Epidemiology of recurrences or reinfections of Clostridium difficile-associated diarrhea

Cost-effectiveness analysis of fidaxomicin versus vancomycin in Clostridium difficile infection

Objectives

Fidaxomicin was non-inferior to vancomycin with respect to clinical cure rates in the treatment of Clostridium difficile infections (CDIs) in two Phase III trials, but was associated with significantly fewer recurrences than vancomycin. This economic analysis investigated the cost-effectiveness of fidaxomicin compared with vancomycin in patients with severe CDI and in patients with their first CDI recurrence.

Methods

A 1 year time horizon Markov model with seven health states was developed from the perspective of Scottish public healthcare providers. Model inputs for effectiveness, resource use, direct costs and utilities were obtained from published sources and a Scottish expert panel. The main model outcome was the incremental cost-effectiveness ratio (ICER), expressed as cost per quality-adjusted life year (QALY), for fidaxomicin versus vancomycin; ICERs were interpreted using willingness-to-pay thresholds of £20 000/QALY and £30 000/QALY. One-way and probabilistic sensitivity analyses were performed.

Results

Total costs were similar with fidaxomicin and vancomycin in patients with severe CDI (£14 515 and £14 344, respectively) and in patients with a first recurrence (£16 535 and £16 926, respectively). Improvements in clinical outcomes with fidaxomicin resulted in small QALY gains versus vancomycin (severe CDI, +0.010; patients with first recurrence, +0.019). Fidaxomicin was cost-effective in severe CDI (ICER £16 529/QALY) and dominant (i.e. more effective and less costly) in patients with a first recurrence. The probability that fidaxomicin was cost-effective at a willingness-to-pay threshold of £30 000/QALY was 60% for severe CDI and 68% in a first recurrence.

Conclusions

Fidaxomicin is cost-effective in patients with severe CDI and in patients with a first CDI recurrence versus vancomycin.

Clostridium difficile Infection: Clinical Challenges and Management Strategies

Clostridium difficile has become the leading cause of nosocomial diarrhea in adults. A substantial increase has occurred in morbidity and mortality associated with disease caused by C difficile and in the identification of new hypervirulent strains, warranting a high clinical index of suspicion for infections due to this organism. Prevention of infection requires a multidisciplinary approach, including early recognition of disease, effective contact isolation precautions, adherence to disinfectant policies, and judicious use of antibiotics. Current treatment approaches are based on the severity of illness. As hypervirulent strains evolve, unsuccessful treatments are more common. Complicated colitis caused by C difficile may benefit from surgical intervention. Subtotal colectomy and end ileostomy have been the procedures of choice, but are associated with a high mortality rate because of late surgical consultation and use of surgery as a salvage therapy. A promising surgical alternative is creation of a diverting loop ileostomy with colonic lavage.

Clinical characteristics of relapses and re-infections in Clostridium difficile infection

The purpose of this study was to identify factors associated with relapses or re-infections in patients with recurring Clostridium difficile infections (CDIs). From September 2008 to January 2012, cases with two or more isolates from consecutive CDI episodes were included. PCR-ribotyping and multilocus variable-number tandem-repeat analysis were performed using paired isolates. Among 473 patients, 68 (14.4%) experienced one to five recurrences. Fifty-one of these with two or more isolates from consecutive CDI episodes were included in the study; 25 (49%) were classified as relapses and 26 (51%) as re-infections. Recurrence interval was shorter in the relapse group (26.0 versus 67.5 p 0.001), but more patients in the re-infection group were hospitalized during recurrence interval (53.8% versus 8.0%, p<0.001). Relapse rates in infections by ribotype 017, ribotype 018 and other ribotypes were 63.6%, 63.6% and 22.2%, respectively (p 0.274, p 0.069, and p 0.005). In multivariate logistic regression, infections by ribotypes 017 and 018 were associated with CDI relapse (OR 4.77, 95% CI 1.02-22.31, p 0.047; OR 11.49, 95% CI 2.07-63.72, p 0.005). Conversely, admission during recurrence interval lowered the risk of relapse (OR 0.044, 95% CI 0.006-0.344, p 0.003). In conclusion, relapse was more likely when infection was caused by PCR ribotypes 017 and 018.

[Fecal microbiota transplantation: review]

Fecal microbiota transplantation (FMT) has gained an increasing medical interest, since the recognition of the role of disturbed microbiota in the development of various diseases. To date, FMT is an established treatment modality for multiple recurrent Clostridium difficile infection (RCDI), despite lack of standardization of the procedure. Persisting normalization of the disturbed colonic microbiota associated with RCDI seems to be responsible for the therapeutic effect of FMT. For other diseases, FMT should be considered strictly experimental, only offered to patients in an investigational clinical setting. Although the concept of FMT is appealing, current expectations should be damped until future evidence arises.

Clinical and economic consequences of vancomycin and fidaxomicin for the treatment of Clostridium difficile infection in Canada

BACKGROUND

Clostridium difficile infection (CDI) represents a public health problem with increasing incidence and severity.

OBJECTIVE

To evaluate the clinical and economic consequences of vancomycin compared with fidaxomicin in the treatment of CDI from the Canadian health care system perspective.

METHODS

A decision-tree model was developed to compare vancomycin and fidaxomicin for the treatment of severe CDI. The model assumed identical initial cure rates and included first recurrent episodes of CDI (base case). Treatment of patients presenting with recurrent CDI was examined as an alternative analysis. Costs included were for study medication, physician services and hospitalization. Cost effectiveness was measured as incremental cost per recurrence avoided. Sensitivity analyses of key input parameters were performed.

RESULTS

In a cohort of 1000 patients with an initial episode of severe CDI, treatment with fidaxomicin led to 137 fewer recurrences at an incremental cost of $1.81 million, resulting in an incremental cost of $13,202 per recurrence avoided. Among 1000 patients with recurrent CDI, 113 second recurrences were avoided at an incremental cost of $18,190 per second recurrence avoided. Incremental costs per recurrence avoided increased with increasing proportion of cases caused by the NAP1/B1/027 strain. Results were sensitive to variations in recurrence rates and treatment duration but were robust to variations in other parameters.

CONCLUSIONS

The use of fidaxomicin is associated with a cost increase for the Canadian health care system. Clinical benefits of fidaxomicin compared with vancomycin depend on the proportion of cases caused by the NAP1/B1/027 strain in patients with severe CDI.

