Clostridium difficile: recent epidemiologic findings and advances in therapy

Update on Commonly Used Molecular Typing Methods for Clostridioides difficile

This review aims to provide a comprehensive overview of the significant Clostridioides difficile molecular typing techniques currently employed in research and medical communities. The main objectives of this review are to describe the key molecular typing methods utilized in C. difficile studies and to highlight the epidemiological characteristics of the most prevalent strains on a global scale. Geographically distinct regions exhibit distinct strain types of C. difficile, with notable concordance observed among various typing methodologies. The advantages that next-generation sequencing (NGS) offers has changed epidemiology research, enabling high-resolution genomic analyses of this pathogen. NGS platforms offer an unprecedented opportunity to explore the genetic intricacies and evolutionary trajectories of C. difficile strains. It is relevant to acknowledge that novel routes of transmission are continually being unveiled and warrant further investigation, particularly in the context of zoonotic implications and environmental contamination.

Clostridium difficile Infections in an Emergency Surgical Unit from North-East Romania

Background and Objectives: Colitis with Clostridium difficile is an important health problem that occurs with an intensity that varies between mild and severe. Surgical interventions are required only in fulminant forms. There is little evidence regarding the best surgical intervention in these cases. Materials and Methods: Patients with C. difficile infection were identified from the two surgery clinics from the 'Saint Spiridon' Emergency Hospital Iași, Romania. Data regarding the presentation, indication for surgery, antibiotic therapy, type of toxins, and post-operative outcomes were collected over a 3-year period. Results: From a total of 12,432 patients admitted for emergency or elective surgery, 140 (1.12%) were diagnosed with C. difficile infection. The mortality rate was 14% (20 cases). Non-survivors had higher rates of lower-limb amputations, bowel resections, hepatectomy, and splenectomy. Additional surgery was necessary in 2.8% of cases because of the complications of C. difficile colitis. In three cases, terminal colostomy was performed and as well as one case with subtotal colectomy with ileostomy. All patients who required the second surgery died within the 30-day mortality period. Conclusions: In our prospective study, the incidence was increased both in cases of patients with interventions on the colon and in those requiring limb amputations. Surgical interventions are rarely required in patients with C. difficile colitis.

Comparing intervention strategies for reducing Clostridioides difficile transmission in acute healthcare settings: an agent-based modeling study

Background

Clostridioides difficile infection (CDI) is one of the most common healthcare infections. Common strategies aiming at controlling CDI include antibiotic stewardship, environmental decontamination, and improved hand hygiene and contact precautions. Mathematical models provide a framework to evaluate control strategies. Our objective is to evaluate the effectiveness of control strategies in decreasing C. difficile colonization and infection using an agent-based model in an acute healthcare setting.

Methods

We developed an agent-based model that simulates the transmission of C. difficile in medical wards. This model explicitly incorporates healthcare workers (HCWs) as vectors of transmission, tracks individual patient antibiotic histories, incorporates varying risk levels of antibiotics with respect to CDI susceptibility, and tracks contamination levels of ward rooms by C. difficile. Interventions include two forms of antimicrobial stewardship, increased environmental decontamination through room cleaning, improved HCW compliance, and a preliminary assessment of vaccination.

Results

Increased HCW compliance with CDI patients was ranked as the most effective intervention in decreasing colonizations, with reductions up to 56%. Antibiotic stewardship practices were highly ranked after contact precaution compliance. Vaccination and reduction of high-risk antibiotics were the most effective intervention in decreasing CDI. Vaccination reduced CDI cases to up to 90%, and the reduction of high-risk antibiotics decreased CDI cases up to 23%.

Conclusions

Overall, interventions that decrease patient susceptibility to colonization by C. difficile, such as antibiotic stewardship, were the most effective interventions in reducing both colonizations and CDI cases.

Protocolized Urine Sampling is Associated with Reduced Catheter-associated Urinary Tract Infections: A Pre- and Postintervention Study

Background

Standard urine sampling and testing techniques do not mitigate against detection of colonization, resulting in false positive catheter-associated urinary tract infections (CAUTI). We aimed to evaluate whether a novel protocol for urine sampling and testing reduces rates of CAUTI.

Methods

A preintervention and postintervention study with a contemporaneous control group was conducted at 2 campuses (test and control) of the same academic medical center. The test campus implemented a protocol requiring urinary catheter removal prior to urine sampling from a new catheter or sterile straight catheterization, along with urine bacteria and pyuria screening prior to culture. Primary outcomes were test campus CAUTI rates, compared between each 9-month pre- and postintervention epoch. Secondary outcomes included the percent reductions in CAUTI rates, compared between the test campus and a propensity score–matched cohort at the control campus.

