulting in a prevalence of 24.0%. The infection was hospital-acquired in most cases (p < 0.001, 82.1%; n = 23/28, versus 29/91, 31.9%). The generally accepted risk factor previous antibiotic use was confirmed in this study (p = 0.002, n = 23/28 CDI patients, 82.1%, versus n = 44/91 non-CDI patients, 48.4%). The following additional risk factors were identified: regular consumption of proton pump inhibitors; PPI (p = 0.011, n = 24/29, 82.8% vs. n = 52/92, 56.5%), CDI patients ate less vegetables (p = 0.001, n = 12/29, 41.4% vs. 69/92, 75.0%). The intake of the diuretic agent torasemid in patients with CDI (p = 0.005, n = 18/29, 62.1%) was higher than in patients without (n = 30/92, 32.6%). More patients with CDI had to undergo a surgery in the previous year (p = 0.022, n = 13/29, 44.8% vs. n = 21/92, 22.8%) and held more birds (p = 0.056, n = 4/29, 13.8%) than individuals of the negative group (n = 3/92, 3.3%). In conclusion, although no antibiotic potential was detected in diuretics, especially torasemid seems to have significant influence for the occurrence of a CDI as well as a nutrition poor in vegetables. A diet rich in vegetables represented a fourfold lower risk for a CDI (OR 0.240, CI (0.0720 - 0.796]).

Evaluation of a Broad-Spectrum Partially Automated Adverse Event Surveillance System: A Potential Tool for Patient Safety Improvement in Hospitals With Limited Resources

OBJECTIVE

The aim of the study was to evaluate the sensitivity and resource efficiency of a partially automated adverse event (AE) surveillance system for routine patient safety efforts in hospitals with limited resources.

METHODS

Twenty-eight automated triggers from the hospital information system's clinical and administrative databases identified cases that were then filtered by exclusion criteria per trigger and then reviewed by an interdisciplinary team. The system, developed and implemented using in-house resources, was applied for 45 days of surveillance, for all hospital inpatient admissions (N = 1107). Each trigger was evaluated for its positive predictive value (PPV). Furthermore, the sensitivity of the surveillance system (overall and by AE category) was estimated relative to incidence ranges in the literature.

RESULTS

The surveillance system identified a total of 123 AEs among 283 reviewed medical records, yielding an overall PPV of 52%. The tool showed variable levels of sensitivity across and within AE categories when compared with the literature, with a relatively low overall sensitivity estimated between 21% and 44%. Adverse events were detected in 23 of the 36 AE categories defined by an established harm classification system. Furthermore, none of the detected AEs were voluntarily reported.

CONCLUSIONS

The surveillance system showed variable sensitivity levels across a broad range of AE categories with an acceptable PPV, overcoming certain limitations associated with other harm detection methods. The number of cases captured was substantial, and none had been previously detected or voluntarily reported. For hospitals with limited resources, this methodology provides valuable safety information from which interventions for quality improvement can be formulated.

Development and validation of a simple and robust model to predict 30-day mortality in patients with Clostridioides difficile-associated enterocolitis

Objective

Clostridioides difficile infection (CDI) is a common healthcare-associated infection and associated with high morbidity and mortality. As current guidelines recommend treatment stratified for disease severity, this study aimed to identify predictors of 30-day mortality in order to develop a robust prediction model.

Design

This was a retrospective analysis of 207 inpatients with CDI who were treated at the Jena University Hospital between September 2011 and December 2015. In a training cohort (n=127), predictors of 30-day mortality were identified by receiver operating characteristics analysis and logistic regression. The derived model was validated in an independent cohort of 80 inpatients with CDI.

Results

Within 30 days, 35 (28%) patients in the training cohort died from any cause. C-reactive protein (CRP) of ≥121 mg/L (OR 3.80; 95% CI 1.64 to 7.80; p=0.003) and lower systolic blood pressure of ≤104 mm Hg (OR 3.73; 95% CI 1.63 to 8.53; p=0.002) at diagnosis as well as development of renal impairment (serum creatinine >1.5×baseline; OR 5.61; 95% CI 1.94 to 16.26; p=0.035) within the first 6 days were associated with 30-day mortality in univariate analysis. The use of these parameters enabled correct mortality prediction in 73% of cases on the day of diagnosis and in 76% at day 6. In the validation cohort, 30-day mortality was 18/80 (23%). Our model enabled a 73.7% correct prediction concerning 30-day mortality on day 6 after diagnosis of CDI.

Conclusion

Hypotension and CRP elevation on the day of diagnosis as well as occurrence of kidney dysfunction during the first 6 days are suitable parameters to predict 30-day mortality in patients with CDI who need to be treated in the hospital.

Antibiotics and healthcare facility-associated Clostridioides difficile infection: systematic review and meta-analysis 2020 update

BACKGROUND

Antibiotic use is the most important modifiable risk factor for healthcare facility-associated Clostridioides difficile infection (HCFA-CDI). Previous systematic reviews cover studies published until 31 December 2012.

OBJECTIVES

To update the evidence for associations between antibiotic classes and HCFA-CDI to 31 December 2020.

METHODS

PubMed, Scopus, Web of Science Core Collection, WorldCat and Proquest Dissertations & Theses were searched for studies published since 1 January 2013. Eligible studies were those conducted among adult hospital inpatients, measured exposure to individual antibiotics or antibiotic classes, included a comparison group and measured the occurrence of HCFA-CDI as an outcome. The Newcastle-Ottawa Scale was used to appraise study quality. To assess the association between each antibiotic class and HCFA-CDI, a pooled random-effects meta-analysis was undertaken. Meta-regression and subgroup analysis was used to investigate study characteristics identified a priori as potential sources of heterogeneity.

RESULTS

Carbapenems and third- and fourth-generation cephalosporin antibiotics remain the most strongly associated with HCFA-CDI, with cases more than twice as likely to have recent exposure to these antibiotics prior to developing HCFA-CDI. Modest associations were observed for fluoroquinolones, clindamycin and β-lactamase inhibitor combination penicillin antibiotics. Individual study effect sizes were variable and heterogeneity was observed for most antibiotic classes.

CONCLUSIONS

This review provides the most up-to-date synthesis of evidence in relation to the risk of HCFA-CDI associated with exposure to specific antibiotic classes. Studies were predominantly conducted in North America or Europe and more studies outside of these settings are needed.

Large Clostridial Toxins: Mechanisms and Roles in Disease

Large clostridial toxins (LCTs) are a family of bacterial exotoxins that infiltrate and destroy target cells. Members of the LCT family include Clostridioides difficile toxins TcdA and TcdB, Paeniclostridium sordellii toxins TcsL and TcsH, Clostridium novyi toxin TcnA, and Clostridium perfringens toxin TpeL. Since the 19th century, LCT-secreting bacteria have been isolated from the blood, organs, and wounds of diseased individuals, and LCTs have been implicated as the primary virulence factors in a variety of infections, including C. difficile infection and some cases of wound-associated gas gangrene. Clostridia express and secrete LCTs in response to various physiological signals. LCTs invade host cells by binding specific cell surface receptors, ultimately leading to internalization into acidified vesicles. Acidic pH promotes conformational changes within LCTs, which culminates in translocation of the N-terminal glycosyltransferase and cysteine protease domain across the endosomal membrane and into the cytosol, leading first to cytopathic effects and later to cytotoxic effects. The focus of this review is on the role of LCTs in infection and disease, the mechanism of LCT intoxication, with emphasis on recent structural work and toxin subtyping analysis, and the genomic discovery and characterization of LCT homologues. We provide a comprehensive review of these topics and offer our perspective on emerging questions and future research directions for this enigmatic family of toxins.