Variations in virulence and molecular biology among emerging strains of Clostridium difficile

Clostridium difficile is a Gram-positive, spore-forming organism which infects and colonizes the large intestine, produces potent toxins, triggers inflammation, and causes significant systemic complications. Treating C. difficile infection (CDI) has always been difficult, because the disease is both caused and resolved by antibiotic treatment. For three and a half decades, C. difficile has presented a treatment challenge to clinicians, and the situation took a turn for the worse about 10 years ago. An increase in epidemic outbreaks related to CDI was first noticed around 2003, and these outbreaks correlated with a sudden increase in the mortality rate of this illness. Further studies discovered that these changes in CDI epidemiology were associated with the rapid emergence of hypervirulent strains of C. difficile, now collectively referred to as NAP1/BI/027 strains. The discovery of new epidemic strains of C. difficile has provided a unique opportunity for retrospective and prospective studies that have sought to understand how these strains have essentially replaced more historical strains as a major cause of CDI. Moreover, detailed studies on the pathogenesis of NAP1/BI/027 strains are leading to new hypotheses on how this emerging strain causes severe disease and is more commonly associated with epidemics. In this review, we provide an overview of CDI, discuss critical mechanisms of C. difficile virulence, and explain how differences in virulence-associated factors between historical and newly emerging strains might explain the hypervirulence exhibited by this pathogen during the past decade.

Fidaxomicin: a minimally absorbed macrocyclic antibiotic for the treatment of Clostridium difficile infections

Fidaxomicin was approved for the treatment of Clostridium difficile infections in 2011. It has a novel mechanism of action and narrow spectrum of activity that makes it unique among the currently used therapies for this disease. Phase III clinical studies demonstrated a benefit of fidaxomicin over vancomycin for the outcomes of recurrence and global cure or sustained clinical response. This observation was confirmed within specific populations, including those of older age, immunocompromised due to active cancers, and patients taking concomitant antibiotics. Additionally, fidaxomicin significantly reduced recurrence rates compared to vancomycin among patients receiving treatment for recurrent C. difficile episodes. Fidaxomicin represents an advance in therapy for the treatment of C. difficile infections.

Efficacy of surotomycin in an in vitro gut model of Clostridium difficile infection

OBJECTIVES

We investigated the efficacy of the cyclic lipopeptide surotomycin in treating clindamycin-induced Clostridium difficile infection (CDI) using an in vitro gut model.

METHODS

Two three-stage chemostat gut models were inoculated with human faeces, spiked with C. difficile spores (∼10(7) cfu/mL, PCR ribotype 027 or 001). Clindamycin (33.9 mg/L, four times daily for 7 days) was dosed to induce CDI. Following high-level toxin production, surotomycin (250 mg/L, twice daily for 7 days) was instilled. Microflora populations, C. difficile vegetative cells and spores, cytotoxin titres and antimicrobial levels (LC-MS/MS and bioassay) were determined. The emergence of C. difficile and enterococci with reduced susceptibility to surotomycin was monitored on breakpoint agar (4 × MIC).

RESULTS

Counts of viable C. difficile were reduced to near the limit of detection on Days 1 and 3 of surotomycin instillation, and cytotoxin was undetectable on Days 3 and 4 of surotomycin instillation in the 027 and 001 models, respectively. Recurrence of vegetative growth and toxin production occurred 11 days (001 model) and 15 days (027 model) after surotomycin instillation had ceased, and remained for the duration of the experiment. Surotomycin instillation decreased populations of bifidobacteria, clostridia, enterococci and lactobacilli, but was sparing of Bacteroides fragilis group populations. All enumerated organisms had recovered to steady-state levels by 3 weeks post-surotomycin instillation. No evidence of the emergence of reduced susceptibility to surotomycin was observed.

CONCLUSIONS

Surotomycin successfully reduced C. difficile vegetative cell counts and toxin levels in the gut model and was sparing of B. fragilis group populations. There was no evidence of decreased susceptibility to surotomycin during exposure or post-exposure.

Comparison of planktonic and biofilm-associated communities of Clostridium difficile and indigenous gut microbiota in a triple-stage chemostat gut model

BACKGROUND

Biofilms are characteristic of some chronic or recurrent infections and this mode of growth tends to reduce treatment efficacy. Clostridium difficile infection (CDI) is associated with a high rate of recurrent symptomatic disease. The presence and behaviour of C. difficile within intestinal biofilms remains largely unexplored, but may factor in recurrent infection.

METHODS

A triple-stage chemostat gut model designed to facilitate the formation of intestinal biofilm was inoculated with a pooled human faecal emulsion. Bacterial populations were allowed to equilibrate before simulated CDI was induced by clindamycin (33.9 mg/L, four times daily, 7 days) and subsequently treated with vancomycin (125 mg/L, four times daily, 7 days). Indigenous gut microbiota, C. difficile total viable counts, spores, cytotoxin and antimicrobial activity in planktonic and biofilm communities were monitored during the 10 week experimental period.

RESULTS

Vancomycin successfully treated the initial episode of simulated CDI, but ∼18 days after therapy cessation, recurrent infection occurred. Germination, proliferation and toxin production were evident within planktonic communities in both initial and recurrent CDI. In contrast, sessile C. difficile remained in dormant spore form for the duration of the experiment. The effects of and recovery from clindamycin and vancomycin exposure for sessile populations was delayed compared with responses for planktonic bacteria.

CONCLUSIONS

Intestinal biofilms provide a potential reservoir for C. difficile spore persistence, possibly facilitating their dispersal into the gut lumen after therapeutic intervention, leading to recurrent infection. Therapeutic options for CDI could have increased efficacy if they are more effective against sessile C. difficile.

Development and validation of a chemostat gut model to study both planktonic and biofilm modes of growth of Clostridium difficile and human microbiota

The human gastrointestinal tract harbours a complex microbial community which exist in planktonic and sessile form. The degree to which composition and function of faecal and mucosal microbiota differ remains unclear. We describe the development and characterisation of an in vitro human gut model, which can be used to facilitate the formation and longitudinal analysis of mature mixed species biofilms. This enables the investigation of the role of biofilms in Clostridium difficile infection (CDI). A well established and validated human gut model of simulated CDI was adapted to incorporate glass rods that create a solid-gaseous-liquid interface for biofilm formation. The continuous chemostat model was inoculated with a pooled human faecal emulsion and controlled to mimic colonic conditions in vivo. Planktonic and sessile bacterial populations were enumerated for up to 46 days. Biofilm consistently formed macroscopic structures on all glass rods over extended periods of time, providing a framework to sample and analyse biofilm structures independently. Whilst variation in biofilm biomass is evident between rods, populations of sessile bacterial groups (log10 cfu/g of biofilm) remain relatively consistent between rods at each sampling point. All bacterial groups enumerated within the planktonic communities were also present within biofilm structures. The planktonic mode of growth of C. difficile and gut microbiota closely reflected observations within the original gut model. However, distinct differences were observed in the behaviour of sessile and planktonic C. difficile populations, with C. difficile spores preferentially persisting within biofilm structures. The redesigned biofilm chemostat model has been validated for reproducible and consistent formation of mixed species intestinal biofilms. This model can be utilised for the analysis of sessile mixed species communities longitudinally, potentially providing information of the role of biofilms in CDI.