Results

A total of 7991 patients from the test campus were included in the primary analysis, and 4264 were included in the propensity score–matched secondary analysis. In the primary analysis, the number of CAUTI cases per 1000 patients was reduced by 77% (6.6 to 1.5), the number of CAUTI cases per 1000 catheter days was reduced by 63% (5.9 to 2.2), and the number of urinary catheter days per patient was reduced by 37% (1.1 to 0.69; all P values ≤ .001). In the propensity score–matched analysis, the number of CAUTI cases per 1000 patients was reduced by 82% at the test campus, versus 57% at the control campus; the number of CAUTI cases per 1000 catheter days declined by 68% versus 57%, respectively; and the number of urinary catheter days per patient decreased by 44% versus 1%, respectively (all P values < .001).

Conclusions

Protocolized urine sampling and testing aimed at minimizing contamination by colonization was associated with significantly reduced CAUTI infection rates and urinary catheter days.

Effect of changing urine testing orderables and clinician order sets on inpatient urine culture testing: Analysis from a large academic medical center

OBJECTIVE

To evaluate the impact of changes to urine testing orderables in computerized physician order entry (CPOE) system on urine culturing practices.

DESIGN

Retrospective before-and-after study.

SETTING

A 1,250-bed academic tertiary-care referral center.

PATIENTS

Hospitalized adults who had ≥1 urine culture performed during their stay.

INTERVENTION

The intervention (implemented in April 2017) consisted of notifications to providers, changes to order sets, and inclusion of the new urine culture reflex tests in commonly used order sets. We compared the urine culture rates before the intervention (January 2015 to April 2016) and after the intervention (May 2016 to August 2017), adjusting for temporal trends.

RESULTS

During the study period, 18,954 inpatients (median age, 62 years; 68.8% white and 52.3% female) had 24,569 urine cultures ordered. Overall, 6,662 urine cultures (27%) were positive. The urine culturing rate decreased significantly in the postintervention period for any specimen type (38.1 per 1,000 patient days preintervention vs 20.9 per 1,000 patient days postintervention; P < .001), clean catch (30.0 vs 18.7; P < .001) and catheterized urine (7.8 vs 1.9; P < .001). Using an interrupted time series model, urine culture rates decreased for all specimen types (P < .05).

CONCLUSIONS

Our intervention of changes to order sets and inclusion of the new urine culture reflex tests resulted in a 45% reduction in the urine cultures ordered. CPOE system format plays a vital role in reducing the burden of unnecessary urine cultures and should be implemented in combination with other efforts.

Reflex urine culture testing in an ambulatory urology clinic: Implications for antibiotic stewardship in urology

OBJECTIVES

To evaluate the performance characteristics of urinalysis and urine microscopy parameters for predicting urine culture results and to implement a reflex urine culture program.

METHODS

We reviewed the charts of all patients presenting to our clinic January-March 2013 and June-August 2014, excluding those who were catheter-dependent or with urinary diversions. We assessed the association of urinalysis and urine microscopy parameters on urine culture outcomes defining a positive urinalysis as nitrite-positive and/or the presence of ≥5 white blood cells per high-powered field with bacteria and a positive urine culture as ≥10 000 colony-forming units/mL excluding diphtheroids. We carried out logistic regression to assess for predictors of positive urine culture to inform implementation of a reflex urine culture program.

RESULTS

A total of 2764 patients were evaluated. Logistic regression using urinalysis variables identified positive nitrites (odds ratio 18.6, P < 0.001) and large leukocyte esterase (odds ratio 41.8, P < 0.001) as the strongest predictors of positive urine culture. Logistic regression using urine microscopy variables identified >50 white blood cells per high-powered field (odds ratio 13.6, P < 0.001) and moderate/many bacteria (odds ratio 16.8, P < 0.001) as the strongest predictors of positive urine culture. We used our positive urinalysis definition to implement the reflex urine culture program and noted a 60% reduction in urine culture rates over the first 3 months of implementation.

CONCLUSIONS

A urine positive for nitrites and/or ≥50 white blood cells per high powered field with bacteria seems to have a strong association with a positive urine culture and the best negative predictive value. A reflex urine culture program is an effective strategy to decrease the rates of unnecessary urine culture and their associated costs.

Clostridium difficile extraintestinal abscess: a rare complication

Extraintestinal Clostridium difficile is rare. A 74-year-old man with a history of ulcerative colitis presented after a fall. Trauma work-up showed liver cirrhosis. Two days later he developed abdominal pain, distension, diarrhoea and leucocytosis. Stool tested positive for C. difficile CT abdomen showed pancolitis with toxic megacolon. Total abdominal colectomy and ileostomy with a rectal stump was performed. He was discharged, but was readmitted with sepsis. CT abdomen showed a 10.4×7.2 cm fluid collection in the pelvis. C. difficile stool was negative. CT-guided abscess drainage grew C. difficile Barium enema was negative for communication from the rectal stump to the abscess. The patient was treated with metronidazole for 2 weeks. In summary, extraintestinal C. difficile can develop from recent antibiotics use, gastrointestinal surgery and microperforations from toxic megacolon. We recommend abscess drainage, concomitant treatment with metronidazole and or vancomycin, and reimaging of abscess location 2-4 weeks after cessation of antibiotics.

