A hospital outbreak of Clostridium difficile disease associated with isolates carrying binary toxin genes

Multilocus sequence typing (MLST) analysis of 104Clostridium difficilestrains isolated from China

The phylogenetic and epidemic relationships of 104 clinical isolatesof Clostridium difficilefrom three hospitals of different geographical and population sources in China were investigated by multilocus sequence typing. Twenty-two sequence types (STs) were identified, four of which, ST117, ST118, ST119 and ST129, were novel. No geographically specific and host population-specific phylogenetic lineages were found and there was no correlation between geographical origin or host population and strain genotype. ST37 was the dominant type in our survey but the four novel STs underline the high genetic diversity and unique polymorphisms inC. difficilefrom China.

Prediction tools for unfavourable outcomes in Clostridium difficile infection: a systematic review

CONTEXT

Identifying patients at risk for adverse outcomes of Clostridium difficile infection (CDI), including recurrence and death, will become increasingly important as novel therapies emerge, which are more effective than traditional approaches but very expensive. Clinical prediction rules (CPRs) can improve the accuracy of medical decision-making. Several CPRs have been developed for CDI, but none has gained a widespread acceptance.

METHODS

We systematically reviewed studies describing the derivation or validation of CPRs for unfavourable outcomes of CDI, in medical databases (Medline, Embase, PubMed, Web of Science and Cochrane) and abstracts of conferences.

RESULTS

Of 2945 titles and abstracts screened, 13 studies on the derivation of a CPR were identified: two on recurrences, five on complications (including mortality), five on mortality alone and one on response to treatment. Two studies on the validation of different severity indices were also retrieved. Most CPRs were developed as secondary analyses using cohorts assembled for other purposes. CPRs presented several methodological limitations that could explain their limited use in clinical practice. Except for leukocytosis, albumin and age, there was much heterogeneity in the variables used, and most studies were limited by small sample sizes. Eight models used a retrospective design. Only four studies reported the incidence of the outcome of interest, even if this is essential to evaluate the potential usefulness of a model in other populations. Only five studies performed multivariate analyses to adjust for confounders.

CONCLUSIONS

The lack of weighing variables, of validation, calibration and measures of reproducibility, the weak validities and performances when assessed, and the absence of sensitivity analyses, all led to suboptimal quality and debatable utility of those CPRs. Evidence-based tools developed through appropriate prospective cohorts would be more valuable for clinicians than empirically-developed CPRs.

Clostridium difficile prevalence rates in a large healthcare system stratified according to patient population, age, gender, and specimen consistency

We evaluated Clostridium difficile prevalence rates in 2,807 clinically indicated stool specimens stratified by inpatient (IP), nursing home patient (NH), outpatient (OP), age, gender, and specimen consistency using bacterial culture, toxin detection, and polymerase chain reaction (PCR) ribotyping. Rates were determined based on the detection of toxigenic C. difficile isolates. We identified significant differences in the rates between patient populations and with age. Specimens from NH had a higher rate (46%) for toxigenic C. difficile than specimens from IP (18%) and OP (17%). There were no gender-related differences in the rates. Liquid specimens had a lower rate (15%) than partially formed and soft specimens (25%) and formed specimens (18%) for the isolation of toxigenic C. difficile. The nontoxigenic rate was lowest for NH (4%) and highest for patients<20 years of age (23%). We identified 31 different toxigenic ribotypes from a sampling of 190 isolates that showed the lowest diversity in NH. Fluoroquinolone resistance was observed in 93% of the 027 isolates, all of the 053 isolates, and in four other ribotypes. We observed different rates for toxigenic C. difficile in stratified patient populations, with the highest rate for NH, a low overall nontoxigenic rate, and fluoroquinolone resistance.

Multifaceted interactions of bacterial toxins with the gastrointestinal mucosa

The digestive tract is one of the ecosystems that harbors the largest number and greatest variety of bacteria. Among them, certain bacteria have developed various strategies, including the synthesis of virulence factors such as toxins, to interact with the intestinal mucosa, and are responsible for various pathologies. A large variety of bacterial toxins of different sizes, structures and modes of action are able to interact with the gastrointestinal mucosa. Some toxins, termed enterotoxins, directly stimulate fluid secretion in enterocytes or cause their death, whereas other toxins pass through the intestinal barrier and disseminate by the general circulation to remote organs or tissues, where they are active. After recognition of a membrane receptor on target cells, toxins can act at the cell membrane by transducing a signal across the membrane in a hormone-like manner, by pore formation or by damaging membrane compounds. Other toxins can enter the cells and modify an intracellular target leading to a disregulation of certain physiological processes or disorganization of some structural architectures and cell death. Toxins are fascinating molecules, which mimic or interfere with eukaryotic physiological processes. Thereby, they have permitted the identification and characterization of new natural hormones or regulatory pathways. Besides use as protective antigens in vaccines, toxins offer multiple possibilities in pharmacology, such as immune modulation or specific delivery of a protein of interest into target cells.

Diverting loop ileostomy and colonic lavage: an alternative to total abdominal colectomy for the treatment of severe, complicated Clostridium difficile associated disease

OBJECTIVE

To determine whether a minimally invasive, colon-preserving approach could serve as an alternative to total colectomy in the treatment of severe, complicated Clostridium difficile-associated disease (CDAD).

BACKGROUND

C. difficile is a significant cause of morbidity and mortality worldwide. Most cases will respond to antibiotic therapy, but 3% to 10% of patients progress to a severe, complicated, or "fulminant" state of life-threatening systemic toxicity. Although the advocated surgical treatment of total abdominal colectomy with end ileostomy improves survival in severe, complicated CDAD, outcomes remain poor with associated mortality rates ranging from 35% to 80%.

METHODS

All patients who were diagnosed with severe, complicated ("fulminant") CDAD and were treated at the University of Pittsburgh Medical Center or VA Pittsburgh Healthcare System between June 2009 and January 2011 were treated with this novel approach. The surgical approach involved creation of a loop ileostomy, intraoperative colonic lavage with warmed polyethylene glycol 3350/electrolyte solution via the ileostomy and postoperative antegrade instillation of vancomycin flushes via the ileostomy. The primary end point for the study was resolution of CDAD. The matching number of patients treated with colectomy for CDAD preceding the initiation of this current treatment strategy was analyzed for historical comparison.

RESULTS

Forty-two patients were treated during this time period. There was no significant difference in age, sex, pharmacologic immunosuppression, and Acute Physiology and Chronic Health Evaluation-II scores between our current cohort and historical controls. The operation was accomplished laparoscopically in 35 patients (83%). This treatment strategy resulted in reduced mortality compared to our historical population (19% vs 50%; odds ratio, 0.24; P = 0.006). Preservation of the colon was achieved in 39 of 42 patients (93%).