Clostridium difficile infection in hospitalized patients at university clinical center tuzla, bosnia and herzegovina: a 4 year experience

Introduction:

Clostridium difficile (C. difficile) is currently the leading cause of healthcare-associated diarrhea, but almost nothing is known about the extent of C. difficile infection (CDI) in Bosnia and Herzegovina.

Goal:

We aimed to retrospectively analyze CDI in hospitalized patients at University Clinical Center (UCC) Tuzla, Bosnia and Herzegovina from January 2009 through June 2012.

Methods:

We analyzed all patients (except children ages 0-2), diagnosed with CDI based on anamnestic and epidemiological, clinical picture and microbiological tests (proof of toxins in the stool by enzyme-linked immunosorbent assay).

Results:

From a total of 989 patients tested for C. difficile toxin (60.2 per 10,000 inpatient days) 347 (35.08%) were positives. The mean incidence rate of CDI was 2.23 per 10,000 inpatient days (range 1.32-2.87). Annual rates of hospitalization were 15.68 per 10,000 admissions (range 8.99-20.35). Most patients had a previously identified risk profile of old age, comorbidity and recent use of antibiotics. 41/276 (14.86%) patients had died, and 11/41 (26.82%) were CDI-associated deaths. Complicated CDI were registered in 53/276 (19.21%) patients, and recurrent infections in 65/276 (23.55%).

Conclusion:

Our data suggest that CDI is largely present in our setting which represents a serious problem and points to the importance of international surveillance, detection and control of CDI.

Oral vancomycin desensitisation to treat Clostridium difficile infection in a vancomycin allergic patient

The prevalence of Clostridium difficile infection (CDI) is increasing worldwide. Oral vancomycin is an effective and frequently used treatment. However, patients with CDI who are allergic to intravenous vancomycin cannot receive oral vancomycin due to the risk of anaphylaxis if given the oral form.

We present a case where oral vancomycin desensitisation was used to successfully treat a vancomycin allergic patient with recurrent CDI.

The effects of statins on the clinical outcomes of Clostridium difficile infection in hospitalised patients

BACKGROUND

An association between exposure to statin drugs and favourable treatment outcomes for various types of infections has been established.

AIM

To determine the clinical characteristics and treatment outcomes of Clostridium difficile infection (CDI) among hospitalised patients taking statin drugs.

METHODS

The medical records were reviewed for consecutive in-patients with CDI confirmed by positive toxin assay (A or B), C. difficile culture, or the presence of pseudomembrane on endoscopy. Treatment success was defined as the resolution of diarrhoea within 6 days of therapy. The primary end points were assessed by average symptom recovery time and treatment response (success or failure).

RESULTS

Among 949 patients, the overall response to metronidazole was 91.9%. The baseline characteristics showed some differences between statin users and statin non-users with respect to mean disease severity score. In the multivariate analysis, successful treatment response was significantly associated with the absence of exposure to proton pump inhibitors (PPIs) (OR = 0.690, 95% CI = 0.513-0.929, P = 0.014) and with exposure to statins (OR = 1.449, 95% CI = 1.015-2.070, P = 0.041). Contrary to the treatment response, univariate and multivariate analyses failed to show that exposure to PPIs or statins affected symptom recovery times. Sixty-day CDI recurrence rates for those patients with statin exposure were significantly lower compared with those patients without statin exposure (3% vs. 7.3%, respectively; RR = 0.393, 95% CI = 0.167-0.926, P = 0.033).

CONCLUSION

Prior statin exposure in patients with C. difficile infection is associated with a successful response to treatment.

Clostridium difficile infections in South East Scotland: mortality and recurrence in a region without PCR ribotype 027

Three hundred and thirty-five patients with laboratory-confirmed Clostridium difficile infections (CDIs) were studied for epidemiological features, clinical presentation and laboratory markers. They were followed up for 1 year to determine recurrence and mortality. Four hundred and thirty-two episodes were recorded. One year mortality was 41.8 % of which CDI was listed on 20 % of the death certificates. One year recurrence rate was 22.9 %. PCR ribotype 001 was the commonest epidemiological type and ribotype 027 was not detected. High total leucocyte count and low albumin were significantly associated with mortality, as was the absence of a GI-invasive procedure in the 12 weeks preceding CDI diagnosis, probably due to patients being unfit for the procedure. No association with acid suppressants, deletion in the tdcC anti-sigma factor or vancomycin-resistant enterococcus/methicillin-resistant Staphylococcus aureus co-infection was detected. One year mortality was higher in patients who developed recurrent infections (P<0.001). Differences in ribotype were observed in 2.3 %, 11.11 %, 20 % and 32.4 % isolates with time intervals between sampling of 0–20, 21–40, 41–60 and >60 days, respectively, suggesting that the arbitrary cut-off of 28 days to call a repeat infection a reinfection may not be correct in some cases.

Overview of severe Clostridium difficile infection

Clostridium difficile is an anaerobic, spore-forming, gram-positive bacillus that can produce severe colitis resulting in death. There has been an overall increase in the incidence of Clostridium difficile-associated disease and, particularly, an increase in the more virulent forms of the disease. Treatment of severe C difficile infection includes management of severe sepsis and shock, pathogen-directed antibiotic therapy, and, in selected cases, surgical intervention. Ultimately, prevention is the key to limiting the devastating effects of this microorganism.

Influence of cohorting patients with Clostridium difficile infection on risk of symptomatic recurrence

BACKGROUND

Cohorting of patients with Clostridium difficile infection (CDI) is recommended when single side-rooms are unavailable. Although patients may remain infectious after cessation of diarrhoea, continued cohorting may place them at increased risk of reinfection.

AIM

To identify risk factors for CDI recurrence and to determine whether cohorting of patients is associated with increased risk of recurrence.

METHODS

Data describing patient demographics, comorbidity, CDI severity and treatment were collected for 248 CDI patients at our hospital between October 2008 and June 2011. The primary outcome was symptomatic recurrence within 30 days of diagnosis.