Microbiological features, epidemiology, and clinical presentation of Clostridioidesdifficile strains from MLST Clade 2: A narrative review

Clostridioides difficile is an emerging One Health pathogen and a common etiologic agent of diarrhea, both in healthcare settings and the community. This bacterial species is highly diverse, and its global population has been classified in eight clades by multilocus sequence typing (MLST). The C. difficile MLST Clade 2 includes the NAP1/RT027/ST01 strain, which is highly recognized due to its epidemicity and association with severe disease presentation and mortality. By contrast, the remaining 83 sequence types (STs) that compose this clade have received much less attention. In response to this shortcoming, we reviewed articles published in English between 1999 and 2020 and collected information for 27 Clade 2 STs, with an emphasis on STs 01, 67, 41 and 188/231/365. Our analysis provides evidence of large phenotypic differences that preclude support of the rather widespread notion that ST01 and Clade 2 strains are "hypervirulent". Moreover, it revealed a profound lack of (meta)data for nearly 70% of the Clade 2 STs that have been identified in surveillance efforts. Targeted studies aiming to relate wet-lab and bioinformatics results to patient and clinical parameters should be performed to gain a more in-depth insight into the biology of this intriguing group of C. difficile isolates.

Decision Analysis: Omadacycline Relative to Moxifloxacin Among Hospitalized Community-Acquired Bacterial Pneumonia Patients at Risk of Clostridioides difficile Infection

BACKGROUND AND OBJECTIVE: Omadacycline is an aminomethylcycline antibiotic approved in the USA as once-daily intravenous/oral monotherapy for adults with community-acquired bacterial pneumonia (CABP). Omadacycline demonstrated noninferiority to the fluoroquinolone moxifloxacin in a phase III CABP trial; adverse-event rates were similar between treatment groups except for Clostridioides difficile infection (CDI), which occurred in 2% of moxifloxacin-treated patients and 0% of patients on omadacycline. Conceptual healthcare-decision analytic models were developed to better understand the economic implications of antibiotic selection and CDI risk in acute-care facilities.

METHODS

A conceptual healthcare-decision analytic model was created to estimate incremental costs associated with treating 100 hospitalized CABP patients with an initial 5-day inpatient regimen of omadacycline instead of moxifloxacin. The underlying model assumption was that treatment with omadacycline has the potential to reduce CDI events relative to moxifloxacin. The model included excess costs associated with each treatment group from admission through discharge. Attributable CDI cost per case in the moxifloxacin group varied from $15,000 to $45,000 (US$). Omadacycline acquisition cost was $300-600/day for 5 days.

RESULTS

At a CDI attributable cost per case of $30,000 (base-case analyses), the incremental treatment cost (US$) per 100 patients ranged from $300,000 to $- 120,000 (cost savings). The excess CDI incidence in moxifloxacin-treated patients would need to be 5-10% for omadacycline to be cost-saving, assuming the attributable CDI cost is approximately $30,000.

CONCLUSION

Targeted omadacycline use may reduce economic burden associated with hospitalized CABP patients treated with moxifloxacin if it can reduce excess cases of moxifloxacin-associated CDI.

High Prevalence of Clostridium difficile in Home Gardens in Western Australia

In recent years, community-associated Clostridium difficile infection (CA-CDI) has emerged as a significant health problem, accounting for ∼50% of all CDI cases. We hypothesized that the home garden environment could contribute to the dissemination of C. difficile spores in the community and investigated 23 homes in 22 suburbs of Perth, Western Australia. We identified a high prevalence of toxigenic C. difficile in this environment. In total, 97 samples consisting of soil (n = 48), compost (n = 15), manure (n = 12), and shoe sole swabs (n = 22) were collected. All samples were cultured anaerobically on C. difficile ChromID agar and enriched in brain heart infusion broth, and isolates were characterized by toxin gene PCR and PCR ribotyping. Two-thirds (67%; 95% confidence interval [CI], 57 to 76%) of home garden samples, including 79% (95% CI, 68 to 91%) of soil, 67% (95% CI, 43 to 90%) of compost, 83% (95% CI, 62% to 100%) of manure, and 32% (95% CI, 12 to 51%) of shoe sole samples, contained C. difficile Of 87 isolates, 38% (95% CI, 28 to 48%) were toxigenic, and 26 PCR ribotypes (RTs), 5 of which were novel, were identified. The toxigenic C. difficile strain RT014/020 was the most prevalent RT. Interestingly, 19 esculin hydrolysis-negative strains giving white colonies were identified on C. difficile ChromID agar, 5 of which were novel toxigenic RTs that produced only toxin A. Clearly, there is the potential for transmission of C. difficile in the community due to the contamination of home gardens. Our findings highlight the importance of a "One Health" approach to dealing with CDI.IMPORTANCE Recently, community-associated Clostridium difficile infection (CA-CDI) has emerged as a significant problem, accounting for ∼50% of all CDI cases and reported to affect a younger population without traditional risk factors. Possible sources of CA-CDI are soil, food, and water contaminated by animal feces, and recent reports show overlapping ribotypes of C. difficile in animals, humans, and the environment; however, the epidemiology of CA-CDI and related risk factors need to be better understood. Our research aimed to determine the prevalence of C. difficile in home gardens and on the shoe soles of homeowners in Perth, Western Australia. There were high rates of contamination with C. difficile in gardens, and some of the ribotypes identified had been isolated from human cases of CDI in Western Australia. This study shows that home gardens and shoes may be a source of C. difficile in CA-CDI.

Assessing risk factors, mortality, and healthcare utilization associated with Clostridioides difficile infection in four Latin American countries

Background

Clostridioides difficile infection (CDI) is the most common cause of healthcare-associated infections in Western countries. Risk factors, mortality, and healthcare utilization for CDI in Latin America are poorly understood. This study assessed risk factors and burden associated with nosocomial CDI in four Latin American countries.

Methods

This retrospective, case-control study used databases and medical records from 8 hospitals in Argentina, Brazil, Chile, and Mexico to identify nosocomial CDI cases from 2014 − 2017. Cases were patients aged ≥18 years with diarrhea and a positive CDI test ≥72 h after hospital admission. Two controls (without diarrhea; length of hospital stay [LOS] ≥3 days; admitted ±14 days from case patient; shared same ward) were matched to each case. CDI-associated risk factors were assessed by univariate and multivariable analyses. CDI burden (LOS, in-hospital mortality) was compared between cases and controls.

Results

The study included 481 cases and 962 controls. Mean age and sex were similar between cases and controls, but mean Charlson comorbidity index (4.3 vs 3.6; p < 0.001) and recent hospital admission (35.3% vs 18.8%; p < 0.001) were higher among cases. By multivariable analyses, CDI risk was associated with prior hospital admission within 3 months (odds ratio [OR], 2.08; 95% CI: 1.45, 2.97), recent antibiotic use (ie, carbapenem; OR, 2.85; 95% CI: 1.75, 4.64), acid suppressive therapy use (OR, 1.71; 95% CI: 1.14, 2.58), and medical conditions (ie, renal disease; OR, 1.48; 95% CI: 1.19, 1.85). In-hospital mortality rate (18.7% vs 6.9%; p < 0.001) and mean overall LOS (33.5 vs 18.8 days; p < 0.001) were higher and longer, respectively, in cases versus controls.