CONCLUSIONS

Loop ileostomy and colonic lavage are an alternative to colectomy in the treatment of severe, complicated CDAD resulting in reduced morbidity and preservation of the colon.

Comparison of clinical severity score indices for Clostridium difficile infection

OBJECTIVE

To compare 8 severity score indices for Clostridium difficile infection (CDI).

DESIGN

Prospective observational study.

METHODS

This study was conducted from July through October 2006. All hospitalized patients in 3 university-affiliated hospitals with a positive fecal Clostridium difficile toxin assay result were evaluated. Infection was considered severe if patients had at least 1 of the following clinical events during their hospitalization: (1) death attributed to CDI within 30 days after diagnosis, (2) colectomy necessitated by CDI, or (3) intensive care unit admission for management of complications attributed to CDI. Severity was assessed on the basis of 8 severity score indices, using published criteria for severe CDI as the benchmark. The 8 severity score indices studied were Beth Israel, University of Pittsburgh Medical Center version 1, University of Pittsburgh Medical Center version 2, Hines VA, modified University of Illinois, University of Calgary version 1, University of Calgary version 2, and University of Temple.

RESULTS

Of 184 patients with CDI evaluated, 19 had severe cases and 165 had nonsevere cases, as assessed on the basis of the defined severe CDI criteria. Sensitivities of the 8 severity score indices studied ranged from 63.2% to 84.2%, and specificities ranged from 59.4% to 93.9%. The Hines VA index had the highest kappa score (0.69 [95% confidence interval, 0.54-0.83]), followed by the University of Pittsburgh Medical Center version 1 index. Independent risk factors for severe CDI determined by multivariate analysis were abdominal distention (P = .007), fever (temperature, 38.0°C or above; P = .042), white blood cell count of at least 20,000 cells/mm(3) (P = .035), and hypoalbuminemia (serum albumin level less than 3 mg/dL; P = .029).

CONCLUSION

The Hines VA CDI severity score index appeared to display the strongest correlation for predicting more severe forms of CDI.

Clinical features of Clostridium difficile infection and molecular characterization of the isolated strains in a cohort of Danish hospitalized patients

The purpose of this study was to compare clinical features of Clostridium difficile infection (CDI) to toxin gene profiles of the strains isolated from Danish hospitalized patients. C. difficile isolates were characterized by PCR based molecular typing methods including toxin gene profiling and analysis of deletions and truncating mutations in the toxin regulating gene tcdC. Clinical features were obtained by questionnaire. Thirty percent of the CDI cases were classified as community-acquired. Infection by C. difficile with genes encoding both toxin A, toxin B and the binary toxin was significantly associated with hospital-acquired/healthcare-associated CDI compared to community-acquired CDI. Significantly higher leukocyte counts and more severe clinical manifestations were observed in patients infected by C. difficile containing genes also encoding the binary toxin together with toxin A and B compared to patients infected by C. difficile harbouring only toxin A and B. In conclusion, infection by C. difficile harbouring genes encoding both toxin A, toxin B and the binary toxin were associated with hospital acquisition, higher leukocyte counts and severe clinical disease.

Detection of Clostridium difficile in animals: comparison of real-time PCR assays with the culture method

Clostridium difficile has emerged as a pathogen or commensal in food animals. There is overlap between isolates from animals, retail meats and humans, suggesting that animals may be a C. difficile reservoir. For direct detection of variant C. difficile strains in faecal samples of symptomatic and asymptomatic animals, we developed and validated a new TaqMan real-time PCR (TMrtPCR) assay targeting the tcdA, tcdB and cdtB genes. We compared it with the enrichment culture method and with two real-time PCR (rtPCR) assays, BrtPCR and PCRFast, targeting tcdB and tcdA/tcdB, respectively. All ten tested C. difficile toxinotypes, except one (XIa) with PCRFast and two (X, XIa) with BrtPCR, were detected with the test assays. A total of 340 (100 %) samples were cultured and amplified with TMrtPCR. Results correlated in 75.3 % samples. Forty (11.8 %) samples were culture positive/TMrtPCR negative, possibly because of the low numbers of bacteria in the samples or because of DNA extraction failure. Forty (11.8 %) samples were TMrtPCR positive/culture negative. Among 79 samples included in the rtPCR assays/culture comparison, 50.6 % were in complete concordance. The results showed that TMrtPCR performed better than BrtPCR and PCRFast, and 67 % of the culture-positive samples were TMrtPCR positive in comparison to 40 % of the samples positive in BrtPCR and 7 % of the samples positive in PCRFast, respectively. Another advantage of TMrtPCR over BrtPCR and PCRFast is its ability to detect a binary toxin gene. Therefore, the TMrtPCR results can provide the first information about the toxin type present in the sample. According to the results of our study, TMrtPCR could be a preferred screening method for the rapid detection of C. difficile in animal faecal samples, although an enrichment culture has to be performed for the specimens with negative or inconclusive rtPCR results.

Temporal trends in disease outcomes related to Clostridium difficile infection in patients with inflammatory bowel disease

BACKGROUND

Clostridium difficile has emerged as an important pathogen in patients with inflammatory bowel disease (IBD) and is associated with increased morbidity and mortality. No studies have examined the temporal change in severity of C. difficile infection (CDI) complicating IBD.

METHODS

Using data from the Nationwide Inpatient Sample, we identified all IBD-related hospitalizations during the years 1998, 2004, and 2007 and examined hospitalizations with a coexisting diagnosis of C. difficile. We compared the absolute outcomes of in-hospital mortality and colectomy in the C. difficile-IBD cohort during these timepoints, and also examined these outcomes relative to non-C. difficile IBD controls during each corresponding year.

RESULTS

During 1998, 2004, and 2007, approximately 1.4%, 2.3%, and 2.9% of all IBD hospitalizations nationwide were complicated by CDI (P < 0.001). The absolute mortality in the C. difficile-IBD cohort increased from 5.9%-7.2% (P = 0.052) with a nonsignificant increase in colectomy rate from 3.8%-4.5% between 1998 and 2007. Compared to non-C. difficile IBD controls, there was an increase in the relative mortality risk associated with C. difficile from 1998 (odds ratio [OR] 2.38, 95% confidence interval [CI]: 1.52-3.72) to 2007 (OR 3.38, 95% CI: 2.66-4.29) (P = 0.15) with a significant increase in total colectomy odds from 1998 (OR 1.39, 95% CI: 0.81-2.37) to 2007 (OR 2.51, 95% CI: 1.90-3.34) (P = 0.03).

CONCLUSION

There has been a temporal increase nationwide in CDI complicating IBD hospitalizations. The excess morbidity associated with C. difficile infection in hospitalized IBD patients has increased between 1998 and 2007.

