Clinical recognition and diagnosis of Clostridium difficile infection

Comparison of Clostridioides difficile strains from animals and humans: First results after introduction of C. difficile molecular typing and characterization at the Istituto Zooprofilattico Sperimentale of Piemonte, Liguria e Valle d'Aosta, Italy

PCR ribotypes (RTs027 and 078) are known causes of Clostridioides difficile infection (CDI) in humans. Molecular typing and characterization of 39 C. difficile strains isolated from samples from humas and animals in 2016-2018 indicated an overlap of RTs between community-acquired patients (CA-CDI) and domestic animals from the same geographical area; 14 RTs were identified: 12 RTs were positive for toxins A/B; RT078, RT080 and RT126 were also positive for binary toxin (CDT). Most of the RTs from the animals (RTs020, 078, 106, 126) were also detected in the samples from humans. Strains grouped into three clusters: cluster I included prevalently human strains, mainly RT 018; clusters II and III included strains from humans and animals, mainly RT078 and RT020. The CA-CDI strains suggested animals as a reservoir of C. difficile isolated together with other microorganisms from animals, highlighting the association of enteric pathogens as a cause of infection and death.

High Prevalence of Multidrug-Resistant Clostridioides difficile Following Extensive Use of Antimicrobials in Hospitalized Patients in Kenya

Introduction

Clostridioides difficile is a neglected pathogen in many African countries as it is generally not regarded as one of the major contributors toward the diarrheal disease burden in the continent. However, several studies have suggested that C. difficile infection (CDI) may be underreported in many African settings. The aim of this study was to determine the prevalence of CDI in hospitalized patients, evaluate antimicrobial exposure, and detect toxin and antimicrobial resistance profiles of the isolated C. difficile strains.

Methods

In this cross-sectional study, 333 hospitalized patients with hospital-onset diarrhoea were selected. The stool samples were collected and cultured on cycloserine-cefoxitin egg yolk agar (CCEY). Isolates were presumptively identified by phenotypic characteristics and Gram stain and confirmed by singleplex real-time PCR (qPCR) assays detecting the species-specific tpi gene, toxin A (tcdA) gene, toxin B (tcdB) gene, and the binary toxin (cdtA/cdtB) genes. Confirmed C. difficile isolates were tested against a panel of eight antimicrobials (vancomycin, metronidazole, rifampicin, ciprofloxacin, tetracycline, clindamycin, erythromycin, and ceftriaxone) using E-test strips.

Results

C. difficile was detected in 57 (25%) of diarrheal patients over the age of two, 56 (98.2%) of whom received antimicrobials before the diarrheal episode. Amongst the 71 confirmed isolates, 69 (97.1%) harbored at least one toxin gene. More than half of the toxigenic isolates harbored a truncated tcdA gene. All isolates were sensitive to vancomycin, while three isolates (2.1%) were resistant to metronidazole (MIC >32 mg/L). High levels of resistance were observed to rifampicin (65/71, 91.5%), erythromycin (63/71, 88.7%), ciprofloxacin (59/71, 83.1%), clindamycin (57/71, 80.3%), and ceftriaxone (36/71, 50.7.8%). Among the resistant isolates, 61 (85.9%) were multidrug-resistant.

Conclusion

Multidrug-resistant C. difficile strains were a significant cause of healthcare facility-onset C. difficile infections in patients with prior antimicrobial exposure in this Kenyan hospital.

Clostridioides difficile Infection in Chronic Kidney Disease-An Overview for Clinicians

Increased incidence of Clostridioides difficile infection (CDI), occurrence of severe and complicated CDI, and more frequent occurrence of drug-resistant, recurrent or non-hospital CDI has become a worldwide clinical problem. CDI is more common in patients with chronic kidney disease (CKD) than in the general population. CDI seems to be associated with frequent hospitalization, frequently used antibiotic therapy, dysbiosis, and abnormalities of the immune system observed in CKD patients. Dysbiosis is a common disorder found in CKD patients. It may be related to insufficient fiber content in the diet, reduced amount of consumed fluids and often reduced physical activity, constipation, impaired gastrointestinal motility, multidrug pharmacotherapy, and uremic milieu in CKD stage 5. In patients with CKD the clinical manifestations of CDI are similar to the general population; however, more frequent recurrence of CDI and higher prevalence of severe CDI are reported. Moreover, the increase in CDI related mortality is observed more in CKD patients than in the general population. The aim of this review paper is to summarize the current knowledge concerning the epidemiology, pathogenesis, clinical picture, and prevention and treatment in CKD patients.

Eravacycline, a novel tetracycline derivative, does not induce Clostridioides difficile infection in an in vitro human gut model

OBJECTIVES

The approval of new antibiotics is essential to combat infections caused by antimicrobial-resistant pathogens; however, such agents should be tested to determine their effect on the resident microbiota and propensity to select for opportunistic pathogens, such as Clostridioides difficile. Eravacycline is a new antibiotic for the treatment of complicated intra-abdominal infections. Here, we determined the effects of eravacycline compared with moxifloxacin on the microbiota and if these were conducive to induction of C. difficile infection (CDI).

METHODS

We seeded in vitro chemostat models, which simulate the physiological conditions of the human colon, with a human faecal slurry and instilled gut-reflective concentrations of either eravacycline or moxifloxacin.

RESULTS

Eravacycline instillation was associated with decreased Bifidobacterium, Lactobacillus and Clostridium species, which recovered 1 week after exposure. However, Bacteroides spp. levels decreased to below the limit of detection and did not recover prior to the end of the experiment. Post-eravacycline, a bloom of aerobic bacterial species occurred, including Enterobacteriaceae, compared with pre-antibiotic, which remained high for the duration of the experiment. These changes in microbiota were not associated with induction of CDI, as we observed a lack of C. difficile spore germination and thus no toxin was detected. Moxifloxacin exposure sufficiently disrupted the microbiota to induce simulated CDI, where C. difficile spore germination, outgrowth and toxin production were seen.

CONCLUSIONS

These model data suggest that, despite the initial impact of eravacycline on the intestinal microbiota, similar to clinical trial data, this novel tetracycline has a low propensity to induce CDI.

The impact of human vaccines on bacterial antimicrobial resistance. A review

At present, the dramatic rise in antimicrobial resistance (AMR) among important human bacterial pathogens is reaching a state of global crisis threatening a return to the pre-antibiotic era. AMR, already a significant burden on public health and economies, is anticipated to grow even more severe in the coming decades. Several licensed vaccines, targeting both bacterial (Haemophilus influenzae type b, Streptococcus pneumoniae, Salmonella enterica serovar Typhi) and viral (influenza virus, rotavirus) human pathogens, have already proven their anti-AMR benefits by reducing unwarranted antibiotic consumption and antibiotic-resistant bacterial strains and by promoting herd immunity. A number of new investigational vaccines, with a potential to reduce the spread of multidrug-resistant bacterial pathogens, are also in various stages of clinical development. Nevertheless, vaccines as a tool to combat AMR remain underappreciated and unfortunately underutilized. Global mobilization of public health and industry resources is key to maximizing the use of licensed vaccines, and the development of new prophylactic vaccines could have a profound impact on reducing AMR.

Systematic Literature Review on Burden of Clostridioides difficile Infection in India

BACKGROUND

Owing to limited diagnostic facilities and surveillance protocols, there is a paucity on the prevalence data of Clostridioides difficile infections (CDIs) in developing countries such as India.

OBJECTIVE

The aims of these studies are (1) to determine the prevalence of CDI in India, (2) to understand the risk factors of CDI, and (3) to determine the impact of different diagnostic methods on reported CDI rates.

METHOD

A systematic literature search was conducted using PubMed and Google Scholar database to identify Indian studies reporting the prevalence of CDI. A total of 31 studies, published between 1990 and 2020 were included in the final analysis. A chi-square test was used to determine statistically significant association between prevalence rates, accuracy of different diagnosis methods, and antibiotic usage rates of CDI.

RESULTS

The prevalence of CDI was in the range of 3.4% to 18%, and the difference between regional prevalence of CDI was statistically significant (P < .001). The use of antibiotics, hospital stay, comorbidities, recent surgery, and the use of proton-pump inhibitors was considered as risk factors for the development of CDI. Compared to other regions, the rate of antibiotic usage was significantly higher in North India (P < .001). Among different diagnostic methods, C. difficile detection was significantly higher with enzyme-linked immunosorbent assay (18.02%) versus other multiple testing methods used (P < .001).

CONCLUSION

There is a significant burden of CDI across the country. Further surveillance studies are required to monitor changes in prevalence of CDI, risk factors, and accuracy of diagnosis methods for a better understanding of the disease burden in India.