Conclusion

Antibiotic exposure, preexisting medical conditions, and recent hospital admission were major risk factors for CDI in Argentina, Brazil, Chile, and Mexico. CDI was associated with increased in-hospital risk of death and longer LOS. These findings are consistent with published literature in Western countries.

Diagnosing Clostridioides difficile infections with molecular diagnostics: multicenter evaluation of revogene C. difficile assay

Clostridioides difficile infections are a significant threat to our healthcare system, and rapid and accurate diagnostics are crucial to implement the necessary infection prevention and control measurements. Nucleic acid amplification tests are such reliable diagnostic tools for the detection of toxigenic Clostridioides difficile strains directly from stool specimens. In this multicenter evaluation, we determined the performance of the revogene C. difficile assay. The analysis was conducted on prospective stool specimens collected from six different sites in Europe. The performance of the revogene C. difficile assay was compared to the different routine diagnostic methods and, for a subset of the specimens, against toxigenic culture. In total, 2621 valid stool specimens were tested, and the revogene C. difficile assay displayed a sensitivity/specificity of 97.1% [93.3-99.0] and 98.9% [98.5-99.3] for identification of Clostridioides difficile infection. Discrepancy analysis using additional methods improved this performance to 98.8% [95.8-99.9] and 99.6% [99.2-99.8], respectively. In comparison to toxigenic culture, the revogene C. difficile assay displayed a sensitivity/specificity of 93.0% [86.1-97.1] and 99.5% [98.7-99.9], respectively. These results indicate that the revogene C. difficile assay is a robust and reliable aid in the diagnosis of Clostridioides difficile infections.

Role of Surgery in Clostridium difficile Infection

Clostridium (reclassified as " Clostridioides ") difficile infection (CDI) occurs as a chronic or an acute illness with intensity varying from mild to severe. Although most cases of CDI can be managed with antibiotics and supportive care, when the patient presents with fulminant disease, the early decision to perform surgery is imperative for survival. The current standard of care is the subtotal colectomy. However, loop ileostomy with vancomycin enemas delivered into the colonic mucosa has been described as a viable option on selected patients.

Perception of quality of life in people experiencing or having experienced a Clostridioides difficile infection: a US population survey

BACKGROUND

Although the incidence, severity and mortality of Clostridioides (Clostridium) difficile infection (CDI) have been increasing, patients' quality of life changes resulting from CDI have not been studied thoroughly. This study aimed at exploring the consequences of CDI on quality of life through patients' perspective.

METHODS

An observational, cross-sectional study involving 350 participants with a self-reported CDI diagnosis was conducted through an online self-administered survey. Participants were grouped into those who had active disease ("Current CDI") and those who had a history of CDI ("Past CDI").

RESULTS

One hundred fifteen participants (33%) reported Current CDI and 235 (67%) reported Past CDI. A large majority of participants admitted that their daily activities were impacted by the infection (93.9% and 64.7% of Current and Past CDI respondents respectively, p < 0.05). Physical and psychological consequences of CDI were experienced by 63.5% and 66.1% of participants with active CDI. Despite the infection being cleared, these consequences were still frequently experienced in Past CDI cohort with similar rates (reported by 73.2% of respondents for both, physical consequences p = 0.08; psychological consequences p = 0.21). After the infection, 56.6% of respondents noted that post-CDI symptoms remained; 40.9% believed they would never get rid of them.

CONCLUSIONS

While the societal burden of CDI is well described in the literature, our study is one of the first aimed at understanding the major burden of CDI on quality of life. Our results highlight the long-lasting nature of CDI and further reinforce the need for enhanced therapeutics in the prevention and treatment of this devastating infection.

Treatment of Severe and Fulminnant Clostridioides difficile Infection

PURPOSE OF REVIEW

This article will review current management strategies for severe and fulminant Clostridioides difficile infection (CDI).

RECENT FINDINGS

Clostridioides difficile is the most common nosocomial cause of infectious diarrhea. With the rise of hypervirulent strains of CDI, almost 8% of patients hospitalized with CDI are afflicted with severe CDI (SCDI) or fulminant CDI (FCDI). A significant proportion of these patients do not respond to recommended anti-CDI antibiotic therapy such as oral vancomycin and fidaxomicin. Current recommendations suggest that patients with refractory CDI should proceed to colectomy or diverting loop ileostomy with colonic lavage. However, both of these surgical interventions result in high rates of post-surgical mortality approaching 30%. Fecal microbiota transplantation (FMT) is a promising therapy that is recommended in recurrent CDI. Recent studies have found that FMT can safely produce cure rates between 70 and 90% in patients with SCDI and FCDI, while significantly decreasing rates of CDI-related mortality and colectomy. A patient population likely to benefit the most from FMT is elderly patients due to their increased risk for CDI, treatment failure, and high comorbidity burden that may preclude surgical intervention. FMT should be considered in patients with SCDI or FCDI particularly when traditional anti-CDI antibiotics are ineffective.

Clostridium difficile intervention timelines for diagnosis, isolation, and treatment

BACKGROUND

Developing timelines of nosocomial Clostridium difficile infection (CDI) is critical to improving control and preventive measures. The objective of this study was to provide data-driven estimates of CDI timelines of diagnosis, isolation, and treatment in a hospital setting.

METHODS

We obtained data for all CDI inpatients with symptoms onset occurring between January 1, 2013, and December 30, 2017, from St Joseph's Healthcare in Hamilton, Canada. We analyzed full empirical distributions of timelines associated with the diagnosis, isolation, and treatment of CDI.

RESULTS

A total of 683 inpatients with CDI symptoms were recorded, of which 243 cases were identified as health care-associated infection (HAI). The mean time intervals between the onset of CDI symptoms after admission and the release of laboratory results were 1.2 days and 1.9 days for the HAI and community-associated infection (CAI) patient groups, respectively. The mean time intervals from symptoms onset to the start of isolation were 1.5 days and 2.6 days for the corresponding patient groups. The initiation of treatment within 2 days of symptoms onset reduced the duration of first isolation (P value < .0001); however, the type of initial antibiotic used for CDI treatment was not associated with the duration of isolation.

CONCLUSIONS

Estimated timelines did not differ (P values > .6) between HAI and CAI patient groups with symptoms onset after admission. These estimates are useful for evaluating the effectiveness of CDI interventions.

The interaction of silver(II) complexes with biological macromolecules and antioxidants

Silver is widely used for its antimicrobial properties, but microbial resistance to heavy metals is increasing. Silver(II) compounds are more oxidizing and therefore have the potential to overcome resistance via extensive attack on cellular components, but have traditionally been hard to stabilize for biological applications. Here, the high oxidation state cation was stabilised using pyridinecarboxylate ligands, of which the 2,6-dicarboxypyridine Ag(II) complex (Ag2,6P) was found to have the best tractability. This complex was found to be more stable in phosphate buffer than DMSO, allowing studies of its interaction with water soluble antioxidants and biological macromolecules, with the aim of demonstrating its potential to oxidize them, as well as determining the reaction products. Spectrophotometric analysis showed that Ag2,6P was rapidly reduced by the antioxidants glutathione, ascorbic acid and vitamin E; the unsaturated lipids arachidonic and linoleic acids, model carbohydrate β-cyclodextrin, and protein cytochrome c also reacted readily. Analysis of the reaction with glutathione by NMR and electrospray mass spectrometry confirmed that the glutathione was oxidized to the disulfide form. Mass spectrometry also clearly showed the addition of multiple oxygen atoms to the unsaturated fatty acids, suggesting a radical mechanism, and cross-linking of linoleic acid was observed. The seven hydroxyl groups of β-cyclodextrin were found to be completely oxidized to the corresponding carboxylates. Treatment of cytochrome c with Ag2,6P led to protein aggregation and fragmentation, and dose-dependent oxidative damage was demonstrated by oxyblotting. Thus Ag2,6P was found to be highly oxidizing to a wide variety of polar and nonpolar biological molecules.