Clostridium difficile binary toxin (CDT) and diarrhea

Clostridium difficile is a major enteropathogen of humans. It produces two main virulence factors, toxins A and B. A third, less well known toxin, C. difficile toxin (CDT), is a binary toxin composed of distinct enzymatic (CdtA) and cell binding/translocation (CdtB) proteins. We used a novel enzyme linked immunoassay (EIA) to detect CdtB protein in feces and culture fluids. Additionally, PCR was used to assay C. difficile isolates from fecal samples for the CDT locus (CdtLoc). Although the results from 80 isolates suggest no relationship between toxin concentrations in situ and in vitro, there is a good correlation between PCR detection of the cdtB gene and EIA detection of CdtB protein in vitro. Possible implications of the detection of CDT in patients are discussed.

Germination response of spores of the pathogenic bacterium Clostridium perfringens and Clostridium difficile to cultured human epithelial cells

Spores of pathogenic Clostridium perfringens and Clostridium difficile must germinate in the food vehicle and/or host's intestinal tract to cause disease. In this work, we examined the germination response of spores of C. perfringens and C. difficile upon incubation with cultured human epithelial cell lines (Caco-2, HeLa and HT-29). C. perfringens spores of various sources were able to germinate to different extents; while spores of a non-food-borne isolate germinated very well, spores of food-borne and animal isolates germinated poorly in human epithelial cells. In contrast, no detectable spore germination (i.e., loss of spore heat resistance) was observed upon incubation of C. difficile spores with epithelial cells; instead, there was a significant (p < 0.01) increase in heat-resistant spore titers. In C. perfringens, the highest spore germination response observed with the HT-29 cell line, might be in part, due to the expression of germination factor with peptidoglycan cortex hydrolysis activity by HT-29 cells. Collectively, these findings might well have implications in understanding the mechanism of clostridial spore germination in vivo.

Clostridium difficile infection: epidemiology, risk factors and management

The epidemiology of Clostridium difficile infection (CDI) has changed over the past decade. There has been a dramatic worldwide increase in its incidence, and new CDI populations are emerging, such as those with community-acquired infection and no previous exposure to antibiotics, children, pregnant women and patients with IBD. Diagnosis of CDI requires identification of C. difficile toxin A or B in diarrheal stool. The accuracy of current diagnostic tests remains inadequate and the optimal diagnostic testing algorithm has not been defined. The first-line agents for CDI treatment are metronidazole and vancomycin, with the latter being the preferred agent in patients with severe disease as it has significantly superior efficacy. The incidence of metronidazole treatment failures has increased, emphasizing the need to find alternative treatment options. Disease recurrence continues to occur in 20-40% of patients and its treatment remains challenging. In patients with CDI who develop fulminant colitis, early surgical consultation is essential. Intravenous immunoglobulin and tigecycline have been used in patients with severe refractory disease but delaying surgery may be associated with worse outcomes. Infection control measures are key to prevent horizontal transmission of infection. Ongoing research into effective treatment protocols and prevention is essential.

Potential value of repeat stool testing for Clostridium difficile stool toxin using enzyme immunoassay?

OBJECTIVE

The aim of this brief review is to summarize the literature as it relates to the potential value of repeat stool testing for Clostridium difficile (C. difficile) toxin using an enzyme immunoassay (EIA) for toxin A&B and also propose a potential newer algorithm for diagnosing C. difficile.

RESEARCH DESIGN AND METHODS

Two investigators conducted independent literature searches using PubMed, Web of Science, and Scopus until May 1st, 2010. All databases were searched using the terms Clostridium difficile, CDAD, antibiotic associated diarrhea, C. difficile in combination with enzyme immunoassay, enzyme linked immunosorbent assay, Clostridium difficile toxin A, Clostridium difficile toxin B, Clostridium difficile toxin and repeat stool testing. Articles which discussed EIA in C. difficile infection (CDI) patients were reviewed and relevant cross references also read and evaluated for inclusion. Selection bias could be a possible limitation of the approach used in selecting or finding articles for this article.

FINDINGS

The evidence for repeat stool testing for C. difficile toxin detection using toxin EIA is becoming weaker. Most recent published practice guidelines recommend a two- or three-step testing algorithm for the detection of C. difficile.

CONCLUSIONS

EIA for C. difficile stool toxin has a limited sensitivity, but, it does not warrant repeat stool testing. The data for this are suggestive but not conclusive. More studies and better tests are needed to have clear guidelines which can specify the number of tests needed in a diagnostic workup of suspected C. difficile infection. A two-step or three-step method in the diagnosis of C. difficile-associated diarrhea offered a marked increase in sensitivity compared to that of toxin A&B EIA alone.

Impact of Clostridium difficile on inflammatory bowel disease

Clostridium difficile infection (CDI) has been increasing in incidence among those with underlying inflammatory bowel disease (IBD) and is associated with substantial morbidity, the need for surgery and even mortality. The similar clinical presentation between CDI and a flare of underlying IBD makes prompt diagnosis essential to prevent deterioration which would accompany an escalation of immunosuppression in the absence of appropriate antibiotic therapy. Classical risk factors (antibiotic or healthcare exposure) or clinical findings (pseudomembranes) may not be found in many IBD patients with CDI and should not be considered essential for entertaining the diagnosis. Enzyme immunoassays detecting both toxins A and B remain the most widely used test for diagnosis and have acceptable sensitivity, but may require testing of multiple samples in select situations. Both vancomycin and metronidazole appear to be effective and treatment with oral vancomycin is preferred in those with severe disease, including those who require hospitalization. Appropriate infection control measures are essential to restrict patient-to-patient spread within healthcare environments and to prevent recurrences. Several novel therapies are currently under study, including new antibiotic agents and monoclonal antibodies targeted against the toxins. There is a need to broaden these studies to the IBD population. There is also the need to prospectively examine whether CDI has long-term disease-modifying consequences in those with underlying IBD.

The ecology and pathobiology of Clostridium difficile infections: an interdisciplinary challenge

Clostridium difficile is a well recognized pathogen of humans and animals. Although C. difficile was first identified over 70 years ago, much remains unknown in regards to the primary source of human acquisition and its pathobiology. These deficits in our knowledge have been intensified by dramatic increases in both the frequency and severity of disease in humans over the last decade. The changes in C. difficile epidemiology might be due to the emergence of a hypervirulent stain of C. difficile, ageing of the population, altered risk of developing infection with newer medications, and/or increased exposure to C. difficile outside of hospitals. In recent years, there have been numerous reports documenting C. difficile contamination of various foods, and reports of similarities between strains that infect animals and strains that infect humans as well. The purposes of this review are to highlight the many challenges to diagnosing, treating, and preventing C. difficile infection in humans, and to stress that collaboration between human and veterinary researchers is needed to control this pathogen.

