Risk factors for development of Clostridium difficile infection due to BI/NAP1/027 strain: a meta-analysis

"Primum, non nocere": The Epidemiology of Toxigenic Clostridioides difficile Strains in the Antibiotic Era-Insights from a Prospective Study at a Regional Infectious Diseases Hospital in Eastern Europe

Clostridioides difficile infection (CDI), though identified nearly five decades ago, still remains a major challenge, being associated with significant mortality rates. The strains classified as hypervirulent, notably 027/NAP1/BI, have garnered substantial attention from researchers and clinicians due to their direct correlation with the severity of the disease. Our study aims to elucidate the significance of toxigenic Clostridioides difficile (CD) strains in the clinical and therapeutic aspects of managing patients diagnosed with CDI. We conducted a single-center prospective study, including patients with CDI from north-eastern Romania. We subsequently conducted molecular biology testing to ascertain the prevalence of the presumptive 027/NAP1/BI strain within aforementioned geographic region. The patients were systematically compared and assessed both clinically and biologically, employing standardized and comparative methodologies. The study enrolled fifty patients with CDI admitted between January 2020 and June 2020. Among the investigated patients, 43 (86%) exhibited infection with toxigenic CD strains positive for toxin B genes (tcdB), binary toxin genes (cdtA and cdtB), and deletion 117 in regulatory genes (tcdC), while the remaining 7 (14%) tested negative for binary toxin genes (cdtA and cdtB) and deletion 117 in tcdC. The presence of the presumptive 027/NAP1/BI strains was linked to a higher recurrence rate (35.56%, p = 0.025), cardiovascular comorbidities (65.1% vs. 14.2%, p = 0.016), and vancomycin treatment (55.8% vs. 14.3%, p = 0.049). The findings of our investigation revealed an elevated incidence of colitis attributed to presumptive 027/NAP1/BI. Despite the prevalence of the presumptive 027 strain and its associated heightened inflammation among the patients studied, no significant differences were observed regarding the clinical course or mortality outcomes.

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.

Mathematical model of the cost-effectiveness of the BioFire FilmArray Blood Culture Identification (BCID) Panel molecular rapid diagnostic test compared with conventional methods for identification of Escherichia coli bloodstream infections

BACKGROUND

Gram-negative pathogens, such as Escherichia coli, are common causes of bloodstream infections (BSIs) and increasingly demonstrate antimicrobial resistance. Molecular rapid diagnostic tests (mRDTs) offer faster pathogen identification and susceptibility results, but higher costs compared with conventional methods. We determined the cost-effectiveness of the BioFire FilmArray Blood Culture Identification (BCID) Panel, as a type of mRDT, compared with conventional methods in the identification of E. coli BSIs.

METHODS

We constructed a decision analytic model comparing BCID with conventional methods in the identification and susceptibility testing of hospitalized patients with E. coli BSIs from the perspective of the public healthcare payer. Model inputs were obtained from published literature. Cost-effectiveness was calculated by determining the per-patient admission cost, the QALYs garnered and the incremental cost-effectiveness ratios (ICERs) where applicable. Monte Carlo probabilistic sensitivity analyses and one-way sensitivity analyses were conducted to assess the robustness of the model. All costs reflect 2019 Canadian dollars.

RESULTS

The Monte Carlo probabilistic analyses resulted in cost savings ($27 070.83 versus $35 649.81) and improved QALYs (8.65 versus 7.10) in favour of BCID. At a willingness to pay up to $100 000, BCID had a 72.6%-83.8% chance of being cost-effective. One-way sensitivity analyses revealed length of stay and cost per day of hospitalization to have the most substantial impact on costs and QALYs.

CONCLUSIONS

BCID was found to be cost-saving when used to diagnose E. coli BSI compared with conventional testing. Cost savings were most influenced by length of stay and cost per day of hospitalization.

A Physician-Driven Quality Improvement Stewardship Intervention Using Lean Six Sigma Improves Patient Care for Community-Acquired Pneumonia

Introduction

The Infectious Diseases Society of America (IDSA) recommends a minimum of 5 days of antibiotic therapy in stable patients who have community-acquired pneumonia (CAP). However, excessive duration of therapy (DOT) is common. Define, measure, analyze, improve, and control (DMAIC) is a Lean Six Sigma methodology used in quality improvement efforts, including infection control; however, the utility of this approach for antimicrobial stewardship initiatives is unknown. To determine the impact of a prospective physician-driven stewardship intervention on excess antibiotic DOT and clinical outcomes of patients hospitalized with CAP. Our specific aim was to reduce excess DOT and to determine why some providers treat beyond the IDSA minimum DOT.

Methods

A single-center, quasi-experimental quality improvement study evaluating rates of excess antimicrobial DOT before and after implementing a DMAIC-based antimicrobial stewardship intervention that included education, prospective audit, and feedback from a physician peer, and daily tracking of excess DOT on a Kaizen board. The baseline period included retrospective CAP cases that occurred between October 2018 and February 2019 (control group). The intervention period included CAP cases between October 2019 and February 2020 (intervention group).

Results

A total of 123 CAP patients were included (57 control and 66 intervention). Median antibiotic DOT per patient decreased (8 versus 5 days; p < 0.001), and the proportion of patients treated for the IDSA minimum increased (5.3% versus 56%; p < 0.001) after the intervention. No differences in mortality, readmission, length of stay, or incidence of Clostridioides difficile infection were observed between groups. Almost half of the caregivers surveyed were aware that as few as 5 days of antibiotic treatment could be appropriate.

Conclusions

A physician-driven antimicrobial quality improvement initiative designed using DMAIC methodology led to reduced DOT and increased compliance with the IDSA treatment guidelines for hospitalized patients with CAP reduced without negatively affecting clinical outcomes.

A Multi-Center Evaluation of Probiotic Use for the Primary Prevention of Clostridioides difficile infection

BACKGROUND

Primary prevention of C. difficile infection (CDI) is a priority for hospitals and probiotics have the potential to interfere with colonization and infection with C. difficile. This study evaluated the impact of a computerized clinical decision support tool (CCDS) to prescribe probiotics for primary prevention of CDI among adult hospitalized patients.

METHODS

A CCDS tool was implemented into the electronic medical record at four hospitals prompting prescription of a probiotic preparation at the time of antibiotic prescription in high-risk patients in May 2019. Interrupted time series using segmented regression analysis was conducted to evaluate hospital-wide CDI incidence for the year pre- and post-CCDS implementation. In addition, multivariable logistic regression was used to evaluate CDI incidence in patients qualifying for probiotics in the pre- versus post-intervention periods adjusting for potential confounders. To adjust for potential differences in patients who received probiotics in the post-intervention period, propensity score matched pairs were developed to evaluate CDI risk by receipt of probiotics.

RESULTS

Quarterly CDI incidence increased over time post-intervention relative to baseline trends (slope change 1.4, 95% CI 0.9-1.9). The odds ratio (OR) of CDI was 1.41 in eligible patients post-intervention compared to pre-intervention (adjusted OR 1.41, 95% CI 1.11, 1.79). Propensity score matched analysis showed that patients who received probiotics did not have lower rates of CDI compared to those who did not receive probiotics (OR 1.46, 95% CI 0.87, 2.45).

CONCLUSIONS

Use of probiotics for primary prevention of CDI among adult inpatients receiving antibiotics is not supported.

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.

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.

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.

Epidemiology, Risk Factors, and Outcomes After Early Posttransplant Clostridiodes difficile Infection in Renal Transplant Recipients

BACKGROUND

Modifiable risk-factors associated with Clostridioides difficile infection (CDI) in renal-transplant (RTX) have not been clearly established and peri-transplant risk has not been described.

