Prevalence of the Clostridium difficile BI/NAP1/027 strain across the United States Veterans Health Administration

Epidemiology of Clostridioides difficile infection at one hospital 10 years after an outbreak of the epidemic C. difficile strain BI/027: changing strain prevalence, antimicrobial susceptibilities, and patient antibiotic exposures

In contrast to the epidemiology 10 years earlier at our hospital when the epidemic restriction endonuclease analysis (REA) group strain BI accounted for 72% of Clostridioides difficile isolates recovered from first-episode C. difficile infection (CDI) cases, BI represented 19% of first-episode CDI isolates in 2013-2015. Two additional REA group strains accounted for 31% of isolates (Y, 16%; DH, 12%). High-level resistance to fluoroquinolones and azithromycin was more common among BI isolates than among DH, Y, and non-BI/DH/Y isolates. Multivariable analysis revealed that BI cases were 2.47 times more likely to be associated with fluoroquinolone exposure compared to non-BI cases (95% confidence interval [CI]: 1.12-5.46). In addition, the odds of developing a CDI after third- or fourth-generation cephalosporin exposure was 2.83 times for DH cases than for non-DH cases (95% CI: 1.06-7.54). Fluoroquinolone use in the hospital decreased from 2005 to 2015 from a peak of 113 to a low of 56 antimicrobial days/1,000 patient days. In contrast, cephalosporin use increased from 42 to 81 antimicrobial days/1,000 patient days. These changes correlated with a decrease in geometric mean MIC for ciprofloxacin (61.03 to 42.65 mg/L, P = 0.02) and an increase in geometric mean MIC for ceftriaxone (40.87 to 86.14 mg/L, P < 0.01) among BI isolates. The BI strain remained resistant to fluoroquinolones, but an overall decrease in fluoroquinolone use and increase in cephalosporin use were associated with a decrease in the prevalence of BI, an increased diversity of C. difficile strain types, and the emergence of strains DH and Y.

Secondary prophylaxis for Clostridioides difficile infection for patients on non-C. difficile antibiotics: a retrospective cohort study

OBJECTIVES

Recurrent Clostridioides difficile infection (CDI) poses healthcare challenges and morbidity. Preventing recurrence with prophylactic oral CDI antibiotics lack consensus.

METHODS

We used data from the largest healthcare provider in Israel to identify all adults aged 18 years or older diagnosed with a first episode of CDI (Index CDI) between February 2018 and December 2022 and subsequently received a non-CDI antibiotic within 2-8 weeks. Patients who received a concurrent prophylactic CDI antibiotic constituted the CDI prophylaxis group. Multivariable Cox proportional hazard regression models were used to examine the association of secondary CDI prophylaxis with CDI recurrence according to the severity of the index CDI (primary objective) and with 4- and 8-week all-cause mortality (secondary objective).

RESULTS

A total of 434 eligible patients were included. Among them, 327 did not receive CDI antibiotic prophylaxis, while 107 did. CDI antibiotic prophylaxis was associated with a significant risk reduction of CDI recurrence with an adjusted HR of 0.51 (95% CI, 0.27-0.97). The magnitude of the association was modified by the severity of the index CDI episode (P for interaction 0.0182). Specifically, the HR for recurrence was 0.163 (95% CI 0.045-0.593) for non-severe CDI, and 1.242 (95% CI 0.524-2.946) for severe CDI. No significant association was found between CDI antibiotic prophylaxis and 4-8 weeks mortality.

CONCLUSION

Secondary prophylaxis with CDI antibiotics appears to be associated with a reduced risk of recurrence in patients with previous non-severe CDI episode. Further studies are needed to confirm this finding.

The changing epidemiology of Clostridioides difficile infection and the NAP1/027 strain in two Québec hospitals: a 17-year time-series study

Objective

To describe the epidemiology of healthcare-associated Clostridioides difficile infection (HA-CDI) in two Québec hospitals in Canada following the 2003 epidemic and to evaluate the impact of antibiotic stewardship on the incidence of HA-CDI and the NAP1/027 strain.

Design

Time-series analysis.

Setting

Two Canadian tertiary care hospitals based in Montréal, Québec.

Patients

Patients with a positive assay for toxigenic C. difficile were identified through infection control surveillance. All cases of HA-CDI, defined as symptoms occurring after 72 hours of hospital admission or within 4 weeks of hospitalization, were included.

Methods

The incidence of HA-CDI and antibiotic utilization from 2003 to 2020 were analyzed with available C. difficile isolates. The impact of antibiotic utilization on HA-CDI incidence was estimated by a dynamic regression time-series model. Antibiotic utilization and the proportion of NAP1/027 strains were compared biannually for available isolates from 2010 to 2020.

Results

The incidence of HA-CDI decreased between 2003 and 2020 at both hospitals from 26.5 cases per 10,000 patient-days in 2003 to 4.9 cases per 10,000 patient-days in 2020 respectively. Over the study period, there were an increase in the utilization of third-generation cephalosporins and a decrease in usage of fluoroquinolones and clindamycin. A decrease in fluoroquinolone utilization was associated with a significant decrease in HA-CDI incidence as well as decrease in the NAP1/027 strain by approximately 80% in both hospitals.

Conclusions

Decreased utilization of fluoroquinolones in two Québec hospitals was associated with a decrease in the incidence of HA-CDI and a genotype shift from NAP1/027 to non-NAP1/027 strains.

Genomic surveillance of Clostridioides difficile transmission and virulence in a healthcare setting

Clostridioides difficile infection (CDI) is a major cause of healthcare-associated diarrhea, despite the widespread implementation of contact precautions for patients with CDI. Here, we investigate strain contamination in a hospital setting and the genomic determinants of disease outcomes. Across two wards over 6 months, we selectively cultured C. difficile from patients (n = 384) and their environments. Whole-genome sequencing (WGS) of 146 isolates revealed that most C. difficile isolates were from clade 1 (131/146, 89.7%), while only one isolate of the hypervirulent ST1 was recovered. Of culture-positive admissions (n = 79), 19 (24%) patients were colonized with toxigenic C. difficile on admission to the hospital. We defined 25 strain networks at ≤2 core gene single nucleotide polymorphisms; two of these networks contain strains from different patients. Strain networks were temporally linked (P < 0.0001). To understand the genomic correlates of the disease, we conducted WGS on an additional cohort of C. difficile (n = 102 isolates) from the same hospital and confirmed that clade 1 isolates are responsible for most CDI cases. We found that while toxigenic C. difficile isolates are associated with the presence of cdtR, nontoxigenic isolates have an increased abundance of prophages. Our pangenomic analysis of clade 1 isolates suggests that while toxin genes (tcdABER and cdtR) were associated with CDI symptoms, they are dispensable for patient colonization. These data indicate that toxigenic and nontoxigenic C. difficile contamination persist in a hospital setting and highlight further investigation into how accessory genomic repertoires contribute to C. difficile colonization and disease.

IMPORTANCE

Clostridioides difficile infection remains a leading cause of hospital-associated diarrhea, despite increased antibiotic stewardship and transmission prevention strategies. This suggests a changing genomic landscape of C. difficile. Our study provides insight into the nature of prevalent C. difficile strains in a hospital setting and transmission patterns among carriers. Longitudinal sampling of surfaces and patient stool revealed that both toxigenic and nontoxigenic strains of C. difficile clade 1 dominate these two wards. Moreover, quantification of transmission in carriers of these clade 1 isolates underscores the need to revisit infection prevention measures in this patient group. We identified unique genetic signatures associated with virulence in this clade. Our data highlight the complexities of preventing transmission of this pathogen in a hospital setting and the need to investigate the mechanisms of in vivo persistence and virulence of prevalent lineages in the host gut microbiome.