Clostridium difficile Infection-Daily Symptoms (CDI-DaySyms™) questionnaire: psychometric characteristics and responder thresholds

Background

The purpose of the current study was to determine the final content validation, psychometric characteristics, clinically meaningful improvement, and responder thresholds of the Clostridium difficile infection (CDI)–Daily Symptoms (CDI-DaySyms™) patient-reported outcome (PRO) questionnaire.

Methods

This validation study was part of two phase III studies (NCT01987895 and NCT01983683) conducted in patients with mild-to-moderate or severe CDI who completed the CDI-DaySyms™ daily throughout the treatment period. The questionnaire was evaluated in three stages: final PRO item content validation (Stage I); psychometric evaluation of reliability and construct validity (Stage II); and determination of clinically meaningful improvement and responder thresholds using distribution-based methods (Stage III).

Results

The analysis included 168 patients. Most patients were female and Caucasian with mild-to-moderate CDI. The mean age was 57.1 years. Initial item analysis supported by confirmatory factor analysis demonstrated the relevance of 10 items grouped into three distinct domains (Diarrhea Symptoms, Abdominal Symptoms, and Systemic/Other Symptoms). Domain scores demonstrated acceptable internal consistency and test-retest reliability, were sensitive to change, and correlated in expected directions with other relevant symptom and disease-severity measures. Responder thresholds were defined as score changes of − 1.00, − 0.80, and − 0.70 in the Diarrhea Symptoms, Abdominal Symptoms, and Systemic/Other Symptoms domains, respectively.

Conclusions

The CDI-DaySyms™ is a valid measure of patient-reported CDI symptoms, with good measurement properties, which supports its utility as an endpoint in clinical studies. Further studies confirming responder thresholds based on anchor-based methods are required.

Trial registration

NCT01987895, registered November 20, 2013; NCT01983683, registered November 14, 2013.

Electronic supplementary material

The online version of this article (10.1186/s12955-019-1142-9) contains supplementary material, which is available to authorized users.

Clostridium difficile isolated from faecal samples in patients with ulcerative colitis

BACKGROUND

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) that is widely identified worldwide. This study aimed to investigate the phenotypic characterization and molecular typing of Clostridium difficile isolates among patients with UC at an inflammatory bowel disease clinic in Iran.

METHODS

In this cross-sectional study, conducted from April 2015 to December 2015, 85 UC patients were assessed for C.difficile infection (CDI). C. difficile isolates were characterized based on their toxin profile and antimicrobial resistance pattern. Multi-locus sequence typing analysis (MLST) and PCR ribotyping were performed to define the genetic relationships between different lineages of toxigenic strains.

RESULTS

The prevalence of C. difficile isolates was 31.8% (27/85) in patients, of those 15 patients (17.6%) had CDI. Three different sequence types (STs) identified based on MLST among the toxigenic isolates, that is ST54 (33.3%), ST2 (53.3%), and ST37 (13.6%). C. difficile strains were divided into four different PCR-ribotypes (012, 014, 017 and IR1). The most common ribotype was 014 accounting for 48.3% (7/15) of all strains. The strains isolated during the first episode and recurrence of CDI usually belonged to PCR ribotype 014 (ST2). A high rate of CDI recurrence (14.1%, 12/85) experienced in UC patients. Colonization of the gastrointestinal tract with non-toxigenic C. difficile strains was frequent among patients with mild disease. All C. difficile isolates were susceptible to metronidazole, and vancomycin, 86 and 67% of isolates were resistant to clindamycin and erythromycin respectively. There was no correlation between the toxin type and antibiotic resistance (p > 0.05).

CONCLUSION

Overall CDI is rather prevalent in UC patients. All patients with CDI experienced moderate to severe disease and exposed to different antimicrobial and anti-inflammatory agents. Close monitoring and appropriate management including early detection and fast treatment of CDI will improve UC outcomes.

Factors Associated With Health Care Utilization of Recurrent Clostridium difficile Infection in New York State

BACKGROUND

The incidence of infection due to Clostridium difficile infection (CDI) and subsequent economic burden are substantial.

GOALS

The impact of changing practice patterns on demographics at risk and utilization of health care resources for recurrence of CDI remains unclear.

STUDY

A total of 291,163 patients hospitalized for CDI were identified from 1995 to 2014 from the New York SPARCS database. The χ test, the Welch t test, and multivariable logistic regression analysis were performed to evaluate factors related to readmission.

RESULTS

Hospital admissions and readmissions for CDI peaked in 2008 at 20,487 and 13,795, respectively, and have since decreased (linear trend, 0.9706 and 0.9464, respectively; P<0.0001). In total, 60,077 (21%) patients required ≥2 admissions. Risk factors for readmission included: age 55 to 74, government insurance, hypertension, diabetes, anemia, hypothyroidism, chronic pulmonary disease, rheumatoid arthritis, renal failure, peripheral vascular disease, and depression (all P<0.05). Trends in surgery showed a similar peak in 2008 at 165 and have since decreased (linear trend, 0.8660; P<0.0001). A total of 1830 (0.63%) patients with CDI underwent surgery, with emergent being more common than elective (71% vs. 29%).

CONCLUSIONS

Hospital admissions and readmissions for CDI peaked in 2008 and have since been steadily declining. These trends may be secondary to improved diagnostic capabilities and evolving antibiotic regimens. More than 1 in 5 hospitalized patients had at least 1 readmission. Numerous risk factors for these patients have been identified. Although <1% of all patients with CDI undergo surgery, these rates have also been declining.

Survey, characterization and antimicrobial susceptibility of Clostridium difficile from marine bivalve shellfish of North Adriatic Sea

Clostridium difficile is a major cause of infectious diarrhea associated to healthcare settings. Community-acquired infections are increasingly reported in the last decade and exposure other than to symptomatic patients rather to contaminated foods or animals is feasible. Occurrence of C. difficile in shellfish raises concern because spores can survive the cooking temperatures given that shellfish is often consumed poorly cooked or raw. Aim of our study was to investigate whether shellfish represents a reservoir of C. difficile human PCR-ribotypes (RTs). 702 shellfish samples of farmed and wild bivalve mollusc species were collected over the 2015-2017 period in North Adriatic Italian Sea to investigate contamination with C. difficile and characterize the isolates in terms of genotypic variability and antimicrobial resistance profile. C. difficile was detected in 16.9% (CI: 14.1%-19.8%) samples: 11.6% mussels and 23.2% clams. Compared to mussels, clams were significantly associated with detection of C. difficile (OR = 2.4, P < 0.01). Overall 113 C. difficile isolates were genotyped and 75 (66.4%) were toxigenic. Fifty-three different RTs were identified. 40.7% C. difficile isolates were among the RTs most commonly involved in human infection in Europe. The profile of antimicrobial susceptibility was determined by E-test; microbiological resistance was frequent against clindamycin (17%), erythromycin (23%), rifampicin (8.8%) and moxifloxacin (10.6%). All isolates were susceptible to metronidazole and one showed MIC > ECOFF for vancomycin. C. difficile strains showed high variety in RTs, most of them already detected in other animals or known as highly virulent and epidemic in humans. These results prompt towards investigating on specific risk mitigation measures against C. difficile and are preliminary for any source attribution and risk assessment study.