FINDINGS

One hundred and thirty-eight (55.6%) CDI patients were admitted to the cohort ward. These patients were more likely to have severe CDI (odds ratio: 1.95; 95% confidence interval: 1.10-3.46; P = 0.022) and receive vancomycin (1.59; 0.94-2.68; P = 0.083) than patients who were not cohorted. Twenty-six patients (10.5%) suffered recurrence (21 cohorted and five not cohorted). Urinary infection on admission (5.16; 2.10-12.64; P < 0.001), cohorting (3.77; 1.37-10.35; P = 0.01) and concomitant antibiotics (2.07; 0.91-4.72; P = 0.083) were associated with increased risk of recurrence. On multivariate analysis, cohorting (3.94; 1.23-12.65; P = 0.021) and urinary infection (4.27; 1.62-11.24; P = 0.003) were significant predictors of recurrence.

CONCLUSION

Patients admitted to a C. difficile cohort ward may be at increased risk of recurrence because they are at increased risk of reinfection. Hospitals using cohort wards to control C. difficile should manage patient flow through the cohort to minimize this risk.

Clostridium difficile infection in children: a comprehensive review

OBJECTIVE

To provide a comprehensive review of the literature relating to Clostridium difficile (C. difficile) infection (CDI) in the pediatric population.

METHODS

Two investigators conducted independent searches of PubMed, Web of Science, and Scopus until March 31st, 2013. All databases were searched using the terms 'Clostridium difficile infection', 'Clostridium difficile associated diarrhea' 'antibiotic associated diarrhea', 'C. difficile', in combination with 'pediatric' and 'paediatric'. Articles which discussed pediatric CDI were reviewed and relevant cross references also read and evaluated for inclusion. Selection bias could be a possible limitation of this approach.

FINDINGS

There is strong evidence for an increased incidence of pediatric CDI. Increasingly, the infection is being acquired from the community, often without a preceding history of antibiotic use. The severity of the disease has remained unchanged. Several medical conditions may be associated with the development of pediatric CDI. Infection prevention and control with antimicrobial stewardship are of paramount importance. It is important to consider the age of the child while testing for CDI. Traditional therapy with metronidazole or vancomycin remains the mainstay of treatment. Newer antibiotics such as fidaxomicin appear promising especially for the treatment of recurrent infection. Conservative surgical options may be a life-saving measure in severe or fulminant cases.

CONCLUSIONS

Pediatric providers should be cognizant of the increased incidence of CDI in children. Early and judicious testing coupled with the timely institution of therapy will help to secure better outcomes for this disease.

[Clostridium difficile infection: epidemiology, disease burden and therapy]

INTRODUCTION

C. difficile causes 25 percent of the antibiotic associated infectious nosocomial diarrhoeas. C. difficile infection is a high-priority problem of public health in each country. The available literature of C. difficile infection's epidemiology and disease burden is limited.

AIM

Review of the epidemiology, including seasonality and the risk of recurrences, of the disease burden and of the therapy of C. difficile infection.

METHOD

Review of the international and Hungarian literature in MEDLINE database using PubMed up to and including 20th of March, 2012.

RESULTS

The incidence of nosocomial C. difficile associated diarrhoea is 4.1/10 000 patient day. The seasonality of C. difficile infection is unproved. 20 percent of the patients have recurrence after metronidazole or vancomycin treatment, and each recurrence increases the chance of a further one. The cost of C. difficile infection is between 130 and 500 thousand HUF (430 € and 1665 €) in Hungary.

CONCLUSIONS

The importance of C. difficile infection in public health and the associated disease burden are significant. The available data in Hungary are limited, further studies in epidemiology and health economics are required.

Risk factors associated with Clostridium difficile infection after kidney and pancreas transplantation

BACKGROUND

Clostridium difficile infection (CDI) is a common cause of nosocomial antibiotic-associated diarrhea with an increased incidence reported in solid organ transplant recipients. We sought to determine if kidney and/or pancreas transplant recipients possess unique risk factors for CDI.

METHODS

Between January 2009 and February 2011, 942 kidney and 56 pancreas transplants were performed at the 2 centers. Of these, 28 recipients (kidney, n = 24; pancreas, n = 4) developed CDI. Cases were matched to controls (n = 56) in a 1:2 ratio.

RESULTS

Those with CDI were mostly male patients (82% vs. 48%, P = 0.003), deceased-donor organ recipients (86% vs. 64%, P = 0.045), more likely to have leukopenia (18% vs. 4%, P = 0.038), and had undergone a gastrointestinal procedure within 3 months preceding CDI diagnosis (18% vs. 4%, P = 0.038). Cases had higher cumulative and restricted antimicrobial exposure in days (37 ± 79 vs. 8 ± 12, P = 0.009 and 27 ± 69 vs. 7 ± 10, P = 0.032). Cephalosporin use was more common among cases (43% vs. 16%, P = 0.008).

CONCLUSION

Careful antimicrobial selection and assurance of optimal treatment duration in the kidney and pancreas transplant population is prudent. Clinicians should have a heightened awareness of CDI risk particularly during periods of leukopenia and in the setting of gastrointestinal procedures.

Clostridium difficile Infection

Clostridium difficile is emerging as a common cause of infectious diarrhea. Incidence has increased dramatically since 2000, associated with a new strain that features both increased toxin production and increased resistance to antibiotics. For patients with mild to moderate disease, oral metronidazole is usually the first choice of treatment, and those with severe disease should be treated with vancomycin, with additional intravenous metronidazole in some cases. Fecal microbiota transplantation is a potentially promising therapy for patients with multiple recurrences of C difficile infection. Prevention of nosocomial transmission is crucial to reducing disease outbreaks in health care settings.

Clinical and Microbiologic Characteristics of Clostridium difficile Infection Caused by Binary Toxin Producing Strain in Korea

BACKGROUND

Binary toxin-producing Clostridium difficile infections (CDI) are known to be more severe and to cause higher case fatality rates than those by binary toxin-negative isolates. There has been few data of binary toxin-producing CDI in Korea. Objective of the study is to characterize clinical and microbiological trait of CDI cause by binary-toxin producing isolates in Korea.

MATERIALS AND METHODS

From September 2008 through January 2010, clinical characteristics, medication history and treatment outcome of all the CDI patients were collected prospectively. Toxin characterization, PCR ribotyping and antibiotic susceptibility were performed with the stool isolates of C. difficile.