Characterization of Non-Toxigenic Clostridioides difficile Strains Isolated from Preterm Neonates and In Vivo Study of Their Protective Effect

In a previous monocentric study in preterm neonates (PN), we described a high Clostridioides difficile colonization rate (74%) with two uncommon non-toxigenic strains (NTCD) belonging to PCR-ribotype (RT) (CE)847 and (CE)032. To determine the extent of carriage of both NTCD in other spatio-temporal settings, strains isolated in PN stools from two multicenter cohorts were characterized by PCR-ribotyping, MLVA and MLST. We also evaluated the protective role of two NTCD from these RT against C. difficile infection in a hamster caecitis model. Animals were administered either each NTCD alone (n = 7), or followed by a 027 strain (n = 9). A control group received only the 027 strain (n = 8). Clinical activity and colonization by C. difficile in stools were monitored daily until death or sacrifice at D20. We isolated 18 RT(CE)032 (ST-83) strains and 2 RT(CE)847 (ST-26) strains among 247 PN from both cohorts. Within each RT, strains were genetically related. The survival rate was significantly increased when animals received a RT(CE)847 or (CE)032 strain before the 027 strain (4/9 deaths, p = 0.029; 1/9 death, p = 0.0004, respectively). We describe two predominant uncommon NTCD strains, in a PN population from different healthcare facilities. Both NTCD provide a potential protection against C. difficile infection.

Fecal Microbiota Transplantation May Be the Best Option in Treating Multiple Clostridioides difficile Infection: A Network Meta-Analysis

Introduction

Clostridioides difficile (formerly Clostridium) infection (CDI) is the most common cause of healthcare-associated diarrhea with high mortality and recurrence rate; furthermore, the treatment of recurrent cases is a challenge. In this network meta-analysis, we aimed to compare all available therapies against multiple recurrent CDI (mrCDI) and rank them by efficacy.

Methods

After a systematic search, randomized controlled trials (RCT) with any interventions against mrCDI were included. Data were extracted to the study database using Excel. Risk of bias assessment was performed with the Cochrane RoB 2 tool. The primary outcome was the clinical cure of CDI and the secondary outcome was the recurrence of CDI. A Bayesian method was performed to investigate the efficacy rank order of therapies. We registered our protocol with the Prospero Center for Reviews and Dissemination (registration no. CRD42020160365).

Results

Six RCTs with seven interventions were included in the quantitative synthesis. According to the surface under the cumulative ranking curve values, fecal microbiota transplantation (FMT) after a short course of vancomycin therapy (83%) shows the highest efficacy for clinical cure. Tolevamer and vancomycin + FMT seemed to be the most effective in preventing recurrence (87% and 75%, respectively).

Conclusion

Vancomycin + FMT is perhaps the most effective option for the treatment and prevention of mrCDI, while tolevamer is also effective in preventing recurrence.

Electronic Supplementary Material

The online version of this article (10.1007/s40121-020-00356-9) contains supplementary material, which is available to authorized users.

Risk of complications and mortality following recurrent and non-recurrent Clostridioides difficile infection: a retrospective observational database study in England

BACKGROUND

Clostridioides difficile infection (CDI) increases the risk of complications and mortality. We assessed the magnitude of these outcomes in a large cohort of English patients with initial and recurrent CDI.

AIM

To compare the risk of complications and all-cause mortality, within 12 months, among hospitalized patients ≥18 years old with hospital-associated- (HA-) CDI and recurrent CDI.

METHODS

Patients with HA-CDI during 2002-2013 were identified using inpatient hospital data linked to primary care and death data. Each HA-CDI case was frequency matched to two hospitalized patients without CDI on age group, sex, calendar year of admission, admission method and number of hospital care episodes. A second CDI episode starting on days 13-56 was defined as recurrence. Risks of mortality and complications at 12 months were analysed using Cox proportional hazard models.

FINDINGS

We included 6862 patients with HA-CDI and 13,724 without CDI. Median age was 81.0 years (IQR 71.0-87.0). Patients with HA-CDI had more comorbidities than those without CDI, and significantly higher risks of mortality (adjusted hazard ratio (95% confidence interval) 1.77 (1.67-1.87)) and complications (1.66 (1.46-1.88)) within 12 months from hospital admission. Of those with HA-CDI, 1140 (16.6%) experienced CDI recurrence. Patients with recurrent versus non-recurrent CDI also had significantly increased risk of mortality (1.32 (1.20-1.45)) and complications (1.37 (1.01-1.84)) in the 12 months from the initial CDI.

CONCLUSIONS

HA-CDI (versus no CDI) and recurrent CDI are both associated with significantly higher risks of complications or death within 12 months of the initial CDI episode.

Safety, immunogenicity, and efficacy of a Clostridioides difficile toxoid vaccine candidate: a phase 3 multicentre, observer-blind, randomised, controlled trial

BACKGROUND

In the absence of a licensed vaccine, Clostridioides (formerly Clostridium) difficile infection represents a substantial health burden. The aim of this study was to evaluate the efficacy, immunogenicity, and safety of a toxoid vaccine candidate.

METHODS

We did a phase 3 multicentre, observer-blind, randomised, controlled trial at 326 hospitals, clinics, and clinical research centres in 27 countries in the USA, Canada, Latin America, Europe, and the Asia-Pacific region. We included adults aged 50 years or older who were considered to be at an increased risk of C difficile infection because they had previously had two hospital stays (each ≥24 h in duration) and had received systemic antibiotics in the previous 12 months (risk stratum 1), or because they were anticipating being admitted to hospital for 72 h or more for elective surgery within 60 days of enrolment (risk stratum 2). Eligible participants were stratified by geographical region and the two risk strata, and randomly assigned (2:1), with a fixed block size of three, to receive either a C difficile toxoid vaccine candidate, containing toxoids A and B (C difficile vaccine candidate group), or a placebo vaccine (placebo group). Participants, investigators, and personnel responsible for collecting safety data and analysing blood and stool samples were masked to group assignment. Personnel responsible for study product preparation and administration were not masked to group assignment. One dose (0·5 mL) of C difficile vaccine candidate or placebo vaccine was administered intramuscularly on days 0, 7, and 30. The primary outcome was the efficacy of the vaccine in preventing symptomatic C difficile infection, defined as having three or more loose stools in a period of 24 h or less, loose stools for 24 h or more, and a PCR-positive test for C difficile toxin B in a loose stool sample, within 3 years after the final vaccine dose. The primary outcome was measured in the modified intention-to-treat population (ie, all participants who received at least one injection of the assigned vaccine). The safety of the vaccine was assessed in the safety analysis set (ie, all participants who had received at least one injection, analysed according to the product received). This study is registered with WHO/ICTRP, number U111-1127-7162, and ClinicalTrials.gov, number NCT01887912, and has been terminated.

FINDINGS

Between July 30, 2013, and Nov 17, 2017, we enrolled and randomly assigned 9302 participants to the C difficile vaccine candidate group (n=6201) or to the placebo group (n=3101). 6173 (99·5%) participants in the C difficile vaccine candidate group and 3085 (99·5%) participants in the placebo group received at least one dose of the vaccine. The study was terminated after the first planned interim analysis because of futility. In the C difficile vaccine candidate group, 34 C difficile infections were reported over 11 697·2 person-years at risk (0·29 infections per 100 person-years [95% CI 0·20-0·41]) compared with 16 C difficile infections over 5789·4 person-years at risk in the placebo group (0·28 infections per 100 person-years [0·16-0·45]), indicating a vaccine efficacy of -5·2% (95% CI -104·1 to 43·5). In the C difficile vaccine candidate group, 2847 (46·6%) of 6113 participants reported an adverse event within 30 days of injection compared with 1282 (41·9%) of 3057 participants in the placebo group. The proportion of participants who had an adverse event leading to study discontinuation was 4·8% in both groups (296 participants in the C difficile vaccine candidate group and 146 participants in the placebo group). 1662 (27·2%) participants in the C difficile vaccine candidate group reported at least one serious adverse event compared with 851 (27·8%) participants in the placebo group.

INTERPRETATION

In adults at risk for C difficile infection, a bivalent C difficile toxoid vaccine did not prevent C difficile infection. Since the C difficile vaccine candidate met the criteria for futility, the study was terminated and clinical development of this vaccine candidate was stopped.

FUNDING

Sanofi Pasteur.

Discordant Clostridioides difficile diagnostic assay and treatment practice: a cross-sectional study in a tertiary care hospital, Geneva, Switzerland

OBJECTIVES

To determine the proportion of patients who received a treatment for Clostridioides difficile infection (CDI) among those presenting a discordant C. difficile diagnostic assay and to identify patient characteristics associated with the decision to treat CDI.

DESIGN

Cross-sectional study.