Cadazolid for the treatment of Clostridium difficile infection: results of two double-blind, placebo-controlled, non-inferiority, randomised phase 3 trials

BACKGROUND

Cadazolid is a novel quinoxolidinone antibiotic developed for treating Clostridium difficile infection. We aimed to investigate the safety and efficacy of cadazolid compared with vancomycin in patients with C difficile infection.

METHODS

IMPACT 1 and IMPACT 2 were identically designed, multicentre, double-blind, placebo-controlled, non-inferiority, randomised phase 3 trials. IMPACT 1 was done in Australia, Brazil, Canada, France, Germany, Italy, the Netherlands, Peru, Poland, Romania, Spain, and the USA, and IMPACT 2 was done in Argentina, Belgium, Brazil, Canada, Chile, Croatia, Czech Republic, Greece, Hungary, Israel, Romania, Slovakia, South Korea, the UK, and the USA. Patients (aged 18 years or older) with mild-to-moderate or severe C difficile infection (diarrhoea with positive glutamate dehydrogenase and toxin A or B enzyme immunoassays) were randomly assigned (1:1) with a randomisation list stratified by centre and C difficile infection episode type (block size of four), and allocation was masked to investigators and participants. Patients received either oral cadazolid 250 mg twice daily with vancomycin-matching placebo capsule four times daily or oral vancomycin 125 mg four times a day with cadazolid-matching placebo suspension twice daily for 10 days, with 30 days of follow-up. The primary efficacy outcome was non-inferiority (margin -10%) of cadazolid versus vancomycin for clinical cure in the modified intention-to-treat and per-protocol populations. Clinical cure was defined as resolution of diarrhoea with no additional treatment for C difficile infection. These trials are registered with ClinicalTrials.gov, numbers NCT01987895 (IMPACT 1) and NCT01983683 (IMPACT 2).

FINDINGS

Between March 28, 2014, and March 24, 2017, for IMPACT 1, and Dec 13, 2013, and May 2, 2017, for IMPACT 2, 1263 participants were randomly assigned to receive cadazolid (306 in IMPACT 1 and 298 in IMPACT 2) or vancomycin (326 in IMPACT 1 and 311 in IMPACT 2). In the modified intention-to-treat population in IMPACT 1, 253 (84%) of 302 had clinical cure in the cadazolid group versus 271 (85%) of 318 in the vancomycin group. In IMPACT 2, 235 (81%) of 290 versus 258 (86%) of 301 had clinical cure. In the per-protocol population, 247 (88%) of 282 versus 264 (92%) of 288 had clinical cure in IMPACT 1 and 214 (87%) of 247 versus 237 (92%) of 259 in IMPACT 2. Non-inferiority for clinical cure to vancomycin was shown in IMPACT 1 but not in IMPACT 2 (IMPACT 1 treatment difference: -1·4 [95% CI -7·2 to 4·3] for modified intention to treat and -4·1 [-9·2 to 1·0] for per protocol; IMPACT 2: -4·7 [-10·7 to 1·3] for modified intention to treat and -4·9 [-10·4 to 0·6] for per protocol). The safety and tolerability profiles of the two antibiotics were similar.

INTERPRETATION

Cadazolid was safe and well tolerated but did not achieve its primary endpoint of non-inferiority to vancomycin for clinical cure in one of two phase 3 C difficile infection trials. Therefore, further commercial development of cadazolid for C difficile infection is unlikely.

FUNDING

Actelion Pharmaceuticals.

Multiscale Evolutionary Dynamics of Host-Associated Microbiomes

The composite members of the microbiota face a range of selective pressures and must adapt to persist in the host. We highlight recent work characterizing the evolution and transfer of genetic information across nested scales of host-associated microbiota, which enable resilience to biotic and abiotic perturbations. At the strain level, we consider the preservation and diversification of adaptive information in progeny lineages. At the community level, we consider genetic exchange between distinct microbes in the ecosystem. Finally, we frame microbiomes as open systems subject to acquisition of novel information from foreign ecosystems through invasion by outsider microbes.

Clostridioides difficile-Associated Diarrhea: Infection Prevention Unknowns and Evolving Risk Reduction Strategies

PURPOSE OF REVIEW

New controversies in the diagnosis and prevention of Clostridiodes difficile are challenging and at times changing infection control practice at many medical centers.

RECENT FINDINGS

Molecular epidemiologic studies are changing our understanding of C. difficile and its spectrum of disease. C. difficile as a hospital-acquired infection is likely largely overdiagnosed given overly sensitive molecular testing and widespread colonization of ill or debilitated patients. Clostridiodes difficile infection continues to challenge infection prevention programs. Shifts in our understanding of the epidemiology of this organism and its spectrum of clinical presentations are changing the approach to prevention efforts. Nevertheless, cleanliness of the healthcare environment and antimicrobial stewardship remain core risk reduction strategies. Other strategies such as screening and isolation are inciting controversy. The optimal infection prevention strategies for C. difficile remain the subject of intense study and debate.

Effectiveness of a Two-Step Testing Algorithm for Reliable and Cost-Effective Detection of Clostridium difficile Infection in a Tertiary Care Hospital in Saudi Arabia

The aim of this study was to evaluate the effectiveness of a two-step algorithm for the detection of Clostridium difficile infection. Setting and Design: A two-step testing algorithm was evaluated for testing stool samples from patients suspected of Clostridium difficile infection (CDI). A total of 103 stool specimens were tested using the C. diff Quik Chek Complete enzyme immunoassay (EIA) test and the Xpert C. difficile PCR test. A two-step algorithm was implemented, and data from 3518 patient samples tested during a two-year period after implementation were analyzed to evaluate the effectiveness. The sensitivity, specificity, and positive and negative predictive values (PPV, NPV) of the Quik Chek Complete EIA test were calculated using the Xpert C. difficile PCR test as a reference method. The sensitivity, specificity, PPV, and NPV of the Quik Chek Complete EIA test for C. difficile toxin were 46.7%, 100%, 100%, and 91%, respectively. The two-step algorithm, which combined the Quik Chek Complete EIA with Xpert C. difficile PCR, improved the sensitivity and also provided rapid detection. When algorithm-based testing was performed daily, there was a 66% reduction in turnaround time compared to batch testing using a lengthy ELISA procedure. Postimplementation data analysis showed that almost 89% of the samples could be reported immediately by initial screening with Quik Chek Complete EIA. Only 11% of the samples gave discrepant results and required PCR confirmation. According to our results, the two-step algorithm is an effective tool for the rapid and reliable detection of toxigenic C. difficile from stool samples.

Genomic Study of a Clostridium difficile Multidrug Resistant Outbreak-Related Clone Reveals Novel Determinants of Resistance

Background:Clostridium difficile infection (CDI) is prevalent in healthcare settings. The emergence of hypervirulent and antibiotic resistant strains has led to an increase in CDI incidence and frequent outbreaks. While the main virulence factors are the TcdA and TcdB toxins, antibiotic resistance is thought to play a key role in the infection by and dissemination of C. difficile.