RESULTS

During the period, CDI caused by 11binary toxin-producing isolates and 105 toxin A & toxin B-positive binary toxin-negative isolates were identified. Comparing the disease severity and clinical findings between two groups, leukocytosis and mucoid stool were more frequently observed in patients with binary toxin-positive isolates (OR: 5.2, 95% CI: 1.1 to 25.4, P = 0.043; OR: 7.6, 95% CI: 1.6 to 35.6, P = 0.010, respectively), but clinical outcome of 2 groups did not show any difference. For the risk factors for acquisition of binary toxin-positive isolates, previous use of glycopeptides was the significant risk factor (OR: 6.2, 95% CI: 1.4 to 28.6, P = 0.019), but use of probiotics worked as an inhibitory factor (OR: 0.1, 95% CI: 0.0 to 0.8; P = 0.026). PCR ribotypes of binary toxinproducing C. difficile showed variable patterns: ribotype 130, 4 isolates; 027, 3 isolates; 267 and 122, 1 each isolate and unidentified C1, 2 isolates. All 11 binary toxin-positive isolates were highly susceptible to clindamycin, moxifloxacin, metronidazole, vancomycin and piperacillin-tazobactam, however, 1 of 11 of the isolates was resistant to rifaximin.

CONCLUSIONS

Binary toxin-producing C. difficile infection was not common in Korea and those isolates showed diverse PCR ribotypes with high susceptibility to antimicrobial agents. Glycopeptide use was a risk factor for CDI by those isolates.

In recurrent C. difficile, the CRP response to the primary C. difficile infection predicts whether the same strain or a different strain will cause a second infection

BACKGROUND

Clostridium difficile is the leading cause of antibiotic-associated diarrhoea and is associated with an increase in morbidity and mortality. There is a wide variance in disease severity with some patients suffering a single, self-limiting episode of diarrhoea while others suffer more intractable problems with recurrent attacks or toxic dilatation. Numerous different C. difficile ribotypes exist, some of which are considered hypervirulent. The magnitude of toxin production alone is not sufficient to explain the varying virulence of these ribotypes, suggesting the involvement of other mechanisms.

METHODS

To test the same patient's response to infection with different C. difficile ribotypes, we reviewed 45 patients who suffered two episodes of C. difficile infection and determined by ribotyping and MLVA whether the second episode was due to the same strain or a different strain.

RESULTS

Patients harbouring a different strain had significantly higher C-reactive protein (CRP) responses on the first assessed infection (143 mg/L ± 20 vs. 55 ± 9.63, p = 0.0001) and a significantly lower CRP on reinfection (p = 0.048). Same strain patients had a non-significant increase in CRP response on second infection.

CONCLUSIONS

This suggests that the inflammatory response to C. difficile is determined by an interaction between host immunobiology, previous exposure and C. difficile strain.

Germination efficiency of clinical Clostridium difficile spores and correlation with ribotype, disease severity and therapy failure

Spore germination is an important part of the pathogenesis of Clostridium difficile infection (CDI). Spores are resistant to antibiotics, including those therapeutically administered for CDI and strains with a high germination rate are significantly more likely to be implicated in recurrent CDI. The role of germination efficiency in cases of refractory CDI where first-line therapy fails remains unclear. We investigated spore germination efficiencies of clinical C. difficile isolates by measuring drop in OD600 and colony forming efficiency. Ribotype 027 isolates exhibited significantly higher germination efficiencies in the presence of 0.1 % (w/v) sodium taurocholate (51.66 ± 8.75 %; 95 % confidence interval (CI) 47.37-55.95 %) than ribotype 106 (41.91 ± 8.35 %; 95 % CI 37.82-46 %) (P<0.05) and ribotype 078 (42.07 ± 8.57 %, 95 % CI 37.22-46.92 %) (P<0.05). Spore outgrowth rates were comparable between the ribotype groups but the exponential phase occurred approximately 4 h later in the absence of sodium taurocholate. Spore germination efficiencies for isolates implicated in severe CDI were significantly higher (49.68 ± 10.00 %, 95 % CI 47.06-52.30 %) than non-severe CDI (40.92 ± 9.29 %, 95 % CI 37.48-44.36 %); P<0.01. Germination efficiencies were also significantly higher in recurrent CDI or when metronidazole therapy failed than when therapy was successful [(49.00 ± 10.49 %, 95 % CI 46.25-51.75 %) versus (41.42 ± 9.43 %, 95 % CI 37.93-44.91 %); P<0.01]. This study suggests an important link between C. difficile spore germination, CDI pathogenesis and response to treatment; however, further work is warranted before the complex interplay between germination dynamics and CDI outcome can be fully understood.

Clostridium difficile-associated diarrhea in dialysis patients

BACKGROUND

Dialysis patients have impaired host defense mechanisms and frequently require antibiotics for various infective complications. In this study, we investigated whether dialysis patients have greater risk for Clostridium difficile-associated diarrhea (CDAD).

METHODS

During the 4-year study period (2004-2008), 85 patients with CDAD were identified based on a retrospective review of C difficile toxin assay or histology records. Nosocomial diarrheal patients without CDAD were considered as controls (n=403). We assessed the association between renal function and the prevalence and clinical outcomes of CDAD.

RESULTS

There was a significant difference in the prevalence rate of chronic kidney disease (CKD) between CDAD and non-CDAD patients (P<0.001). Sixteen patients (18.8%) of the CDAD group were treated with dialysis, whereas 21 patients (5.2%) of the non-CDAD group were treated with dialysis. There was a significant association between renal function and CDAD in patients on dialysis [odds ratio (OR)=4.44, 95% confidence interval (CI) 2.19-8.99, P<0.001], but not in patients with CKD stage 3-5 (OR=1.10, 95% CI 0.63-1.92, P=0.73). In multivariate analysis, CKD stage 5D was an independent risk factor for the development of CDAD (OR=13.36, 95% CI 2.94-60.67, P=0.001).

CONCLUSION

Our data indicate that dialysis patients might be at a greater risk of developing CDAD, which suggests that particular attention should be provided to CDAD when antibiotic treatment is administered to dialysis patients.

Can we identify patients at high risk of recurrent Clostridium difficile infection?

Although most patients with Clostridium difficile infection (CDI) can be managed effectively with discontinuation of prescribed antibiotics and additional treatment with oral metronidazole or vancomycin, up to 25% experience disease recurrence, usually within 30 days of treatment. Failure to mount a systemic anti-toxin antibody response differentiates patients with CDI and recurrent CDI from symptomless carriers of toxinogenic C. difficile. The immunological senescence that accompanies ageing may lead to impaired immune responses to C. difficile and contribute to the significant association between advancing age and increased risk of CDI recurrence. Inadequate immunity may also explain why previous episodes of recurrence constitute a significant risk factor for further CDI recurrences. Other risk factors for recurrent CDI include concurrent use of antibiotics for non-C. difficile infections (which perpetuate the loss of colonization resistance), proton-pump inhibitors, and other gastric acid anti-secretory medications, prolonged hospitalization, and severe underlying illness (as reflected by a high Horn index score). Prominent risk factors have been examined to develop and validate a clinical prediction tool for recurrent CDI, with three factors (age >65 years, severe underlying disease (by the Horn index score), and continued use of antibiotics for non-CDI infections) being highly predictive of CDI recurrence. Such simple clinical prediction rules have the potential to identify patients at high risk of recurrent CDI, and can alert the treating physician to the need for prompt recognition, confirmatory diagnosis and treatment with regimens ideally designed to mitigate the risk of subsequent recurrences.