In vitro susceptibility of Clostridium difficile to rifaximin and rifampin in 359 consecutive isolates at a university hospital in Houston, Texas

AIM

This was an in vitro study to analyse the susceptibility of Clostridium difficile isolates to rifampin and rifaximin.

METHODS

Stool samples from patients who had nosocomial diarrhoea and C difficile toxin B at a university hospital between August 2006 and December 2007 were cultured for C difficile. Susceptibility of C difficile isolates to rifaximin and rifampin was determined by agar dilution and E strips, respectively. C difficile isolates were analysed via PCR for genes encoding toxins A and B, for binary toxin (BT), and for partial deletions of the tcdC gene (tcdC-del).

RESULTS

Rifaximin exhibited high-level activity against 359 C difficile isolates, with MIC(50) <0.01 microg/ml and MIC(90) 0.25 microg/ml; rifampin had MIC(50) <0.002 microg/ml and MIC(90) 4 microg/ml. Among isolates analysed, 55 (15%) were positive for BT and tcdC-del. 28 (8% of 359) isolates were resistant to rifampin (> or = 32 microg/ml), of which 6 (2% of 359) were resistant to rifaximin and rifampin with MIC values > or = 32 microg/ml. 2 of the 28 isolates resistant to rifampin were A(+)/B(+)/BT(+)/tcdC-del(+), 5 were A(+)/B(+)/BT(-)/tcdC-del(+), 4 were A(+)/B(+)/BT(+)/tcdC-del(-), 13 were A(+)/B(+)/BT(-)/tcdC-del(-), and 4 had no detectable toxin genes. Of the 11 isolates resistant to rifaximin alone, 1 was A(+)/B(+)/BT(-)/tcdC-del(+), 2 were A(+)/B(+)/BT(+)/tcdC-del(-), 6 were A(+)/B(+)/BT(-)/tcdC-del(-), and 2 had no detectable toxin genes.

CONCLUSIONS

The study demonstrates that rifaximin has high-level activity against C difficile in vitro. Determination of resistance to rifampin by E strip did not predict rifaximin resistance.

Clostridium difficile

Clostridium difficile has re-emerged as a major hospital-acquired infection since 2001. Despite development of polymerase chain reaction-based testing, no single clinical diagnostic test has emerged with sufficient sensitivity, specificity, and turnaround time to be entirely reliable for disease diagnosis. The importance of C difficile acquired outside the hospital environment remains an unknown factor and awaits further epidemiologic investigation. This article discusses the changing epidemiology, clinical presentation, and pathogenesis of C difficile infection and highlights the ongoing challenges of laboratory diagnosis, treatment, and disease relapse.

Real-time multiplex polymerase chain reaction assay for rapid detection of Clostridium difficile toxin-encoding strains

Clostridium difficile is considered an important emerging pathogen capable of causing disease in humans and animal species. In our study, we developed and evaluated a multiplex real-time polymerase chain reaction (PCR) assay for the detection of C. difficile genes encoding toxin A (tcdA), toxin B (tcdB), and binary toxin (cdtA and cdtB). The standardized real-time PCR assay for toxin genes of C. difficile was used to screen for toxigenic C. difficile in fecal samples from 71 preweaned calves, 53 retail ground meat samples, and 27 pasteurized milk samples. All samples were also examined for C. difficile using traditional culture techniques to validate the PCR assay. A total of 24 fecal samples (33.80%) were positive for toxigenic C. difficile using either multiplex real-time PCR or culture. Toxin-encoding C. difficile was detected in 23 enriched fecal samples using the multiplex real-time PCR assay and only 15 samples using culture techniques. C. difficile was not detected in ground meat or pasteurized milk by traditional culture or real-time PCR assay. Eleven fecal samples were positive for all 4 toxin genes, suggesting that preweaned calves may be a likely source for toxigenic C. difficile. On the basis of findings of our study, it can be concluded that multiplex real-time PCR carried out on samples enriched for C. difficile is a reliable, sensitive, and specific diagnostic tool for rapid screening and identification of samples contaminated with C. difficile.

Recognition and prevention of hospital-associated enteric infections in the intensive care unit

The objectives of this article were to review the causes and extent of hospital-associated infectious diarrhea and associated risks in the general hospital ward and intensive care unit (ICU), to compare microorganisms with similar symptoms to aid in recognition that will lead to timely and appropriate treatment and control measures, and to propose infection prevention protocols that could decrease human process errors in the ICU. This literature review describes epidemiology, comparison of microbial characteristics for potential hospital-associated enteric pathogens, diagnosis, and prevention, especially if important in the ICU, and particularly in regard to Clostridium difficile. Enteric organisms that most commonly cause hospital-associated infectious diarrhea in acute care settings and the ICU are C. difficile, rotavirus, and norovirus, although others may also be important, particularly in developing countries. To recognize and control infectious diarrhea successfully in the ICU, intensivists should be aware that epidemiology, risks, and prevention measures may differ between these microorganisms. In addition, intensivists should be ready to implement systems changes related to notification, isolation precautions and prevention, and environmental cleaning in the ICU.

Evaluation of a rapid molecular screening approach for the detection of toxigenic Clostridium difficile in general and subsequent identification of the tcdC Δ117 mutation in human stools

We have developed and validated a rapid molecular screening protocol for toxigenic Clostridium difficile, that also enables the identification of the hypervirulent epidemic 027/NAP1 strain. We describe a multiplex real-time PCR assay, which detects the presence of the tcdA and tcdB genes directly in stool samples. In case of positive PCR results, a separate multiplex real-time PCR typing assay was performed targeting the tcdC gene frame shift mutation at position 117. We prospectively compared the results of the screening PCR with those of a cytotoxicity assay (CTA), and a rapid immuno-enzyme assay for 161 stool samples with a specific request for diagnosis of C. difficile infection (CDI). A total of 16 stool samples were positive by CTA. The screening PCR assay confirmed all 16 samples, and gave a PCR positive signal in eight additional samples. The typing PCR assay detected the tcdC Δ117 mutation in 2/24 samples suggesting the presence of the epidemic strain in these samples. This was confirmed by PCR ribotyping and sequencing of the tcdC gene. Using CTA as the "gold standard", the sensitivity, specificity, positive predictive value, and negative predictive value, for the screening PCR were 100%, 94.4%, 66.7%, and 100%, respectively. In conclusion, PCR may serve as a rapid negative screening assay for patients suspected of having CDI, although the low PPV hamper the use of PCR as a standalone test. However, PCR results may provide valuable information for patient management and minimising the spread of the epidemic 027/NAP1 strain.

