Colitis due to Clostridium difficile toxins: underdiagnosed, highly virulent, and nosocomial

Clostridioides difficile Colitis

Clostridioides difficile colitis is an important source of hospital-acquired diarrhea associated with antibiotic use. Symptoms are profuse watery diarrhea, typically following a course of antibiotics; however, some cases of fulminant disease may manifest with shock, ileus, or megacolon. Nonfulminant colitis is treated with oral fidaxomicin. C difficile colitis has a high potential for recurrence, and recurrent episodes are also treated with fidaxomicin. Bezlotoxumab is another medication that may be used in populations at high risk for further recurrence. Fulminant disease is treated with maximal medical therapy and early surgical consultation. Antibiotic stewardship is critical to preventing C difficile colitis.

Pre-colonization with the fungus Candida glabrata exacerbates infection by the bacterial pathogen Clostridioides difficile in a murine model

The contributions of commensal fungi to human health and disease are not well understood. Candida species such as C. albicans and C. glabrata are opportunistic pathogenic fungi and common colonizers of the human intestinal tract. They have been shown to affect the host immune system and interact with the gut microbiome and pathogenic microorganisms. Therefore, Candida species could be expected to play important ecological roles in the host gastrointestinal tract. Previously, our group demonstrated that pre-colonization of mice with C. albicans protected them against lethal C. difficile infection (CDI). Here, we show that mice pre-colonized with C. glabrata succumbed to CDI more rapidly than mice that were not pre-colonized suggesting an enhancement in C. difficile pathogenesis. Further, when C. difficile was added to pre-formed C. glabrata biofilms, an increase in matrix and overall biomass was observed. These effects were also shown with C. glabrata clinical isolates. Interestingly, the presence of C. difficile increased C. glabrata biofilm susceptibility to caspofungin, indicating potential effects on the fungal cell wall. Defining this intricate and intimate relationship will lead to an understanding of the role of Candida species in the context of CDI and novel aspects of Candida biology. IMPORTANCE Most microbiome studies have only considered the bacterial populations while ignoring other members of the microbiome such as fungi, other eukaryotic microorganisms, and viruses. Therefore, the role of fungi in human health and disease has been significantly understudied compared to their bacterial counterparts. This has generated a significant gap in knowledge that has negatively impacted disease diagnosis, understanding, and the development of therapeutics. With the development of novel technologies, we now have an understanding of mycobiome composition, but we do not understand the roles of fungi in the host. Here, we present findings showing that Candida glabrata, an opportunistic pathogenic yeast that colonizes the mammalian gastrointestinal tract, can impact the severity and outcome of a Clostridioides difficile infection (CDI) in a murine model. These findings bring attention to fungal colonizers during CDI, a bacterial infection of the gastrointestinal tract.

Antibiotic Treatment Induces Long-Lasting Effects on Gut Microbiota and the Enteric Nervous System in Mice

The side effects of antibiotic treatment directly correlate with intestinal dysbiosis. However, a balanced gut microbiota supports the integrity of the enteric nervous system (ENS), which controls gastrointestinal neuromuscular functions. In this study, we investigated the long-term effects of antibiotic-induced microbial dysbiosis on the ENS and the impact of the spontaneous re-establishment of the gut microbiota on gastrointestinal functions. C57BL/6J mice were treated daily for two weeks with antibiotics. After 0-6 weeks of antibiotics wash-out, we determined (a) gut microbiota composition, (b) gastrointestinal motility, (c) integrity of the ENS, (d) neurochemical code, and (e) inflammation. Two weeks of antibiotic treatment significantly altered gut microbial composition; the genera Clostridium, Lachnoclostridium, and Akkermansia did not regain their relative abundance following six weeks of antibiotic discontinuation. Mice treated with antibiotics experienced delayed gastrointestinal transit and altered expression of neuronal markers. The anomalies of the ENS persisted for up to 4 weeks after the antibiotic interruption; the expression of neuronal HuC/D, glial-derived neurotrophic factor (Gdnf), and nerve growth factor (Ngf) mRNA transcripts did not recover. In this study, we strengthened the idea that antibiotic-induced gastrointestinal dysmotility directly correlates with gut dysbiosis as well as structural and functional damage to the ENS.