In vitro activity of cadazolid against Clostridium difficile strains isolated from primary and recurrent infections in Stockholm, Sweden

One hundred thirty-three Clostridium difficile strains were collected from 71 patients and analyzed for the presence of C. difficile toxin B by the cell cytotoxicity neutralization assay, genes for toxin A, toxin B, binary toxin and TcdC deletion by PCR. All strains were also PCR-ribotyped and analyzed for sporulation frequency. The MICs of the isolates were determined against cadazolid and seven other antimicrobial agents by the agar dilution method. All isolates were positive for toxin B by the cell cytotoxicity neutralization assay. One hundred fourteen isolates were positive for toxin A and B and 16 isolates were positive for toxin A, toxin B and binary toxin by PCR. Three isolates were negative for toxin A but positive for toxin B. Thirty-three different ribotypes were identified. No strain of ribotype 027 was found. No differences in sporulation were noticed between the primary and recurrent isolates. All 133 isolates were sensitive to cadazolid (0.064-0.5 mg/l), fidaxomicin (0.008-0.125 mg/l), metronidazole (0.125-2 mg/l), vancomycin (0.125-1 mg/l) and tigecycline (0.032-0.25 mg/l). Three isolates were resistant to linezolid (8 mg/l), 15 isolates were resistant to moxifloxacin (8-32 mg/l) and 103 isolates were resistant to clindamycin (8-256 mg/l). No association between toxins A, B and binary toxin, ribotypes or the sporulation and the sensitivity to cadazolid could be found. Cadazolid has a potent in vitro activity against C. difficile.

Hyperimmune bovine colostrum for treatment of GI infections: a review and update on Clostridium difficile

Hyperimmune bovine colostrum (HBC), produced by vaccination of a cow during gestation, is rich in targeted immunoglobulins, and can be used to treat a variety of diseases. The published history of HBC use for treating gastrointestinal infections in humans has developed over the past several decades and demonstrates the promise of this type of therapeutic for GI infectious disease. HBC, or purified derivative products, have been used successfully for treatment or prevention of cryptosporidiosis, shigellosis, rotavirus, enterotoxigenic E. coli, and C. difficile infection (CDI). Given the positive results of previous studies using HBC for treatment of CDI, we have produced HBC with antibodies against the two most important virulence factors of C. difficile, TcdA and TcdB, using a novel recombinant vaccine. Our preliminary results demonstrate efficacy of the HBC product for treatment of CDI in the gnotobiotic piglet model, and warrant more thorough investigation. HBC may provide an effective treatment alternative to antibiotics, which can spare the normal gut microflora, and reduce rates of recurrence and antibiotic resistance.

Characterization of a stable, metronidazole-resistant Clostridium difficile clinical isolate

Background

Clostridium difficile are Gram-positive, spore forming anaerobic bacteria that are the leading cause of healthcare-associated diarrhea, usually associated with antibiotic usage. Metronidazole is currently the first-line treatment for mild to moderate C. difficile diarrhea however recurrence occurs at rates of 15–35%. There are few reports of C. difficile metronidazole resistance in the literature, and when observed, the phenotype has been transient and lost after storage or exposure of the bacteria to freeze/thaw cycles. Owing to the unstable nature of the resistance phenotype in the laboratory, clinical significance and understanding of the resistance mechanisms is lacking.

Methodology/Principal Findings

Genotypic and phenotypic characterization was performed on a metronidazole resistant clinical isolate of C. difficile. Whole-genome sequencing was used to identify potential genetic contributions to the phenotypic variation observed with molecular and bacteriological techniques. Phenotypic observations of the metronidazole resistant strain revealed aberrant growth in broth and elongated cell morphology relative to a metronidazole-susceptible, wild type NAP1 strain. Comparative genomic analysis revealed single nucleotide polymorphism (SNP) level variation within genes affecting core metabolic pathways such as electron transport, iron utilization and energy production.

Conclusions/Significance

This is the first characterization of stable, metronidazole resistance in a C. difficile isolate. The study provides an in-depth genomic and phenotypic analysis of this strain and provides a foundation for future studies to elucidate mechanisms conferring metronidazole resistance in C. difficile that have not been previously described.

Characterisation of Clostridium difficile biofilm formation, a role for Spo0A

Clostridium difficile is a Gram-positive anaerobic, spore-forming bacillus that is the leading cause of nosocomial diarrhoea worldwide. We demonstrate that C. difficile aggregates and forms biofilms in vitro on abiotic surfaces. These polymicrobial aggregates are attached to each other and to an abiotic surface by an extracellular polymeric substance (EPS). The EPS matrix provides the scaffold bonding together vegetative cells and spores, as well as forming a protective barrier for vegetative cells against oxygen stress. The master regulator of sporulation, Spo0A, may play a key role in biofilm formation, as genetic inactivation of spo0A in strain R20291 exhibits decreased biofilm formation. Our findings highlight an important attribute of C. difficile pathogenesis, which may have significant implications for infection, treatment and relapse.

PPI therapy and albumin are better predictors of recurrent Clostridium difficile colitis than choice of antibiotics

BACKGROUND

Recurrent Clostridium difficile colitis (RCDC) is common, but data regarding recurrence rates and predisposing factors are sparse.

METHODS

A retrospective case-control study was performed, identifying all inpatients and outpatients ≥18 years of age with C. difficile colitis (CDC) confirmed by a positive stool sample collected at our institution from January 2008 to August 2011. Factors associated with RCDC, the number of RCDC episodes, and the need for admission for RCDC were sought.

RESULTS

A total of 739 patients (male, 47 %) were studied, of whom 527 (71 %) received inpatient treatment for their index episode of CDC. There was no difference (p = 0.53) between RCDC rates for inpatients (17.6 %) and outpatients (19.8 %). While severity score and albumin were associated with RCDC in our population, use of proton pump inhibitors (PPIs) correlated with decreased RCDC (p = 0.006) and decreased need for admission (p = 0.005). The addition of vancomycin to metronidazole therapy did not lower RCDC rates (p = 0.52) or decrease the need for admission (p = 0.78).