Array comparative hybridisation reveals a high degree of similarity between UK and European clinical isolates of hypervirulent Clostridium difficile

Background

Clostridium difficile is a Gram-positive, anaerobic, spore-forming bacterium that is responsible for C. difficile associated disease in humans and is currently the most common cause of nosocomial diarrhoea in the western world. This current status has been linked to the emergence of a highly virulent PCR-ribotype 027 strain. The aim of this work was to identify regions of sequence divergence that may be used as genetic markers of hypervirulent PCR-ribotype 027 strains and markers of the sequenced strain, CD630 by array comparative hybridisation.

Results

In this study, we examined 94 clinical strains of the most common PCR-ribotypes isolated in mainland Europe and the UK by array comparative genomic hybridisation. Our array was comprehensive with 40,097 oligonucleotides covering the C. difficile 630 genome and revealed a core genome for all the strains of 32%. The array also covered genes unique to two PCR-ribotype 027 strains, relative to C. difficile 630 which were represented by 681 probes. All of these genes were also found in the commonly occuring PCR-ribotypes 001 and 106, and the emerging hypervirulent PCR-ribotype 078 strains, indicating that these are markers for all highly virulent strains.

Conclusions

We have fulfilled the aims of this study by identifying markers for CD630 and markers associated with hypervirulence, albeit genes that are not just indicative of PCR-ribotype 027 strains. We have also extended this study and have defined a more stringent core gene set compared to those previously published due to the comprehensive array coverage. Further to this we have defined a list of genes absent from non-toxinogenic strains and defined the nature of the specific toxin deletion in the strain CD37.

A time-series analysis of clostridium difficile and its seasonal association with influenza

OBJECTIVE

To characterize the temporal progression of the monthly incidence of Clostridium difficile infections (CDIs) and to determine whether the incidence of CDI is related to the incidence of seasonal influenza.

DESIGN

A retrospective study of patients in the Nationwide Inpatient Sample during the period from 1998 through 2005.

METHODS

We identified all hospitalizations with a primary or secondary diagnosis of CDI with use of International Classification of Diseases, 9th Revision, Clinical Modification codes, and we did the same for influenza. The incidence of CDI was modeled as an autoregression about a linear trend. To investigate the association of CDI with influenza, we compared national and regional CDI and influenza series data and calculated cross-correlation functions with data that had been prewhitened (filtered to remove temporal patterns common to both series). To estimate the burden of seasonal CDI, we developed a proportional measure of seasonal CDI.

RESULTS

Time-series analysis of the monthly number of CDI cases reveals a distinct positive linear trend and a clear pattern of seasonal variation (R2 = 0.98). The cross-correlation functions indicate that influenza activity precedes CDI activity on both a national and regional basis. The average burden of seasonal (ie, winter) CDI is 23%.

CONCLUSIONS

The epidemiologic characteristics of CDI follow a pattern that is seasonal and associated with influenza, which is likely due to antimicrobial use during influenza seasons. Approximately 23% of average monthly CDI during the peak 3 winter months could be eliminated if CDI remained at summer levels.

Clostridium difficile infection: a critical overview

Clostridium difficile is a gram-positive, spore-forming, toxin-producing anaerobic bacillus identified as the causal agent of a variety of manifestations typically isolated to the colon, but in its severe form, it can lead to sepsis and death. C. difficile infection due to a toxin gene variant strain (BI/NAP1) has been identified at the center of outbreaks and has resulted in increased mortality. Many questions remain as to how this strain appeared so quickly and has harmed or killed so many patients. We present a review of C. difficile infection, discussing its clinical presentation, diagnosis, management, and prevention.

Clostridium difficile and inflammatory bowel disease

The past decade has seen an alarming increase in the burden of disease associated with Clostridium difficile. Several studies have now demonstrated an increasing incidence of C difficile infection in patients with inflammatory bowel disease (IBD) with a more severe course of disease compared with the non-IBD population. This article summarizes the available literature on the impact of C difficile infection on IBD and discusses the various diagnostic testing and treatment options available. Also reviewed are clinical situations specific to patients with IBD that are important for the treating physician to recognize.

Clostridium difficile and inflammatory bowel disease

The past decade has seen an alarming increase in the burden of disease associated with Clostridium difficile. Several studies have now demonstrated an increasing incidence of C difficile infection in patients with inflammatory bowel disease (IBD) with a more severe course of disease compared with the non-IBD population. This article summarizes the available literature on the impact of C difficile infection on IBD and discusses the various diagnostic testing and treatment options available. Also reviewed are clinical situations specific to patients with IBD that are important for the treating physician to recognize.

Serum anti-toxin B antibody correlates with protection from recurrent Clostridium difficile infection (CDI)

BACKGROUND

Previous studies have demonstrated a correlation between Clostridium difficile anti-toxin A serum antibodies and protection against symptomatic disease and recurrence.

METHODS

A neutralizing monoclonal antibody to C. difficile toxin A (CDA1) developed by MBL and Medarex, Inc. was studied in a phase II, randomized, double-blind, placebo-controlled trial in patients receiving standard of care treatment for C. difficile infection (CDI). Twenty-nine subjects received a single intravenous infusion of 10mg/kg CDA1 and 17 subjects received placebo and were evaluated for recurrence of CDI during the 56-day study period. Serum antibodies against C. difficile toxin A and B were measured by ELISA and cytotoxicity assay at various time points before and after infusion.

FINDINGS

CDI recurrence occurred in 5 of 29 (17%) in the CDA1 group and 3 of 17 (18%) (p=NS) in the placebo group with a trend toward delay in time to recurrence in the group treated with CDA1. The geometric mean concentration of antibody to an epitope of the receptor-binding domain of toxin B (0.300 and 1.20microg/ml, respectively; p=0.02) and geometric mean titer of neutralizing B antibody (8.00 and 100, respectively; p=0.02) at study day 28 were lower for those subjects with recurrence compared to those who did not recur. In addition, a significantly greater proportion of subjects who recurred were infected with the epidemic BI/NAP1/027 strain compared with those that did not recur (88% vs. 22%; p=0.002). Finally, in a multiple logistic regression analysis neutralizing anti-toxin B at day 14 (p<0.001), anti-toxin A at day 28 (p<0.001) and infection with the BI/NAP1/027 strain at enrollment (p=0.002) were all predictive of CDI recurrence.

INTERPRETATION

In this prospective study, lower concentrations of neutralizing anti-toxin B and anti-toxin A antibody and infection with the BI/NAP1/027 strain of C. difficile were significantly associated with recurrence of CDI.