SETTING

Monocentric study in a tertiary care hospital, Geneva, Switzerland.

PARTICIPANTS

Among 4562 adult patients tested for C. difficile between March 2017 and March 2019, 208 patients with discordant tests' results (positive nucleic acid amplification test (NAAT+)/negative enzyme immunoassay (EIA-)) were included.

MAIN OUTCOME MEASURES

Treatment for CDI.

RESULTS

CDI treatment was administered in 147 (71%) cases. In multivariate analysis, an abdominal CT scan with signs of colitis (OR 14.7; 95% CI 1.96 to 110.8) was the only factor associated with CDI treatment.

CONCLUSIONS

The proportion of NAAT+/EIA- patients who received treatment questions the contribution of the EIA for the detection of toxin A/B after NAAT to limit overtreatment. Additional studies are needed to investigate if other factors are associated with the decision to treat.

Clostridioides difficile in transplant patients: early diagnosis, treatment, and prevention

PURPOSE OF REVIEW

Clostridioides difficile infection is common in solid organ transplant and hematopoietic stem-cell transplant recipients and is associated with significant morbidity and mortality. These populations are also underrepresented in clinical trials, making optimal management difficult. Because of this, management of these populations follows national guideline recommendations. This review aims to summarize the recent relevant literature pertaining to the clinical management of C. difficile infection in transplant patients, with a particular focus on diagnosis, treatment, and prevention.

RECENT FINDINGS

Early diagnosis of C. difficile colonization may mitigate both horizontal and vertical transmission (progression from colonization to colitis) of infection. Once diagnosed, recent literature suggests antibiotic treatment should align with that recommended by national guidelines. Fecal microbiota transplant is an emerging therapy for recurrent C. difficile infection, and recent data have demonstrated safety and efficacy. Prevention strategies including antimicrobial stewardship, probiotic administration, antibiotic administration, and bezlotoxumab may be beneficial in transplant populations, but more data are needed to confirm recent findings.

SUMMARY

Studies evaluating C. difficile infection in transplant patients are only recently starting to emerge. Further research is needed to identify optimal treatment and prevention strategies, and to examine novel strategies such as microbiome manipulation.

Risk Factors for Primary Clostridium difficile Infection; Results From the Observational Study of Risk Factors for Clostridium difficile Infection in Hospitalized Patients With Infective Diarrhea (ORCHID)

Background: There are inconsistent data on the risk factors for Clostridium difficile infection (CDI) in the literature.

Aims: To use two C. difficile infection (CDI) case-control study groups to compare risk factors in hospitalized patients with diarrhea across different countries.

Methods: A multi-center group of CDI cases/controls were identified by standardized testing from seven countries from the prior EUropean, multi-center, prospective bi-annual point prevalence study of CLostridium difficile Infection in hospitalized patients with Diarrhea (EUCLID). A second group of CDI cases/controls was identified from a single center in Germany [parallel study site (PSS)]. Data were extracted from the medical notes to assess CDI risk factors. Univariate analyses and multivariate logistic regression models were used to identify and compare risk factors between the two groups.

Results: There were 253 and 158 cases and 921 and 584 controls in the PSS and EUCLID groups, respectively. Significant variables from univariate analyses in both groups were age ≥65, number of antibiotics (OR 1.2 for each additional antibiotic) and prior hospital admission (all p < 0.001). Congestive heart failure, diabetes, admission from assisted living or Emergency Department, proton pump inhibitors, and chronic renal disease were significant in PSS (all p < 0.05) but not EUCLID. Dementia and admitted with other bacterial diseases were significant in EUCLID (p < 0.05) but not PSS. Following multivariate analyses, age ≥ 65, number of antibiotics and prior hospital admission were consistently identified as CDI risk factors in each individual group and combined datasets.

Conclusion: Our results show that the same CDI risk factors were identified across datasets. These were age ≥ 65 years, antibiotic use and prior hospital admission. Importantly, the odds of developing CDI increases with each extra antibiotic prescribed.

Acquired Genetic Elements that Contribute to Antimicrobial Resistance in Frequent Gram-Negative Causative Agents of Healthcare-Associated Infections

Antimicrobial resistance (AMR) is a worldwide public health problem that reduces therapeutic options and increases the risk of death. The causative agents of healthcare-associated infections (HAIs) are drug-resistant microorganisms of the nosocomial environment, which have developed different mechanisms of AMR. The hospital-associated microbiota has been proposed to be a reservoir of genes associated with AMR and an environment where the transfer of genetic material among organisms may occur. The ESKAPE group (Enterococcus faecalis and Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter aerogenes and Escherichia coli) is a frequent causative agents of HAIs. In this review, we address the issue of acquired genetic elements that contribute to AMR in the most frequent Gram-negative of ESKAPE, with a focus on last resort antimicrobial agents and the role of transference of genetic elements for the development of AMR.

Sequential introduction of a multistep testing algorithm and nucleic acid amplification testing leading to an increase in Clostridioides difficile detection and a trend toward increased strain diversity

BACKGROUND

Most clinical microbiology laboratories have replaced toxin immunoassay (EIA) alone with multistep testing (MST) protocols or nucleic acid amplification testing (NAAT) alone for the detection of C. difficile.

OBJECTIVE

Study the effect of changing testing strategies on C. difficile detection and strain diversity.

DESIGN

Retrospective study.

SETTING

A Veterans' Affairs hospital.

METHODS

Initially, toxin EIA testing was replaced by an MST approach utilizing a glutamate dehydrogenase (GDH) and toxin EIA followed by tcdB NAAT for discordant results. After 18 months, MST was replaced by a NAAT-only strategy. Available patient stool specimens were cultured for C. difficile. Restriction endonuclease analysis (REA) strain typing and quantitative in vitro toxin testing were performed on recovered isolates.

RESULTS

Before MST (toxin EIA), 79 of 708 specimens (11%) were positive, and after MST (MST-A), 121 of 517 specimens (23%) were positive (P < .0001). Prior to NAAT-only testing (MST-B), 80 of the 490 specimens (16%) were positive by MST, and after NAAT-only testing was implemented, 67 of the 368 specimens (18%) were positive (P = nonsignificant). After replacing toxin EIA testing, REA strain group diversity increased (8, 13, 13, and 10 REA groups in the toxin EIA, MST-A, MST-B, and NAAT-only periods, respectively) and in vitro toxin concentration decreased. The average log10 toxin concentration of the isolates were 2.08, 1.88, 1.20 and 1.55 ng/mL for the same periods, respectively.

CONCLUSIONS

MST and NAAT had similar detection rates for C. difficile. Compared to toxin testing alone, they detected increased diversity of C. difficile strains, many of which were low toxin producing.

Temporal change of risk factors in hospital-acquired Clostridioides difficile infection using time-trend analysis

OBJECTIVE

Given recent changes in the epidemiology of Clostridioides difficile infection (CDI) and prevention efforts, we investigated temporal changes over a period of 11 years (2006-2016) in incidence and risk factors for CDI.

DESIGN

Retrospective matched case-control study.

SETTING/PATIENTS

Pediatric and adult inpatients (n = 694,849) discharged from 3 hospitals (tertiary and quaternary care, community, and pediatric) in a large, academic health center in New York City.

METHODS

Risk factors were identified in cases and controls matched by length of stay at a ratio of 1:4. A Cochran-Armitage or Mann-Kendall test was used to investigate trends of incidence and risk factors.

RESULTS

Of 694,849 inpatients, 6,038 (0.87%) had CDI: 44% of these cases were hospital acquired (HA-CDI) and 56% were community acquired (CA-CDI). We observed temporal downward trends in HA-CDI (-0.03% per year) and upward trends in CA-CDI (+0.04% per year). Over time, antibiotics were administered to more patients (+3% per year); the use of high-risk antibiotics declined (-1.2% per year); and antibiotic duration increased in patients with HA-CDI (+4.4% per year). Fewer proton-pump inhibitors and more histamine-2 blockers were used (-3.8% and +7.3% per year, respectively; all Ptrend <.05).

CONCLUSIONS

Although the incidence of HA-CDI decreased over time, CA-CDI simultaneously increased. Continued efforts to assure judicious use of antibiotics in inpatient and community settings is clearly vital. Measuring the actual the level of exposure of an antibiotic (incidence density) should be used for ongoing surveillance and assessment.