A leaky human colon model reveals uncoupled apical/basal cytotoxicity in early Clostridioides difficile toxin exposure

Clostridioides difficile (C. difficile) toxins A (TcdA) and B (TcdB) cause antibiotic-associated colitis in part by disrupting epithelial barrier function. Accurate in vitro models are necessary to detect early toxicity kinetics, investigate disease etiology, and develop preclinical models for new therapies. Properties of cancer cell lines and organoids inherently limit these efforts. We developed adult stem cell-derived monolayers of differentiated human colonic epithelium (hCE) with barrier function, investigated the impact of toxins on apical/basal aspects of monolayers, and evaluated whether a leaky epithelial barrier enhances toxicity. Single-cell RNA-sequencing (scRNAseq) mapped C. difficile-relevant genes to human lineages. Transcriptomics compared hCE to Caco-2, informed timing of in vitro stem cell differentiation, and revealed transcriptional responses to TcdA. Transepithelial electrical resistance (TEER) and fluorescent permeability assays measured cytotoxicity. Contribution of TcdB toxicity was evaluated in a diclofenac-induced leaky gut model. scRNAseq demonstrated broad and variable toxin receptor expression. Absorptive colonocytes in vivo displayed increased toxin receptor, Rho GTPase, and cell junction gene expression. Advanced TcdA toxicity generally decreased cytokine/chemokine and increased tight junction and death receptor genes. Differentiated Caco-2 cells remained immature whereas hCE monolayers were similar to mature colonocytes in vivo. Basal exposure of TcdA/B caused greater toxicity and apoptosis than apical exposure. Apical exposure to toxins was enhanced by diclofenac. Apical/basal toxicities are uncoupled with more rapid onset and increased magnitude postbasal toxin exposure. Leaky junctions enhance toxicity of apical TcdB exposure. hCE monolayers represent a physiologically relevant and sensitive system to evaluate the impact of microbial toxins on gut epithelium.NEW & NOTEWORTHY Novel human colonocyte monolayer cultures, benchmarked by transcriptomics for physiological relevance, detect early cytopathic impacts of Clostridioides difficile toxins TcdA and TcdB. A fluorescent ZO-1 reporter in primary human colonocytes is used to track epithelial barrier disruption in response to TcdA. Basal TcdA/B exposure generally caused more rapid onset and cytotoxicity than apical exposure. Transcriptomics demonstrate changes in tight junction, chemokine, and cytokine receptor gene expression post-TcdA exposure. Diclofenac-induced leaky epithelium enhanced apical exposure toxicity.

Clostridium difficile Induced Inflammasome Activation and Coagulation Derangements

C. difficile enterocolitis (CDAC) is the most common hospital infection, burdened by an increased incidence of coagulation-related complications such as deep vein thrombosis (DVT) and disseminated intravascular coagulation (DIC) as well as a significant sepsis-related mortality. In this review, we analyzed the available data concerning the correlation between coagulation complications related to C. difficile infection (CDI) and inflammasome activation, in particular the pyrin-dependent one. The little but solid available preclinical and clinical evidence shows that inflammasome activation increases the risk of venous thromboembolism (VTE). As proof of this, it has been observed that in vitro inhibition of the molecules (e.g., tissue factor) mainly involved in coagulation activation could block the process. In vivo studies show that it could be possible to reduce the incidence of complications associated with C. difficile infection (CDI) and mortality due to a state of hypercoagulability. A personalized therapeutic approach to reduce the inflammatory activity and prevent thromboembolic complications could be preliminarily defined to reduce mortality.

Study of microbiome changes in patients with ulcerative colitis in the Central European part of Russia

Ulcerative colitis (UC) is an inflammatory disease that affects the colon and rectum. Recently, evidence has emerged about the influence of microbiota on the development of this disease. However, studies on the role of intestinal microbiota in the pathogenesis of UC have been incomplete. In addition, there are no comprehensive studies of the causes of ulcerative colitis and data on the microbiological composition of the intestines of patients with ulcerative colitis in Russia. We carried out a study of the microbiological composition of the intestines of patients with ulcerative colitis and healthy individuals. We found significant changes in the bacteria genera and species in patients with UC compared with the control group using sequencing on the IonTorrent PGM system and subsequent data analysis. In our study we observed a significant increase of the genus Haemophilus, Olsenella, Prevotella, Cedecea, Peptostreptococcus, Faecalibacterium, Lachnospira, Negativibacillus, Butyrivibrio, and the species Bacteroides coprocola, Phascolarctobacterium succinatutens, Dialister succinatiphilus, Sutterella wadsworthensis, Faecalibacterium prausnitzii in patients with ulcerative colitis. In addition, in patients with ulcerative colitis there was a significant decrease in the genus Fusicatenibacter, Butyricimonas, Lactococcus, Eisenbergiella, Coprobacter, Cutibacterium, Falsochrobactrum, Brevundimonas, Yersinia, Leuconostoc and in the species Fusicatenibacter saccharivorans. We found confirmation of our data with literary sources and studies of UC. In addition, we discovered a few taxa such as Negativibacillus spp. and Falsochrobactrum spp. that have not been previously found in human stool samples. Our data confirm that more research is needed to understand the role of microbiome changes in the development of UC in different people populations.