Diversity of moxifloxacin resistance during a nosocomial outbreak of a predominantly ribotype ARU 027 Clostridium difficile diarrhea

To characterize the extent and diversity of moxifloxacin resistance among Clostridium difficile isolates recovered during a predominantly Anaerobe Reference Unit (ARU) ribotype 027-associated nosocomial outbreak of antibiotic associated diarrhea we measured the susceptibility of 34 field isolates and 6 laboratory strains of C. difficile to moxifloxacin. We ribotyped the isolates as well as assaying them by PCR for the metabolic gene, gdh, and the virulence genes, tcdA, tcdB, tcdC, cdtA and cdtB. All the laboratory isolates, including the historical ARU 027 isolate Cd196, were susceptible to moxifloxacin (<or=2 microg/mL). 13 field isolates were susceptible to <or=2 microg/mL. Five were resistant to from 4 to 12 microg/mL (moderate resistance); 16 were resistant to >or=16 microg/mL (high resistance). We sequenced the quinolone resistance determining regions of gyrA (position 71-460) and gyrB (position 1059-1448) from two susceptible laboratory strains, all five isolates with moderate resistance and two highly resistant isolates. Two highly resistant isolates (Pitt 40, ribotype ARU 027 and Pitt 33, ribotype ARU 001) had the same C245T (Thr(82)Delta Ile) mutation. No other changes were seen. Amplification with primer pairs specific for the C245T mutant gyrA and for the wild type gene respectively confirmed all 16 highly resistant ARU 027 isolates, as well as the highly resistant isolates from other ribotypes, had the C245T mutation and that the mutation was absent from all other isolates. Among the five isolates with moderate resistance we found combinations of mutations within gyrA (T128A, Val(43)Delta Asp and G349T, Ala(117)Delta Ser) and gyrB (G1276A, Arg(426)Delta Asn). The G1396A (Glu(466)Delta Lys) mutation was not associated with increased resistance.

Comparative genome and phenotypic analysis of Clostridium difficile 027 strains provides insight into the evolution of a hypervirulent bacterium

A genome comparison of non-epidemic and epidemic strains of Clostridium difficile reveals gene gains that could explain how a hypervirulent strain has emerged

Background

The continued rise of Clostridium difficile infections worldwide has been accompanied by the rapid emergence of a highly virulent clone designated PCR-ribotype 027. To understand more about the evolution of this virulent clone, we made a three-way genomic and phenotypic comparison of an 'historic' non-epidemic 027 C. difficile (CD196), a recent epidemic and hypervirulent 027 (R20291) and a previously sequenced PCR-ribotype 012 strain (630).

Results

Although the genomes are highly conserved, the 027 genomes have 234 additional genes compared to 630, which may contribute to the distinct phenotypic differences we observe between these strains relating to motility, antibiotic resistance and toxicity. The epidemic 027 strain has five unique genetic regions, absent from both the non-epidemic 027 and strain 630, which include a novel phage island, a two component regulatory system and transcriptional regulators.

Conclusions

A comparison of a series of 027 isolates showed that some of these genes appeared to have been gained by 027 strains over the past two decades. This study provides genetic markers for the identification of 027 strains and offers a unique opportunity to explain the recent emergence of a hypervirulent bacterium.

Bacteremia with a large clostridial toxin-negative, binary toxin-positive strain of Clostridium difficile

Bacteremia caused by Clostridium difficile is rare. In this report, we describe a case of C. difficile bacteremia caused by an unusual strain of C. difficile. The isolate contained neither toxin A nor B genes, however, binary toxin genes were present (tcdA(-), tcdB(-), cdtA(+), cdtB(+)) and a 7.2-kb element unrelated to the PaLoc was found inserted within the PaLoc integration site. The clinical relevance of the isolate could not be determined.

A survey of physician's attitudes regarding management of severe group A streptococcal infections

Intravenous immunoglobulins (IVIG) use in the management of streptococcal toxic shock syndrome remains highly controversial. To evaluate the current management of severe group A streptococcal infections and the feasibility of a randomized controlled trial comparing immunoglobulins versus placebo for streptococcal toxic shock syndrome and/or necrotizing fasciitis, a 32-question mail and web-based survey of Canadian infectious disease specialists was conducted between December 2003 and February 2004. Overall, 172 respondents (90.5%) recommended immunoglobulins as adjunctive treatment of streptococcal toxic shock compared to 67 (35.3%) for fasciitis without toxic shock and 93 (48.9%) for invasive group A streptococcal infections with hypotension. A considerable proportion of respondents agreed that a randomized clinical trial in streptococcal toxic shock (70.1%, 131/187) and necrotizing fasciitis without toxic shock (88.2%, 162/186) would be ethical. From these, a great majority would be willing to enroll patients in a trial comparing IVIG to placebo for streptococcal toxic shock (125/131, 95.4%) and necrotizing fasciitis without shock (152/162, 93.8%). These initial results clearly demonstrate ambivalence in the utilization of intravenous immunoglobulins (IVIG) in invasive group A streptococcal infections in Canada and emphasize the need for further clinical data on immunoglobulin use in streptococcal toxic shock syndrome. They also demonstrate that, although the majority of physicians recommend immunoglobulins, there is important variability between physician recommendations with regard to the indications of use, dose, and time of administration.

Clostridium difficile associated infection, diarrhea and colitis

A new, hypervirulent strain of Clostridium difficile, called NAP1/BI/027, has been implicated in C. difficile outbreaks associated with increased morbidity and mortality since the early 2000s. The epidemic strain is resistant to fluoroquinolones in vitro, which was infrequent prior to 2001. The name of this strain reflects its characteristics, demonstrated by different typing methods: pulsed-field gel electrophoresis (NAP1), restriction endonuclease analysis (BI) and polymerase chain reaction (027). In 2004 and 2005, the US Centers for Disease Control and Prevention (CDC) emphasized that the risk of C. difficile-associated diarrhea (CDAD) is increased, not only by the usual factors, including antibiotic exposure, but also gastrointestinal surgery/manipulation, prolonged length of stay in a healthcare setting, serious underlying illness, immune-compromising conditions, and aging. Patients on proton pump inhibitors (PPIs) have an elevated risk, as do peripartum women and heart transplant recipients. Before 2002, toxic megacolon in C. difficile-associated colitis (CDAC), was rare, but its incidence has increased dramatically. Up to two-thirds of hospitalized patients may be infected with C. difficile. Asymptomatic carriers admitted to healthcare facilities can transmit the organism to other susceptible patients, thereby becoming vectors. Fulminant colitis is reported more frequently during outbreaks of C. difficile infection in patients with inflammatory bowel disease (IBD). C. difficile infection with IBD carries a higher mortality than without underlying IBD. This article reviews the latest information on C. difficile infection, including presentation, vulnerable hosts and choice of antibiotics, alternative therapies, and probiotics and immunotherapy. We review contact precautions for patients with known or suspected C. difficile-associated disease. Healthcare institutions require accurate and rapid diagnosis for early detection of possible outbreaks, to initiate specific therapy and implement effective control measures. A comprehensive C. difficile infection control management rapid response team (RRT) is recommended for each health care facility. A communication network between RRTs is recommended, in coordination with each country’s department of health. Our aim is to convey a comprehensive source of information and to guide healthcare professionals in the difficult decisions that they face when caring for these oftentimes very ill patients.