OBJECTIVE

Evaluate epidemiology, risk-factors and outcomes after CDI occurring in the first 90 days after RTX (CDI-90).Methods: Observational cohort study/survival analysis of adult RTX recipients from 1/1/2012-12/31/2015. Primary outcome was CDI-90 incidence/risk-factors. Secondary outcome was evaluation of post-90 day transplant outcomes.

RESULTS

982 patients met inclusion criteria; 46 with CDI-90 and 936 without (comparator). CDI incidence in the total population was 4.7% at 90 days, 6.3% at 1 year, and 6.4% at 3 years. Incidence of CDI-90 was 5%; time to diagnosis was 19.4±25 days (median 7). Risk-factors for CDI-90 were alemtuzumab induction (Hazard ratio [HR] 1.5, 95% CI(1.1-2.0), p = 0.005) and age at transplant (HR 1.007/year, 95% CI (1.002-1.012), p= 0.007). However, risk-factors for CDI at any time were different; donation-after-circulatory-death (DCD) donor (HR 2.5 95% CI (1.3-4.9), p = 0.008) and female gender (HR 1.6 95% CI (1.0-2.7), p = 0.049). On Kaplan-Meier, CDI-90 appeared to have an impact on patient/graft survival, however when analyzed in a multivariable stepwise Cox proportional hazards model, only age was significantly associated with survival (p = 0.002).

CONCLUSION AND RELEVANCE

Incidence of CDI-90 is low, mostly occurring in the first post-operative month. Risk-factors vary temporally based on time from transplant. In the early post-op period induction agent and age at transplant are significant, but not after. Associations between CDI and negative graft outcomes appear to be largely driven by age. Future studies validating these risk-factors as well as targeted prophylaxis strategies and their effect on long term graft outcomes and the host microbiome are needed.

Gastrointestinal Tract Disorders in Older Age

Considering an increase in the life expectancy leading to a rise in the elderly population, it is important to recognize the changes that occur along the process of aging. Gastrointestinal (GI) changes in the elderly are common, and despite some GI disorders being more prevalent in the elderly, there is no GI disease that is limited to this age group. While some changes associated with aging GI system are physiologic, others are pathological and particularly more prevalent among those above age 65 years. This article reviews the most important GI disorders in the elderly that clinicians encounter on a daily basis. We highlight age-related changes of the oral cavity, esophagus, stomach, small and large bowels, and the clinical implications of these changes. We review epidemiology and pathophysiology of common diseases, especially as they relate to clinical manifestation in elderly. Details regarding management of specific disease are discussed in detail if they significantly differ from the management for younger groups or if they are associated with significant challenges due to side effects or polypharmacy. Cancers of GI tract are not included in the scope of this article.

Clostridium difficile in patients attending tuberculosis hospitals in Cape Town, South Africa, 2014-2015

Background

Diarrhoea due to Clostridium difficile infection (CDI) poses a significant burden on healthcare systems around the world. However, there are few reports on the current status of the disease in sub-Saharan Africa.

Objectives

This study examined the occurrence of CDI in a South African population of tuberculosis patients, as well as the molecular epidemiology and antibiotic susceptibility profiles of C. difficile strains responsible for disease.

Methods

Toxigenic C. difficile in patients with suspected CDI attending two specialist tuberculosis hospitals in the Cape Town area were detected using a PCR-based diagnostic assay (Xpert^® C. difficile). C. difficile strains isolated from PCR-positive specimens were characterised by ribotyping, multilocus variable-number tandem-repeat analysis and antibiotic susceptibility testing.

Results

The period prevalence of CDI was approximately 70.07 cases per 1000 patient admissions. Strains belonging to ribotype 017 (RT017) made up over 95% of the patient isolates and all of them were multi-drug resistant. Multilocus variable-number tandem-repeat analysis revealed several clusters of highly related C. difficile RT017 strains present in tuberculosis patients in several wards at each hospital.

Conclusion

Tuberculosis patients represent a population that may be at an increased risk of developing CDI and, in addition, may constitute a multi-drug resistant reservoir of this bacterium. This warrants further investigation and surveillance of the disease in this patient group and other high-risk patient groups in sub-Saharan Africa.

Evaluation of Risk Factors for Clostridium difficile Infection Based on Immunochromatography Testing and Toxigenic Culture Assay

In recent years, the diagnostic method of choice for Clostridium difficile infection (CDI) is a rapid enzyme immunoassay in which glutamate dehydrogenase (GDH) antigen and C. difficile toxin can be detected (C. diff Quik Chek Complete; Alere Inc.) (Quik Chek). However, the clinical significance remains unclear in cases that demonstrate a positive result for GDH antigen and are negative for toxin. In this study, we used the Quik Chek test kit on fecal samples, with an additional toxin detection step using a toxigenic culture assay for the aforementioned cases. CDI risk factors were assessed among the 3 groups divided by the Quik Chek test results. The study involved 1,565 fecal samples from patients suspected to have CDI who were hospitalized during the period of April 2012 to March 2014. The 3 groups were defined as follows: both GDH antigen positive and toxin positive (by Quik Chek test) (toxin-positive [TP] group, n = 109), both GDH antigen and toxin negative (toxin-negative [TN] group, n = 111), and positive only for GDH antigen but toxin positive with subsequent toxigenic culture (toxigenic culture [TC] group, n = 72). The gender, age, number of hospitalization days, white blood cell (WBC) counts, serum albumin levels, body mass index (BMI), fecal consistency, and use of antibacterials and proton pump inhibiters (PPIs) were analyzed. The positive rate for the fecal direct Quik Chek test was 7.0% (109/1,565 cases). However, toxigenic culture assays using the Quik Chek test for only the GDH-antigen-positive/toxin-negative samples were 35.3% positive (72/204 cases). As a result, the true positive rate for C. difficile toxin detection was estimated to be 11.6% (181/1,565 cases). Moreover, significant differences (P < 0.05) in the number of hospitalization days (>50 days), WBC counts (>10,000 WBCs/μl), and use of PPIs comparing the TN, TP, and TC groups, were observed. The odds ratios (ORs) for the development of CDI were 1.61 (95% confidence interval [CI], 0.94 to 2.74) and 2.98 (95% CI, 1.59 to 5.58) for numbers of hospitalization days, 2.16 (95% CI, 1.24 to 3.75) and 2.24 (95% CI, 1.21 to 4.14) for WBC counts, and 9.03 (95% CI, 4.9 to 16.6) and 9.15 (95% CI, 4.59 to 18.2) for use of PPIs in the TP and TC groups, respectively. These findings demonstrated that the use of PPIs was a significant risk factor for CDI development. Moreover, antibacterials such as carbapenems, cephalosporins, and fluoroquinolones were demonstrated to be risk factors. In conclusion, identification of the TC group of patients is thought to be important, as this study demonstrates that this group bears the same high risk of developing CDI as the TP group.

Novel Clade C-I Clostridium difficile strains escape diagnostic tests, differ in pathogenicity potential and carry toxins on extrachromosomal elements

The population structure of Clostridium difficile currently comprises eight major genomic clades. For the highly divergent C-I clade, only two toxigenic strains have been reported, which lack the tcdA and tcdC genes and carry a complete locus for the binary toxin (CDT) next to an atypical TcdB monotoxin pathogenicity locus (PaLoc). As part of a routine surveillance of C. difficile in stool samples from diarrheic human patients, we discovered three isolates that consistently gave negative results in a PCR-based screening for tcdC. Through phenotypic assays, whole-genome sequencing, experiments in cell cultures, and infection biomodels we show that these three isolates (i) escape common laboratory diagnostic procedures, (ii) represent new ribotypes, PFGE-types, and sequence types within the Clade C-I, (iii) carry chromosomal or plasmidal TcdBs that induce classical or variant cytopathic effects (CPE), and (iv) cause different levels of cytotoxicity and hamster mortality rates. These results show that new strains of C. difficile can be detected by more refined techniques and raise questions on the origin, evolution, and distribution of the toxin loci of C. difficile and the mechanisms by which this emerging pathogen causes disease.