Survey finds improvement in cognitive biases that drive overtreatment of asymptomatic bacteriuria after a successful antimicrobial stewardship intervention

BACKGROUND

Lack of guideline knowledge and cognitive biases are barriers that drive overtreatment of catheter-associated asymptomatic bacteriuria (ASB). We explored whether providers' knowledge and attitudes toward management of ASB differed before and after a multifaceted guidelines implementation intervention, reported elsewhere.

METHODS

We surveyed providers' knowledge of guidelines, cognitive-behavioral constructs, and self-reported familiarity with the relevant Infectious Diseases Society of America guidelines. The survey was administered to providers in the preintervention (n = 169) and postintervention (n = 157) periods at the intervention site and postintervention (n = 65) at the comparison site.

RESULTS

At the intervention site, the mean knowledge score increased significantly during the postintervention period (from 57.5%-69.9%; P < .0001) and fewer providers reported following incorrect cognitive cues (pyuria and organism type) for treatment of ASB. The knowledge of guidelines was higher in the postintervention sample after adjusting for provider type in the multiple linear regression analysis. Cognitive behavioral constructs (ie, self-efficacy, behavior, social norms, and risk perceptions) and self-reported familiarity with the guidelines also significantly improved during the postintervention period.

CONCLUSIONS

We identified and targeted specific barriers that drive overtreatment of ASB. Guideline implementation interventions targeting cognitive biases are essential for encouraging the application of ASB guidelines into practice.

Antimicrobial Stewardship and Environmental Decontamination for the Control of Clostridium difficile Transmission in Healthcare Settings

We implement an agent-based model for Clostridium difficile transmission in hospitals that accounts for several processes and individual factors including environmental and antibiotic heterogeneity in order to evaluate the efficacy of various control measures aimed at reducing environmental contamination and mitigating the effects of antibiotic use on transmission. In particular, we account for local contamination levels that contribute to the probability of colonization and we account for both the number and type of antibiotic treatments given to patients. Simulations illustrate the relative efficacy of several strategies for the reduction of nosocomial colonizations and nosocomial diseases.

Polymer antidotes for toxin sequestration

Toxins delivered by envenomation, secreted by microorganisms, or unintentionally ingested can pose an immediate threat to life. Rapid intervention coupled with the appropriate antidote is required to mitigate the threat. Many antidotes are biological products and their cost, methods of production, potential for eliciting immunogenic responses, the time needed to generate them, and stability issues contribute to their limited availability and effectiveness. These factors exacerbate a world-wide challenge for providing treatment. In this review we evaluate a number of polymer constructs that may serve as alternative antidotes. The range of toxins investigated includes those from sources such as plants, animals and bacteria. The development of polymeric heavy metal sequestrants for use as antidotes to heavy metal poisoning faces similar challenges, thus recent findings in this area have also been included. Two general strategies have emerged for the development of polymeric antidotes. In one, the polymer acts as a scaffold for the presentation of ligands with a known affinity for the toxin. A second strategy is to generate polymers with an intrinsic affinity, and in some cases selectivity, to a range of toxins. Importantly, in vivo efficacy has been demonstrated for each of these strategies, which suggests that these approaches hold promise as an alternative to biological or small molecule based treatments.

Highlighting clinical needs in Clostridium difficile infection: the views of European healthcare professionals at the front line

BACKGROUND

Clostridium difficile infection (CDI) is the leading cause of infectious nosocomial diarrhoea in Europe. Despite increased focus, its incidence and severity are increasing in many European countries.

AIM

We developed a series of consensus statements to identify unmet clinical needs in the recognition and management of CDI.

METHODS

A consortium of European experts prepared a series of 29 statements representing their collective views on the diagnosis and management of CDI in Europe. The statements were grouped into the following six broad themes: diagnosis; definitions of severity; treatment failure, recurrence and its consequences; infection prevention and control interventions; education and antimicrobial stewardship; and National CDI clinical guidance and policy. These statements were reviewed using questionnaires by 1047 clinicians involved in managing CDI, who indicated their level of agreement with each statement.

FINDINGS

Levels of agreement exceeded the 66% threshold for consensus for 27 out of 29 statements (93.1%), indicating strong support. Variance between countries and specialties was analysed and showed strong alignment with the overall consensus scores.

CONCLUSION

Based on the consensus scores of the respondent group, recommendations are suggested for the further development of CDI services in order to reduce transmission and recurrence and to ensure that appropriate diagnosis and treatment strategies are applied across all healthcare settings.