Methods: A CDI outbreak involving 12 patients was detected in a tertiary care hospital, in Lisbon, which extended from January to July, with a peak in February, in 2016. The C. difficile isolates, obtained from anaerobic culture of stool samples, were subjected to antimicrobial susceptibility testing with Etest^®strips against 11 antibiotics, determination of toxin genes profile, PCR-ribotyping, multilocus variable-number tandem-repeat analysis (MLVA) and whole genome sequencing (WGS).

Results: Of the 12 CDI cases detected, 11 isolates from 11 patients were characterized. All isolates were tcdA^-/tcdB⁺ and belonged to ribotype 017, and showed high level resistance to clindamycin, erythromycin, gentamicin, imipenem, moxifloxacin, rifampicin and tetracycline. The isolates belonged to four genetically related MLVA types, with six isolates forming a clonal cluster. Three outbreak isolates, each from a different MLVA type, were selected for WGS. Bioinformatics analysis showed the presence of several antibiotic resistance determinants, including the Thr82Ile substitution in gyrA, conferring moxifloxacin resistance, the substitutions His502Asn and Arg505Lys in rpoB for rifampicin resistance, the tetM gene, associated with tetracycline resistance, and two genes encoding putative aminoglycoside-modifying enzymes, aadE and aac(6′)-aph(2″). Furthermore, a not previously described 61.3 kb putative mobile element was identified, presenting a mosaic structure and containing the genes ermG, mefA/msrD and vat, associated with macrolide, lincosamide and streptogramins resistance. A substitution found in a class B penicillin-binding protein, Cys721Ser, is thought to contribute to imipenem resistance.

Conclusion: We describe an epidemic, tcdA^-/tcdB⁺, multidrug resistant clone of C. difficile from ribotype 017 associated with a hospital outbreak, providing further evidence that the lack of TcdA does not impair the infectious potential of these strains. We identified several determinants of antimicrobial resistance, including new ones located in mobile elements, highlighting the importance of horizontal gene transfer in the pathogenicity and epidemiological success of C. difficile.

The C. difficile puzzle: Putting it all together

This article explores Clostridium difficile infection (CDI) versus colonization, regulations surrounding CDI reporting, the varied types of CDI testing methods available, and the important role nurses have in thoughtful submission of stool specimens for C. difficile testing.

Molecular epidemiologic study of Clostridium difficile infections in university hospitals: Results of a nationwide study in Japan

We conducted a nationwide molecular epidemiological study of Clostridium difficile infection (CDI) in Japan investigated the correlation between the presence of binary toxin genes and CDI severity. This is the first report on molecular epidemiological analyses for CDI in multiple university hospitals in Japan, to our knowledge. We examined 124,484 hospitalized patients in 25 national and public university hospitals in Japan between December 2013 and March 2014, investigating antimicrobial susceptibilities and toxin-related genes for C. difficile isolates from stools. Epidemiological genetic typing was performed by PCR-ribotyping and repetitive sequence-based (rep)-PCR to examine the genetic similarities. The results detected toxin A-positive, toxin B-positive, binary toxin-negative (A⁺B⁺CDT^-) detected from 135 isolates (80.8%) and toxin A-negative, toxin B-positive, binary toxin-negative (A^-B⁺CDT^-) in 23 (13.8%). Toxin A-positive, toxin B-positive, and binary toxin-positive (A⁺B⁺CDT⁺) were seen in 9 isolates (5.4%). Vancomycin (n = 81, 37.7%) or metronidazole (n = 88, 40.9%) therapies were undertaken in analyzed cases. Ribotypes detected from isolates were 017/subgroup 1, 070, 078, 126, 176, 449, 475/subgroup 1, 499, 451, 566 and newtypes. Rep-PCR classified 167 isolates into 28 cluster groups including 2-15 isolates. In addition, 2 pairs of strains isolated from different institutions belonged to the same clusters. Seven out of 9 (77.8%) of the patients with binary toxin producing strains had "mild to moderate" outcome in evaluated symptoms. In conclusion, we found that binary toxin did not show regional specificity and had no relevance to severity of CDI.

Antibacterial and antivirulence activities of auranofin against Clostridium difficile

Clostridium difficile is a deadly, opportunistic bacterial pathogen. In the last two decades, C. difficile infections (CDIs) have become a national concern because of the emergence of hypervirulent mutants with increased capability to produce toxins and spores. This has resulted in an increased number of infections and deaths associated with CDI. The scarcity of anticlostridial drugs has led to unsatisfactory cure rates, elevated recurrence rates and permitted enhanced colonization with other drug-resistant pathogens (such as vancomycin-resistant enterococci) in afflicted patients. Therefore, both patients and physicians are facing an urgent need for more effective therapies to treat CDI. In an effort to find new anticlostridial drugs, we investigated auranofin, an FDA-approved oral antirheumatic drug that has recently been found to possess antibacterial activity. Auranofin exhibited potent activity against C. difficile isolates, inhibiting growth at a concentration of 1 µg/mL against 50% of all tested isolates. Auranofin inhibited both toxin production and spore formation, a property lacking in both vancomycin and metronidazole (the primary agents used to treat CDI). Auranofin had a direct protective activity against C. difficile toxin-mediated inflammation and inhibited the growth of vancomycin-resistant enterococci. Auranofin is a promising candidate that warrants further investigation as a treatment option for C. difficile infections.

Impact of superimposed Clostridium difficile infection in Crohn's or ulcerative colitis flares in the outpatient setting

PURPOSE

The prospective assessment of Clostridium difficile infection (CDI) impact in inflammatory bowel disease (IBD) flare in outpatient setting has been poorly investigated. We aimed to evaluate the prevalence and the associated factors with CDI in IBD outpatients presenting colitis flares as well as the outcomes following treatment.

METHODS

In this prospective cohort study, conducted from October, 2014, to July, 2016, 120 IBD patients (55% presenting colitis flare) and 40 non-IBD controls were assessed for CDI. Multivariate regression analysis was performed to identify predictors of CDI. Outcome analysis was estimated for recurrent CDI, hospitalization, colectomy, and CDI-associated mortality.

RESULTS

The number of patients with CDI was significantly higher in IBD patients experiencing flares than in both inactive IBD and non-IBD groups (28.8 vs. 5.6 vs. 0%, respectively; p = 0.001). Females (OR = 1.39, 95% CI, 1.13-17.18), younger age (OR = 0.77, 95% CI, 0.65-0.92), steroid treatment (OR = 7.42, 95% CI, 5.17-40.20), and infliximab therapy (OR = 2.97, 95% CI, 1.99-24.63) were found to be independently associated with CDI. There was a dose-related increase in the risks of CDI on patients which had taken prednisone. Those treated with vancomycin had a satisfactory response to therapy, but 21% presented recurrent CDI and 16% were hospitalized. Neither necessity of colectomy nor mortality was noticed in any patient during the investigation.

CONCLUSIONS

In IBD outpatients presenting colitis flares, CDI is highly prevalent. Females, younger age, infliximab, and notably steroid therapy were independently associated with CDI. Most patients with CDI experienced mild-to-moderate disease, and prompt treatment with vancomycin was highly effective, which seems to reduce the serious complication risks.