Observational study of chemotherapy-induced Clostridium difficile infection in patients with lung cancer

BACKGROUND

Diarrhea post-antibiotic use is primarily attributed to Clostridium difficile infection (CDI)-induced mucosal lesions, and evidence of CDI in patients undergoing chemotherapy without prior antibiotic treatment is also increasing. However, few studies have investigated the relationship between chemotherapy use and diarrhea. This study aimed to determine whether the incidence of CDI increased in patients with lung cancer undergoing chemotherapy even without prior antibiotic treatment.

METHODS

We conducted a retrospective study and investigated the presence of Clostridium difficile (C. difficile) and its toxins in patients who experience diarrhea during chemotherapy. If grade 2 or higher diarrhea was noted, a stool culture was performed to detect anaerobic organisms and C. difficile toxins A and B.

RESULTS

A total of 345 consecutive patients (492 in terms of chemotherapy regimens) were enrolled in the study. Grade 2 or higher diarrhea was observed in patients using 36 (7.3%) of these regimens, among which CDI without prior antibiotic exposure was confirmed in patients using 8 regimens (22.2%).

CONCLUSIONS

CDI may remain undetected in patients undergoing chemotherapy even in those who had not received antibiotic treatment previously, unless due attention is paid to its possibility. Testing for C. difficile toxins is highly recommended to expedite timely treatment for diarrhea in such patients. Further studies are needed to clarify the relationship between chemotherapy drug use and CDI to facilitate prevention.

Antibiotic susceptibility and resistance profiles of Romanian Clostridioides difficile isolates

This study investigated the antibiotic susceptibility patterns and genetic resistance markers of 35 C. difficile strains isolated from patients with C. difficile infection. Vancomycin, metronidazole, tigecycline, teicoplanin, rifampicin, moxifloxacin, cefotaxime, tetracycline, erythromycin, clindamycin, chloramphenicol, linezolid and imipenem MICs were determined for toxigenic strains belonging to PCR ribotypes (PR) 012 (2), 014 (4), 017 (3), 018 (2), 027 (17), 046 (2), 087 (3) and 115 (2). Results showed vancomycin, metronidazole, tigecycline and teicoplanin to be active against all isolates. High resistance rates were noticed against cefotaxime (n = 35), clindamycin (n = 33), imipenem (n = 31), moxifloxacin (n = 25), erythromycin (n = 25) and rifampicin (n = 22). Linezolid-resistance was found in three isolates (PR 017/2, PR 012/1), showing complex resistance (7-9 antibiotics). PR 012, 017, 018, 027 and 046 isolates (n = 26) were resistant to 5-9 antibiotics. Twelve resistance profiles (2-9 antibiotics) were detected. Rifampicin-moxifloxacin-cefotaxime-erythromycin-clindamycin-imipenem-resistance was predominant, being expressed by 18 strains (PR 027/17, PR 018/1). PCR results suggested tetracycline-resistance to be induced by the gene tetM. Three tetM-positive isolates (PRs 012, 046), were also tndX-positive, suggesting the presence of a Tn5397-like element. Only two MLSB-resistant strains (PR 012) had the ermB gene and chloramphenicol-resistance determinant catD was not detected, leaving room for further investigating resistance mechanisms. Multidrug resistance could be attributed to most analysed strains, underlining, once more, the impact of wide-spectrum antimicrobial over prescription, still a tendency in our country, on transmission of antimicrobial resistance and emergence of epidemic C. difficile strains generating outbreaks.

Risk factors for Clostridium difficile infections - an overview of the evidence base and challenges in data synthesis

Background

Recognition of a broad spectrum of disease and development of Clostridium difficile infection (CDI) and recurrent CDI (rCDI) in populations previously considered to be at low risk has renewed attention on differences in the risk profile of patients. In the absence of primary prevention for CDI and limited treatment options, it is important to achieve a deep understanding of the multiple factors that influence the risk of developing CDI and rCDI.

Methods

We conducted a review of systematic reviews and meta–analyses on risk factors for CDI and rCDI published between 1990 and October 2016.

Results

22 systematic reviews assessing risk factors for CDI (n = 19) and rCDI (n = 6) were included. Meta–analyses were conducted in 17 of the systematic reviews. Over 40 risk factors have been associated with CDI and rCDI and can be classified into three categories: pharmacological risk factors, host–related risk factors, and clinical characteristics or interventions. Most systematic reviews and meta–analyses have focused on antibiotic use (n = 8 for CDI, 3 for rCDI), proton pump inhibitors (n = 8 for CDI, 4 for rCDI), and histamine 2 receptor antagonists (n = 4 for CDI) and chronic kidney disease (n = 4 for rCDI). However, other risk factors have been assessed. We discuss the state of the evidence, methods, and challenges for data synthesis.

Conclusion

Several studies, synthesized in different systematic review, provide valuable insights into the role of different risk factors for CDI. Meta–analytic evidence of association has been reported for factors such as antibiotics, gastric acid suppressants, non–selective NSAID, and some co–morbidities. However, despite statistical significance, issues of high heterogeneity, bias and confounding remain to be addressed effectively to improve overall risk estimates. Large, prospective primary studies on risk factors for CDI with standardised case definitions and stratified analyses are required to develop more accurate and robust estimates of risk effects that can inform targeted–CDI clinical management procedures, prevention, and research.

Evaluation of the US Food and Drug Administration sentinel analysis tools in confirming previously observed drug-outcome associations: The case of clindamycin and Clostridium difficile infection

PURPOSE

The Food and Drug Administration's Sentinel System developed parameterized, reusable analytic programs for evaluation of medical product safety. Research on outpatient antibiotic exposures, and Clostridium difficile infection (CDI) with non-user reference groups led us to expect a higher rate of CDI among outpatient clindamycin users vs penicillin users. We evaluated the ability of the Cohort Identification and Descriptive Analysis and Propensity Score Matching tools to identify a higher rate of CDI among clindamycin users.

METHODS

We matched new users of outpatient dispensings of oral clindamycin or penicillin from 13 Data Partners 1:1 on propensity score and followed them for up to 60 days for development of CDI. We used Cox proportional hazards regression stratified by Data Partner and matched pair to compare CDI incidence.

RESULTS

Propensity score models at 3 Data Partners had convergence warnings and a limited range of predicted values. We excluded these Data Partners despite adequate covariate balance after matching. From the 10 Data Partners where these models converged without warnings, we identified 807 919 new clindamycin users and 8 815 441 new penicillin users eligible for the analysis. The stratified analysis of 807 769 matched pairs included 840 events among clindamycin users and 290 among penicillin users (hazard ratio 2.90, 95% confidence interval 2.53, 3.31).

CONCLUSIONS

This evaluation produced an expected result and identified several potential enhancements to the Propensity Score Matching tool. This study has important limitations. CDI risk may have been related to factors other than the inherent properties of the drugs, such as duration of use or subsequent exposures.