Microbiota-Based Live Biotherapeutic Products for Clostridioides Difficile Infection- The Devil is in the Details

Clostridioides difficile infection (CDI) remains a significant contributor to healthcare costs and morbidity due to high rates of recurrence. Currently, available antibiotic treatment strategies further disrupt the fecal microbiome and do not address the alterations in commensal flora (dysbiosis) that set the stage for CDI. Advances in microbiome-based research have resulted in the development of new agents, classified as live biotherapeutic products (LBPs), for preventing recurrent CDI (rCDI) by restoring eubiosis. Prior to the LBPs, fecal microbiota transplantation (FMT) was available for this purpose; however, lack of large-scale availability and safety concerns have remained barriers to its widespread use. The LBPs are an exciting development, but questions remain. Some are derived directly from human stool while other developmental products contain a defined microbial consortium manufactured ex vivo, and they may be composed of either living bacteria or their spores, making it difficult to compare members of this heterogenous drug class to one another. None have been studied head-to head or against FMT in preventing rCDI. As a class, they have considerable variability in their biologic composition, biopharmaceutic science, route of administration, stages of development, and clinical trial data. This review will start by explaining the role of dysbiosis in CDI, then give the details of the biopharmaceutical components for the LBPs which are approved or in development including how they differ from FMT and from one another. We then discuss the clinical trials of the LBPs currently approved for rCDI and end with the future clinical directions of LBPs beyond C. difficile.

Genomic surveillance of Clostridioides difficile transmission and virulence in a healthcare setting

Clostridioides difficile infection (CDI) is a major cause of healthcare-associated diarrhea, despite the widespread implementation of contact precautions for patients with CDI. Here, we investigate strain contamination in a hospital setting and genomic determinants of disease outcomes. Across two wards over six months, we selectively cultured C. difficile from patients (n=384) and their environments. Whole-genome sequencing (WGS) of 146 isolates revealed that most C. difficile isolates were from clade 1 (131/146, 89.7%), while only one isolate of the hypervirulent ST1 was recovered. Of culture-positive admissions (n=79), 19 (24%) of patients were colonized with toxigenic C. difficile on admission to the hospital. We defined 25 strain networks at ≤ 2 core gene SNPs; 2 of these networks contain strains from different patients. Strain networks were temporally linked (p<0.0001). To understand genomic correlates of disease, we conducted WGS on an additional cohort of C. difficile (n=102 isolates) from the same hospital and confirmed that clade 1 isolates are responsible for most CDI cases. We found that while toxigenic C. difficile isolates are associated with the presence of cdtR , nontoxigenic isolates have an increased abundance of prophages. Our pangenomic analysis of clade 1 isolates suggests that while toxin genes ( tcdABER and cdtR ) were associated with CDI symptoms, they are dispensable for patient colonization. These data indicate toxigenic and nontoxigenic C. difficile contamination persists in a hospital setting and highlight further investigation into how accessory genomic repertoires contribute to C. difficile colonization and disease.

Potential causal effect of contact precautions and isolation on Clostridioides difficile infection in the hyperendemic setting: Interrupted time-series analyses before and after implementation

BACKGROUND

Recent studies disputed the effectiveness of efforts to comply with contact precautions and isolation (CPI) considering relatively low intra-hospital transmission rate of healthcare facility-associated Clostridioides difficile infection (HCFA-CDI). We evaluated the potential causal effect of CPI on HCFA-CDI occurrence by comparing the incidence rate (IR) for different time periods with and without CPI implementation.

METHODS

Long-term observational time-series data were separated into three periods (pre-CPI: January 2012-March 2016, CPI: April 2016-April 2021, post-CPI: May 2021-December 2022). CPI was suspended owing to the restriction of isolation rooms during the COVID-19 pandemic. We inferred potential causal outcomes by comparing predicted and observed IRs of HCFA-CDI using interrupted time-series analyses, including the Bayesian structural time-series or autoregressive integrated moving average (ARIMA) model in the R-language or SAS software.

RESULTS

The monthly observed IR (44.9/100,000 inpatient-days) during the CPI period was significantly lower than the predicted IR (90.8) (-50.6% relative effect, P = 0.001). However, the observed IR (52.3) during the post-CPI period was significantly higher than the predicted IR (39.1) (33.6%, P = 0.001). The HCFA-CDI IR decreased during CPI (-14.3, P < 0.001) and increased post-CPI (5.4, P < 0.001) in the multivariable ARIMA model, which controlled for antibiotic usage, handwashing with soap and water, and number of toxin tests.

CONCLUSIONS

Various time-series models revealed that CPI implementation had a potential causal effect on the reduction of HCFA-CDI incidence.

Virulence and genomic diversity among clinical isolates of ST1 (BI/NAP1/027) Clostridioides difficile

Clostridioides difficile produces toxins that damage the colonic epithelium, causing colitis. Variation in disease severity is poorly understood and has been attributed to host factors and virulence differences between C. difficile strains. We test 23 epidemic ST1 C. difficile clinical isolates for their virulence in mice. All isolates encode a complete Tcd pathogenicity locus and achieve similar colonization densities. However, disease severity varies from lethal to avirulent infections. Genomic analysis of avirulent isolates reveals a 69-bp deletion in the cdtR gene, which encodes a response regulator for binary toxin expression. Deleting the 69-bp sequence in virulent R20291 strain renders it avirulent in mice with reduced toxin gene transcription. Our study demonstrates that a natural deletion within cdtR attenuates virulence in the epidemic ST1 C. difficile isolates without reducing colonization and persistence. Distinguishing strains on the basis of cdtR may enhance the specificity of diagnostic tests for C. difficile colitis.

Virulence and genomic diversity among clinical isolates of ST1 (BI/NAP1/027) Clostridioides difficile

Clostridioides difficile (C. difficile) , a leading cause of nosocomial infection, produces toxins that damage the colonic epithelium and results in colitis that varies from mild to fulminant. Variation in disease severity is poorly understood and has been attributed to host factors (age, immune competence and intestinal microbiome composition) and/or virulence differences between C. difficile strains, with some, such as the epidemic BI/NAP1/027 (MLST1) strain, being associated with greater virulence. We tested 23 MLST1(ST1) C. difficile clinical isolates for virulence in antibiotic-treated C57BL/6 mice. All isolates encoded a complete Tcd pathogenicity locus and achieved similar colonization densities in mice. Disease severity varied, however, with 5 isolates causing lethal infections, 16 isolates causing a range of moderate infections and 2 isolates resulting in no detectable disease. The avirulent ST1 isolates did not cause disease in highly susceptible Myd88 -/- or germ-free mice. Genomic analysis of the avirulent isolates revealed a 69 base-pair deletion in the N-terminus of the cdtR gene, which encodes a response regulator for binary toxin (CDT) expression. Genetic deletion of the 69 base-pair cdtR sequence in the highly virulent ST1 R20291 C. difficile strain rendered it avirulent and reduced toxin gene transcription in cecal contents. Our study demonstrates that a natural deletion within cdtR attenuates virulence in the epidemic ST1 C. difficile strain without reducing colonization and persistence in the gut. Distinguishing strains on the basis of cdtR may enhance the specificity of diagnostic tests for C. difficile colitis.

Trends in Clostridioides difficile prevalence, mortality, severity, and age composition during 2003-2014, the national inpatient sample database in the US

BACKGROUND

Clostridioides difficile (formerly known as Clostridium difficile) infection (CDI) is one of the most prevalent healthcare-associated infections in the United States (US). In the early 2000s, CDI emerged as a great threat with increasing prevalence, mortality, and severity, especially in advanced age. We investigated the US national trends in in-hospital CDI prevalence, mortality, severity, and age composition from 2003 to 2014.

METHODS

We identified the patients with CDI using the national inpatient sample data from 2003 to 2014. We performed Poisson regression model and Kendall's tau-b correlation test for our analyses.

RESULTS

Adjusted overall CDI prevalence did not significantly change during 2003-2014. In-hospital mortality of overall CDI did not significantly change during 2003-2008, then significantly decreased during 2008-2014. Severity of overall CDI significantly increased during 2003-2008, then decreased during 2008-2014. The proportions of patients with age ≥ 65 years decreased in CDI prevalence, mortality, and severity during 2003-2014.