Implementation of Polymerase Chain Reaction to Rule Out Clostridium difficile Infection Is Associated With Reduced Empiric Antibiotic Duration of Therapy

PURPOSE

The polymerase chain reaction (PCR) test has higher sensitivity and a faster turnaround time than the enzyme immunoassay (EIA) for identification of Clostridium difficile, although the clinical implications of these variables are not well described.

METHODS

Inpatients with a negative EIA (n = 79) or PCR (n = 87) test were retrospectively evaluated. Patients were excluded if they had a positive EIA or PCR test during the same hospitalization or if they were currently receiving treatment for C. difficile infection (CDI) prior to admission. The primary outcome was empiric CDI antibiotic duration of therapy associated with each test method.

RESULTS

Empiric CDI antibiotic duration of therapy was 2.31 (95% confidence interval [CI], 1.48-3.15) days for the EIA group and 0.88 (0.45-1.33) days for the PCR group (P = .007). Number of diagnostic laboratory tests performed per patient were 2.73 (2.64-2.83) and 1.16 (1.04-1.28) tests, respectively (P < .001).

CONCLUSION

Use of the PCR test to rule out CDI was associated with reduced duration of empiric CDI antibiotic therapy and fewer diagnostic laboratory tests performed per patient. When combined with fewer diagnostic laboratory tests performed per patient and shorter duration of contact isolation, the higher acquisition cost of the PCR test was offset, resulting in cost neutrality. These findings provide additional data to support the routine use of the PCR test.

Clostridium difficile infection: molecular pathogenesis and novel therapeutics

The Gram-positive anaerobic bacterium Clostridium difficile produces toxins A and B, which can cause a spectrum of diseases from pseudomembranous colitis to C. difficile-associated diarrhea. A limited number of C. difficile strains also produce a binary toxin that exhibits ADP ribosyltransferase activity. Here, the structure and the mechanism of action of these toxins as well as their role in disease are reviewed. Nosocomial C. difficile infection is often contracted in hospital when patients treated with antibiotics suffer a disturbance in normal gut microflora. C. difficile spores can persist on dry, inanimate surface for months. Metronidazole and oral vancomycin are clinically used for treatment of C. difficile infection but clinical failure and concern about promotion of resistance are motivating the search for novel non-antibiotic therapeutics. Methods for controlling both toxins and spores, replacing gut microflora by probiotics or fecal transplant, and killing bacteria in the anaerobic gut by photodynamic therapy are discussed.

The roles of host and pathogen factors and the innate immune response in the pathogenesis of Clostridium difficile infection

Clostridium difficile (C. difficile) is the most common cause of nosocomial antibiotic-associated diarrhea and the etiologic agent of pseudomembranous colitis. The clinical manifestation of C. difficile infection (CDI) is highly variable, from asymptomatic carriage, to mild self-limiting diarrhea, to the more severe pseudomembranous colitis. Furthermore, in extreme cases, colonic inflammation and tissue damage can lead to toxic megacolon, a condition requiring surgical intervention. C. difficile expresses two key virulence factors; the exotoxins, toxin A (TcdA) and toxin B (TcdB), which are glucosyltransferases that target host-cell monomeric GTPases. In addition, some hypervirulent strains produce a third toxin, binary toxin or C. difficile transferase (CDT), which may contribute to the pathogenesis of CDI. More recently, other factors such as surface layer proteins (SLPs) and flagellin have also been linked to the inflammatory responses observed in CDI. Although the adaptive immune response can influence the severity of CDI, the innate immune responses to C. difficile and its toxins play crucial roles in CDI onset, progression, and overall prognosis. Despite this, the innate immune responses in CDI have drawn relatively little attention from clinical researchers. Targeting these responses may prove useful clinically as adjuvant therapies, especially in refractory and/or recurrent CDI. This review will focus on recent advances in our understanding of how C. difficile and its toxins modulate innate immune responses that contribute to CDI pathogenesis.

Clostridium difficile colitis in the United States: a decade of trends, outcomes, risk factors for colectomy, and mortality after colectomy

BACKGROUND

Clostridium difficile colitis (CDC) is a major health concern in the United States (US), with earlier reports demonstrating a rising incidence. Studies analyzing predictors for total colectomy and mortality after colectomy are limited by small numbers.

STUDY DESIGN

The Nationwide Inpatient Sample (NIS) 2001 to 2010 was retrospectively reviewed for CDC trends, the associated colectomy and mortality rates. Patient and hospital variables were used in the LASSO algorithm for logistic regression with 10-fold cross validation to build a predictive model for colectomy requirement and mortality after colectomy. The association of colectomy day with mortality was also examined on multivariable logistic regression analysis.