Lauric Acid Is an Inhibitor of Clostridium difficile Growth in Vitro and Reduces Inflammation in a Mouse Infection Model

Clostridium difficile is a Gram-positive, spore-forming anaerobic human gastrointestinal pathogen. C. difficile infection (CDI) is a major health concern worldwide, with symptoms ranging from diarrhea to pseudomembranous colitis, toxic megacolon, sepsis, and death. CDI onset and progression are mostly caused by intestinal dysbiosis and exposure to C. difficile spores. Current treatment strategies include antibiotics; however, antibiotic use is often associated with high recurrence rates and an increased risk of antibiotic resistance. Medium-chain fatty acids (MCFAs) have been revealed to inhibit the growth of multiple human bacterial pathogens. Components of coconut oil, which include lauric acid, have been revealed to inhibit C. difficile growth in vitro. In this study, we demonstrated that lauric acid exhibits potent antimicrobial activities against multiple toxigenic C. difficile isolates in vitro. The inhibitory effect of lauric acid is partly due to reactive oxygen species (ROS) generation and cell membrane damage. The administration of lauric acid considerably reduced biofilm formation and preformed biofilms in a dose-dependent manner. Importantly, in a mouse infection model, lauric acid pretreatment reduced CDI symptoms and proinflammatory cytokine production. Our combined results suggest that the naturally occurring MCFA lauric acid is a novel C. difficile inhibitor and is useful in the development of an alternative or adjunctive treatment for CDI.

Potential Adverse Effects of Broad-Spectrum Antimicrobial Exposure in the Intensive Care Unit

Background

The potential adverse effects of empiric broad-spectrum antimicrobial use among patients with suspected but subsequently excluded infection have not been fully characterized. We sought novel methods to quantify the risk of adverse effects of broad-spectrum antimicrobial exposure among patients admitted to an intensive care unit (ICU).

Methods

Among all adult patients admitted to ICUs at a single institution, we selected patients with negative blood cultures who also received ≥1 broad-spectrum antimicrobials. Broad-spectrum antimicrobials were categorized in ≥1 of 5 categories based on their spectrum of activity against potential pathogens. We performed, in serial, 5 cohort studies to measure the effect of each broad-spectrum category on patient outcomes. Exposed patients were defined as those receiving a specific category of broad-spectrum antimicrobial; nonexposed were all other patients in the cohort. The primary outcome was 30-day mortality. Secondary outcomes included length of hospital and ICU stay and nosocomial acquisition of antimicrobial-resistant bacteria (ARB) or Clostridium difficile within 30 days of admission.

Results

Among the study cohort of 1918 patients, 316 (16.5%) died within 30 days, 821 (42.8%) had either a length of hospital stay >7 days or an ICU length of stay >3 days, and 106 (5.5%) acquired either a nosocomial ARB or C. difficile. The short-term use of broad-spectrum antimicrobials in any of the defined broad-spectrum categories was not significantly associated with either primary or secondary outcomes.

Conclusions

The prompt and brief empiric use of defined categories of broad-spectrum antimicrobials could not be associated with additional patient harm.

Clostridium difficile infection in the elderly: an update on management

The burden of Clostridium difficile infection (CDI) is profound and growing. CDI now represents a common cause of health care–associated diarrhea, and is associated with significant morbidity, mortality, and health care costs. CDI disproportionally affects the elderly, possibly explained by the following risk factors: age-related impairment of the immune system, increasing antibiotic utilization, and frequent health care exposure. In the USA, recent epidemiological studies estimate that two out of every three health care–associated CDIs occur in patients 65 years or older. Additionally, the elderly are at higher risk for recurrent CDI. Existing therapeutic options include metronidazole, oral vancomycin, and fidaxomicin. Choice of agent depends on disease severity, history of recurrence, and, increasingly, the drug cost. Bezlotoxumab, a recently approved monoclonal antibody targeting C. difficile toxin B, offers an exciting advancement into immunologic therapies. Similarly, fecal microbiota transplantation is gaining popularity as an effective option mainly for recurrent CDI. The challenge of decreasing CDI burden in the elderly involves adopting preventative strategies, optimizing initial treatment, and decreasing the risk of recurrence. Expanded strategies are certainly needed to improve outcomes in this high-risk population. This review considers available data from prospective and retrospective studies as well as case reports to illustrate the merits and gaps in care related to the management of CDI in the elderly.

Nosocomial-acquired and community-onset Clostridium difficile infection at an academic hospital in Italy: Epidemiology, recurrences and toxin genes distribution

Toxinogenic Clostridium difficile infection (CDI) is a leading cause of infectious diarrhea. In this retrospective cohort study the molecular epidemiology of hospital-acquired and community-associated CDI was investigated in patients admitted to a tertiary care hospital. CD in stools samples was revealed by a two steps diagnostic algorithm, firstly screening for positivity to GDH antigen and thereafter RT-PCR analysis. Increased CDI incidence was observed ranging from 1.70episodes/10000patient-days in the 1st year, to 2.62 in the 2nd year, mostly hospitalized in the medicine wards, followed by outpatients (5.74 and 5.12episodes/10.000patient-days respectively). CDI positive were older than CDI negative patients and presented increased trend of diarrhea episodes as the patients' age increased. RT-PCR positive patients (n° = 314) were classified according to the CD toxin producing genes in three groups (1-3, carrying tcdB, both tcdB and cdt, and the two genes plus the deletion Δ117 of tcdC, respectively). The incidence of the group 2 and 3 increased statistically with the age of the patients showing correlation with the gender. Higher frequency of patients belonging to group 1 and group 3 was observed in the medical wards. Of note was the high incidence of group 3 in outpatients. Interestingly, patients with previous health care contacts had higher risk (RR = 1.88) of being infected by CD strains with higher toxicity than community patients. Recurrence rate was 15.9%. In conclusion the knowledge of the toxigenic profiles and of their relationships to gender, age and wards distribution may help the clinicians in the clinical management of the disease.

Antimicrobial susceptibility of Clostridium difficile isolates in Israel

OBJECTIVES

An increase of Clostridium difficile isolates with reduced susceptibility to various antimicrobial agents has been observed, including isolates that are non-susceptible to antibiotics that are routinely used for treatment of C. difficile, such as vancomycin and metronidazole. We determined the susceptibility rates of C. difficile isolates from hospitals in northern Israel to various antibiotics including tigecycline, which was not previously reported from Israel.

METHODS

A total of 81 stool samples were collected from three hospitals in northern Israel from patients with C. difficile infection. Specimens were screened for BI/NAP1/027 ribotype, cultured, and sensitivity tests were performed for vancomycin, metronidazole, moxifloxacin, and tigecycline. Statistical tests were applied for analysing the differences in distribution of resistance between the different antibiotics and between BI/NAP1/027 and resistance of antibiotics.

RESULTS

Reduced susceptibility was found among 6/81 isolates for vancomycin, 4/81 for metronidazole, and 17/81 for moxifloxacin. Only 1 isolate had reduced susceptibility to tigecycline, with a mean MIC of 0.05μg/mL. Reduced susceptibility to moxifloxacin was significantly associated with reduced susceptibility to vancomycin (p=0.016) and to metronidazole (p=0.0276), and reduced susceptibility to metronidazole was associated with reduced susceptibility to vancomycin (p=0.0259). Eight of 81 isolates (9.9%) were positive for BI/NAP1/027 ribotype and had significantly higher non-susceptibility rates to moxifloxacin and vancomycin compared with BI/NAP1/027 negative isolates (p<0.0001 and p=0.0113, respectively).

CONCLUSIONS

We found higher non-susceptibility rates to vancomycin and metronidazole than most previous studies, while tigecycline resistance rates are very low in northern Israel, rendering it a potential agent for treating CDI.

Severe complicated Clostridium difficile infection: Can the UPMC proposed scoring system predict the need for surgery?

INTRODUCTION

Clostridium difficile infection (CDI) is one of the most common health care-associated infections, and it continues to have significant morbidity and mortality. The onset of fulminant colitis often requires total abdominal colectomy with ileostomy, which has a mortality rate of 35% to 57%. University of Pittsburgh Medical Center (UPMC) developed a scoring system for severity and recommended surgical consultation for severe complicated disease. The aim of this study was to evaluate if the UPMC-proposed scoring system for severe complicated CDI can predict the need for surgical intervention.