CONCLUSIONS

Compared to the earlier years 2003-2008, overall CDI outcome improved in the later years 2008-2014. Younger patients increasingly contributed to CDI prevalence, mortality, and severity during 2003-2014. More studies to understand underlying driving forces of changes in CDI trends are warranted to mitigate CDI.

Comparative biofilm-forming ability between Clostridioides difficile strains isolated in Latin America and the epidemic NAP1/027 strain

Introduction

One of the challenges in treating Clostridioides difficile infection (CDI) is that the bacterium forms biofilms, a critical virulence mechanism known to promote antibiotic resistance and, as a result, consequently, a higher recurrence of the disease. The goal of this study was to compare the ability of three MLST Clade 2 strains to form a biofilm in vitro: ICC-45 (ribotype SLO231/UK[CE]821), a ST41 toxinotype IXb isolated in Brazil; and two epidemic NAP1/027/ST01 strains: NAP1/027/ST01 (LIBA5756), isolated during a 2010 outbreak in Costa Rica and the reference epidemic strain NAP1/027/ST01 (R20291); and ATCC700057, a non-toxigenic strain.

Methods

The ability of strains to form biofilm was evaluated using crystal violet staining. In addition, samples were stained with the Film Tracer biofilm matrix (Invitrogen®) and the biofilm matrix thickness was measured using confocal microscopy. The matrix architecture was determined using Scanning electron microscop. Confocal microscopy was used to detect the presence of toxin A (tcdA) using an anti-Clostridioides difficile TcdA antibody. The expression of virulence genes (tcdA, tcdB, tcdC, cdtB, spo0A, slpA, cwp66 and cwp84) was examined, as well as the effect of antibiotics metronidazole (MTZ) and vancomycin (VAN) on biofilm growth.

Results

All of the strains tested formed a moderate biofilm with 1.1 <DO_570nm>3.5. After 72h, biofilm biomass of the NAP1/027/ST01 epidemic strains (LIBA5756 and R20291) was significantly higher than ICC-45 and ATCC 700057 biofilms, as confirmed by electron and confocal microscopy. At 120h, the LIBA5756 biofilm biomass decreased compared to other strains. The toxigenic strains R20291 or LIBA 5756 had higher expression of genes tcdA, tcdB, tcdC, cdtA, slpA and spo0A than ICC-45, but there were no significant differences in the expression levels of cdtB, cwp66 and cwp84. In epidemic strains, VAN and MTZ inhibited biofilm formation; however, in the ICC-45 strain, MIC concentrations of VAN and MIC and 4MIC of MTZ did not inhibit biofilm formation.

Conclusion

The three MLST Clade 2 isolated from different rybotipes, two of which were isolated from Latin America, are competent biofilm-forming bacteria, indicating their ability to induce C. difficile infection recurrence, making treatment difficult.

Metronidazole for Treatment of Clostridioides difficile Infections in Brazil: A Single-Center Experience and Risk Factors for Mortality

We describe the epidemiology of C. difficile infections (CDIs) focused on treatment and analyze the risk factors for mortality. This is a retrospective cohort study of CDI cases with a positive A/B toxin in the stool in 2017–2018. We analyzed the demographic data, comorbidities, previous use of antimicrobials, severity, and treatment, and we performed multivariate analysis to predict the 30-days mortality. We analyzed 84 patients, 37 (44%) of which were male, where the mean age was 68.1 years and 83 (99%) had comorbidities. The percentage of positivity of the A/B toxin was 11.6%, and the overall incidence density was 1.78/10,000 patient days. Among the patients, 65.4% had previous use of antimicrobials, with third-generation cephalosporins being the class most prescribed, and 22.6% of cases were severe. Treatment was prescribed for 70 (83.3%) patients, and there was no statistically significant difference between the initial treatment with metronidazole and vancomycin even in severe cases. The 30-day mortality was 7/84 (8.3%), and the risk factors associated with mortality was a severity score ≥2 (OR: 6.0; CI: 1.15–31.1; p = 0.03). In this cohort of CDI-affected patients with comorbidities and cancer, metronidazole was shown to be a good option for treating CDIs, and the severity score was the only independent risk factor for death.

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

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

Establishment of a gnotobiotic pig model of Clostridioides difficile infection and disease

Clostridioides difficile (C. difficile) is a gram-positive, spore-forming, anaerobic bacterium known to be the most common cause of hospital-acquired and antibiotic-associated diarrhea. C. difficile infection rates are on the rise worldwide and treatment options are limited, indicating a clear need for novel therapeutics. Gnotobiotic piglets are an excellent model to reproduce the acute pseudomembranous colitis (PMC) caused by C. difficile due to their physiological similarities to humans and high susceptibility to infection. Here, we established a gnotobiotic pig model of C. difficile infection and disease using a hypervirulent strain. C. difficile-infected pigs displayed classic signs of C. difficile infection, including severe diarrhea and weight loss. Inoculated pigs had severe gross and microscopic intestinal lesions. C. difficile infection caused an increase in pro-inflammatory cytokines in samples of serum, large intestinal contents, and pleural effusion. C. difficile spores and toxins were detected in the feces of inoculated animals as tested by anaerobic culture and cytotoxicity assays. Successful establishment of this model is key for future work as therapeutics can be evaluated in an environment that accurately mimics what happens in humans. The model is especially suitable for evaluating potential prophylactics and therapeutics, including vaccines and passive immune strategies.

Non-inferiority of metronidazole to vancomycin in the treatment of first episode non-severe Clostridioides difficile infection: a single center retrospective cohort study

OBJECTIVES

We sought to assess the effectiveness of oral vancomycin compared to metronidazole on recurrence and mortality among hospitalized patients with non-severe Clostridioides difficile infection (CDI).

METHODS

A single center retrospective cohort study was conducted, including adult patients hospitalized between 2015 and 2020 with a first episode of non-severe CDI, treated with metronidazole or vancomycin as monotherapy for at least 10 days. We assessed recurrence of CDI requiring hospitalization (primary outcome) and all-cause mortality up to 8 weeks, post discharge.

RESULTS

Overall, 160 patients were treated with vancomycin and 149 treated with metronidazole. Re-hospitalization within 8 weeks due to CDI occurred in 10 (6.2%) patients in the vancomycin group, and 13 (8.7%) in the metronidazole group (P value = 0.407). Eight-week mortality occurred in 39 patients (26.2%) in the metronidazole group and 46 patients (28.8%) in the vancomycin group (P value = 0.61). After adjusting for age, gender, Ischemic heart disease, white blood cell count, neutrophile count and CRP, there was no significant difference between the two treatments (Re-hospitalization in 8 weeks due to CDI P = 0.5059; In-hospital death P = 0.7950; 4-week mortality P = 0.2988; 8-week mortality P = 0.8237).

CONCLUSION

There is no benefit of using vancomycin compared to metronidazole concerning recurrence rate requiring hospitalization, in-hospital and up to 4- and 8-week mortality rate in non-severe first episode of CDI.

Genomic Analysis of Clostridioides difficile in 2 Regions of the United States Reveals a Diversity of Strains and Limited Transmission

BACKGROUND

The distribution of Clostridioides difficile strains and transmission dynamics in the United States are not well defined. Whole-genome sequencing across 2 Centers for Disease Control and Prevention Emerging Infections Program C. difficile infection (CDI) surveillance regions (Minnesota and New York) was performed to identify predominant multilocus sequence types (MLSTs) in community-associated (CA) and healthcare-associated (HCA) disease and assess transmission.

METHODS

Whole-genome sequencing was performed on C. difficile isolates from patients with CDI over 3 months between 2016 and 2017. Patients were residents of the catchment area without a positive C. difficile test in the preceding 8 weeks. CDI cases were epidemiologically classified as HCA or CA.