Predictors of serious complications due to Clostridium difficile infection

BACKGROUND

Identifying individuals with severe Clostridium difficile infection (CDI) at risk for major complications has become an important objective. Presence of clinical variables that predict complications from CDI would have the potential to strongly influence management.

AIM

To determine which clinical variables predict complications from CDI.

METHODS

Cross-sectional study of all individuals admitted to Temple University Hospital between 12/1/03 and 7/1/08 with the primary discharge diagnosis of CDI were eligible. Only patients experiencing their first episode of CDI were included. Abstracted data included demographic, physiological, laboratory, radiological, endoscopic, pharmacy and outcome data. Response was categorized as none, partial or complete. Complications attributed to CDI were defined as colon resection or death.

RESULTS

Overall 32 of 200 patients (16%) experienced a complication due to CDI including death (n = 20) and colectomy (n = 12). White blood cell count above 30,000 cells/mm(3) (OR = 4.06; 95% CI, 1.28-12.87) and a rise in the creatinine to over 50% above baseline (OR = 7.13; 95% CI, 3.05-16.68) predicted a complication. AROC for percent rise in serum creatinine was 0.73 (95% CI: 0.64-0.85) and 0.62 (95% CI: 0.58-0.80) for white blood cell count.

CONCLUSIONS

Severe white blood cell count elevation and a rise in the creatinine to over 50% above baseline are important independent predictors of serious adverse events due to CDI. These patients likely would benefit from more intensive care and early surgical consultation.

Assessment of changes in the epidemiology of Clostridium difficile isolated from diarrheal patients in Hungary

150 Clostridium difficile strains isolated from diarrheal feces were collected from three parts of Hungary and the presence of genes responsible for toxin A and B, and binary toxin production were examined. MIC distribution against clindamycin, erythromycin, metronidazole, moxifloxacin and rifampin of 80 toxigenic strains selected from the above-mentioned strains and 20 large clostridial toxins (LCTs)-positive strains chosen from our earlier strain collection were determined. 80% of the examined 150 strains were positive for both tcdA and tcdB, and no toxin A-negative, toxin B-positive isolates were found during the study period. 5.3% of toxigenic strains proved to be positive for binary toxin too. Among binary toxin-positive strains, one strain showed the same pattern characteristic of PCR ribotype 027. Comparison of recent findings and our earlier results, the prevalence of toxin-producing and binary toxin-positive strains among C. difficile isolated from diarrheal specimens increased. No metronidazole resistant isolate was detected among strains isolated in 2002-2003 and 2006-2007. The rates of resistance to erythromycin, clindamycin, moxifloxacin and rifampin among strains isolated between 2006 and 2007 were 25%, 27.5%, 25% and 6.3%, respectively. Erythromycin resistance was frequently associated with clindamycin and moxifloxacin resistance, however this resistant phenotype was not found among strains isolated in 2002-2003.

What have we learned about antimicrobial use and the risks for Clostridium difficile-associated diarrhoea?

Clostridium difficile is recognized as a major cause of antibiotic-associated diarrhoea and colitis. Antimicrobial agents have been repeatedly recognized as a causative risk for C. difficile-associated diarrhoea (CDAD) and more recently fluoroquinolones have been particularly implicated. Unfortunately, not all reports of antimicrobial associations with CDAD have excluded variables other than antimicrobial use. Prevention of CDAD usually involves infection control interventions and antimicrobial restriction policies may not be fully substantiated by currently available data; however, antimicrobial drug restriction seems prudent in outbreak situations.

Clostridium difficile and inflammatory bowel disease

Clostridium difficile colitis has doubled in North America over the past 5 years and recent reports have demonstrated an increase in incidence and severity of these infections in patients with inflammatory bowel disease (IBD; Crohn's disease, ulcerative colitis). Studies from single institutions as well as trends identified in nationwide inpatient databases have shown that IBD patients with concomitant C. difficile infection experience increased morbidity and mortality. Results from our center have shown that over half of C. difficile-infected IBD patients will require hospitalization and the colectomy rate may approach 20%. Because C. difficile colitis will both mimic and precipitate an IBD flare, it is essential that clinicians be vigilant to identify and address this infectious complication, as empiric treatment with corticosteroids without appropriate antibiotics may precipitate deterioration. The majority of IBD patients appear to contract C. difficile as outpatients, and a prior history of colitis appears to be the most significant risk factor for acquiring this infection. In addition to C. difficile colitis, IBD patients are now known to be at risk for C. difficile enteritis as well as infections in reconstructed ileoanal pouches. An additional challenge facing C. difficile infections in IBD patients is the decreased efficacy of metronidazole, and the need for oral vancomycin in patients requiring hospitalization. In this review we summarize the present knowledge regarding C. difficile infection in the setting of IBD, including unique clinical scenarios facing IBD patients, diagnostic algorithms, and treatment approaches.

Peripartum Clostridium difficile infection: case series and review of the literature

Clostridium difficile infection (CDI) in nonhospitalized patients has been reported with increased frequency. An association between CDI and pregnancy has not been stressed. This review will report 4 cases of peripartum CDI with characterization of the infecting strain and a literature review. A PubMed search identified 24 recorded cases of peripartum CDI; information was available for 14 cases. Most patients (91%) received prophylactic antibiotics during delivery or for treatment of bacterial infections (50%). All patients reported diarrhea. Two of our reported cases without known risk factors were found by polymerase chain reaction analysis to be infected with an epidemic and hypervirulent C difficile strain. These cases demonstrate the need for clinicians to consider CDI in patients with severe diarrhea, even if they do not have the traditional risk factors for CDI, such as antibiotic use or concurrent hospitalizations. Further research into the scope and risk factors for peripartum CDI is warranted.

Attributable outcomes of endemic Clostridium difficile-associated disease in nonsurgical patients

CDAD led to significantly worse outcomes in these patients.

Data are limited on the attributable outcomes of Clostridium difficile–associated disease (CDAD), particularly in CDAD-endemic settings. We conducted a retrospective cohort study of nonsurgical inpatients admitted for >48 hours in 2003 (N = 18,050). The adjusted hazard ratios for readmission (hazard ratio 2.19, 95% confidence interval [CI] 1.87–2.55) and deaths within 180 days (hazard ratio 1.23, 95% CI 1.03–1.46) were significantly different among CDAD case-patients and noncase patients. In a propensity score matched-pairs analysis that used a nested subset of the cohort (N = 706), attributable length of stay attributable to CDAD was 2.8 days, attributable readmission at 180 days was 19.3%, and attributable death at 180 days was 5.7%. CDAD patients were significantly more likely than controls to be discharged to a long-term-care facility or outside hospital. Even in a nonoutbreak setting, CDAD had a statistically significant negative impact on patient illness and death, and the impact of CDAD persisted beyond hospital discharge.