METHODS

This is a retrospective review of all patients who developed severe complicated CDI at Geisinger Medical Center between January 2007 and December 2012 as defined by the UPMC scoring system. Main outcomes were the need for surgical intervention and 30-day mortality.

RESULTS

Eighty-eight patients had severe complicated CDI based on the UPMC scoring system. Fifty-nine patients (67%) required surgery and 29 did not. All patients had a diagnosis of CDI as shown by positive toxin assays. There was no difference between the groups with respect to age, sex, body mass index, or comorbidities. When comparing the surgical group to the nonsurgical cohort, the surgical cohort averaged 20 points on the scoring system compared to 9 in the nonoperative cohort. In patients with severe complicated CDI, 15 or more points predicted the need for surgery 75% of the time. Forty-two percent of the surgical cohort had respiratory failure requiring mechanical ventilation compared to 0% in the nonsurgical cohort (p < 0.0001). Forty-nine percent of the surgical cohort required vasopressors for septic shock before surgery compared to 0% in the nonsurgical cohort (p < 0.0001). Acute kidney injury was present in 92% of the surgical cohort versus 72% within the nonsurgical cohort (p = 0.026). Seventy-six percent of the surgical patients were admitted to the ICU before surgery. Within the nonsurgical cohort, only 24% of patients required ICU stay during admission. Overall, 30-day mortality in the surgical cohort was 30%, and there was no mortality in the nonsurgical cohort.

CONCLUSIONS

The UPMC scoring system for severe complicated CDI can help us predict patients who need a surgical consult and the need for surgical intervention. In patients with severe complicated CDI, evidence of end-organ failure predicts surgical intervention.

LEVEL OF EVIDENCE

Prognostic study, level III; therapeutic study, level IV.

Occurrence of Clostridium difficile ribotype 027 in hospitals of Silesia, Poland

Clostridium difficile is an important healthcare-associated pathogen, responsible for a broad spectrum of diarrheal diseases. The aim of this prospective study was to determine the occurrence of C. difficile infection (CDI), to characterize cultured C. difficile strains and to investigate the association of fecal lactoferrin with CDI. Between January 2013 and June 2014, 148 stool samples were obtained from adult diarrheal patients (C. difficile as a suspected pathogen) hospitalized in different healthcare facilities of 15 Silesian hospitals. Out of 134 isolated C. difficile strains, 108 were ribotyped: 82.4% belonged to Type 027, 2.8% to Type 176, 2.8% to Type 014, 1.9% to Type 010 and 0.9% to Types 001, 018, 020 and 046 each. In total, 6.5% non-typable strains were identified. All Type 027 isolates contained both toxin genes tcdA & tcdB, and binary toxin genes (cdtA &cdtB). Susceptibility testing revealed that all Type 027 isolates were sensitive to metronidazole and vancomycin and resistant to moxifloxacin, ciprofloxacin, imipenem and erythromycin. Of 89 Type 027 strains, 16 had a ermB (688 bp) gene coinciding with high levels of erythromycin resistance (MIC >256 μg/mL). Of 16 ermB positive strains, 14 demonstrated also high level of resistance to clindamycin (>256 μg/mL). A significant difference (p = 0.004) in lactoferrin level was found between C. difficile toxin-positive (n = 123; median 185.9 μg/mL; IQR 238.8) and toxin-negative (n = 25; median 22.4 μg/mL; IQR 141.7) fecal samples. Stool samples from n = 89 patients with CDI caused by Type 027 demonstrated significantly higher (p = 0.03) lactoferrin level (median 173.0 μg/mL; IQR 237.3) than from patients with CDI caused by other ribotypes and non-typable C. difficile strains (median 189.4 μg/mL; IQR 190.8).

The burden of healthcare-associated Clostridium difficile infection in a non-metropolitan setting

OBJECTIVE

Healthcare-associated Clostridium difficile infection (HCA-CDI) remains a major cause of morbidity and mortality in industrialized countries. However, few data exist on the burden of HCA-CDI in multi-site non-metropolitan settings. This study examined the introduction of an antimicrobial stewardship programme (ASP) in relation to HCA-CDI rates, and the effect of HCA-CDI on length of stay (LOS) and hospital costs.

METHODS

A comparative before-and-after intervention study of patients aged ≥16 years with HCA-CDI from December 2010 to April 2016 across the nine hospitals of a non-metropolitan health district in New South Wales, Australia was undertaken. The intervention comprised a multi-site ASP supported by a clinical decision support system, with subsequent introduction of email feedback of HCA-CDI cases to admitting medical officers.

MAIN OUTCOME MEASURES

HCA-CDI rates, comparative LOS and hospital costs, prior use of antimicrobials and proton pump inhibitors, and appropriateness of CDI treatment.

RESULTS

HCA-CDI rates rose from 3.07 to 4.60 cases per 10,000 occupied bed-days pre-intervention, and remained stable at 4 cases per 10,000 occupied bed-days post-intervention (P=0.24). Median LOS (17 vs six days; P<0.01) and hospital costs (AU$19,222 vs $7861; P<0.01) were significantly greater for HCA-CDI cases (N=91) than for matched controls (N=172). Half of the patients with severe HCA-CDI (4/8) did not receive initial appropriate treatment (oral vancomycin).

CONCLUSIONS

HCA-CDI placed a significant burden on the regional and rural health service through increased LOS and hospital costs. Interventions targeting HCA-CDI could be employed to consolidate the effects of ASPs.

Mathematical Modeling of the Transmission Dynamics of Clostridium difficile Infection and Colonization in Healthcare Settings: A Systematic Review

BACKGROUND

We conducted a systematic review of mathematical models of transmission dynamic of Clostridium difficile infection (CDI) in healthcare settings, to provide an overview of existing models and their assessment of different CDI control strategies.

METHODS

We searched MEDLINE, EMBASE and Web of Science up to February 3, 2016 for transmission-dynamic models of Clostridium difficile in healthcare settings. The models were compared based on their natural history representation of Clostridium difficile, which could include health states (S-E-A-I-R-D: Susceptible-Exposed-Asymptomatic-Infectious-Resistant-Deceased) and the possibility to include healthcare workers and visitors (vectors of transmission). Effectiveness of interventions was compared using the relative reduction (compared to no intervention or current practice) in outcomes such as incidence of colonization, CDI, CDI recurrence, CDI mortality, and length of stay.

RESULTS

Nine studies describing six different models met the inclusion criteria. Over time, the models have generally increased in complexity in terms of natural history and transmission dynamics and number/complexity of interventions/bundles of interventions examined. The models were categorized into four groups with respect to their natural history representation: S-A-I-R, S-E-A-I, S-A-I, and S-E-A-I-R-D. Seven studies examined the impact of CDI control strategies. Interventions aimed at controlling the transmission, lowering CDI vulnerability and reducing the risk of recurrence/mortality were predicted to reduce CDI incidence by 3-49%, 5-43% and 5-29%, respectively. Bundles of interventions were predicted to reduce CDI incidence by 14-84%.

CONCLUSIONS

Although CDI is a major public health problem, there are very few published transmission-dynamic models of Clostridium difficile. Published models vary substantially in the interventions examined, the outcome measures used and the representation of the natural history of Clostridium difficile, which make it difficult to synthesize results and provide a clear picture of optimal intervention strategies. Future modeling efforts should pay specific attention to calibration, structural uncertainties, and transparent reporting practices.