Clostridium difficile Infection Epidemiology over a Period of 8 Years—A Single Centre Study

Clostridium difficile infection (CDI) is the most common infectious disease related to antibiotic-associated diarrhoea and is a current leading cause of morbidity/mortality, with substantial consequences for healthcare services and overall public health. Thus, we performed a retrospective epidemiological study of CDI for a long period (8 years), in an infectious hospital located in north-western Romania, which serves an entire county of the country (617,827 inhabitants). From 2011 to 2018, 877 patients were diagnosed with CDI; the mean incidence of this disease was 2.76 cases/10,000 patient-days, with an increasing trend in the annual incidence until 2016, at which point there was a decrease. The most commonly afflicted were patients in the 75–84 age group, observed in winter and spring. The results show that the antibiotics were administered in 679 (77.42%) subjects, within the last 3 months before CDI, statistically significant more than proton-pump inhibitors (PPIs)—128 (14.60%) and antidepressant medications—60 (6.84%), which were administered during the same period (p < 0.001). No medication was reported in 10 (6.84%) cases of CDI, in the last 3 months of the study. The fatality rate attained 4.1%, tripling in 2018 vs. 2011. CDI became a significant public health conundrum that can, nevertheless, be combatted through a judicious use of antibiotics.

Ultrasensitive Clostridioides difficile Toxin Testing for Higher Diagnostic Accuracy

Currently available diagnostic tests for Clostridioides difficile infection (CDI) lack specificity or sensitivity, which has led to guideline recommendations for multistep testing algorithms. Ultrasensitive assays for detection of C. difficile toxins provide measurements of disease-specific markers at very low concentrations. These assays may show improved accuracy compared to that of current testing methods and offer a potential standalone solution for CDI diagnosis, although large studies of clinical performance and accuracy are lacking.

The economic burden of Clostridioides difficile infection in patients with hematological malignancies in the United States: A case-control study

OBJECTIVE

The primary study aim was to describe all direct healthcare costs associated with Clostridioides difficile infection (CDI), both in and out of the hospital, in patients with hematologic malignancies in the United States.

DESIGN

A retrospective analysis was conducted utilizing data from US databases of Truven Health Analytics.

PATIENTS

We analyzed health insurance claims between January 2014 and December 2017 of patients diagnosed with hematological cancer: acute myeloid leukemia (AML), acute lymphoblastic leukemia, Hodgkin's lymphoma, and non-Hodgkin's lymphoma (NHL).

METHODS

Patients with CDI after cancer diagnosis (CDI+, cases) were matched with patients without CDI reported (CDI-, controls). Matched cases and controls were compared to identify the CDI-associated costs in the 90 days following the onset of CDI.

RESULTS

We matched 622 CDI+ patients with 11,111 CDI- patients. NHL (41.7%) and AML (30.9%) were the predominant underlying diseases in the CDI+ groups. During study period, the average time in-hospital of CDI+ patients was 23.1 days longer than for CDI- patients (P < 2×10-16). Overall, CDI onset increased costs of care by an average of US$57,159 per patient (P = 6×10-12), mainly driven by hospital costs.

CONCLUSIONS

This study confirms the significant economic burden associated with CDI in the United States, especially in patients with hematological malignancies. These findings highlight the need for prevention of CDI in this specific patient population.

Human microbiome and homeostasis: insights into the key role of prebiotics, probiotics, and symbiotics

The interest in the study of the gut microbiome has grown exponentially. Indeed, its impact on health and disease has been increasingly reported, and the importance of keeping gut microbiome homeostasis clearly highlighted. However, and despite many advances, there are still some gaps, as well as the real discernment on the contribution of some species falls far short of what is needed. Anyway, it is already more than a solid fact of its importance in maintaining health and preventing disease, as well as in the treatment of some pathologies. In this sense, and given the existence of some ambiguous opinions, the present review aims to discuss the importance of gut microbiome in homeostasis maintenance, and even the role of probiotics, prebiotics, and symbiotics in both health promotion and disease prevention.

Isolation and Characterization of the Novel Phage JD032 and Global Transcriptomic Response during JD032 Infection of Clostridioides difficile Ribotype 078

C. difficile is one of the most clinically significant intestinal pathogens. Although phages have been shown to effectively control C. difficile infection, the host responses to phage predation have not been fully studied. In this study, we reported the isolation and characterization of a new phage, JD032, and analyzed the global transcriptomic changes in the hypervirulent RT078 C. difficile strain, TW11, during phage JD032 infection. We found that bacterial host mRNA was progressively replaced with phage transcripts, three temporal categories of JD032 gene expression, the extensive interplay between phage-bacterium, antiphage-like responses of the host and phage evasion, and decreased expression of sporulation- and virulence-related genes of the host after phage infection. These findings confirmed the complexity of interactions between C. difficile and phages and suggest that phages undergoing a lytic cycle may also cause different phenotypes in hosts, similar to prophages, which may inspire phage therapy for the control of C. difficile.

Insights into the interaction between phages and their bacterial hosts are crucial for the development of phage therapy. However, only one study has investigated global gene expression of Clostridioides (formerly Clostridium) difficile carrying prophage, and transcriptional reprogramming during lytic infection has not been studied. Here, we presented the isolation, propagation, and characterization of a newly discovered 35,109-bp phage, JD032, and investigated the global transcriptomes of both JD032 and C. difficile ribotype 078 (RT078) strain TW11 during JD032 infection. Transcriptome sequencing (RNA-seq) revealed the progressive replacement of bacterial host mRNA with phage transcripts. The expressed genes of JD032 were clustered into early, middle, and late temporal categories that were functionally similar. Specifically, a gene (JD032_orf016) involved in the lysis-lysogeny decision was identified as an early expression gene. Only 17.7% (668/3,781) of the host genes were differentially expressed, and more genes were downregulated than upregulated. The expression of genes involved in host macromolecular synthesis (DNA/RNA/proteins) was altered by JD032 at the level of transcription. In particular, the expression of the ropA operon was downregulated. Most noteworthy is that the gene expression of some antiphage systems, including CRISPR-Cas, restriction-modification, and toxin-antitoxin systems, was suppressed by JD032 during infection. In addition, bacterial sporulation, adhesion, and virulence factor genes were significantly downregulated. This study provides the first description of the interaction between anaerobic spore-forming bacteria and phages during lytic infection and highlights new aspects of C. difficile phage-host interactions.

IMPORTANCEC. difficile is one of the most clinically significant intestinal pathogens. Although phages have been shown to effectively control C. difficile infection, the host responses to phage predation have not been fully studied. In this study, we reported the isolation and characterization of a new phage, JD032, and analyzed the global transcriptomic changes in the hypervirulent RT078 C. difficile strain, TW11, during phage JD032 infection. We found that bacterial host mRNA was progressively replaced with phage transcripts, three temporal categories of JD032 gene expression, the extensive interplay between phage-bacterium, antiphage-like responses of the host and phage evasion, and decreased expression of sporulation- and virulence-related genes of the host after phage infection. These findings confirmed the complexity of interactions between C. difficile and phages and suggest that phages undergoing a lytic cycle may also cause different phenotypes in hosts, similar to prophages, which may inspire phage therapy for the control of C. difficile.

Treatment of Helicobacter pylori Is Not Associated With Future Clostridium difficile Infection

INTRODUCTION

Helicobacter pylori (HP) infection is associated with many gastrointestinal disorders, including gastric cancer, and consensus guidelines recommend eradication after detection. There is a theoretical, yet uninvestigated, concern that HP treatment could increase the risk of Clostridium difficile infection (CDI). Using the data from a large cohort of patients with HP, we investigated whether HP eradication is associated with CDI.

METHODS

A retrospective cohort study within the Veterans Health Administration on 38,535 patients (median age 61.8 years; 91.8% men) with detected HP between January 1, 1994, and December 31, 2018 was conducted. Primary outcome was a positive laboratory test for CDI within 3 months of HP detection. Multivariable logistic regression evaluated the following: patient demographics, previous CDI, recent hospitalization, and whether the patient received HP eradication therapy (by antibiotic and regimen, and including proton pump therapy). Secondary analysis of those treated evaluated whether eradication of HP was associated with CDI.

RESULTS

Among 38,535 patients, 28,818 (74.8%) were treated for HP and 284 (0.74%) developed CDI. In multivariable analysis, prominent factors included hospital discharge within 12 weeks (odds ratio [OR] 2.15; 95% confidence interval [CI]: 1.22-3.77) and 4 weeks (OR 3.46; 95% CI: 2.18-5.48), P < 0.001, and previous CDI (OR 12.5; 95% CI: 9.21-17.0, P < 0.001). Treatment of HP was not associated with future CDI. In secondary analysis of those treated, confirmation of eradication was not associated with future CDI (OR 1.49; 95% CI: 0.67-3.29).

DISCUSSION

In a large study of US patients with HP, we demonstrate that neither treatment nor eradication of HP is associated with CDI. Previous C. difficile infection and recent hospital discharge, established risk factors for CDI, are strongly associated. These findings suggest that treatment should be continued to be prescribed when HP is detected (http://links.lww.com/AJG/B507).