Clostridium difficile colitis and zoonotic origins-a narrative review

Clostridium difficile is a major cause of hospital-associated diarrhoea, and in severe cases leads to pseudomembranous colitis and toxic megacolon. The frequency of C. difficile infection (CDI) has increased in recent decades, with 453 000 cases identified in 2011 in the USA. This is related to antibiotic-selection pressure, disruption of normal host intestinal microbiota and emergence of antibiotic-resistant C. difficile strains. The burden of community-acquired CDI has been increasingly appreciated, with disease identified in patients previously considered low-risk, such as young women or patients with no prior antibiotic exposure. C. difficile has been identified in livestock animals, meat products, seafood and salads. It has been postulated that the pool of C. difficile in the agricultural industry may contribute to human CDI. There is widespread environmental dispersal of C. difficile spores. Domestic households, turf lawns and public spaces are extensively contaminated, providing a potential reservoir for community-acquired CDI. In Australia, this is particularly associated with porcine-derived C. difficile UK PCR ribotype 014/020. In this article, the epidemiological differences between hospital- and community-acquired CDI are discussed, including some emerging evidence for community-acquired CDI being a possible zoonosis.

Characterization of Bacteriophages Infecting Clinical Isolates of Clostridium difficile

Clostridium difficile is recognized as a problematic pathogen, causing severe enteric diseases including antibiotic-associated diarrhea and pseudomembranous colitis. The emergence of antibiotic resistant C. difficile has driven a search for alternative anti-infection modalities. A promising strategy for controlling bacterial infection includes the use of bacteriophages and their gene products. Currently, knowledge of phages active against C. difficile is still relatively limited by the fact that the isolation of phages for this organism is a technically demanding method since bacterial host themselves are difficult to culture. To isolate and characterize phages specific to C. difficile, a genotoxic agent, mitomycin C, was used to induce temperate phages from 12 clinical isolates of C. difficile. Five temperate phages consisting of ΦHR24, ΦHN10, ΦHN16-1, ΦHN16-2, and ΦHN50 were successfully induced and isolated. Spotting assays were performed against a panel of 92 C. difficile isolates to screen for susceptible bacterial hosts. The results revealed that all the C. difficile phages obtained in this work displayed a relatively narrow host range of 0-6.5% of the tested isolates. Electron microscopic characterization revealed that all isolated phages contained an icosahedral head connected to a long contractile tail, suggesting that they belonged to the Myoviridae family. Restriction enzyme analysis indicated that these phages possess unique double-stranded DNA genome. Further electron microscopic characterization revealed that the ΦHN10 absorbed to the bacterial surface via attachment to cell wall, potentially interacting with S-layer protein. Bacteriophages isolated from this study could lead to development of novel therapeutic agents and detection strategies for C. difficile.

Carbon storage regulator CsrA plays important roles in multiple virulence-associated processes of Clostridium difficile

The carbon storage regulator CsrA is a global regulator that controls multiple virulence-associated processes including host cell invasion, virulence secretion, quorum sensing, biofilm formation, and motility in many pathogenic bacteria. However, the roles of CsrA in Clostridium difficile still remain unclear. In this study, a C. difficile strain overexpressing csrA was constructed to investigate its effects on multiple virulence associated processes. Overexpression of csrA resulted in flagella defect and poor motility in C. difficile 630Δerm, suggesting that CsrA involves in the regulation of flagellum synthesis. The levels of toxin production were increased in the C. difficile 630Δerm overexpressing of csrA. Moreover, csrA overexpression enhanced the adherence ability to Caco-2 cells and solvent production of C. difficile 630Δerm. Altogether, CsrA of C. difficile participates in multiple virulence processes including toxin production, motility, and adherence, and in the regulation of carbon metabolism. These results enhance our understanding of the regulatory functions of CsrA and reveal that CsrA is an important regulator in C. difficile contributing to virulence regulation.

Interventions to Reduce the Incidence of Hospital-Onset Clostridium difficile Infection: An Agent-Based Modeling Approach to Evaluate Clinical Effectiveness in Adult Acute Care Hospitals

Background

Despite intensified efforts to reduce hospital-onset Clostridium difficile infection (HO-CDI), its clinical and economic impacts continue to worsen. Many institutions have adopted bundled interventions that vary considerably in composition, strength of evidence, and effectiveness. Considerable gaps remain in our knowledge of intervention effectiveness and disease transmission, which hinders HO-CDI prevention.

Methods

We developed an agent-based model of C. difficile transmission in a 200-bed adult hospital using studies from the literature, supplemented with primary data collection. The model includes an environmental component and 4 distinct agent types: patients, visitors, nurses, and physicians. We used the model to evaluate the comparative clinical effectiveness of 9 single interventions and 8 multiple-intervention bundles at reducing HO-CDI and asymptomatic C. difficile colonization.

Results

Daily cleaning with sporicidal disinfectant and C. difficile screening at admission were the most effective single-intervention strategies, reducing HO-CDI by 68.9% and 35.7%, respectively (both P < .001). Combining these interventions into a 2-intervention bundle reduced HO-CDI by 82.3% and asymptomatic hospital-onset colonization by 90.6% (both, P < .001). Adding patient hand hygiene to healthcare worker hand hygiene reduced HO-CDI rates an additional 7.9%. Visitor hand hygiene and contact precaution interventions did not reduce HO-CDI, compared with baseline. Excluding those strategies, healthcare worker contact precautions were the least effective intervention at reducing hospital-onset colonization and infection.

Conclusions

Identifying and managing the vast hospital reservoir of asymptomatic C. difficile by screening and daily cleaning with sporicidal disinfectant are high-yield strategies. These findings provide much-needed data regarding which interventions to prioritize for optimal C. difficile control.

Nasogastric tube and outcomes of Clostridium difficile infection: A systematic review and meta-analysis

AIMS

Clostridium difficile infection (CDI) is a major concern for public health worldwide. Interestingly, the risk of poor clinical outcomes of CDI in patients with nasogastric tube (NGT) insertion is still controversial. The aim of this study was to assess the outcomes of CDI in patients with NGT insertion.

METHODS

A literature search was performed using MEDLINE, EMBASE, and The Cochrane Database of Systematic Reviews from inception through November 2017. Studies that reported relative risks, odds ratios, or hazard ratios comparing the clinical outcome of CDI in patients with NGT versus those who did not were included. Pooled risk ratios (RR) and 95% confidence interval (CI) were calculated using a random-effect, generic inverse variance method.

RESULTS

Eight observational studies were included in our analysis to assess the association between NGT insertion and risk of poor outcome of CDI. The pooled RR of severe or complicated clinical outcomes of CDI in patients with NGT insertion was 1.81 (95% CI: 1.17 to 2.81).

CONCLUSIONS

This study demonstrated a statistically significant association between NGT insertion and risk of poor outcomes of CDI. This finding may impact clinical management and primary prevention of CDI. Avoidance of unnecessary NGT uses would improve the clinical outcomes of CDI.