RESULTS

An estimated 2,773,521 discharges with a diagnosis of CDC were identified in the US over a decade. Colectomy was required in 19,374 cases (0.7%), with an associated mortality of 30.7%. Compared with the 2001 to 2005 period, the 2006 to 2010 period witnessed a 47% increase in the rate of CDC and a 32% increase in the rate of colectomies. The LASSO algorithm identified the following predictors for colectomy: coagulopathy (odds ratio [OR] 2.71), weight loss (OR 2.25), teaching hospitals (OR 1.37), fluid or electrolyte disorders (OR 1.31), and large hospitals (OR 1.18). The predictors of mortality after colectomy were: coagulopathy (OR 2.38), age greater than 60 years (OR 1.97), acute renal failure (OR 1.67), respiratory failure (OR 1.61), sepsis (OR 1.40), peripheral vascular disease (OR 1.39), and congestive heart failure (OR 1.25). Surgery more than 3 days after admission was associated with higher mortality rates (OR 1.09; 95% CI 1.05 to 1.14; p < 0.05).

CONCLUSIONS

Clostridium difficile colitis is increasing in the US, with an associated increase in total colectomies. Mortality rates after colectomy remain elevated. Progression to colectomy and mortality thereafter are associated with several patient and hospital factors. Knowledge of these risk factors may help in risk-stratification and counseling.

Colonoscopic versus nasogastric fecal transplantation for the treatment of Clostridium difficile infection: a review and pooled analysis

BACKGROUND

Fecal microbiota transplantation (FMT) has been demonstrated to be highly effective for the treatment of recurrent Clostridium difficile infection (CDI). However, the best route of administration has not been established. We present a pooled analysis of the reported cases of CDI treated with FMT via colonoscopy or nasogastric tube (NGT) to evaluate treatment efficacy.

METHODS

PubMed was searched for English-written articles published up to December 2011. Studies that reported cases of FMT for recurrent CDI using either colonoscopy or NGT-guided fecal infusion were reviewed.

RESULTS

A total of 182 patients from 12 published studies were identified; 148 patients received FMT via colonoscopy (colonoscopy group) and 34 patients received FMT via NGT (NGT group). The median age in the colonoscopy group as compared with the NGT group was 72 and 82 years, respectively. There were differences regarding pre-FMT treatment for CDI; 134 patients (90.5 %, 134/148) received lavage with/without antibiotic in the colonoscopy group and 34 patients (100.0 %, 34/34) received antibiotic without lavage in the NGT group, P < 0.001. A higher stool volume was used for FMT in the colonoscopy group (121 patients, 81.8 %, used 100-400 ml) than in the NGT group (33 patients, 97.0 %, used <100 ml), P < 0.001. The treatment efficacy did not differ significantly; 93.2 % (138/148) success for the colonoscopy group as compared to 85.3 % success (29/34) for the NGT group, P = 0.162. Recurrence of CDI after FMT was also similar in both the colonoscopy group (8/148 5.4 %) versus the NGT group (2/34, 5.9 %), P = 1.000.

CONCLUSIONS

Despite procedural differences, FMT via colonoscopy or NGT appears to be highly effective and safe for the management of recurrent CDI.

Current strategies for management of initial Clostridium difficile infection

In the past decade, an epidemic strain of Clostridium difficile has led to increased incidence and severity of nosocomial C. difficile infections (CDI). Responsiveness to standard antimicrobial care for this strain is declining, and the morbidity and mortality of CDI and recurrent CDI are rising. Effective management requires a coordinated effort among all members of the healthcare team to facilitate early identification of patients at risk for CDI, early recognition of disease onset and confirmatory testing, prompt initiation of the most appropriate management approach, and ongoing monitoring throughout the continuum of care. Hospitalists, as coordinators of patient care, are in an ideal position to ensure that patients receive prompt and optimal treatment based on current clinical evidence and severity of the disease.

Fulminant Clostridium difficile toxic megacolon in a pediatric heart transplant recipient

CD can be a cause of diarrhea in pediatric heart transplant recipients. Fulminant colitis can develop in immunocompromised patients with CD and progress to toxic megacolon. We report a case of a 10-yr-old girl who developed CD diarrhea and subsequently fulminant colitis with clinical signs and symptoms of abdominal compartment syndrome. She was taken to the operating room emergently and found to have toxic megacolon. She underwent a sub-total abdominal colectomy and end-ileostomy, and made a rapid recovery. Rapid recognition of the severity of the disease in the post-operative transplant patient is imperative as abdominal compartment syndrome may develop requiring surgical management. In pediatric heart transplant patients with diarrhea, we recommend a heightened clinical awareness with aggressive treatment given the risk of progression to fulminant CD and toxic megacolon.