CONCLUSIONS

Hypoalbuminemia strongly correlated with higher recurrence rates, while PPI therapy actually reduced RCDC, representing previously underappreciated potential therapeutic targets for lowering CDC recurrence. The addition of vancomycin to metronidazole did not improve RCDC rates.

Predictors of first recurrence of Clostridium difficile infection: implications for initial management

Symptomatic recurrence of Clostridium difficile infection (CDI) occurs in approximately 20% of patients and is challenging to treat. Identifying those at high risk could allow targeted initial management and improve outcomes. Adult toxin enzyme immunoassay–positive CDI cases in a population of approximately 600 000 persons from September 2006 through December 2010 were combined with epidemiological/clinical data. The cumulative incidence of recurrence ≥14 days after the diagnosis and/or onset of first-ever CDI was estimated, treating death without recurrence as a competing risk, and predictors were identified from cause-specific proportional hazards regression models. A total of 1678 adults alive 14 days after their first CDI were included; median age was 77 years, and 1191 (78%) were inpatients. Of these, 363 (22%) experienced a recurrence ≥14 days after their first CDI, and 594 (35%) died without recurrence through March 2011. Recurrence risk was independently and significantly higher among patients admitted as emergencies, with previous gastrointestinal ward admission(s), last discharged 4–12 weeks before first diagnosis, and with CDI diagnosed at admission. Recurrence risk also increased with increasing age, previous total hours admitted, and C-reactive protein level at first CDI (all P < .05). The 4-month recurrence risk increased by approximately 5% (absolute) for every 1-point increase in a risk score based on these factors. Risk factors, including increasing age, initial disease severity, and hospital exposure, predict CDI recurrence and identify patients likely to benefit from enhanced initial CDI treatment.

Fidaxomicin inhibits spore production in Clostridium difficile

Fidaxomicin (FDX) is a novel antimicrobial agent with narrow-spectrum and potent bactericidal activity against Clostridium difficile. In recent clinical trials, FDX was superior to vancomycin in preventing recurrences of C. difficile infection. A possible mechanism of reducing recurrence may be through an inhibitory effect on sporulation. The effect of FDX and its major metabolite, OP-1118, on C. difficile growth and sporulation kinetics was compared with that of vancomycin, metronidazole, and rifaximin. Drugs at subminimum inhibitory concentrations (sub-MICs) were added to cells at an early stationary phase of growth; this was followed by collection of cells at various intervals for quantitation of total viable cell and heat-resistant spore counts on taurocholate-containing media. The effect of the drugs at 2-2.5× MIC on the expression of sporulation genes in C. difficile was also compared using quantitative reverse-transcriptase polymerase chain reaction. Both FDX and OP-1118 (1/4× MIC) inhibited sporulation when added to early-stationary-phase cells in C. difficile strains, including the epidemic NAP1/BI/027 strain. In contrast, vancomycin, metronidazole, and rifaximin (at similar sub-MICs) did not inhibit sporulation. The number of spores following treatment with comparator drugs increased to the same level as the no-drug control treatment. Expression of mother cell-specific (spoIIID) and forespore-specific (spoIIR) sporulation genes also was inhibited by FDX and OP-1118 but not significantly by vancomycin. Both FDX and OP-1118 (unlike vancomycin, rifaximin, and metronidazole) effectively inhibited sporulation by C. difficile. The inhibitory effect of FDX on C. difficile sporulation may contribute to its superior performance in sustaining clinical response and reducing recurrences and may also be beneficial in decreasing shedding and transmission of this pathogen.

Relapse versus reinfection: recurrent Clostridium difficile infection following treatment with fidaxomicin or vancomycin

Our study sought to compare the strain types of Clostridium difficile causing initial and recurrent episodes of C. difficile infection (CDI) in adult patients with a first episode of CDI or 1 prior episode of CDI within the previous 90 days. Strains originated from patients who had been entered into two phase 3 randomized clinical trials of fidaxomicin versus vancomycin. Isolates of C. difficile from the initial and recurrent episodes within 28 (± 2) days of cure of CDI were compared using restriction endonuclease analysis (REA) typing. Paired isolates were available from 90 of 194 (46%) patients with recurrent CDI. Patients with isolates available were significantly younger (P = .008) and more likely to be from Canadian sites (P = .0001), compared with patients without isolates. In 75 of 90 subjects (83.3%), the identical REA type strain was identified at recurrence and the initial episode (putative relapse). Early recurrences (0-14 days after treatment completion) were relapses in 86.7% and a new strain (reinfection) in 13.3%. Later recurrences (15-31 days after treatment) were relapses in 76.7% and reinfections in 23.3%. Mean time (± standard deviation) to recurrence was 12.2 (± 6.4) days for relapses and 14.7 (± 6.8) days for reinfections (P = .177). The most common BI/NAP1/027 group and the previous US epidemic REA group J/NAP2/001 had a significantly higher combined rate of recurrence with the same strain (relapse), compared with the other REA groups (39 of 42 [93%] vs 36 of 48 [75%], respectively; P = .023). We found a higher than historic rate of recurrent CDI caused by the same isolate as the original episode, a finding that may be related to the relatively short observation period in this study and the high frequency of isolation of epidemic strains, such as groups BI and J, for which relapse rates may be higher than for other REA groups. Caution in generalizing these observations is required, because the patients studied were younger and more likely to be from Canadian sites than were patients with recurrence who did not provide isolates.

Treatment of first recurrence of Clostridium difficile infection: fidaxomicin versus vancomycin

Recurrence of Clostridium difficile infection (CDI) occurs in approximately 25% of successfully treated patients. Two phase 3 randomized, double-blind trials were conducted at 154 sites in the United States, Canada, and Europe to compare fidaxomicin vs vancomycin in treating CDI. Patients with CDI received fidaxomicin 200 mg twice daily or vancomycin 125 mg 4 times daily for 10 days. The primary end point was clinical cure of CDI at end of treatment, and a secondary end point was recurrence during the 28 days following clinical cure. In all, 1164 subjects were enrolled, of which a subgroup of 128 in the per-protocol population had another recent episode of CDI prior to the CDI diagnosis at study enrollment. In the analysis of this subgroup, initial response to therapy was similar for both drugs (>90% cure). However, recurrence within 28 days occurred in 35.5% of patients treated with vancomycin and 19.7% of patients treated with fidaxomicin (−15.8% difference; 95% confidence interval, −30.4% to −0.3%; P = .045). Early recurrence (within 14 days) was reported in 27% of patients treated with vancomycin and 8% of patients treated with fidaxomicin (P = .003). In patients with a first recurrence of CDI, fidaxomicin was similar to vancomycin in achieving a clinical response at end of therapy but superior in preventing a second recurrence within 28 days.