Infection control measures to limit the spread of Clostridium difficile

Clostridium difficile-associated diarrhoea (CDAD) presents mainly as a nosocomial infection, usually after antimicrobial therapy. Many outbreaks have been attributed to C. difficile, some due to a new hyper-virulent strain that may cause more severe disease and a worse patient outcome. As a result of CDAD, large numbers of C. difficile spores may be excreted by affected patients. Spores then survive for months in the environment; they cannot be destroyed by standard alcohol-based hand disinfection, and persist despite usual environmental cleaning agents. All these factors increase the risk of C. difficile transmission. Once CDAD is diagnosed in a patient, immediate implementation of appropriate infection control measures is mandatory in order to prevent further spread within the hospital. The quality and quantity of antibiotic prescribing should be reviewed to minimise the selective pressure for CDAD. This article provides a review of the literature that can be used for evidence-based guidelines to limit the spread of C. difficile. These include early diagnosis of CDAD, surveillance of CDAD cases, education of staff, appropriate use of isolation precautions, hand hygiene, protective clothing, environmental cleaning and cleaning of medical equipment, good antibiotic stewardship, and specific measures during outbreaks. Existing local protocols and practices for the control of C. difficile should be carefully reviewed and modified if necessary.

Comparison of real-time PCR for detection of the tcdC gene with four toxin immunoassays and culture in diagnosis of Clostridium difficile infection

We have developed a rapid real-time PCR method using fluorescence resonance energy transfer probes and the LightCycler (Roche Diagnostics), which will detect the presence of the tcdC gene of Clostridium difficile in stool samples. Our PCR method also will identify the presence of base pair deletions, one of which (18 bp) has been associated with the "epidemic" toxin-hyperproducing strains. We compared the results of this PCR with those of three C. difficile toxin-detecting enzyme immunoassays (EIAs), an EIA for the detection of glutamate dehydrogenase (GDH), and culture of C. difficile. A total of 200 stool specimens were studied by the methods under comparison. C. difficile was isolated from 49 specimens by culture, and 44 of these were confirmed as containing one of the genes associated with toxin production ("toxigenic culture"). Using toxigenic culture as the "gold standard", the sensitivities, specificities, and positive and negative predictive values, respectively, of the assays were 48%, 98%, 88%, and 87% for the Premier toxin A and B test; 48%, 99%, 91%, and 87% for the ImmunoCard toxin A & B test; 48%, 84%, 46%, and 85% for the Xpect C. difficile toxin A/B test; 32%, 100%, 100%, and 84% for the Triage C. difficile panel (for toxin A); and 86%, 97%, 90%, and 96% for the LightCycler PCR. Thus, in comparison to the sensitivity of toxigenic culture, the sensitivities of the toxin immunoassays were unacceptably low, while the LightCycler real-time PCR assay for the detection of the tcdC gene of C. difficile is sensitive and specific.

Heterogeneity of large clostridial toxins: importance of Clostridium difficile toxinotypes

Clostridium difficile toxinotypes are groups of strains defined by changes in the PaLoc region encoding two main virulence factors: toxins TcdA and TcdB. Currently, 24 variant toxinotypes (I-XXIV) are known, in addition to toxinotype 0 strains, which contain a PaLoc identical to the reference strain VPI 10463. Variant toxinotypes can also differ from toxinotype 0 strains in their toxin production pattern. The most-studied variant strains are TcdA-, TcdB+ (A-B+) strains and binary toxin CDT-producing strains. Variations in toxin genes are also conserved on the protein level and variant toxins can differ in size, antibody reactivity, pattern of intracellular targets (small GTPases) and consequently in their effects on the cell. Toxinotypes do not correlate with particular forms of disease or patient populations, but some toxinotypes (IIIb and VIII) are currently associated with disease of increased severity and outbreaks worldwide. Variant toxinotypes are very common in animal hosts and can represent from 40% to 100% of all isolates. Among human isolates, variant toxinotypes usually represent up to 10% of strains but their prevalence is increasing.

Fucoidin prevents Clostridium difficile toxin-A-induced ileal enteritis in mice

Recent reports suggest increased incidence and severity of Clostridium difficile-associated diseases. These facts have raised the need for additional clarification of pathogenesis and for a search for new therapeutic strategies. This study evaluated the effects of the polysaccharide fucoidin, an L-selectin blocker, on toxin-A-induced mouse enteritis. Fucoidin (25 mg/kg) or saline (0.1 ml) were injected systemically (ocular plexus) 5 min prior to local challenge with toxin A (5 microg/ileal loop) or phosphate-buffered saline (PBS). Intestinal fluid volume/length and ileal loop weight/length ratios were calculated 3 h later. Ileal tissues were collected for histopathology and measurement of myeloperoxidase and adenosine deaminase activity. Fucoidin significantly (P < 0.05) prevented the toxin-A-induced increase in weight/length and volume/length ratios and reduced mucosal disruption, as shown in histopathology. Fucoidin also significantly (P < 0.05) reduced toxin-A-induced myeloperoxidase and adenosine deaminase activities. In conclusion, fucoidin reduces tissue injury and inflammation in toxin-A-induced mouse enteritis.

Short- and long-term attributable costs of Clostridium difficile-associated disease in nonsurgical inpatients

BACKGROUND

The incidence of Clostridium difficile-associated disease (CDAD) is increasing. There are few data on the short-term and long-term attributable costs of CDAD. The objective of this study was to determine the acute and 180-day attributable inpatient costs of CDAD.

METHODS

We performed a retrospective cohort study of all patients without operating room costs who were admitted for > or =48 h to Barnes-Jewish Hospital, a tertiary care hospital in St. Louis, Missouri, 1 January 2003-31 December 2003 (n = 24,691). Attributable costs of CDAD were determined by multivariable linear regression and propensity-score matched-pairs analyses (n = 684) for the hospitalization in which CDAD occurred and per patient over a 180-day period, including the initial hospitalization.

RESULTS

CDAD was associated with $2454 (95% confidence interval, $2380-$2950; increase in cost, 41%) attributable costs per CDAD episode by linear regression and with $3240 attributable costs (P < .001; increase in cost, 33%) by propensity-score matched-pairs analysis. CDAD was associated with $5042 (95% confidence interval, $3797-$6481; increase in cost, 53%) attributable inpatient costs over 180 days by linear regression and with $7179 attributable costs for inpatient care (P < .001; 48% increase in costs) by propensity-score matched-pairs analysis.

CONCLUSIONS

CDAD was associated with a significant increase in costs for inpatient care and increased costs at 180 days after the initial hospitalization when the CDAD episode occurred.