Rifaximin Is Effective for the Treatment of Clostridium difficile-Associated Diarrhea: Results of an Open-Label Pilot Study

Objectives. This open-label trial assessed the efficacy and safety of rifaximin as first-line therapy in hospitalized patients with Clostridium difficile-associated diarrhea (CDAD). Methods. We enrolled thirteen patients who had a confirmed diagnosis of CDAD characterized by ≥3 unformed stools/day and positive C. difficile toxin assay. Those patients received rifaximin 400 mg three times daily for 10 days. Resolution of symptoms, repeat assay 10 days after treatment, and followup for recurrence were assessed. Results. Eight patients completed the study, and all reported symptom resolution during treatment. Mean time to last unformed stool was 132 h ± 42.5 h. Seven patients had no relapse by week 2 and in longer followup (median 162 days). One patient had recurrent CDAD during a repeat hospitalization. Conclusions. Rifaximin was effective and safe as first-line treatment for CDAD and did not result in recurrence in most patients.

CSI: a severity index for Clostridium difficile infection at the time of admission

Clostridium difficile is a common cause of nosocomial diarrhoea in the USA. To develop a score model that would help to identify severe versus mild or moderate C. difficile infection (CDI) upon admission we performed a retrospective cohort study. Between January 2004 and December 2007, 255 patients met inclusion criteria for this study. Severe CDI was defined as cases that required colectomy, intensive care unit management, ended in death, or hospitalisation of >10 days. Data recorded included past medical history, physical examination on admission, laboratory data and imaging/colonoscopy data. To create the CDI severity index (CSI) score, we included four risk factors for severe CDI that were identified by univariate analysis: history of malignancy, white blood cell count at admission >20,000/dL, blood albumin <3.0mg/dL, and creatinine at admission >1.5-fold the baseline value. One point was assigned to each of the risk factors. As indicated by a c-statistic of 0.78, the CSI score predicted severe CDI much better than chance (c-statistics of 0.50). The risk of developing severe CDI increased by a factor of 2.9 (95% CI: 1.82-4.59) for each 1-point increase in the CSI score. A CSI score with a cut-off value of 2 had a sensitivity and specificity of 82% and 65%, respectively. The CSI score may quantify the risk of severe CDI at the time of admission, and help in early identification of patients who may benefit from more aggressive treatment.

Super toxins from a super bug: structure and function of Clostridium difficile toxins

Clostridium difficile, a highly infectious bacterium, is the leading cause of antibiotic-associated pseudomembranous colitis. In 2009, the number of death certificates mentioning C. difficile infection in the U.K. was estimated at 3933 with 44% of certificates recording infection as the underlying cause of death. A number of virulence factors facilitate its pathogenicity, among which are two potent exotoxins; Toxins A and B. Both are large monoglucosyltransferases that catalyse the glucosylation, and hence inactivation, of Rho-GTPases (small regulatory proteins of the eukaryote actin cell cytoskeleton), leading to disorganization of the cytoskeleton and cell death. The roles of Toxins A and B in the context of C. difficile infection is unknown. In addition to these exotoxins, some strains of C. difficile produce an unrelated ADP-ribosylating binary toxin. This toxin consists of two independently produced components: an enzymatic component (CDTa) and the other, the transport component (CDTb) which facilitates translocation of CDTa into target cells. CDTa irreversibly ADP-ribosylates G-actin in target cells, which disrupts the F-actin:G-actin equilibrium leading to cell rounding and cell death. In the present review we provide a summary of the current structural understanding of these toxins and discuss how it may be used to identify potential targets for specific drug design.

A Retrospective Analysis of Risk Factors and Therapeutic Outcomes for Clostridium difficile Infection

Purpose

To determine the Clostridium difficile infection (CDI) recurrence rate at the Veterans Affairs Medical Center (VAMC) in Fargo, North Dakota, and to determine whether certain variables (eg, type of antibiotic, medication, chronic disease state, CDI symptom control) were predictive of CDI recurrence.

Methods

Demographic information and laboratory data from 174 adult outpatients and inpatients were collected from electronic medical records between January 1997 and September 2009. In addition, information about the duration of non-CDI antibiotic therapy and the use of proton pump inhibitors, histamine H2 blockers, corticosteroids, and immunosuppressive medications within 60 days of CDI was collected. Information regarding comorbid conditions (eg, cancer, liver or renal disease, diabetes, chronic heart failure) in patients at the time of CDI was also collected.

Results

Patients below the median age of 69.5 years were more likely to continue to have diarrhea after CDI treatment than patients who were older than the median age (relative risk 1.86; 95% CI, 1.06-3.26). No association was observed between previous non-CDI treatment antibiotic use, other medication use, or comorbid conditions and the recurrence of CDI.

Conclusion

CDI recurrence rate at VAMC was 14%. No statistically significant association could be made between recurrence of CDI and antibiotic or medication used within 60 days of infection or with chronic disease states at the time of CDI infection. Patients younger than 69.5 years were more likely to continue to have diarrhea after CDI treatment.