Clinical Trials Registration. NCT00314951 and NCT00468728.

Association of relapse of Clostridium difficile disease with BI/NAP1/027

Recurrent Clostridium difficile infection (CDI) occurs in up to 35% of patients. Recurrences can be due to either relapse with the same strain or reinfection with another strain. In this study, multilocus variable-number tandem-repeat analysis (MLVA) was performed on C. difficile isolates from patients with recurrent CDI to distinguish relapse from reinfection. In addition, univariate and multivariate analyses were performed to identify risk factors associated with relapse. Among patients with a single recurrence, relapse due to the original infecting strain was more prevalent than reinfection and the interval between episodes was shorter than among patients who had reinfections. Among patients with >1 recurrence, equal distributions of relapse and reinfection or a combination of the two episode types were observed. Initial infection with the BI/NAP1/027 epidemic clone was found to be a significant risk factor for relapse. This finding may have important implications for patient therapy. Classification of recurrent CDI episodes by MLVA can be utilized to make informed patient care decisions and to accurately define new CDI cases for infection control and reimbursement purposes.

Clostridium difficile in young farm animals and slaughter animals in Belgium

Faecal carriage of Clostridium difficile in healthy animals has been reported recently, especially in piglets and calves. However there is limited data about carriage in animals just prior to slaughter in Europe. The main objective of this study was to determine the presence of C. difficile in pigs and cattle at the slaughterhouse. C. difficile was isolated in 6.9% of the cattle at the slaughterhouse. None of the pig slaughter samples were positive for C. difficile after an enrichment time of 72 h. For complementary data, a short study was conducted in piglets and calves at farms. C. difficile was more prevalent in piglets (78.3%) than in calves (22.2%) on the farms. Regarding the piglet samples, 27.8% of the positive samples were detected without enrichment of stools. The PCR ribotype 078 was predominant in farm animals. Samples isolated from slaughter cattle presented the widest range in PCR-ribotype variety, and the most prevalent PCR ribotype was 118a UCL. The results of this study confirm that C. difficile is present in slaughter animals in Belgium with a large percentage of toxigenic strains also commonly found in humans.

Evaluation of NVB302 versus vancomycin activity in an in vitro human gut model of Clostridium difficile infection

OBJECTIVES

First-line treatment options for Clostridium difficile infection (CDI) are limited. NVB302 is a novel type B lantibiotic under evaluation for the treatment of CDI. We compared the responses to NVB302 and vancomycin when used to treat simulated CDI in an in vitro gut model.

METHODS

We used ceftriaxone to elicit simulated CDI in an in vitro gut model primed with human faeces. Vancomycin and NVB302 were instilled into separate gut models and the indigenous gut microbiota and C. difficile total viable counts, spores and toxin levels were monitored throughout.

RESULTS

Ceftriaxone instillation promoted C. difficile germination and high-level toxin production. Commencement of NVB302 and vancomycin instillation reduced C. difficile total viable counts rapidly with only C. difficile spores remaining within 3 and 4 days, respectively. Cytotoxin was reduced to undetectable levels 5 and 7 days after vancomycin and NVB302 instillation commenced in vessel 2 and 3, respectively, and remained undetectable for the remainder of the experiments. C. difficile spores were unaffected by the presence of vancomycin or NVB302. NVB302 treatment was associated with faster resolution of Bacteroides fragilis group.

CONCLUSIONS

Both NVB302 and vancomycin were effective in treating simulated CDI in an in vitro gut model. C. difficile spore recrudescence was not observed following successful treatment with either NVB302 or vancomycin. NVB302 displayed non-inferiority to vancomycin in the treatment of simulated CDI, and had less deleterious effects against B. fragilis group. NVB302 warrants further clinical investigation as a potentially novel antimicrobial agent for the treatment of CDI.

Clostridium difficile Infection in Children: Current State and Unanswered Questions

The incidence of Clostridium difficile infection (CDI) in children has increased over the past decade. In recent years, new and intriguing data on pediatric CDI have emerged. Community-onset infections are increasingly recognized, even in children who have not previously received antibiotics. A hypervirulent strain is responsible for up to 20% of pediatric CDI cases. Unique risk factors for CDI in children have been identified. Advances in diagnostic testing strategies, including the use of nucleic acid amplification tests, have raised new questions about the optimal approach to diagnosing CDI in children. Novel therapeutic options are available for adult patients with CDI, raising questions about the use of these agents in children. Updated recommendations about infection prevention and control measures are now available. We summarize these recent developments in pediatric CDI in this review and also highlight remaining knowledge gaps that should be addressed in future research efforts.

Novel management strategies in the treatment of severe Clostridium difficile infection

CDI is increasing in incidence and severity. Clinicians must have a low threshold to consider the diagnosis and to treat patients with the clinical syndrome and risk factors before laboratory confirmation of the diagnosis. In patients who have signs of advanced disease, escalation of care with antimicrobial strategies and multidisciplinary care including surgical consultation is necessary. Furthermore, lowering the threshold for surgery compared with traditional approaches likely results in improved survival. Novel surgical approaches may obviate total abdominal colectomy and the associated immediate and long-term morbidity in this often fragile patient population, thus allowing clinicians to embrace surgical therapy earlier in the course of severe, complicated disease.

[Treatment of refractory or recurrent Clostridium difficile infection]

The incidence and severity of Clostridium difficile infection (CDI) has increased over the past decades. It is related to the emergence of hypervirulent strains and increased use of antibiotics. The incidence of refractory CDI to standard therapies and the risk for recurrent CDI are also increasing. Current guidelines recommend the first recurrence to be treated with the same agent used for the initial episode. However, data are lacking to support any particular treatment strategy for severe refractory CDI or cases with multiple recurrence. Treatments currently available for CDI are inadequate to prevent recurrence. Widely used method for managing a subsequent recurrence involves tapering followed by pulsed doses of vancomycin. Other potentially effective strategies for recurrent CDI are use of other antibiotics such as fidaxomicin, nitazoxanide, rifaximin, tigecycline, and teicoplanin. There are efforts to recover gut microflora and to optimize immune response to CDI. These include use of probiotics, fecal microbiota transplantation, intravenous immunoglobulin, monoclonal antibodies directed against C. difficile toxins, and active vaccination. However treatment of patients with refractory CDI and those with multiple CDI recurrences is based on limited clinical evidence, and there is an ongoing need for continued research to improve the outcomes these patients.