RESULTS

Of 422 isolates, 212 (50.2%) were HCA and 203 (48.1%) were CA. Predominant MLSTs were sequence type (ST) 42 (9.3%), ST8 (7.8%), and ST2 (8.1%). MLSTs associated with HCA-CDI included ST1 (76%), ST53 (83.3%), and ST43 (80.0%), while those associated with CA-CDI included ST3 (76.9%) and ST41 (77.8%). ST1 was more frequent in New York than in Minnesota (10.8% vs 3.1%). Thirty-three pairs were closely related genomically, 14 of which had potential patient-to-patient transmission supported by record review.

CONCLUSIONS

The genomic epidemiology of C. difficile across 2 regions of the United States indicates the presence of a diverse strain profile and limited direct transmission.

Epidemiology of Clostridioides difficile in South Africa

Background

Clostridioides difficile (CD) is the most common healthcare-associated enteric infection. There is currently limited epidemiological evidence on CD incidence in South Africa.

Aim

To estimate the burden of CD infection (CDI) in the South African public sector between 1 July 2016 and 30 June 2017.

Methods

A retrospective cohort study utilizing secondary data was conducted to describe the epidemiology of CD in South Africa. We assessed the patient-level association between variables of interest, CD, and CD recurrence, by undertaking both univariate and multivariable analysis. Adjusted incidence rate ratios (aIRR) were calculated utilizing multivariable Poisson regression. The incidence of CD, CD recurrence and CD testing was estimated by Poisson regression for various levels of care and provinces.

Results

A total of 14 023 samples were tested for CD during the study period. After applying exclusion criteria, we were left with a sample of 10 053 of which 1 860 (18.50%) tested CD positive. A positive and significant association between CDI and level of care is found, with patients treated in specialized tuberculosis (TB) hospitals having a five-fold increased adjusted incidence risk ratio (aIRR) for CDI (aIRR 4.96 CI95% 4.08–6.04,) compared to those managed in primary care. Patients receiving care at a secondary, tertiary, or central hospital had 35%, 66% and 41% increased adjusted incidence of CDI compared to those managed in primary care, respectively. National incidence of CDI is estimated at 53.89 cases per 100 000 hospitalizations (CI95% 51.58–56.29), the incidence of recurrence at 21.39 (CI95% 15.06–29.48) cases per 1 000 cases and a recurrence rate of 2.14% (CI95% 1.51–2.94).

Conclusion

Compared to European countries, we found a comparable incidence of CD. However, our estimates are lower than those for the United States. Compared to high-income countries, this study found a comparatively lower CD recurrence.

An aniline-substituted bile salt analog protects both mice and hamsters from multiple Clostridioides difficile strains

Clostridioides difficile infection (CDI) is the major identifiable cause of antibiotic-associated diarrhea. The emergence of hypervirulent C. difficile strains has led to increases in both hospital- and community-acquired CDI. Furthermore, CDI relapse from hypervirulent strains can reach up to 25%. Thus, standard treatments are rendered less effective, making new methods of prevention and treatment more critical. Previously, the bile salt analog CamSA was shown to inhibit spore germination in vitro and protect mice and hamsters from C. difficile strain 630. Here, we show that CamSA was less active at preventing spore germination of other C. difficile ribotypes, including the hypervirulent strain R20291. Strain-specific in vitro germination activity of CamSA correlated with its ability to prevent CDI in mice. Additional bile salt analogs were screened for in vitro germination inhibition activity against strain R20291, and the most active compounds were tested against other strains. An aniline-substituted bile salt analog, (CaPA), was found to be a better anti-germinant than CamSA against eight different C. difficile strains. In addition, CaPA was capable of reducing, delaying, or preventing murine CDI signs in all strains tested. CaPA-treated mice showed no obvious toxicity and showed minor effects on their gut microbiome. CaPA's efficacy was further confirmed by its ability to prevent CDI in hamsters infected with strain 630. These data suggest that C. difficile spores respond to germination inhibitors in a strain-dependent manner. However, careful screening can identify anti-germinants with broad CDI prophylaxis activity.

Environmental Contamination of Contact Precaution and Non-Contact Precaution Patient Rooms in Six Acute Care Facilities

BACKGROUND

Environmental contamination is an important source of hospital multidrug-resistant organism (MDRO) transmission. Factors such as patient MDRO contact precautions (CP) status, patient proximity to surfaces, and unit type likely influence MDRO contamination and bacterial bioburden levels on patient room surfaces. Identifying factors associated with environmental contamination in patient rooms and on shared unit surfaces could help identify important environmental MDRO transmission routes.

METHODS

Surfaces were sampled from MDRO CP and non-CP rooms, nursing stations, and mobile equipment in acute care, intensive care, and transplant units within 6 acute care hospitals using a convenience sampling approach blinded to cleaning events. Precaution rooms had patients with clinical or surveillance tests positive for methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, carbapenem-resistant Enterobacteriaceae or Acinetobacter within the previous 6 months, or Clostridioides difficile toxin within the past 30 days. Rooms not meeting this definition were considered non-CP rooms. Samples were cultured for the above MDROs and total bioburden.

RESULTS

Overall, an estimated 13% of rooms were contaminated with at least 1 MDRO. MDROs were detected more frequently in CP rooms (32% of 209 room-sample events) than non-CP rooms (12% of 234 room-sample events). Surface bioburden did not differ significantly between CP and non-CP rooms or MDRO-positive and MDRO-negative rooms.

CONCLUSIONS

CP room surfaces are contaminated more frequently than non-CP room surfaces; however, contamination of non-CP room surfaces is not uncommon and may be an important reservoir for ongoing MDRO transmission. MDRO contamination of non-CP rooms may indicate asymptomatic patient MDRO carriage, inadequate terminal cleaning, or cross-contamination of room surfaces via healthcare personnel hands.

Functional analyses of epidemic Clostridioides difficile toxin B variants reveal their divergence in utilizing receptors and inducing pathology

Clostridioides difficile toxin B (TcdB) is a key virulence factor that causes C. difficile associated diseases (CDAD) including diarrhea and pseudomembranous colitis. TcdB can be divided into multiple subtypes/variants based on their sequence variations, of which four (TcdB1-4) are dominant types found in major epidemic isolates. Here, we find that these variants are highly diverse in their receptor preference: TcdB1 uses two known receptors CSPG4 and Frizzled (FZD) proteins, TcdB2 selectively uses CSPG4, TcdB3 prefers to use FZDs, whereas TcdB4 uses neither CSPG4 nor FZDs. By creating chimeric toxins and systematically switching residues between TcdB1 and TcdB3, we determine that regions in the N-terminal cysteine protease domain (CPD) are involved in CSPG4-recognition. We further evaluate the pathological effects induced by TcdB1-4 with a mouse intrarectal installation model. TcdB1 leads to the most severe overall symptoms, followed by TcdB2 and TcdB3. When comparing the TcdB2 and TcdB3, TcdB2 causes stronger oedema while TcdB3 induces severer inflammatory cell infiltration. These findings together demonstrate divergence in the receptor preference and further lead to colonic pathology for predominant TcdB subtypes.

Clostridioides difficile is a major cause of nosocomial and community-associated gastrointestinal infections. The bacterium produces three exotoxins including TcdA, TcdB, and CDT, of which TcdB is known as a key virulence factor causing the diseases. Since C. difficile was first linked to antibiotic-associated infections in 1978, a large number of clinically relevant strains were characterized and many of them were found to harbor some variant forms of TcdB. In this study, we examined four predominant TcdB variants from epidemic C. difficile strains. We found that these variants are highly diverse in preference to the known receptors, CSPG4 and Frizzled proteins. By conducting a systematically designed mutagenesis study, we determined that TcdB interacts with CSPG4 via regions across multiple domains. We also found that TcdB variants could induce distinguishable pathological phenotypes in a mouse model, suggesting C. difficile strains harboring divergent TcdB variants might exhibit different disease progression. Our study provides new insights into the toxicology and pathology of C. difficile toxin variants.