Two case reports of Clostridium difficile bacteremia, one with the epidemic NAP-1 strain

Clostridium difficile bacteremia is rare. Here, we report two cases of C. difficile bacteremia in patients with significant underlying gastrointestinal pathology. In one case, the bacteremia was caused by the North American pulsed-field gel electrophoresis (PFGE) type 1 (NAP-1) strain, which is responsible for recent outbreaks of C. difficile infections of increased severity.

Pseudo-outbreak of Clostridium difficile associated diarrhea (CDAD) in a tertiary-care hospital

The objective of this study was to describe a pseudo-outbreak of C. difficile in a hospital, following a change in the method used to detect the toxin. In February 2002, there were two cases of CDAD and in March 7 occurred, coinciding with a change of the test (from detection of toxin A to toxin A/B). An outbreak was suspected. Active surveillance and education of staff were started. A CDAD case was defined as a patient with acute onset of diarrhea (> or = three episodes of liquid stools) and a positive stool test. They were classified as hospital or community-acquired. Stool samples were also collected for C. difficile culture and isolates were typed using AP-PCR. From March 2002 through December 2003 there were 138 cases of CDAD: 70% were hospital-acquired and among the 30% with CDAD present on admission, most (81%) came directly from the community (50% had no history of hospitalization). Fifty-two percent of hospital-acquired CDAD and 94% of cases on admission had already used antibiotics. The incidence of CDAD in hospitalized patients during surveillance was 3.3 per 1000 patient-admissions. The incidence of CDAD present on admission was 6.1/1000 patients. Sixteen isolates were typed and presented 13 different profiles. In conclusion, the CDAD increase in our study occurred due to change in diagnostic methods and not due to an outbreak, as suspected initially. The incidence in hospitalized patients was much lower than in reported outbreaks. There were 13 molecular types suggesting that an outbreak did not occur. CDAD was largely community-acquired.

The enterotoxicity of Clostridium difficile toxins

The major virulence factors of Clostridium difficile infection (CDI) are two large exotoxins A (TcdA) and B (TcdB). However, our understanding of the specific roles of these toxins in CDI is still evolving. It is now accepted that both toxins are enterotoxic and proinflammatory in the human intestine. Both purified TcdA and TcdB are capable of inducing the pathophysiology of CDI, although most studies have focused on TcdA. C. difficile toxins exert a wide array of biological activities by acting directly on intestinal epithelial cells. Alternatively, the toxins may target immune cells and neurons once the intestinal epithelial barrier is disrupted. The toxins may also act indirectly by stimulating cells to produce chemokines, proinflammatory cytokines, neuropeptides and other neuroimmune signals. This review considers the mechanisms of TcdA- and TcdB-induced enterotoxicity, and recent developments in this field.

Review of medical and surgical management of Clostridium difficile infection

Clostridium difficile infection (CDI) has become an important area in our daily clinical practice. C. difficile is known to cause a broad spectrum of conditions ranging from asymptomatic carriage, through mild or moderately severe disease with watery diarrhoea, to the life-threatening pseudomembranous colitis (PMC), with toxic megacolon and ileus. Peoples who have been treated with broad-spectrum antibiotics, patients with serious underlying co-morbidities and the elderly are at greatest risk. Over 80% of CDIs reported are in people aged over 65. Due to the alarming increase in its frequency, appearance of more virulent strains and occasional need for life-saving surgical intervention, a more coherent multidisciplinary approach is needed. Combination of rapid turn round time and accurate diagnosis will result in a better management of CDI and a timely implementation of infection control measure. Discontinuation of causative agents such as antibiotic treatment is often curative. In more serious cases, oral administration of metronidazole or vancomycin is the treatment of choice. Relapses of CDI have been reported in about 20-25% of cases, this may increase to 45-60% after the first recurrence. Patients should be treated as soon as possible when the diagnosis of Clostridium difficile colitis is made to avoid sepsis or bowel perforation. Colectomy may improve the outcome of the patient with systemic or complicated Clostridium difficile colitis. This article reviews the changing epidemiological picture, microbiology, histopathology and both medical and surgical managements.

Fecal bacteriotherapy for recurrent Clostridium difficile infection

Clostridium difficile infection (CDI) has emerged as a major complication associated with the use of systemic antimicrobial agents. Broad-spectrum antimicrobial agents disrupt the ecological bacterial balance in the colon and create an opportunity for C. difficile overgrowth with attendant production of toxins and clinical symptoms of colitis. Recommended therapies for CDI include oral administration of metronidazole or vancomycin for 10-14 days. However, 5% to 35% of patients experience infection relapse after completion of treatment. Recently, patients who failed to resolve their infection with conventional therapies and went on to develop chronic relapsing CDI were successfully treated with fecal bacteriotherapy. Stool obtained from a healthy individual was instilled from either end of the GI tract. Although the published experience with fecal bacteriotherapy is still limited, the published treatment results for 100 patients have demonstrated an average success-rate close to 90%. Fecal bacteriotherapy is a low tech procedure which is easy to perform, and breaks the cycles of repeated antibiotic use, which in turn reduces the risk of antibiotic associated resistance and adds potential cost savings when compared to repeated antibiotic administration and hospitalizations.