Epidemiology, Diagnosis, and Management of Clostridium difficile Infection in Patients with Inflammatory Bowel Disease

Clostridium difficile infection (CDI) is a major source of morbidity and mortality for the U.S. health care system and frequently complicates the course of inflammatory bowel disease (IBD). Patients with IBD are more likely to be colonized with C. difficile and develop active infection than the general population. They are also more likely to have severe CDI and develop subsequent complications such as IBD flare, colectomy, or death. Even after successful initial treatment and recovery, recurrent CDI is common. Management of CDI in IBD is fraught with diagnostic and therapeutic challenges because the clinical presentations of CDI and IBD flare have considerable overlap. Fecal microbiota transplantation can be successful in curing recurrent CDI when other treatments have failed, but may also trigger IBD flare and this warrants caution. New experimental treatments including vaccines, monoclonal antibodies, and nontoxigenic strains of C. difficile offer promise but are not yet available for clinicians. A better understanding of the complex relationship between the gut microbiota, CDI, and IBD is needed.

A MLST Clade 2 Clostridium difficile strain with a variant TcdB induces severe inflammatory and oxidative response associated with mucosal disruption

The epidemiology of Clostridium difficile infections is highly dynamic as new strains continue to emerge worldwide. Here we present a detailed analysis of a new C. difficile strain (ICC-45) recovered from a cancer patient in Brazil that died from severe diarrhea. A polyphasic approach assigned a new PCR-ribotype and PFGE macrorestriction pattern to strain ICC-45, which is toxigenic (tcdA(+), tcdB(+) and ctdB(+)) and classified as ST41 from MLST Clade 2 and toxinotype IXb. Strain ICC-45 encodes for a variant TcdB that induces a distinct CPE in agreement with its toxinotype. Unlike epidemic NAP1/027 strains, which are also classified to MLST Clade 2, strain ICC-45 is susceptible to fluoroquinolones and does not overproduce toxins TcdA and TcdB. However, supernatants from strain ICC-45 and a NAP1/027 strain produced similar expression of pro-inflammatory cytokines, epithelial damage, and oxidative stress response in the mouse ileal loop model. These results highlight inflammation and oxidative stress as common features in the pathogenesis of C. difficile Clade 2 strains. Finally, this work contributes to the description of differences in virulence among various C. difficile strains.

Nosocomial transmission of Clostridium difficile ribotype 027 in a Chinese hospital, 2012-2014, traced by whole genome sequencing

Background

The rapid spread of Clostridium difficile NAP1/BI/027 (C. difficile 027) has become one of the leading threats of healthcare-associated infections worldwide. However, C. difficile 027 infections have been rarely reported in Asia, particularly in China.

Results

In this study, we identified a rare C. difficile bloodstream infection (BSI) from three isolates of a patient during repeated hospital admission. This finding triggered a retrospective epidemiological study to scan all cases and strains emerged from this ward during the past three years. Using medical personnel interviews, medical record reviews and the genomic epidemiology, two outbreaks in 2012 and 2013–2014 were identified. Through using whole genome sequencing, we succeeded to trace the origin of the BSI strain. Surprisingly, we found the genome sequences were similar to C. difficile 027 strain R20291, indicating the occurrence of a rare C. difficile 027 strain in China. Integrated epidemiological investigation and whole genome sequencing of all strains, we constructed a nosocomial transmission map of these two C. difficile 027 outbreaks and traced the origin of the infection.

Conclusions

By genome sequencing, spatio-temporal analysis and field epidemiology investigation, we can estimate their complex transform network and reveal the possible modes of transmission in this ward. Based on their genetic diversity, we can assume that the toilets, bathroom, and janitor’s equipment room may be contaminated area, which may be suggested to improve infection control measures in the following health care.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-2708-0) contains supplementary material, which is available to authorized users.

Clostridium difficile infection following systemic antibiotic administration in randomised controlled trials: a systematic review and meta-analysis

Antibiotics have been the most important risk factor for Clostridium difficile infection (CDI). However, only data from non-randomised studies have been reviewed. We sought to evaluate the risk for development of CDI associated with the major antibiotic classes by analysing data from randomised controlled trials (RCTs). The PubMed, Cochrane and Scopus databases were searched and the references of selected RCTs were also hand-searched. Eligible studies should have compared only one antibiotic versus another administered systemically. Inclusion of studies comparing combinations of antibiotics was allowed only if the second antibiotic was the same or from the same class or if it was administered in a subset of the enrolled patients who were equally distributed in the two arms. Only a minority of the selected RCTs (79/1332; 5.9%) reported CDI episodes. Carbapenems were associated with more CDI episodes than fluoroquinolones [risk ratio (RR) = 2.44, 95% confidence interval (CI) 1.32-4.49] and cephalosporins (RR = 2.24, 95% CI 1.46-3.42), but not penicillins (RR = 2.53, 95% CI 0.87-7.41). Cephalosporins were associated with more CDIs than penicillins (RR = 2.36, 95% CI 1.32-4.23) and fluoroquinolones (RR = 2.84, 95% CI 1.60-5.06). There was no difference in CDI frequency between fluoroquinolones and penicillins (RR = 1.34, 95% CI 0.55-3.25). Finally, clindamycin was associated with more CDI episodes than cephalosporins and penicillins (RR = 3.92, 95% CI 1.15-13.43). In conclusion, data from RCTs showed that clindamycin and carbapenems were associated with more CDIs than other antibiotics.

Comparison of pediatric and adult antibiotic-associated diarrhea and Clostridium difficile infections

Antibiotic-associated diarrhea (AAD) and Clostridum difficile infections (CDI) have been well studied for adult cases, but not as well in the pediatric population. Whether the disease process or response to treatments differs between pediatric and adult patients is an important clinical concern when following global guidelines based largely on adult patients. A systematic review of the literature using databases PubMed (June 3, 1978-2015) was conducted to compare AAD and CDI in pediatric and adult populations and determine significant differences and similarities that might impact clinical decisions. In general, pediatric AAD and CDI have a more rapid onset of symptoms, a shorter duration of disease and fewer CDI complications (required surgeries and extended hospitalizations) than in adults. Children experience more community-associated CDI and are associated with smaller outbreaks than adult cases of CDI. The ribotype NAP1/027/BI is more common in adults than children. Children and adults share some similar risk factors, but adults have more complex risk factor profiles associated with more co-morbidities, types of disruptive factors and a wider range of exposures to C. difficile in the healthcare environment. The treatment of pediatric and adult AAD is similar (discontinuing or switching the inciting antibiotic), but other treatment strategies for AAD have not been established. Pediatric CDI responds better to metronidazole, while adult CDI responds better to vancomycin. Recurrent CDI is not commonly reported for children. Prevention for both pediatric and adult AAD and CDI relies upon integrated infection control programs, antibiotic stewardship and may include the use of adjunctive probiotics. Clinical presentation of pediatric AAD and CDI are different than adult AAD and CDI symptoms. These differences should be taken into account when rating severity of disease and prescribing antibiotics.

Antibiotic prescribing at the transition from hospitalization to discharge: a target for antibiotic stewardship

Of 300 patients prescribed oral antibiotics at the time of hospital discharge, urinary tract infection, community-acquired pneumonia, and skin infections accounted for 181 of the treatment indications (60%). Half of the prescriptions were antibiotics with broad Gram-negative activity. Discharge prescriptions were inappropriate in 79 of 150 cases reviewed (53%).