Clostridium difficile in patients with nosocomial diarrhea, Northwest of Iran

Background: Clostridium difficile is known as a prevalent pathogen leading to infections ranging from mild diarrhea to severe disease and death. The aim of the present study was to evaluate the incidence of C. difficile from inpatients with nosocomial diarrhea hospitalized in different wards in the northwest region of Iran.

Methods: In this cross-sectional study, 485 diarrheal stool samples were collected from 384 patients referred from different wards of Imam Reza, Sina and Pediatric hospitals, Tabriz and transferred to the laboratory from 25 March 2015 till 1 March 2018. Immuno-chromatographicassay for detection of toxins A and B of C. difficile was used for identification.

Results: Clostridium difficile was isolated from 24 (4.7%) out of 485 samples. Fifteen patients(62.5%) were males and 9 were females (37.5%). Twelve positive patients were from the gastrointestinal ward (50%), 5 patients (20.8%) from surgery ward, 3 patients from infectious disease ward (12.5%), 3 patients from rheumatology ward (12.5%) and 1 patient (4.1%) were collected from neurology ward. 95.3% of diarrhea samples had no signs from toxin A and B.

Conclusion: These results indicate most of infected patients were from the gastrointestinaland surgery wards which show a different pattern of infection compared to previous studies.The neurology department had the lowest rate of infection. C. difficile is a health threat afterantibiotic consumption and for health promotion, developing strategies for less antibioticconsumption and preventing these emerging infections is critical. The low rate of this infection shows improvement in knowledge and effect of stewardships in physicians.

Antimicrobial susceptibility of Clostridioides difficile isolated from diarrhoeal stool specimens of Canadian patients: summary of results from the Canadian Clostridioides difficile (CAN-DIFF) surveillance study from 2013 to 2017

Objectives

To summarize data generated by the Canadian Clostridioides difficile (CAN-DIFF) surveillance study from 2013 to 2017.

Methods

Isolates of C. difficile (n = 2158) were cultured from toxin-positive diarrhoeal stool specimens submitted by eight hospital laboratories to a coordinating laboratory. Antimicrobial susceptibility testing was performed according to the CLSI agar dilution method (M11, 2018). Isolate ribotypes were determined using an international, standardized, high-resolution capillary gel-based electrophoresis protocol.

Results

Of the 2158 isolates of C. difficile, 2133 (98.8%) had vancomycin MICs ≤2 mg/L [i.e. were vancomycin susceptible (EUCAST breakpoint tables, v 9.0, 2019) or WT (CLSI M100, 29th edition, 2019)]. Fidaxomicin MICs were lower than those of all other agents tested (MIC90, 0.5 mg/L); however, one isolate with a fidaxomicin MIC of &gt;8 mg/L was identified. Metronidazole MICs ranged from 0.12 to 4 mg/L; all isolates were metronidazole susceptible by the CLSI breakpoint (≤8 mg/L) compared with 96.8% susceptible by the EUCAST breakpoint (≤2 mg/L). In total, 182 different ribotypes were identified from 2013 to 2017. The most common ribotypes identified were 027 (19.3% of isolates) and 106 (8.2%). Ribotype 027 isolates were frequently moxifloxacin resistant (87.3% of isolates) and MDR (48.6%), associated with vancomycin (10/25, 40.0%) and metronidazole (58/69, 84.1%) resistance and from patients aged ≥80 years. The prevalence of ribotype 027 decreased significantly (P &lt; 0.0001) from 2013 (27.5%) to 2017 (9.0%) and was replaced by increases in ribotype 106 (P = 0.0003) and multiple less common ribotypes.

Conclusions

Periodic surveillance is required to monitor clinical isolates of C. difficile for changes to in vitro susceptibility testing profiles and ribotype evolution.

Fecal Metabolites As Non-Invasive Biomarkers of Gut Diseases

Recent studies have shown the importance of the human intestinal microbiome in maintaining a healthy gastrointestinal tract, as well as in the development of pathological processes. The intestinal microbiome manifests itself primarily as fecal metabolites. In the past decade, there has been growing interest in studying its composition, which for the most part had to do with the possibility of using the metabolomic analysis in clinical diagnosis. In contrast to the comprehensive description of blood serum, urine, saliva, and cerebrospinal fluid metabolites, data on fecal metabolites is sparse. Despite the instrumental and methodological achievements in the metabolomic analysis in general, the analysis of fecal metabolome remains less well developed, mainly because of the inhomogeneity of its composition and the lack of standardized methods for collecting, processing, and analyzing fecal samples. This review summarizes data on methods for studying and describing various groups of fecal metabolites. It also assesses their potential as tools in the diagnosis of gastrointestinal diseases.

Management of difficult-to-treat Clostridioides difficile in a patient with chronic osteomyelitis

A 61-year-old male patient being treated with intravenous antibiotics for left foot osteomyelitis presented to the hospital septic, with several days of worsening abdominal pain, bloating and watery bowel movements. Investigation revealed that the patient had severe, treatment-resistant Clostridioides difficile colitis. He was initially treated with oral vancomycin and intravenous metronidazole, which was switched to oral fidaxomicin. After no improvement in the patient's symptoms, he was treated with two faecal microbiota transplants. He was offered a third faecal microbiota transplant but declined. The patient was placed back on oral fidaxomicin and saw ultimate resolution of his symptoms. This case provides an example of a treatment pathway for refractory C. difficile infection.

The Clinical Burden of Clostridioides difficile in Ontario, Canada

Background

To understand the clinical burden of Clostridioides difficile infection (CDI), we analyzed health outcome data from Ontario, Canada for CDI associated with and manifested in acute care hospitals (ACH), long-term care facilities (LTCF), the community, or ACH-associated with community-onset.

Methods

We performed a retrospective analysis using individual-level data from Ontario databases (April 1, 2005 to March 31, 2015), identifying CDI cases ≥18 years requiring hospitalization, and stratifying into cohorts based on association and onset location. Cohort members were matched to controls on demographics and medical conditions at onset, for outcomes including 30- and 180-day all-cause mortality and rehospitalization.

Results

We stratified 22 617 individuals hospitalized with CDI during the study period: 13 152 (58.1%) ACH-associated/ACH-onset, 7116 (31.5%) community-associated/community-onset, 1847 (8.2%) ACH-associated/community-onset, and 502 (2.2%) LTCF-associated/LTCF-onset. Compared with controls, unadjusted 30-day rehospitalization rates were significantly higher (P < .0001) for ACH-associated/ACH-onset CDI (9.5% vs 0.4%), LTCF-associated/LTCF-onset (7.2% vs 1.1%), community-associated/community-onset (7.8% vs 0.8%), and ACH-associated/community-onset (10.9% vs 0.7%). One hundred eighty-day mortality rates were higher in the community-associated/community-onset and the LTCF-associated/LTCF-onset cohorts than controls: 66.3% vs 12.3% (P < .0001) and 30.9% vs 3.1% (P < .0001), respectively. All differences remained significant after adjusting for patient factors.

Conclusions

Clostridioides difficile infection is associated with higher rates of 30-day rehospitalization compared with controls. In addition, mortality rates within 180-days of hospital discharge are significantly higher for community-associated/community-onset and LTCF-associated/LTCF-onset CDI cohorts than controls. Clostridioides difficile infection warrants increased prevention and monitoring efforts.

Which probiotic has the best effect on preventing Clostridium difficile-associated diarrhea? A systematic review and network meta-analysis

OBJECTIVE

Clostridium difficile-associated diarrhea (CDAD) accounts for up to 25% of patients with antibiotic-associated diarrhea (AAD). We aimed to determine which probiotic is most effective in preventing CDAD using a network meta-analysis.

METHODS

Studies were identified by searching PubMed, EMBASE and the Cochrane Library databases for randomized controlled trials (RCTs) that evaluated the efficacy of probiotic interventions for CDAD. Primary outcomes were the incidence rates of AAD and CDAD, and secondary outcomes were the duration of diarrhea and the time until onset of diarrhea. The PROSPERO registered number of this study is CRD42018106115.

RESULTS

Ten RCTs including 11 analyses and including 4 692 patients were identified. Compared with the control group, probiotic intervention reduced the incidence rates of CDAD (odds ratio [OR] 0.33, 95% confidence interval [CI] 0.17-0.61) and AAD (OR 0.39, 95% CI 0.23-0.66). Similar results were observed regarding the duration of diarrhea and the time until onset of diarrhea. Meta-regression analysis showed a correlation between the type of probiotic used and the incidence of CDAD and AAD. All nine kinds of probiotic interventions were statistically more effective than the placebo, with Lactobacillus casei ranking as the best intervention (OR 0.19, 95% credible interval [CrI] 0.06-0.63) for decreasing the incidence rate of CDAD. L. casei also ranked the highest in reducing the incidence rate of AAD (OR 0.32, 95% CrI 0.14-0.74).