Nitazoxanide and probiotics for the treatment of recurrent Clostridium difficile infection in a peritoneal dialysis patient

Nitazoxanide has been proven to be efficacious for the treatment of Clostridium difficile infection (CDI), but data is limited in peritoneal dialysis (PD) patients. This report details the successful utilization of nitazoxanide and probiotics to treat multirecurrent CDI in a PD patient. A 58-year-old woman was admitted with hypotension, nausea and vomiting attributed to metronidazole therapy for CDI, her third CDI treatment regimen in 3 months. During her admission, the patient developed CDI and was started on a 6-week regimen of nitazoxanide and probiotics to assist in re-establishing the colonic flora. The regimen was well tolerated and the patient remained disease free at follow up, four months later.

Quasiexperimental study of the effects of antibiotic use, gastric acid-suppressive agents, and infection control practices on the incidence of Clostridium difficile-associated diarrhea in hospitalized patients

The objective of this study was to evaluate the effects of antimicrobial drug use, gastric acid-suppressive agent use, and infection control practices on the incidence of Clostridium difficile-associated diarrhea (CDAD) in a 426-bed general teaching hospital in Northern Ireland. The study was retrospective and ecological in design. A multivariate autoregressive integrated moving average (time-series analysis) model was built to relate CDAD incidence with antibiotic use, gastric acid-suppressive agent use, and infection control practices within the hospital over a 5-year period (February 2002 to March 2007). The findings of this study showed that temporal variation in CDAD incidence followed temporal variations in expanded-spectrum cephalosporin use (average delay = 2 months; variation of CDAD incidence = 0.01/100 bed-days), broad-spectrum cephalosporin use (average delay = 2 months; variation of CDAD incidence = 0.02/100 bed-days), fluoroquinolone use (average delay = 3 months; variation of CDAD incidence = 0.004/100 bed-days), amoxicillin-clavulanic acid use (average delay = 1 month; variation of CDAD incidence = 0.002/100 bed-days), and macrolide use (average delay = 5 months; variation of CDAD incidence = 0.002/100 bed-days). Temporal relationships were also observed between CDAD incidence and use of histamine-2 receptor antagonists (H2RAs; average delay = 1 month; variation of CDAD incidence = 0.001/100 bed-days). The model explained 78% of the variance in the monthly incidence of CDAD. The findings of this study highlight a temporal relationship between certain classes of antibiotics, H2RAs, and CDAD incidence. The results of this research can help hospitals to set priorities for restricting the use of specific antibiotic classes, based on the size-effect of each class and the delay necessary to observe an effect.

Good effect of IgY against Pseudomonas aeruginosa infections in cystic fibrosis patients

This is an extended open study of oral prophylactic treatment with egg yolk antibodies against Pseudomonas aeruginosa, Anti-Pseudomonas IgY, of 17 Swedish patients with cystic fibrosis. They have been on prophylactic IgY treatment for up to 12 years and altogether for 114 patient years. A group of 23 Danish CF patients served as control. There has been a total absence of adverse events. Only 29 cultures have been positive for P. aeruginosa (cultures after chronic colonization not included), that is, 2.3/100 treatment months compared to 7.0/100 months in the control group (P = 0.028). In the IgY treated group only one pair of siblings (2/17) has been chronically colonized with P. aeruginosa compared to seven patients (7/23) in the control group. Atypical mycobacteria, S. maltophilia, A. xylosoxidans, and A. fumigatus have appeared only sporadically. There have been no cultures positive for B. cepacia. There was no decrease in pulmonary functions (P = 0.730) within the IgY group. Body mass index values were normal or close to normal for all IgY treated patients. In conclusion, Anti-Pseudomonas IgY has great potential to prevent P. aeruginosa infections.

Update on the changing epidemiology of Clostridium difficile-associated disease

In the past, Clostridium difficile-associated disease (CDAD) was thought of mainly as a nosocomial disease associated with the use of broad-spectrum antibiotics, but its epidemiology seems to be changing. Since 2002, outbreaks of severe CDAD associated with increased mortality and reduced effectiveness of treatment with metronidazole have focused attention on this challenging pathogen. A fluoroquinolone-resistant strain of C. difficile (BI/NAP1/027) has been predominantly associated with these outbreaks. Changes in the epidemiology of CDAD include the emergence of new at-risk populations and the increased incidence of the disease. Infection control programs and more effective treatments offer hope that future outbreaks of CDAD can be controlled.