Burden of Nursing Home-Onset Clostridium difficile Infection in the United States: Estimates of Incidence and Patient Outcomes

Background.  Approximately 4 million Americans receive nursing home (NH) care annually. Nursing home residents commonly have risk factors for Clostridium difficile infection (CDI), including advanced age and antibiotic exposures. We estimated national incidence of NH-onset (NHO) CDI and patient outcomes. Methods.  We identified NHO-CDI cases from population-based surveillance of 10 geographic areas in the United States. Cases were defined by C difficile-positive stool collected in an NH (or from NH residents in outpatient settings or ≤3 days after hospital admission) without a positive stool in the prior 8 weeks. Medical records were reviewed on a sample of cases. Incidence was estimated using regression models accounting for age and laboratory testing method; sampling weights were applied to estimate hospitalizations, recurrences, and deaths. Results.  A total of 3503 NHO-CDI cases were identified. Among 262 sampled cases, median age was 82 years, 76% received antibiotics in the 12 weeks prior to the C difficile-positive specimen, and 57% were discharged from a hospital in the month before specimen collection. After adjusting for age and testing method, the 2012 national estimate for NHO-CDI incidence was 112 800 cases (95% confidence interval [CI], 93 400-131 800); 31 400 (28%) were hospitalized within 7 days after a positive specimen (95% CI, 25 500-37 300), 20 900 (19%) recurred within 14-60 days (95% CI, 14 600-27 100), and 8700 (8%) died within 30 days (95% CI, 6600-10 700). Conclusions.  Nursing home onset CDI is associated with substantial morbidity and mortality. Strategies focused on infection prevention in NHs and appropriate antibiotic use in both NHs and acute care settings may decrease the burden of NHO CDI.

Fluoroquinolone and Macrolide Exposure Predict Clostridium difficile Infection with the Highly Fluoroquinolone- and Macrolide-Resistant Epidemic C. difficile Strain BI/NAP1/027

Antibiotics have been shown to influence the risk of infection with specific Clostridium difficile strains as well as the risk of C. difficile infection (CDI). We performed a retrospective case-control study of patients infected with the epidemic BI/NAP1/027 strain in a U.S. hospital following recognition of increased CDI severity and culture of stools positive by C. difficile toxin immunoassay. Between 2005 and 2007, 72% (103/143) of patients with first-episode CDIs were infected with the BI strain by restriction endonuclease analysis (REA) typing. Most patients received multiple antibiotics within 6 weeks of CDI onset (median of 3 antibiotic classes). By multivariate analysis, fluoroquinolone and macrolide exposure was more frequent among BI cases than among non-BI-infected controls (odds ratio [OR] for fluoroquinolones, 3.2; 95% confidence interval [CI], 1.3 to 7.5; (P < 0.001; OR for macrolides, 5.2; 95% CI, 1.1 to 24.0; P = 0.04)). In contrast, clindamycin use was less frequent among the BI cases than among the controls (OR, 0.1; 95% CI, 0.03 to 0.4; P = 0.001). High-level resistance to moxifloxacin and azithromycin was more frequent among BI strains (moxifloxacin, 49/102 [48%] BI versus 0/40 non-BI, P = 0.0001; azithromycin, 100/102 [98%] BI versus 22/40 [55%] non-BI, P = 0.0001). High-level resistance to clindamycin was more frequent among non-BI strains (22/40 [55%] non-BI versus 7/102 [7%] BI, P = 0.0001). Fluoroquinolone use, macrolide use, and C. difficile resistance to these antibiotic classes were associated with infection by the epidemic BI strain of C. difficile in a U.S. hospital during a time when CDI rates were increasing nationally due to the highly fluoroquinolone-resistant BI/NAP1/027 strain.

Clostridium difficile infection (CDI) severity and outcome among patients infected with the NAP1/BI/027 strain in a non-epidemic setting

OBJECTIVE

Determine whether the NAP1 strain identified by polymerase chain reaction (PCR)-based stool assay is correlated with CDI severity and clinical outcomes.

METHODS

Medical records of adult patients with positive stool Xpert® Clostridium difficile PCR assay for an initial episode of CDI between January 2012 and January 2013 at a tertiary care hospital in Chicago were reviewed. Two patients diagnosed with CDI caused by a non-NAP1 strain (positive Xpert® C. difficile assay but negative Xpert® C. difficile Epi assay) were included for each patient diagnosed with CDI caused by a NAP1 strain (positive Epi assay). Patient charts were reviewed for markers of severity, risk factors, treatment regimens, and outcomes.

RESULTS

Of 494 stool specimens, 90 (18%) that were positive for C. difficile by PCR were positive for NAP1 strain. In total, 37 patients with CDI due to NAP1 were matched with 74 patients with CDI due to non-NAP1 strains. Multivariable model revealed individuals ≥65 years old were 3 times more likely to have NAP1 strain than individuals <65 (P=.02). Residents of a nursing home prior to hospitalization were 10 times more likely to have NAP1 strain than patients residing in their homes (P=.001). More NAP1 cases had a change in treatment from metronidazole to oral vancomycin plus intravenous metronidazole (P=.01). The severity of CDI, incidence of mortality and recurrent CDI were similar between groups.

CONCLUSIONS

In a nonepidemic setting, NAP1 strains were more common in older patients and individuals admitted from nursing homes. Identification of NAP1 by PCR of stool specimens was associated in a change of therapy but did not predict worse outcomes. Reporting strain results may not be clinically useful in routine settings.

Epidemiology of Clostridium difficile in Germany based on a single center long-term surveillance and German-wide genotyping of recent isolates provided to the advisory laboratory for diagnostic reasons

Epidemiology of Clostridium difficile is characterized by worldwide increase of C. difficile infections (CDI) and the emergence of new epidemic outbreak strains with the capacity for global spreading. Long-term local surveillance at the University of Saarland Medical Center between 2000 and 2013 shows that the incidence rate of laboratory-confirmed CDI was influenced by local epidemiology as well as by testing strategies. Since 2008, molecular typing of C. difficile was regularly performed for symptomatic hospitalized patients by surface-layer protein A sequence typing (slpAST), which is an established highly standardized technique for genotyping of C. difficile. The results were assigned to known ribotypes for better comparison to international data. It could be demonstrated that distribution of genotypes was different between age groups. Older patients were predominantly infected with ribotype 001 and 027, whereas ribotype 027 was not detected in the pediatric population. Molecular typing of German isolates sent to the advisory laboratory between 2011 and 2013 revealed that ribotype 027 is present with high percentages in most German regions except for the very North. In conclusion, optimized testing of all hospitalized patients with diarrhea should be generally implemented to avoid under-diagnosis of C. difficile infection. Ribotype 027 is highly prevalent in Germany, but its infections are restricted to older patients, while absent in children. Molecular typing of suspected hospital outbreaks and of patients with severe or recurrent disease may help to better understand virulence and epidemic spreading of C. difficile.

Defining the Roles of TcdA and TcdB in Localized Gastrointestinal Disease, Systemic Organ Damage, and the Host Response during Clostridium difficile Infections

Clostridium difficile is a leading cause of antibiotic-associated diarrhea, a significant animal pathogen, and a worldwide public health burden. Most disease-causing strains secrete two exotoxins, TcdA and TcdB, which are considered to be the primary virulence factors. Understanding the role that these toxins play in disease is essential for the rational design of urgently needed new therapeutics. However, their relative contributions to disease remain contentious. Using three different animal models, we show that TcdA⁺ TcdB⁻ mutants are attenuated in virulence in comparison to the wild-type (TcdA⁺ TcdB⁺) strain, whereas TcdA⁻ TcdB⁺ mutants are fully virulent. We also show for the first time that TcdB alone is associated with both severe localized intestinal damage and systemic organ damage, suggesting that this toxin might be responsible for the onset of multiple organ dysfunction syndrome (MODS), a poorly characterized but often fatal complication of C. difficile infection (CDI). Finally, we show that TcdB is the primary factor responsible for inducing the in vivo host innate immune and inflammatory responses. Surprisingly, the animal infection model used was found to profoundly influence disease outcomes, a finding which has important ramifications for the validation of new therapeutics and future disease pathogenesis studies. Overall, our results show unequivocally that TcdB is the major virulence factor of C. difficile and provide new insights into the host response to C. difficile during infection. The results also highlight the critical nature of using appropriate and, when possible, multiple animal infection models when studying bacterial virulence mechanisms.