Continued decline in the prevalence of the Clostridioides difficile BI/NAP1/027 strain across the United States Veterans Health Administration

In 2018, we demonstrated a decreased prevalence of the hypervirulent Clostridioides difficile BI/NAP1/027 strain across the United States (US) Veterans Health Administration (VHA) from 2011 through 2016. The objective of this retrospective study was to update the prevalence of the BI/NAP1/027 strain within the VHA from 2017 through 2020. Patients with positive tests for the presence of toxigenic C. difficile at any Veterans Affairs Medical Center found to also routinely test for BI/NAP1/027 strain presence were included between July 1, 2016 and June 30, 2020. In total, 7490 patients had 8148 positive C. difficile tests that had a corresponding BI/NAP1/027 test. Of those, there were 1031 (12.6%) presumptive positive tests for the BI/NAP1/027 strain. The overall prevalence of BI/NAP1/027 decreased from a high of 15.4% in 2017 to 8.21% in 2020. Statistically significant reductions in rates from 2017 to 2020 occurred in 4 of 9 US Census Bureau regions.

Outcomes associated with recent guideline recommendations removing metronidazole for treatment of non-severe Clostridioides difficile infection: a retrospective, observational, nationwide cohort study

OBJECTIVES

The 2017 Society for Healthcare Epidemiology of America (SHEA) and Infectious Diseases Society of America (IDSA) Clinical Practice Guidelines for Clostridioides difficile (C. difficile) infection (CDI) removed metronidazole as a preferred option for initial episodes of non-severe CDI. This study aimed to determine if the shift away from metronidazole improved clinical outcomes of initial episodes of non-severe CDI.

METHODS

The study was a retrospective, observational, nationwide cohort study using a Veterans Health Administration national clinical administrative database. Adult patients treated for non-severe CDI before and after the February 2018 publication of the 2017 IDSA/SHEA C. difficile Clinical Practice Guidelines were included. The primary outcome was the composite of treatment failure or probable recurrence.

RESULTS

A total of 3608 patients were included, with 1809 in the pre-guideline cohort (mean [SD] age, 65.5 [14.2] years; 1602 [88.6%] male) and 1799 in the post-guideline cohort (mean [SD] age, 64 [14.6] years; 1584 [88%] male). Overall composite of treatment failure or probable recurrence was similar between both cohorts (318 of 1809 [17.6%] pre-guideline cohort vs. 317 of 1799 [17.6%] post-guideline cohort [P = 0.97]).

CONCLUSION

The shift away from metronidazole as a preferred option in initial non-severe Clostridioides difficile infection did not improve the composite of treatment failure or recurrence.

Retrospective Definition of Clostridioides difficile PCR Ribotypes on the Basis of Whole Genome Polymorphisms: A Proof of Principle Study

Clostridioides difficile is a cause of health care-associated infections. The epidemiological study of C. difficile infection (CDI) traditionally involves PCR ribotyping. However, ribotyping will be increasingly replaced by whole genome sequencing (WGS). This implies that WGS types need correlation with classical ribotypes (RTs) in order to perform retrospective clinical studies. Here, we selected genomes of hyper-virulent C. difficile strains of RT001, RT017, RT027, RT078, and RT106 to try and identify new discriminatory markers using in silico ribotyping PCR and De Bruijn graph-based Genome Wide Association Studies (DBGWAS). First, in silico ribotyping PCR was performed using reference primer sequences and 30 C. difficile genomes of the five different RTs identified above. Second, discriminatory genomic markers were sought with DBGWAS using a set of 160 independent C. difficile genomes (14 ribotypes). RT-specific genetic polymorphisms were annotated and validated for their specificity and sensitivity against a larger dataset of 2425 C. difficile genomes covering 132 different RTs. In silico PCR ribotyping was unsuccessful due to non-specific or missing theoretical RT PCR fragments. More successfully, DBGWAS discovered a total of 47 new markers (13 in RT017, 12 in RT078, 9 in RT106, 7 in RT027, and 6 in RT001) with minimum q-values of 0 to 7.40 × 10^-5, indicating excellent marker selectivity. The specificity and sensitivity of individual markers ranged between 0.92 and 1.0 but increased to 1 by combining two markers, hence providing undisputed RT identification based on a single genome sequence. Markers were scattered throughout the C. difficile genome in intra- and intergenic regions. We propose here a set of new genomic polymorphisms that efficiently identify five hyper-virulent RTs utilizing WGS data only. Further studies need to show whether this initial proof-of-principle observation can be extended to all 600 existing RTs.

Spo0A Suppresses sin Locus Expression in Clostridioides difficile

Clostridioides difficile is the leading cause of nosocomial infection and is the causative agent of antibiotic-associated diarrhea. The severity of the disease is directly associated with toxin production, and spores are responsible for the transmission and persistence of the organism. Previously, we characterized sin locus regulators SinR and SinR' (we renamed it SinI), where SinR is the regulator of toxin production and sporulation. The SinI regulator acts as its antagonist. In Bacillus subtilis, Spo0A, the master regulator of sporulation, controls SinR by regulating the expression of its antagonist, sinI However, the role of Spo0A in the expression of sinR and sinI in C. difficile had not yet been reported. In this study, we tested spo0A mutants in three different C. difficile strains, R20291, UK1, and JIR8094, to understand the role of Spo0A in sin locus expression. Western blot analysis revealed that spo0A mutants had increased SinR levels. Quantitative reverse transcription-PCR (qRT-PCR) analysis of its expression further supported these data. By carrying out genetic and biochemical assays, we show that Spo0A can bind to the upstream region of this locus to regulates its expression. This study provides vital information that Spo0A regulates the sin locus, which controls critical pathogenic traits such as sporulation, toxin production, and motility in C. difficile IMPORTANCE Clostridioides difficile is the leading cause of antibiotic-associated diarrheal disease in the United States. During infection, C. difficile spores germinate, and the vegetative bacterial cells produce toxins that damage host tissue. In C. difficile, the sin locus is known to regulate both sporulation and toxin production. In this study, we show that Spo0A, the master regulator of sporulation, controls sin locus expression. Results from our study suggest that Spo0A directly regulates the expression of this locus by binding to its upstream DNA region. This observation adds new detail to the gene regulatory network that connects sporulation and toxin production in this pathogen.

Inpatient fluoroquinolone use in Veterans' Affairs hospitals is a predictor of Clostridioides difficile infection due to fluoroquinolone-resistant ribotype 027 strains

BACKGROUND

Reduction in the use of fluoroquinolone antibiotics has been associated with reductions in Clostridioides difficile infections (CDIs) due to fluoroquinolone-resistant strains.

OBJECTIVE

To determine whether facility-level fluoroquinolone use predicts healthcare facility-associated (HCFA) CDI due to fluoroquinolone-resistant 027 strains.

METHODS

Using a nationwide cohort of hospitalized patients in the Veterans' Affairs Healthcare System, we identified hospitals that categorized >80% of CDI cases as positive or negative for the 027 strain for at least one-quarter of fiscal years 2011-2018. Within these facilities, we used visual summaries and multilevel logistic regression models to assess the association between facility-level fluoroquinolone use and rates of HCFA-CDI due to 027 strains, controlling for time and facility complexity level, and adjusting for correlated outcomes within facilities.

RESULTS

Between 2011 and 2018, 55 hospitals met criteria for reporting 027 results, including a total of 5,091 HCFA-CDI cases, with 1,017 infections (20.0%) due to 027 strains. Across these facilities, the use of fluoroquinolones decreased by 52% from 2011 to 2018, with concurrent reductions in the overall HCFA-CDI rate and the proportion of HCFA-CDI cases due to the 027 strain of 13% and 55%, respectively. A multilevel logistic model demonstrated a significant effect of facility-level fluoroquinolone use on the proportion of infections in the facility due to the 027 strain, most noticeably in low-complexity facilities.