CONCLUSION

Lactobacilli strains, especially L. casei, have a good effect on the prevention of CDAD and AAD.

Pseudomembranous Colitis in Four Ethiopian Patients: A Case Series

We present a series of four patients who had been admitted to two hospitals in Addis Ababa after presenting with persistent and chronic diarrhoea. All patients were subsequently diagnosed to have Clostridioides difficile-associated pseudomembranous colitis, a disease that has long been regarded as a rare diagnosis in sub-Saharan Africa, and which has not yet been reported in Ethiopia. This case series is believed to create a much-needed awareness among physicians on the existence of this treatable but potentially fatal disease.

Evaluation of anti-infective-related Clostridium difficile-associated colitis using the Japanese Adverse Drug Event Report database

Clostridium difficile-associated colitis (CDAC) may cause gastrointestinal illness, ranging in severity from mild diarrhea to fulminant colitis and even mortality. The purpose of this study was to evaluate anti-infective-related CDAC profiles using the Japanese Adverse Drug Event Report (JADER) database. Methods: We selected case reports of adverse events of CDAC as specified in the Medical Dictionary for Regulatory Activities. The association between the number of administered anti-infectives and aging was evaluated using reporting odds ratio (ROR) and adjusted for covariates using multiple-logistic regression. We also evaluated anti-infective-related CDAC-onset profiles using Weibull shape parameter. Results: The JADER database contained 534 688 reports from April 2004 to June 2018. There were 1222 anti-infective related CDAC events. The top five anti-infectives were as follows: third-generation cephalosporins (Anatomical Therapeutic Chemical (ATC) code: J01DD, 313 cases), fluoroquinolones (ATC code: J01MA, 201 cases), macrolides (ATC code: J01FA, 146 cases), carbapenems (ATC code: J01DH, 143 cases), and penicillins with extended spectrum (ATC code: J01CA, 103 cases). The adjusted RORs (95% confidence interval) in individuals using 1, 2, and ≥ 3 anti-infectives were 8.88 (7.05-11.18), 9.77 (6.89-13.86), and 18.39 (11.85-28.54), respectively. Moreover, 47.2% of CDACs occurred within 7 days of anti-infective therapy initiation. The adjusted ROR of interaction terms of ≥ 70 years × 1 drug was 21.81 (14.56-32.68). Conclusion: Our results suggest that the number of administered anti-infectives and patient age are associated with CDAC. These data may be particularly beneficial to prescribers and would contribute to improving the management of CDAC.

Predictors of Clostridioides difficile recurrence across a national cohort of veterans in outpatient, acute, and long-term care settings

PURPOSE

The greatest challenge in treating Clostridioides difficile infection (CDI) is disease recurrence, which occurs in about 20% of patients, usually within 30 days of treatment cessation. We sought to identify independent predictors of first recurrence among a national cohort of veterans with CDI.

METHODS

We conducted a case-control study among acute and long-term care Veterans Affairs (VA) inpatients and outpatients with a first CDI episode (positive stool sample for C. difficile toxin[s] and receipt of at least 2 days of CDI treatment) between 2010 and 2014. Cases experienced first recurrence within 30 days from the end of treatment. Controls were those without first recurrence matched 4:1 to cases on year, facility, and severity. Multivariable conditional logistic regression was used to identify predictors of first recurrence.

RESULTS

We identified 32 predictors of first recurrence among 974 cases and 3,896 matched controls. Significant predictors included medication use prior to (probiotics, fluoroquinolones, laxatives, third- or fourth-generation cephalosporins), during (first- or second-generation cephalosporins, penicillin/amoxicillin/ampicillin, third- and fourth-generation cephalosporins), and after CDI treatment (probiotics, any antibiotic, proton pump inhibitors [PPIs], and immunosuppressants). Other predictors included current biliary tract disease, malaise/fatigue, cellulitis/abscess, solid organ cancer, medical history of HIV, multiple myeloma, abdominal pain, and ulcerative colitis.

CONCLUSION

In a large national cohort of outpatient and acute and long-term care inpatients, treatment with certain antibiotics, PPIs, immunosuppressants, and underlying disease were among the most important risk factors for first CDI recurrence.

Interaction of the microbiota with the human body in health and diseases

The human body contains many microorganisms, including a large number of bacteria, viruses, fungi, and protozoa, which are referred to as the microbiota. Compared with the number of cells comprising the human body, that of the microbiota has been found to be much larger. The microbiome is defined as microorganisms and their genomes have been shown to contain about 100 times more genes than the human genome. The microbiota affects many vital functions in the human body. It contributes to regulation of the immune system, digestion of food, production of vitamins such as B12 and K, metabolization of xenobiotic materials, and many other tasks. Many factors affect the microbiota biodiversity, such as diet, medicines including antibiotics, relationships with the environment, pregnancy, and age. Studies have shown that the lack of microbiota diversity leads to many diseases like autoimmune diseases such as diabetes type I, rheumatism, muscular dystrophy, problems in blood coagulation due to lack of vitamin K, and disturbances in the transfer of nerve cells due to lack of vitamin B12, in addition to its involvement in a number of conditions such as cancer, memory disorders, depression, stress, autism, and Alzheimer's disease. The aim of this review is to summarize the latest studies discussing the relationship between the microbiota and the human body in health and diseases.

Prevalence and characterization of Clostridioides difficile isolates from retail food products (vegetables and meats) in Japan

The present study aimed to elucidate the prevalence of Clostridioides difficile in Japanese retail food products. For this purpose, retail food samples (242 fresh vegetables and 266 retail meat samples: 89 chicken meat; 28 chicken liver; 200 pork meat; 24 pig liver; 127 beef meat) were collected from 14 supermarkets between 2015 and 2019. C. difficile was isolated from eight (3.3%) fresh vegetable, six (6.7%) chicken meat, one (3.6%) chicken liver, one (0.5%) pork meat, and two (1.6%) beef meat samples; it was not isolated from pig liver. Of these isolates, 35% were toxigenic. All isolates were typable by PCR ribotyping and were resolved into 12 PCR ribotypes. Among these isolates, ribotype 014, which is distributed worldwide including in Japanese clinical cases, was detected among vegetable isolates. Therefore, although the C. difficile contamination rate in Japanese retail foods was low, these sources can be contaminated and could transmit these bacteria to humans.

Performance Evaluation of the Luminex Aries C. difficile Assay in Comparison to Two Other Molecular Assays within a Multihospital Health Care Center

Clostridioides difficile infection (CDI) remain a serious issue in the United States. Fast and accurate diagnosis of CDI is paramount to achieve immediate infection control initiation, triaging, and isolation, as well as appropriate antibiotic treatment. However, both, over- and underdiagnosis can lead to adverse patient outcomes, such as unnecessary administration of antibiotics or unwanted spread of spores in any hospital setting, respectively.

Clostridioides difficile infection (CDI) remain a serious issue in the United States. Fast and accurate diagnosis of CDI is paramount to achieve immediate infection control initiation, triaging, and isolation, as well as appropriate antibiotic treatment. However, both, over- and underdiagnosis can lead to adverse patient outcomes, such as unnecessary administration of antibiotics or unwanted spread of spores in any hospital setting, respectively. In this prospective study, we evaluated the FDA-cleared Aries C. difficile assay and compared its performance and workflow characteristics to those of the BD Max Cdiff and Xpert C. difficile/Epi assays. Out of 302 samples tested, 55 (18.2%) samples were positive, and 234 (77.5%) samples were negative for C. difficile by all three testing methods. Comparison results showed a positive and negative percent agreement (PPA and NPA, respectively) between the Aries and Xpert assays of 95.2% (59/62) and 99.2% (238/240), respectively. The PPA and NPA between the Aries and BD Max assays were 91.8% (56/61) and 96.6% (230/238), respectively. Invalid result rates were determined to be 2.6% for the BD Max assay, 1.0% for the Aries assay, and 0% for the Xpert assay. Hands-on time (HoT) and total turnaround time (TAT) varied considerably depending on the sample number and instrument throughput. The HoT ranged from 1.2 to 3.5 min per sample, and the TAT was 1 to 2.3 h. Overall, the results demonstrated that the Aries assay is a rapid and sensitive method for the diagnosis of CDI in clinical laboratories.