Clostridium difficile is a leading cause of antibiotic-associated diarrhea and an important hospital pathogen. TcdA and TcdB are thought to be the primary virulence factors responsible for disease symptoms of C. difficile infections (CDI). However, the individual contributions of these toxins to disease remain contentious. Using three different animal models of infection, we show for the first time that TcdB alone causes severe damage to the gut, as well as systemic organ damage, suggesting that this toxin might be responsible for MODS, a serious but poorly understood complication of CDI. These findings provide important new insights into the host response to C. difficile during infection and should guide the rational development of urgently required nonantibiotic therapeutics for the treatment of CDI.

Clostridium difficile in Crete, Greece: epidemiology, microbiology and clinical disease

We studied the epidemiology and microbiology of Clostridium difficile and the characteristics of patients with C. difficile infection (CDI) in Crete in three groups of hospitalized patients with diarrhoea: group 1 [positive culture and positive toxin by enzyme immunoassay (EIA)]; group 2 (positive culture, negative toxin); group 3 (negative culture, negative toxin). Patients in group 1 were designated as those with definitive CDI (20 patients for whom data was available) and matched with cases in group 2 (40 patients) and group 3 (40 patients). C. difficile grew from 6% (263/4379) of stool specimens; 14·4% of these had positive EIA, of which 3% were resistant to metronidazole. Three isolates had decreased vancomycin susceptibility. Patients in groups 1 and 2 received more antibiotics (P = 0·03) and had more infectious episodes (P = 0·03) than patients in group 3 prior to diarrhoea. Antibiotic administration for C. difficile did not differ between groups 1 and 2. Mortality was similar in all three groups (10%, 12·5% and 5%, P = 0·49). CDI frequency was low in the University Hospital of Crete and isolates were susceptible to metronidazole and vancomycin.

Environmental transmission of Clostridium difficile: association between hospital room size and C. difficile Infection

OBJECTIVE

To evaluate the association between hospital room square footage and acquisition of nosocomial Clostridium difficile infection (CDI).

METHODS

A case-control study was conducted at a university hospital during the calendar year of 2011. Case patients were adult inpatients with nosocomial CDI. Control patients were hospitalized patients without CDI and were randomly selected and matched to cases in a 2:1 ratio on the basis of hospital length of stay in 3-day strata. A multivariate model was developed using conditional logistic regression to evaluate risk factors for nosocomial CDI.

RESULTS

A total of 75 case patients and 150 control patients were included. On multivariate analyses, greater square footage of the hospital room was associated with a significantly increased risk of acquiring CDI (odds ratio for every 50 ft² increase, 3.00; 95% CI, 1.75-5.16; P<.001). Other factors associated with an increased risk of CDI were location in a single room (odds ratio, 3.43; 95% CI, 1.31-9.05; P=.01), malignant tumor (4.56; 1.82-11.4; P=.001), and receipt of cefepime (2.48; 1.06-5.82; P=.04) or immunosuppressants (6.90; 2.07-23.0; P=.002) within the previous 30 days.

CONCLUSIONS

Greater room square footage increased the risk of acquisition of CDI in the hospital setting, likely owing to increased environmental contamination and/or difficulty in effective disinfection. Future studies are needed to determine feasible and effective cleaning protocols based on patient and room characteristics.

Regional differences in Clostridium difficile infections in relation to fluoroquinolone and proton pump inhibitor use, Finland, 2008-2011

BACKGROUND

Several antimicrobial agents and proton pump inhibitors (PPIs) have been identified as risk factors for Clostridium difficile infections (CDIs). Nationwide laboratory-based surveillance of CDIs in Finland since 2008 has shown variation in regional CDI rates. We evaluated whether regional differences in CDI rates were associated with antibacterial and PPI use.

METHODS

Data on mean annual incidence rates of CDIs during 2008-2011 in 21 healthcare districts (HDs) were obtained from the National Infectious Disease Register, consumption (median annual use) of antimicrobials and PPIs from the Finnish Medical Agency, availability of molecular diagnostics by a laboratory survey and data on ribotypes from the national reference laboratory. The association over the 4 years was measured by incidence rate ratio (IRR) and we performed both bivariate and multivariate analyses.

RESULTS

During 2008-2011, PPI use increased 27% but fluoroquinolone use was stable. The level of fluoroquinolone use was strongly associated with the mean annual CDI incidence rate in different HDs over the 4-year period, but PPI use had less effect. The molecular diagnostics methodology and PCR ribotype 027 were not independently associated with CDI rate. The final multivariable model only included fluoroquinolone and PPI use; IRR for fluoroquinolones was 2.20 (95% confidence interval (CI), 1.32-3.67; p = 0.003).

CONCLUSIONS

Fluoroquinolone use may play a role in regional differences in CDI rates. Although the use has not recently increased, regionally targeted antimicrobial stewardship campaigns promoting appropriate use of fluoroquinolones should still be encouraged since they may decrease the incidence of CDIs.

The epidemiology of Clostridium difficile infection inside and outside health care institutions

This article describes the global changes in Clostridium difficile epidemiology since the late twentieth century and into the twenty-first century when the new epidemic strain BI/NAP1/027 emerged. The article provides an overview of how understanding of C difficile epidemiology has rapidly evolved since its initial association with colitis in 1974. It also discusses how C difficile has spread across the globe, the role of asymptomatic carriers in disease transmission, the increased recognition of C difficile outside health care settings, the changes in epidemiology of C difficile infection in children, and the risk factors for disease.

Diagnosis and treatment of Clostridium difficile in adults: a systematic review

IMPORTANCE

Since 2000, the incidence and severity of Clostridium difficile infection (CDI) have increased.

OBJECTIVE

To review current evidence regarding best practices for the diagnosis and treatment of CDI in adults (age ≥ 18 years).

EVIDENCE REVIEW

Ovid MEDLINE and Cochrane databases were searched using keywords relevant to the diagnosis and treatment of CDI in adults. Articles published between January 1978 and October 31, 2014, were selected for inclusion based on targeted keyword searches, manual review of bibliographies, and whether the article was a guideline, systematic review, or meta-analysis published within the past 10 years. Of 4682 articles initially identified, 196 were selected for full review. Of these, the most pertinent 116 articles were included. Clinical trials, large observational studies, and more recently published articles were prioritized in the selection process.

FINDINGS

Laboratory testing cannot distinguish between asymptomatic colonization and symptomatic infection with C difficile. Diagnostic approaches are complex due to the availability of multiple testing strategies. Multistep algorithms using polymerase chain reaction (PCR) for the toxin gene(s) or single-step PCR on liquid stool samples have the best test performance characteristics (for multistep: sensitivity was 0.68-1.00 and specificity was 0.92-1.00; and for single step: sensitivity was 0.86-0.92 and specificity was 0.94-0.97). Vancomycin and metronidazole are first-line therapies for most patients, although treatment failures have been associated with metronidazole in severe or complicated cases of CDI. Recent data demonstrate clinical success rates of 66.3% for metronidazole vs 78.5% for vancomycin for severe CDI. Newer therapies show promising results, including fidaxomicin (similar clinical cure rates to vancomycin, with lower recurrence rates for fidaxomicin, 15.4% vs vancomycin, 25.3%; P = .005) and fecal microbiota transplantation (response rates of 83%-94% for recurrent CDI).

CONCLUSIONS AND RELEVANCE

Diagnostic testing for CDI should be performed only in symptomatic patients. Treatment strategies should be based on disease severity, history of prior CDI, and the individual patient's risk of recurrence. Vancomycin is the treatment of choice for severe or complicated CDI, with or without adjunctive therapies. Metronidazole is appropriate for mild disease. Fidaxomicin is a therapeutic option for patients with recurrent CDI or a high risk of recurrence. Fecal microbiota transplantation is associated with symptom resolution of recurrent CDI but its role in primary and severe CDI is not established.