CONCLUSIONS

Our findings provide support for interventions to reduce use of fluroquinolones as a control measure for CDI, particularly in settings where fluoroquinolone use is high and fluoroquinolone-resistant strains are common causes of infection.

Clostridium difficile infection in an academic medical center in Saudi Arabia: prevalence and risk factors

BACKGROUND

Clostridium difficile infection is one of the most common causes of diarrhea in healthcare facilities. More studies are needed to identify patients at high risk of C difficile infection in our community.

OBJECTIVES

Estimate the prevalence of C difficile infection among adult patients and evaluate the risk factors associated with infection.

DESIGN

Retrospective record review.

SETTING

Tertiary academic medical center in Jeddah.

PATIENTS AND METHODS

Eligible patients were adults (≥18 years old) with confirmed C difficile diagnosis between January 2013 and May 2018.

MAIN OUTCOME MEASURES

Prevalence rate and types of risk factors.

SAMPLE SIZE

Of 1886 records, 129 patients had positive lab results and met the inclusion criteria.

RESULTS

The prevalence of C difficile infection in our center over five years was 6.8%. The mean (SD) age was 56 (18) years, and infection was more prevalent in men (53.5%) than in women (46.5%). The most common risk factors were use of proton-pump inhibitors (PPI) and broad-spectrum antibiotics. The overlapping exposure of both PPIs and broad-spectrum antibiotics was 56.6%. There was no statistically significant difference between the type of PPI (P=.254) or antibiotic (P=.789) and the onset of C difficile infection.

CONCLUSION

The overall C difficile infection prevalence in our population was low compared to Western countries. The majority of the patients who developed C difficile infection were using PPIs and/or antibiotics. No differences were observed in the type of antibiotic or PPI and the onset of C difficile infection development. Appropriate prescribing protocols for PPIs and antibiotics in acute settings are needed.

LIMITATIONS

Single center and retrospective design.

CONFLICT OF INTEREST

None.

Trends in U.S. Burden of Clostridioides difficile Infection and Outcomes

BACKGROUND

Efforts to prevent Clostridioides difficile infection continue to expand across the health care spectrum in the United States. Whether these efforts are reducing the national burden of C. difficile infection is unclear.

METHODS

The Emerging Infections Program identified cases of C. difficile infection (stool specimens positive for C. difficile in a person ≥1 year of age with no positive test in the previous 8 weeks) in 10 U.S. sites. We used case and census sampling weights to estimate the national burden of C. difficile infection, first recurrences, hospitalizations, and in-hospital deaths from 2011 through 2017. Health care-associated infections were defined as those with onset in a health care facility or associated with recent admission to a health care facility; all others were classified as community-associated infections. For trend analyses, we used weighted random-intercept models with negative binomial distribution and logistic-regression models to adjust for the higher sensitivity of nucleic acid amplification tests (NAATs) as compared with other test types.

RESULTS

The number of cases of C. difficile infection in the 10 U.S. sites was 15,461 in 2011 (10,177 health care-associated and 5284 community-associated cases) and 15,512 in 2017 (7973 health care-associated and 7539 community-associated cases). The estimated national burden of C. difficile infection was 476,400 cases (95% confidence interval [CI], 419,900 to 532,900) in 2011 and 462,100 cases (95% CI, 428,600 to 495,600) in 2017. With accounting for NAAT use, the adjusted estimate of the total burden of C. difficile infection decreased by 24% (95% CI, 6 to 36) from 2011 through 2017; the adjusted estimate of the national burden of health care-associated C. difficile infection decreased by 36% (95% CI, 24 to 54), whereas the adjusted estimate of the national burden of community-associated C. difficile infection was unchanged. The adjusted estimate of the burden of hospitalizations for C. difficile infection decreased by 24% (95% CI, 0 to 48), whereas the adjusted estimates of the burden of first recurrences and in-hospital deaths did not change significantly.

CONCLUSIONS

The estimated national burden of C. difficile infection and associated hospitalizations decreased from 2011 through 2017, owing to a decline in health care-associated infections. (Funded by the Centers for Disease Control and Prevention.).

Incidence and economic burden of Clostridioides difficile infection in Ontario: a retrospective population-based study

BACKGROUND

Understanding the impact of prevention programs on Clostridioides difficile infection rates is important, and decisions on future program changes, including how to use vaccines currently in development, requires a detailed understanding of the epidemiologic features of C. difficile infection. We analyzed Ontario health administrative data to determine incidence rates and medical costs of C. difficile infection, based on whether acquisition and onset occurred in acute care hospitals (ACHs), long-term care facilities or the community.

METHODS

We performed a retrospective analysis using individual-level data from Ontario health databases from Apr. 1, 2005, to Mar. 31, 2015, identifying rates of C. difficile infection requiring hospital admission per 100 000 person-years in adults aged 18 years or more for categories of acquisition and onset. We estimated health care system costs of infection 180 and 365 days after admission by matching patients with C. difficile infection with control patients with similar characteristics.

RESULTS

Over the study period, 33 909 people in Ontario were admitted to hospital with C. difficile infection; 17 272 cases (50.9%) were associated with ACHs. The number of cases per 100 000 person-years ranged from 27.7 in 2009/10 to 37.0 in 2012/13. Annually, the highest incidence of infection was for ACH-associated/ACH-onset. Community-associated infection became more prevalent over time, rising from 19.4% of cases in 2005/06 to 29.2% in 2014/15. Infection costs were mostly due to hospital admission within 180 days after hospital discharge. Infection associated with ACHs had the highest total costs and the largest cost attributable to C. difficile infection (median $38 953 for infected patients v. $13 542 for control patients). Median costs attributable to C. difficile infection were $1051 for that associated with long-term care facilities, $13 249 for community-associated infection and $11 917 for ACH-associated/community-onset infection.

INTERPRETATION

Community-associated C. difficile infection had similar health care cost implications as hospital-associated infection. With rates of community-associated C. difficile infection on the rise, family physicians should be supported to prevent this infection in their patients.

Risk Factors for BI/NAP1/027 Clostridioides difficile Infections and Clinical Outcomes Compared With Non-NAP1 Strains

We aim to describe the characteristics, risk factors, and clinical outcomes associated with NAP1 strain Clostridioides difficile infection (CDI) in this single-center, retrospective, case–control (1:1) study. We found that the NAP1 strain accounted for 19.7% of CDI, and risk factors for acquisition included residence in skilled nursing facilities, previous CDI, and proton pump inhibitor use.

Clostridioides difficile infection and recurrence among 2622 solid organ transplant recipients

BACKGROUND

Clostridioides difficile infection (CDI) is common after solid organ transplant (SOT) and is associated with high morbidity and mortality.

METHODS

We assessed incidence, risk factors, and outcomes of CDI among SOT patients at a large multi-organ transplant center. Multivariable logistic regression was used to identify risk factors for initial and recurrent CDI.

RESULTS

A total of 2622 SOT patients were included. 224 (8.5%) had CDI 1 year post-SOT. The highest incidence of CDI was among pancreas recipients (12.5%) followed by lung (11.7%), liver (11.0%), heart (10.8%), and kidney (5.8%). Median time to CDI was 56 days (range 2-354) post-SOT. About 64% of patients had severe CDI. About 56.3% were treated with metronidazole, 13.8% with oral vancomycin, and 28.6% with both. About 28.6% of patients had recurrent CDI. In multivariable modeling, lung transplant recipient status was the only significant predictor of recurrent CDI (OR 4.97, 95% CI 2.11-11.78, P < .001) controlling for age, severe CDI, and pre-SOT CDI. Post-SOT CDI nearly doubled the risk of mortality at one year, in particular among those with severe CDI.

CONCLUSIONS

In summary, CDI is highly prevalent, occurs early in the post-transplant period, usually severe, with a high rate of recurrence, and associated with increased mortality within 1 year after transplant. The early post-transplant period may be a crucial window to reduce CDI rates.