Ultrasensitive Detection of Clostridioides difficile Toxins in Stool by Use of Single-Molecule Counting Technology: Comparison with Detection of Free Toxin by Cell Culture Cytotoxicity Neutralization Assay

Laboratory tests for Clostridioides difficile infection (CDI) rely on the detection of free toxin or molecular detection of toxin genes. The Singulex Clarity C. diff toxins A/B assay is a rapid, automated, and ultrasensitive assay that detects C. difficile toxins A and B in stool. We compared CDI assays across two prospective multicenter studies to set a cutoff for the Clarity assay and to independently validate the performance compared with that of a cell culture cytotoxicity neutralization assay (CCCNA). The cutoff was set by two sites testing fresh samples from 897 subjects with suspected CDI and then validated at four sites testing fresh samples from 1,005 subjects with suspected CDI. CCCNA testing was performed at a centralized laboratory. Samples with discrepant results between the Clarity assay and CCCNA were retested with CCCNA when the Clarity result agreed with that of at least one comparator method; toxin enzyme immunoassays (EIA), glutamate dehydrogenase (GDH) detection, and PCR were performed on all samples. The cutoff for the Clarity assay was set at 12.0 pg/ml. Compared to results with CCCNA, the Clarity assay initially had 85.2% positive agreement and 92.4% negative agreement. However, when samples with discrepant results between the Clarity assay and CCCNA in the validation study were retested by CCCNA, 13/17 (76.5%) Clarity-negative but CCCNA-positive samples (Clarity⁺/CCCNA^-) became CCCNA^-, and 5/26 (19.2%) Clarity⁺/CCCNA^- samples became CCCNA⁺, resulting in a 96.3% positive agreement and 93.0% negative agreement between Clarity and CCCNA results. The toxin EIA had 59.8% positive agreement with CCCNA. The Clarity assay was the most sensitive free-toxin immunoassay, capable of providing CDI diagnosis in a single-step solution. A different CCCNA result was reported for 42% of retested samples, increasing the positive agreement between Clarity and CCCNA from 85.2% to 96.3% and indicating the challenges of comparing free-toxin results to CCCNA results as a reference standard.

Increased Clinical Specificity with Ultrasensitive Detection of Clostridioides difficile Toxins: Reduction of Overdiagnosis Compared to Nucleic Acid Amplification Tests

Clostridioides difficile infection (CDI) is one of the most common health care-associated infections, resulting in significant morbidity, mortality, and economic burden. Diagnosis of CDI relies on the assessment of clinical presentation and laboratory tests. We evaluated the clinical performance of ultrasensitive single-molecule counting technology for detection of C. difficile toxins A and B. Stool specimens from 298 patients with suspected CDI were tested with the nucleic acid amplification test (NAAT; BD MAX Cdiff assay or Xpert C. difficile assay) and Singulex Clarity C. diff toxins A/B assay. Specimens with discordant results were tested with the cell cytotoxicity neutralization assay (CCNA), and the results were correlated with disease severity and outcome. There were 64 NAAT-positive and 234 NAAT-negative samples. Of the 32 NAAT⁺/Clarity^- and 4 NAAT^-/Clarity⁺ samples, there were 26 CCNA^- and 4 CCNA^- samples, respectively. CDI relapse was more common in NAAT⁺/toxin⁺ patients than in NAAT⁺/toxin^- and NAAT^-/toxin^- patients. The clinical specificity of Clarity and NAAT was 97.4% and 89.0%, respectively, and overdiagnosis was more than three times more common in NAAT⁺/toxin^- than in NAAT⁺/toxin⁺ patients. The Clarity assay was superior to NAATs for the diagnosis of CDI, by reducing overdiagnosis and thereby increasing clinical specificity, and the presence of toxins was associated with negative patient outcomes.

Characteristics of Campylobacter and Salmonella Infections and Acute Gastroenteritis in Older Adults in Australia, Canada, and the United States

BACKGROUND

The early detection of enteric infections in older adults is challenging because typical signs and symptoms of disease may be less common, absent, or overlooked. Understanding illness characteristics of enteric infections among older adults could improve the timeliness and accuracy of clinical diagnoses, thereby improving patient outcomes and increasing cases reported to surveillance.

METHODS

Here, we describe illness characteristics (percentage reporting bloody diarrhea, fever, vomiting, abdominal pain; percentage hospitalized; duration of hospitalization; and duration of illness) among older adults (≥65 years) with acute gastroenteritis and culture-confirmed Campylobacter and nontyphoidal Salmonella infections in Australia, Canada, and the United States and compare these characteristics with those among younger people (<5 years, 5-24 years, and 25-64 years).

RESULTS

A significant negative correlation was found between all symptoms and increasing age group, except for bloody diarrhea in cases of acute gastroenteritis. Adults aged ≥85 years reported bloody diarrhea in only 9% of nontyphoidal Salmonella and 4% of Campylobacter infections compared with 59% and 55% among children aged <5 years. Conversely, a greater percentage of older adults (≥65) than younger persons (<5, 5-24, 25-64) reported being hospitalized, with an increasing linear relationship in age groups 65 years and older.

CONCLUSIONS

Although older adults are more likely to have severe illness and be hospitalized, we found that the proportion of persons reporting symptoms typically associated with enteric infections decreases with age. These findings have implications for clinical recognition and treatment of gastrointestinal illness, as well as for public health research.

Trends in Incidence and Outcomes of Clostridium difficile Colitis in Hospitalized Patients of Febrile Neutropenia: A Nationwide Analysis

INTRODUCTION

Clostridium difficile infection (CDI) has been attracting attention lately as the most common hospital acquired infection. Patients with neutropenia because of malignancy seem to be at an increased risk for developing CDI. There is currently limited data that assesses the national burden and outcomes of CDI in Febrile Neutropenia (FN).

METHODS

We analyzed the National Inpatient Sample (NIS) database for all subjects with discharge diagnosis of FN with or without CDI (ICD-9 codes 288.00, 288.03,780.60, and 008.45) as primary or secondary diagnosis during the period from 2008 to 2014. All analyses were performed with SAS, version 9.4 (SAS Institute).

RESULTS

From 2008 to 2014 there were total 19422 discharges of FN patients with CDI. There was a rising incidence of CDI in patients with FN from 4.11% (in 2008) to 5.83% (in 2014). The In-hospital mortality showed a decreasing trend from 7.79% (in 2008) to 5.32% (in 2014), likely because of improvements in diagnostics and treatment. The overall mortality (6.37% vs. 4.61%), length of stay >5 days (76.45% vs. 50.98%), hospital charges >50,000 dollars (64.43% vs. 40.29%), colectomy and colostomy (0.35% vs. 0.15%), and discharge to skilled nursing facility (10.47% vs. 6.43%) was significantly more in FN patients with CDI versus without CDI over 7 years (2008 to 2014). Age above 65 years, Hispanic race, hematological malignancies, urban hospital settings, and sepsis were significant predictors of mortality in febrile neutropenia patients with CDI.

DISCUSSION

Despite the significant decrease in mortality, the incidence of CDI is rising in hospitalized FN patients with underlying hematological malignancies. Risk factor modification, with the best possible empiric antibiotic regimen is imperative for reducing mortality and health care costs in this cohort.

Human Serum Albumin Is an Essential Component of the Host Defense Mechanism Against Clostridium difficile Intoxication

Background

The pathogenic effects of Clostridium difficile are primarily attributable to the production of the large protein toxins (C difficile toxins [Tcd]) A (TcdA) and B (TcdB). These toxins monoglucosylate Rho GTPases in the cytosol of host cells, causing destruction of the actin cytoskeleton with cytotoxic effects. Low human serum albumin (HSA) levels indicate a higher risk of acquiring and developing a severe C difficile infection (CDI) and are associated with recurrent and fatal disease.

Methods

We used a combined approach based on docking simulation and biochemical analyses that were performed in vitro on purified proteins and in human epithelial colorectal adenocarcinoma cells (Caco-2), and in vivo on stem cell-derived human intestinal organoids and zebrafish embryos.

Results

Our results show that HSA specifically binds via its domain II to TcdA and TcdB and thereby induces their autoproteolytic cleavage at physiological concentrations. This process impairs toxin internalization into the host cells and reduces the toxin-dependent glucosylation of Rho proteins.

Conclusions

Our data provide evidence for a specific HSA-dependent self-defense mechanism against C difficile toxins and provide an explanation for the clinical correlation between CDI severity and hypoalbuminemia.

An Automated Microrobotic Platform for Rapid Detection of C. diff Toxins

OBJECTIVE

Clostridium difficile (C. diff) infection leads to hundreds of nosocomial infections, and early diagnosis of this toxin-mediated disease is important. This paper aims to develop a microrobotic system and related methods that enable the automated and rapid detection of toxins secreted by C. diff that exist in patient's stool.