The Novel Phages phiCD5763 and phiCD2955 Represent Two Groups of Big Plasmidial Siphoviridae Phages of Clostridium difficile

Until recently, Clostridium difficile phages were limited to Myoviruses and Siphoviruses of medium genome length (32–57 kb). Here we report the finding of phiCD5763, a Siphovirus with a large extrachromosomal circular genome (132.5 kb, 172 ORFs) and a large capsid (205.6 ± 25.6 nm in diameter) infecting MLST Clade 1 strains of C. difficile. Two subgroups of big phage genomes similar to phiCD5763 were identified in 32 NAP_CR1/RT012/ST-54 C. difficile isolates from Costa Rica and in whole genome sequences (WGS) of 41 C. difficile isolates of Clades 1, 2, 3, and 4 from Canada, USA, UK, Belgium, Iraq, and China. Through comparative genomics we discovered another putative big phage genome in a non-NAP_CR1 isolate from Costa Rica, phiCD2955, which represents other big phage genomes found in 130 WGS of MLST Clade 1 and 2 isolates from Canada, USA, Hungary, France, Austria, and UK. phiCD2955 (131.6 kb, 172 ORFs) is related to a previously reported C. difficile phage genome, phiCD211/phiCDIF1296T. Detailed genome analyses of phiCD5763, phiCD2955, phiCD211/phiCDIF1296T, and seven other putative C. difficile big phage genome sequences of 131–136 kb reconstructed from publicly available WGS revealed a modular gene organization and high levels of sequence heterogeneity at several hotspots, suggesting that these genomes correspond to biological entities undergoing recombination. Compared to other C. difficile phages, these big phages have unique predicted terminase, capsid, portal, neck and tail proteins, receptor binding proteins (RBPs), recombinases, resolvases, primases, helicases, ligases, and hypothetical proteins. Moreover, their predicted gene load suggests a complex regulation of both phage and host functions. Overall, our results indicate that the prevalence of C. difficile big bacteriophages is more widespread than realized and open new avenues of research aiming to decipher how these viral elements influence the biology of this emerging pathogen.

Proton pump inhibitors therapy and risk of Clostridium difficile infection: Systematic review and meta-analysis

AIM

To perform a systematic review and meta-analysis on proton pump inhibitors (PPIs) therapy and the risk of Clostridium difficile infection (CDI).

METHODS

We conducted a systematic search of MEDLINE/PubMed and seven other databases through January 1990 to March 2017 for published studies that evaluated the association between PPIs and CDI. Adult case-control and cohort studies providing information on the association between PPI therapy and the development of CDI were included. Pooled odds ratios (ORs) estimates with 95% confidence intervals (CIs) were calculated using the random effect. Heterogeneity was assessed by I² test and Cochran’s Q statistic. Potential publication bias was evaluated via funnel plot, and quality of studies by the Newcastle-Otawa Quality Assessment Scale (NOS).

RESULTS

Fifty-six studies (40 case-control and 16 cohort) involving 356683 patients met the inclusion criteria and were analyzed. Both the overall pooled estimates and subgroup analyses showed increased risk for CDI despite substantial statistical heterogeneity among studies. Meta-analysis of all studies combined showed a significant association between PPI users and the risk of CDI (pooled OR = 1.99, CI: 1.73-2.30, P < 0.001) as compared with non-users. The association remained significant in subgroup analyses: by design-case-control (OR = 2.00, CI: 1.68-2.38, P < 0.0001), and cohort (OR = 1.98, CI: 1.51-2.59, P < 0.0001); adjusted (OR = 1.95, CI: 1.67-2.27, P < 0.0001) and unadjusted (OR = 2.02, CI: 1.41-2.91, P < 0.0001); unicenter (OR = 2.18, CI: 1.72-2.75, P < 0.0001) and multicenter (OR = 1.82, CI: 1.51-2.19, P < 0.0001); age ≥ 65 years (OR = 1.93, CI: 1.40-2.68, P < 0.0001) and < 65 years (OR = 2.06, CI: 1.11-3.81, P < 0.01). No significant differences were found in subgroup analyses (test for heterogeneity): P = 0.93 for case-control vs cohort, P = 0.85 for adjusted vs unadjusted, P = 0.24 for unicenter vs multicenter, P = 0.86 for age ≥ 65 years and < 65 years. There was significant heterogeneity across studies (I² = 85.4%, P < 0.001) as well as evidence of publication bias (funnel plot asymmetry test, P = 0.002).

CONCLUSION

This meta-analysis provides further evidence that PPI use is associated with an increased risk for development of CDI. Further high-quality, prospective studies are needed to assess whether this association is causal.

The role of tigecycline in the management of Clostridium difficile infection: a retrospective cohort study

OBJECTIVE

We aimed to compare the outcomes of patients with C.difficile infection (CDI) treated either with tigecycline associated with vancomycin, or with vancomycin alone.

METHODS

This single-centre retrospective cohort study included all adults hospitalized from September 2014 through August 2015 for symptomatic, incident CDI confirmed by polymerase chain reaction for C. difficile toxin in stools. The primary outcome was the rate of favourable outcome, defined as a composite of clinical response (resolution of symptoms without need for additional CDI therapy) and achieving discharge without CDI-related surgery or intensive care; a secondary outcome was CDI recurrence. We constructed a non-parsimonious logistic regression model to calculate a propensity score (PS) for those receiving tigecycline.

RESULTS

In all, 266 patients were included: 62 patients received both vancomycin and tigecycline, and 204 patients received vancomycin alone. The patients from the two groups were similar regarding demographics and comorbidities but patients in the tigecycline group had a more severe CDI. A favourable outcome in the tigecycline group versus the vancomycin group was found in 50/62 (81%) versus 193/204 (95%). We matched patients receiving tigecycline or not according to the PS and 86 patients (43 pairs) could be matched. The OR for favourable outcome with tigecycline in the matched analysis was 0.92 (95% CI 0.60-1.44; p 0.74). The rate of CDI recurrences was 8/62 (13%) in the tigecycline group versus 39/204 (19%) in the vancomycin group (p 0.2).

CONCLUSION

Adding tigecycline to CDI standard therapy did not increase the clinical cure nor reduce the rate of CDI recurrences.

Assessing the effect of patient screening and isolation on curtailing Clostridium difficile infection in hospital settings

BACKGROUND

Patient screening at the time of hospital admission is not recommended as a routine practice, but may be an important strategy for containment of Clostridium difficile infection (CDI) in hospital settings. We sought to investigate the effect of patient screening in the presence of asymptomatic carriers and in the context of imperfect patient isolation.

METHODS

We developed and parameterized a stochastic simulation model for the transmission dynamics of CDI in a hospital ward.

RESULTS

We found that the transmission of CDI in the hospital, either through asymptomatic carriers or as a results of ineffective implementation of infection control practices, at the time of hospital admission. The results show that, for a sufficiently high reproduction number of CDI, the disease can persist within a hospital setting in the presence of in-ward transmission, even when there are no asymptomatically colonized patients at the time of hospital admission.

CONCLUSIONS

Our findings have significant public health and clinical implications, especially in light of the emergence and community spread of hypervirulent CDI strains with enhanced transmission rates and toxin production. Rapid detection of colonized patients remains an important component of CDI control, especially in the context of asymptomatic transmission. Screening of in-hospital patients with potential exposure to colonized patients or contaminated environment and equipment can help reduce the rates of silent transmission of CDI through asymptomatic carriers.

Primary prevention of Clostridium difficile infections - how difficult can it be?

C. difficile infections (CDI) have been a challenging disease to treat, much less to prevent, for decades. Efforts for primary prevention have mainly focused on improving infection control practices, but CDI outbreaks continue to plague healthcare facilities. Areas covered: A literature search from 1970-December 2016 found 13 facility-level and 2 patient-level strategies that were evidence-based. The aim of this manuscript is to assess the current state of the literature on primary prevention of CDI and offer insights into which strategies may be more effective. Expert commentary: The strongest evidence for primary prevention is based on multi-faceted infection control bundles, while there is promising moderate evidence involving facility-wide use of specific probiotics. Moderate-level evidence was found for patient-level use of specific probiotics and low level evidence for vaccines. Future suggestions include use of consistent outcome metrics, measurements of implementation compliance and program sustainability.