Epidemiologic Trends in Clostridioides difficile Infections in a Regional Community Hospital Network

IMPORTANCE

Clostridioides difficile infection (CDI) remains a leading cause of health care facility-associated infection. A greater understanding of the regional epidemiologic profile of CDI could inform targeted prevention strategies.

OBJECTIVES

To assess trends in incidence of health care facility-associated and community-acquired CDI among hospitalized patients over time and to conduct a subanalysis of trends in the NAP1 strain of CDI over time.

DESIGN, SETTING, AND PARTICIPANTS

This long-term multicenter cohort study reviewed records of patients (N = 2 025 678) admitted to a network of 43 regional community hospitals primarily in the southeastern United States from January 1, 2013, through December 31, 2017. Generalized linear mixed-effects models were used to adjust for potential clustering within facilities and changing test method (nucleic acid amplification testing or toxin enzyme immunoassay) over time.

MAIN OUTCOMES AND MEASURES

Clostridioides difficile infection incidence rates were counted as cases per 1000 admissions for community-acquired and total CDI cases or cases per 10 000 patient-days for health care facility-associated CDI. Long-term trends in the proportion of cases acquired in the community and in NAP1 strain incidence were also evaluated.

RESULTS

A total of 2 025 678 admissions and 21 254 CDI cases were included (12 678 [59.6%] female; median [interquartile range] age, 69 [55-80] years). Median (interquartile range) total CDI incidence increased slightly from 7.9 (3.5-12.4) cases per 1000 admissions in 2013 to 9.3 (4.9-13.7) cases per 1000 admissions in 2017. After adjustment, the overall incidence of health care facility-associated CDI declined (incidence rate ratio [IRR], 0.995; 95% CI, 0.990-0.999; P = .03), whereas insufficient evidence was found for either an increase or a decrease in community-acquired CDI (IRR, 1.004; 95% CI, 0.999-1.009; P = .14). The proportion of cases classified as community acquired increased over time from a mean (SD) of 0.49 (0.28) in 2013 to 0.61 (0.26) in 2017 (odds ratio, 1.010 per month; 95% CI, 1.006-1.015; P < .001). Rates of the NAP1 strain of CDI varied widely between facilities, with no statistically significant change in NAP1 strain incidence over time in the community setting (IRR, 1.007; 95% CI, 0.994-1.021) or health care facility setting (IRR, 1.011; 95% CI, 0.990-1.032).

CONCLUSIONS AND RELEVANCE

The findings suggest that, despite the modest improvement in health care facility-associated CDI rates, a better understanding of community-acquired CDI incidence is needed for future infection prevention efforts.

Impact of Reduced Fluoroquinolone Use on Clostridioides difficile Infections Resulting From the Fluoroquinolone-Resistant Ribotype 027 Strain in a Veterans Affairs Medical Center

Background

Fluoroquinolone restriction has been proposed as a control measure for Clostridioides difficile infection (CDI) outbreaks associated with fluoroquinolone-resistant ribotype 027 strains. However, relatively few reports of fluoroquinolone restriction interventions have evaluated the impact on C. difficile strain types and fluoroquinolone resistance.

Methods

In a hospital and affiliated long-term care facility (LTCF), antimicrobial stewardship and environmental cleaning interventions were implemented between 2009 and 2018, and C. difficile isolates during this period (~20 per year) were ribotyped and tested for fluoroquinolone resistance by moxifloxacin minimum inhibitory concentrations (MICs). Pearson's correlation coefficient was used to assess the association between use of fluoroquinolones and the percentage of CDI cases due to the 027 strain over time.

Results

Between 2009 and 2018, prescribing of fluoroquinolones to inpatients decreased by 43%, coinciding with significant reductions in the healthcare-associated CDI rates in the hospital and LTCF and a decline in the percentage of C. difficile isolates that were ribotype 027 from 70% to 10%. Ninety-five percent of ribotype 027 and 6% of non-027 isolates were moxifloxacin resistant. Hospital fluoroquinolone use was strongly correlated with the incidence of hospital-associated CDI (r = 0.79, 95% confidence interval, 0.31-0.95), but LTCF fluoroquinolone use was not correlated with LTCF-associated CDI (r = 0.29, 95% confidence interval, -0.43-0.77). During the study period, there were statistically significant downward trends in the use of penicillins, intravenous vancomycin, carbapenems, and clindamycin.

Conclusion

Our results provide support for fluoroquinolone restriction as a control measure for CDI outbreaks due to fluoroquinolone-resistant 027 strains, but also highlight the need for randomized trials as factors such as reduction in other antibiotic classes and improved cleaning may also impact CDI rates.

Incidence of Clostridioides difficile infections among young and middle-aged adults: Veterans Health Administration

Objective:

Clostridioides difficile infection (CDI) remains a significant public health concern, resulting in excess morbidity, mortality, and costs. Additional insight into the burden of CDI in adults aged <65 years is needed.

Design/Setting:

A 6-year retrospective cohort study was conducted using data extracted from United States Veterans Health Administration electronic medical records.

Patients/Methods:

Patients aged 18–64 years on January 1, 2011, were followed until incident CDI, death, loss-to-follow-up, or December 31, 2016. CDI was identified by a diagnosis code accompanied by metronidazole, vancomycin, or fidaxomicin therapy, or positive laboratory test. The clinical setting of CDI onset was defined according to 2017 SHEA-IDSA guidelines.

Results:

Of 1,073,900 patients, 10,534 had a CDI during follow-up. The overall incidence rate was 177 CDIs per 100,000 person years, rising steadily from 164 per 100,000 person years in 2011 to 189 per 100,000 person years in 2016. Those with a CDI were slightly older (55 vs 51 years) and sicker, with a higher baseline Charlson comorbidity index score (1.4 vs 0.5) than those without an infection. Nearly half (48%) of all incident CDIs were community associated, and this proportion rose from 41% in 2011 to 56% in 2016.

Conclusions:

The findings from this large retrospective study indicate that CDI incidence, driven primarily by increasing community-associated infection, is rising among young and middle-aged adult Veterans with high service-related disability. The increasing burden of community associated CDI in this vulnerable population warrants attention. Future studies quantifying the economic and societal burden of CDI will inform decisions surrounding prevention strategies.

Expanding the repertoire of conservative site-specific recombination in Clostridioides difficile

Recent genomic analysis of an epidemic ribotype 027 (RT027) Clostridioides difficile strain revealed the presence of several chromosomal site-specific invertible sites hypothesized to control the expression of adjacent genes in a bimodal on-off mode. This process, named phase variation, is thought to enhance phenotypic variability under homogeneous conditions ultimately increasing population fitness in unpredictable environmental fluctuations. The full extent of phase variation mediated by DNA-inversions in C. difficile is currently unknown. Here, we sought to expand our previous analysis by screening for site-specific inversions in isolates that belong to the rapidly emerging ribotypes RT017 and RT078. We report the finding of one novel inversion site for which we demonstrate the inversion potential and quantify inversion proportions during exponential and stationary growth in both historic and modern isolates of the same ribotype. We then employ a computational approach to assess the prevalence of all sites identified so far in a large collection of sequenced C. difficile isolates. We show that phase-variable loci are widespread with some sites being present in virtually all analyzed strains. Furthermore, in our small subset of RT017 and RT078 strains, we detect no evidence of gain or loss of invertible sites in historic versus modern isolates demonstrating the relative stability of those genomic elements. Overall, our results support the idea that C. difficile has adopted phase variation mediated by DNA inversions as its major generator of diversity which could be beneficial during the pathogenesis process.