METHODS

We utilize the fluorescent magnetic spore-based microrobot (FMSM), a microscale mobile sensing tool, to efficiently detect C. diff toxins by utilizing its property of selective fluorescence responses to C. diff toxins. A plug-and-play (PnP) electromagnetic coil system integrated with fluorescence microscopy is developed for actuation, control and observation of FMSMs. In order to track in real time and accurately obtain the fluorescence parameters of a FMSM under varied background noise in fluorescence signal, an image gradient-based method is proposed. For accelerating the FMSM-toxin interaction in different samples, an automated navigation control scheme for the FMSM is proposed and implemented. Moreover, data post-processing methods that can optimally extract the fluorescence decay trend from the dense and fluctuated fluorescence data are developed.

RESULTS

This automated mobile detection process finishes within only 20 minutes, and the toxin detection result is immediately given by adopting the proposed system and methods. Experimental results on different biological samples confirm the qualitative detection capability. And, C. diff toxins are automatically detected from the clinical stool of infectious patients and the relationship between the fluorescence decay and the toxin concentration is calibrated for semi-quantitative detection purpose.

SIGNIFICANCE

The proposed automated microrobotic platform provides a rapid and low-cost detection technique for C. diff toxins, and it has good competency for future clinical use.

The Antibiotic Bacitracin Protects Human Intestinal Epithelial Cells and Stem Cell-Derived Intestinal Organoids from Clostridium difficile Toxin TcdB

Bacitracin is an established antibiotic for local application and inhibits the cell wall synthesis of Gram-positive bacteria. Recently, we discovered a completely different mode of action of bacitracin and reported that this drug protects human cells from intoxication by a variety of medically relevant bacterial protein toxins including CDT, the binary actin ADP-ribosylating toxin of Clostridium (C.) difficile. Bacitracin prevents the transport of CDT into the cytosol of target cells, most likely by inhibiting the transport function of the binding subunit of this toxin. Here, we tested the effect of bacitracin towards TcdB, a major virulence factor of C. difficile contributing to severe C. difficile-associated diseases (CDAD) including pseudomembranous colitis. Bacitracin protected stem cell-derived human intestinal organoids as well as human gut epithelial cells from intoxication with TcdB. Moreover, it prevented the TcdB-induced disruption of epithelia formed by gut epithelium cells in vitro and maintained the barrier function as detected by measuring transepithelial electrical resistance (TEER). In the presence of bacitracin, TcdB was not able reach its substrate Rac1 in the cytosol of human epithelial cells, most likely because its pH-dependent transport across cell membranes into the cytosol is decreased by bacitracin. In conclusion, in addition to its direct antibiotic activity against C. difficile and its inhibitory effect towards the toxin CDT, bacitracin neutralizes the exotoxin TcdB of this important pathogenic bacterium.

Influence of Diagnostic Method on Outcomes in Phase 3 Clinical Trials of Bezlotoxumab for the Prevention of Recurrent Clostridioides difficile Infection: A Post Hoc Analysis of MODIFY I/II

Background

The optimum diagnostic test method for Clostridioides difficile infection (CDI) remains controversial due to variation in accuracy in identifying true CDI. This post hoc analysis examined the impact of CDI diagnostic testing methodology on efficacy outcomes in phase 3 MODIFY I/II trials.

Methods

In MODIFY I/II (NCT01241552/NCT01513239), participants received bezlotoxumab (10 mg/kg) or placebo during anti-CDI treatment for primary/recurrent CDI (rCDI). Using MODIFY I/II pooled data, initial clinical cure (ICC) and rCDI were assessed in participants diagnosed at baseline using direct detection methods (enzyme immunoassay [EIA]/cell cytotoxicity assay [CCA]) or indirect methods to determine toxin-producing ability (toxin gene polymerase chain reaction [tgPCR]/toxigenic culture).

Results

Of 1554 participants who received bezlotoxumab or placebo in MODIFY I/II, 781 (50.3%) and 773 (49.7%) were diagnosed by tgPCR/toxigenic culture and toxin EIA/CCA, respectively. Participants diagnosed by toxin EIA/CCA were more likely to be inpatients, older, and have severe CDI. In bezlotoxumab recipients, ICC rates were slightly higher in the toxin EIA/CCA subgroup (81.7%) vs tgPCR/toxigenic culture (78.4%). Bezlotoxumab significantly reduced the rCDI rate vs placebo in both subgroups; however, the magnitude of reduction was substantially larger in participants diagnosed by toxin EIA/CCA (relative difference, –46.6%) vs tgPCR/toxigenic culture (–29.1%). In bezlotoxumab recipients, the rCDI rate was lower in the toxin EIA/CCA subgroup (17.6%) vs tgPCR/toxigenic culture (23.6%; absolute difference, –6.0%; 95% confidence interval, –12.4 to 0.3; relative difference, –25.4%).

Conclusions

Diagnostic tests that detect fecal C. difficile toxins are of fundamental importance to accurately diagnosing CDI, including in clinical trial design, ensuring that therapeutic efficacy is not underestimated.

Clostridium difficile colitis: CT findings and differential diagnosis

Clostridium difficile infection (CDI) is a severe and potentially deadly infectious colitis whose incidence is dramatically increasing in the last decades, with more virulent strains. CDI should be suspected in case of unexplained diarrhea and abdominal pain in patients with a recent history of antibiotic use and healthcare exposures; diagnosis is based on a combination of clinical and laboratory findings with demonstration of C. difficile toxins by stool test. The advantages of contrast-enhanced computed tomography (CECT) are the noninvasiveness and the ability to evaluate both the colonic wall and the adjacent soft tissues. Considerable overlap exists between the CECT findings of CDI and those of colitis of other origins, such as typhlitis, ischemic colitis, graft-versus-host disease, radiation colitis and inflammatory bowel diseases; however, some features may help distinguish between these conditions. This paper provides a comprehensive overview of the imaging features of Clostridium difficile colitis and its mimics, with a view to assist the radiologist in reaching the correct diagnosis.

A sustained systemic inflammatory response syndrome is associated with shunt-dependent hydrocephalus after aneurysmal subarachnoid hemorrhage

OBJECTIVE

The authors sought to evaluate whether a sustained systemic inflammatory response was associated with shunt-dependent hydrocephalus following aneurysmal subarachnoid hemorrhage.

METHODS

A retrospective analysis of 193 consecutive patients with aneurysmal subarachnoid hemorrhage was performed. Management of hydrocephalus followed a stepwise algorithm to determine the need for external CSF drainage and subsequent shunt placement. Systemic inflammatory response syndrome (SIRS) data were collected for all patients during the first 7 days of hospitalization. Patients who met the SIRS criteria every day for the first 7 days of hospitalization were considered as having a sustained SIRS. Univariate and multivariate regression analyses were used to determine predictors of shunt dependence.

RESULTS

Sixteen percent of patients required shunt placement. Sustained SIRS was observed in 35% of shunt-dependent patients compared to 14% in non-shunt-dependent patients (p = 0.004). On multivariate logistic regression, female sex (OR 0.35, 95% CI 0.142-0.885), moderate to severe vasospasm (OR 3.78, 95% CI 1.333-10.745), acute hydrocephalus (OR 21.39, 95% CI 2.260-202.417), and sustained SIRS (OR 2.94, 95% CI 1.125-7.689) were significantly associated with shunt dependence after aneurysmal subarachnoid hemorrhage. Receiver operating characteristic analysis revealed an area under the curve of 0.83 for the final regression model.

CONCLUSIONS

Sustained SIRS was a predictor of shunt-dependent hydrocephalus following aneurysmal subarachnoid hemorrhage even after adjustment for potential confounding variables in a multivariate logistic regression model.

Enterotoxic Clostridia: Clostridioides difficile Infections

Clostridioides difficile is a Gram-positive, anaerobic, spore forming pathogen of both humans and animals and is the most common identifiable infectious agent of nosocomial antibiotic-associated diarrhea. Infection can occur following the ingestion and germination of spores, often concurrently with a disruption to the gastrointestinal microbiota, with the resulting disease presenting as a spectrum, ranging from mild and self-limiting diarrhea to severe diarrhea that may progress to life-threating syndromes that include toxic megacolon and pseudomembranous colitis. Disease is induced through the activity of the C. difficile toxins TcdA and TcdB, both of which disrupt the Rho family of GTPases in host cells, causing cell rounding and death and leading to fluid loss and diarrhea. These toxins, despite their functional and structural similarity, do not contribute to disease equally. C. difficile infection (CDI) is made more complex by a high level of strain diversity and the emergence of epidemic strains, including ribotype 027-strains which induce more severe disease in patients. With the changing epidemiology of CDI, our understanding of C. difficile disease, diagnosis, and pathogenesis continues to evolve. This article provides an overview of the current diagnostic tests available for CDI, strain typing, the major toxins C. difficile produces and their mode of action, the host immune response to each toxin and during infection, animal models of disease, and the current treatment and prevention strategies for CDI.