A global to local genomics analysis of Clostridioides difficile ST1/RT027 identifies cryptic transmission events in a northern Arizona healthcare network

Clostridioides difficile is a ubiquitous, diarrhoeagenic pathogen often associated with healthcare-acquired infections that can cause a range of symptoms from mild, self-limiting disease to toxic megacolon and death. Since the early 2000s, a large proportion of C. difficile cases have been attributed to the ribotype 027 (RT027) lineage, which is associated with sequence type 1 (ST1) in the C. difficile multilocus sequence typing scheme. The spread of ST1 has been attributed, in part, to resistance to fluoroquinolones used to treat unrelated infections, which creates conditions ideal for C. difficile colonization and proliferation. In this study, we analysed 27 isolates from a healthcare network in northern Arizona, USA, and 1352 publicly available ST1 genomes to place locally sampled isolates into a global context. Whole genome, single nucleotide polymorphism analysis demonstrated that at least six separate introductions of ST1 were observed in healthcare facilities in northern Arizona over an 18-month sampling period. A reconstruction of transmission networks identified potential nosocomial transmission of isolates, which were only identified via whole genome sequence analysis. Antibiotic resistance heterogeneity was observed among ST1 genomes, including variability in resistance profiles among locally sampled ST1 isolates. To investigate why ST1 genomes are so common globally and in northern Arizona, we compared all high-quality C. difficile genomes and identified that ST1 genomes have gained and lost a number of genomic regions compared to all other C. difficile genomes; analyses of other toxigenic C. difficile sequence types demonstrate that this loss may be anomalous and could be related to niche specialization. These results suggest that a combination of antimicrobial resistance and gain and loss of specific genes may explain the prominent association of this sequence type with C. difficile infection cases worldwide. The degree of genetic variability in ST1 suggests that classifying all ST1 genomes into a quinolone-resistant hypervirulent clone category may not be appropriate. Whole genome sequencing of clinical C. difficile isolates provides a high-resolution surveillance strategy for monitoring persistence and transmission of C. difficile and for assessing the performance of infection prevention and control strategies.

Changes in molecular epidemiology and antimicrobial resistance profiles of Clostridioides (Clostridium) difficile strains in the United States between 2011 and 2017

PCR ribotyping and antimicrobial susceptibility testing were used to characterize 940 Clostridioides (Clostridium) difficile isolates collected from 26 U S. hospitals over three time periods from 2011 to 2017. The proportion of ribotype (RT) 027 isolated during the three surveys decreased significantly over time from 31% in 2011-2012, to 22% in 2013-2014, and to 14% in 2015-2017 (p < 0.001 and p = 0.010, respectively), while we observed an increase in prevalence of RT106, that rose from 7% in our first survey to 19% of isolates in our last survey (p < 0.001). In addition, both RT056 and RT002 rose from 3% to 10% (p < 0.001). The proportions of all other ribotypes remained steady over time, and RT014/020 was the third most common strain type in our convenience sample in the final survey. Overall, resistance to moxifloxacin, rifampin, and vancomycin decreased during our studies, mainly due to the decline in RT027 isolates. A decrease in moxifloxacin resistance and an increase in tetracycline resistance were found among RT027 strains isolated in the last survey. Although the proportion of RT027 isolates declined, multidrug resistance among this ribotype continues to be common.

The Hypervirulent Strain of Clostridium Difficile: NAP1/B1/027 - A Brief Overview

Clostridium difficile is a gram-positive bacterium notorious for causing epidemic diarrhea globally with a significant health burden. The pathogen is clinically challenging with increasing antibiotic resistance and recurrence rate. We provide here an in-depth review of one particular strain/ribotype 027, commonly known as NAP1/B1/027 or North American pulsed-field gel electrophoresis type 1, restriction endonuclease analysis type B1, polymerase chain reaction ribotype 027, which has shown a much higher recurrence rate than other strains.

Leveraging Quality Improvement Science to Reduce C. difficile Infections in a Community Hospital

BACKGROUND

The most common infection acquired in US hospitals is Clostridium difficile, which can lead to protracted diarrhea, severe abdominal cramping, and infectious colitis and an attributable mortality of 6.5%. The mortality associated with C. difficile is of major clinical importance. The best strategy to prevent such infections is an open question.

METHODS

A multiyear quality improvement initiative was performed in our community hospital to determine where hospitals should focus their resources to achieve sustainable reductions in hospital-acquired C. difficile infection (CDI). Quality improvement methodology was used to evaluate the impact of sequential interventions in environmental cleaning, infection prevention, and antibiotic stewardship over time.

RESULTS

After four years, hospital-acquired CDI declined 55.5%, from 12.2 to 5.4 cases/10,000 patient-days (Poisson rate test, p = 0.002). High-risk antibiotic use declined 88.1%, from 63.7 to 7.6 days on treatment/1,000 patient-days (Student's t-test, p < 0.001). The highest-impact intervention was stewardship on diagnostics and high-risk antibiotics using home-grown decision support tools.

CONCLUSION

Translating scientific evidence into clinical practice using quality improvement methods led to sustained reductions in C. difficile transmission and identified high-risk antibiotics and diagnostics as key leverage points.

Epidemiology and outcomes of Clostridium difficile infection among hospitalised patients: results of a multicentre retrospective study in South Africa

Introduction

Limited data exist on Clostridium difficile infection (CDI) in low-resource settings and settings with high prevalence of HIV. We aimed to determine baseline CDI patient characteristics and management and their contribution to mortality.

Methods

We reviewed adult patients hospitalised with diarrhoea and a C. difficile test result in 2015 from four public district hospitals in the Western Cape, South Africa. The primary outcome measures were risk factors for mortality. Secondary outcomes were C. difficile risk factors (positive vs negative) and CDI treatment.

Results

Charts of patients with diarrhoea tested for C. difficile (n=250; 112 C. difficile positive, 138 C. difficile negative) were reviewed. The study population included more women (65%). C. difficile-positive patients were older (46.5 vs 40.7 years, p<0.01). All-cause mortality was more common in the C. difficile-positive group (29% vs 8%, p<0.0001; HR 2.0, 95% CI 1.1 to 3.6). Tuberculosis (C. difficile positive 54% vs C. difficile negative 32%, p<0.001), 30-day prior antibiotic exposure (C. difficile positive 83% vs C. difficile negative 46%, p<0.001) and prior hospitalisation (C. difficile positive 55% vs C. difficile negative 22%, p<0.001) were also more common in the C. difficile-positive group. C. difficile positive test result (OR 4.7, 95% CI 2.0 to 11.2; p<0.001), male gender (OR 2.8, 95% CI 1.1 to 7.2; p=0.031) and tuberculosis (OR 2.3, 95% CI 1.0 to 5.0; p=0.038) were independently associated with mortality. Of patients starting treatment, metronidazole was the most common antimicrobial therapy initiated (70%, n=78); 32 C. difficile-positive (29%) patients were not treated.

Conclusion

Patients testing positive for C. difficile are at high risk of mortality at public district hospitals in South Africa. Tuberculosis should be considered an additional risk factor for CDI in populations with high tuberculosis and HIV comorbidity. Interventions for CDI prevention and management are urgently needed.

Poor yield of Clostridium difficile testing algorithms using glutamate dehydrogenase antigen and C. difficile toxin enzyme immunoassays in a pediatric population with declining prevalence of clostridium difficile strain BI/NAP1/027

We compared the performance of algorithmic Clostridium difficile infection (CDI) diagnosis with four molecular tests in children. Stool samples in patients 1-18 years old were tested with an algorithm (C. Diff Quik Chek Complete (QCC) reflexed to illumigene C. difficile); AmpliVue C. difficile (ACD); Lyra Direct C. difficile (Lyra); BD MAX C diff (BDM); and Xpert C. difficile (XCD). The gold standard was positivity by two tests. Sensitivity, specificity, positive predictive value, and negative predictive value were 85%, 99%, 93%, 97% for the algorithm; 21%, 99%, 78%, 87% for QCC's toxin component; 94%, 99%, 94%, 99% for ACD; 88%, 99%, 94%, 98% for Lyra; 94%, 100%, 100%, 99% for BDM, and 94%, 99%, 94% and 99% for XCD. 9.6% of samples were ribotype 027. Algorithms may detect CDI with lower sensitivity compared to molecular methods in children. This may be related to low prevalence of NAP-1/ribotype 027.