Reducing Spread of Infections with a Photocatalytic Reactor-Potential Applications in Control of Hospital Staphylococcus aureus and Clostridioides difficile Infections and Inactivation of RNA Viruses

Contaminated surfaces and indoor environments are important sources of infectious spread within hospital and non-hospital facilities. Bacterial infections such as infections with Clostridioides (formerly Clostridium) difficile (C. difficile) and Staphylococcus aureus (S. aureus) and its antibiotic resistant strains continue to pose a significant risk to healthcare workers and patients. Additionally, the recent emergence of the coronavirus disease 2019 (COVID-19) pandemic, which is caused by the novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), highlights the need for safe and effective methods to decontaminate surfaces to control infection spread in hospitals and the community. To address these critical needs, we tested a photocatalytic reactor decontamination method to disinfect contaminated surfaces in a hospital and a laboratory setting. By placing the reactor in a test hospital room, growth of S. aureus and C. difficile were significantly reduced compared with a control room. Additionally, using a model enveloped positive-sense single-stranded RNA virus, dengue virus type 2 (DENV2), we showed that the use of the photocatalytic reactor reduces viral infectivity. Collectively, the results demonstrate the potential utility of photocatalytic reactors in reducing the spread of highly contagious bacterial and viral infections through contaminated surfaces and environments.

Recommendations for the diagnosis and treatment of Clostridioides difficile infection: An official clinical practice guideline of the Spanish Society of Chemotherapy (SEQ), Spanish Society of Internal Medicine (SEMI) and the working group of Postoperative Infection of the Spanish Society of Anesthesia and Reanimation (SEDAR)

This document gathers the opinion of a multidisciplinary forum of experts on different aspects of the diagnosis and treatment of Clostridioides difficile infection (CDI) in Spain. It has been structured around a series of questions that the attendees considered relevant and in which a consensus opinion was reached. The main messages were as follows: CDI should be suspected in patients older than 2 years of age in the presence of diarrhea, paralytic ileus and unexplained leukocytosis, even in the absence of classical risk factors. With a few exceptions, a single stool sample is sufficient for diagnosis, which can be sent to the laboratory with or without transportation media for enteropathogenic bacteria. In the absence of diarrhoea, rectal swabs may be valid. The microbiology laboratory should include C. difficile among the pathogens routinely searched in patients with diarrhoea. Laboratory tests in different order and sequence schemes include GDH detection, presence of toxins, molecular tests and toxigenic culture. Immediate determination of sensitivity to drugs such as vancomycin, metronidazole or fidaxomycin is not required. The evolution of toxin persistence is not a suitable test for follow up. Laboratory diagnosis of CDI should be rapid and results reported and interpreted to clinicians immediately. In addition to the basic support of all diarrheic episodes, CDI treatment requires the suppression of antiperistaltic agents, proton pump inhibitors and antibiotics, where possible. Oral vancomycin and fidaxomycin are the antibacterials of choice in treatment, intravenous metronidazole being restricted for patients in whom the presence of the above drugs in the intestinal lumen cannot be assured. Fecal material transplantation is the treatment of choice for patients with multiple recurrences but uncertainties persist regarding its standardization and safety. Bezlotoxumab is a monoclonal antibody to C. difficile toxin B that should be administered to patients at high risk of recurrence. Surgery is becoming less and less necessary and prevention with vaccines is under research. Probiotics have so far not been shown to be therapeutically or preventively effective. The therapeutic strategy should be based, rather than on the number of episodes, on the severity of the episodes and on their potential to recur. Some data point to the efficacy of oral vancomycin prophylaxis in patients who reccur CDI when systemic antibiotics are required again.

The Carbamate Aldicarb Altered the Gut Microbiome, Metabolome, and Lipidome of C57BL/6J Mice

The gut microbiome is highly involved in numerous aspects of host physiology, from energy harvest to stress response, and can confer many benefits to the host. The gut microbiome development could be affected by genetic and environmental factors, including pesticides. The carbamate insecticide aldicarb has been extensively used in agriculture, which raises serious public health concerns. However, the impact of aldicarb on the gut microbiome, host metabolome, and lipidome has not been well studied yet. Herein, we use multiomics approaches, including16S rRNA sequencing, shotgun metagenomics sequencing, metabolomics, and lipidomics, to elucidate aldicarb-induced toxicity in the gut microbiome and the host metabolic homeostasis. We demonstrated that aldicarb perturbed the gut microbiome development trajectory, enhanced gut bacterial pathogenicity, altered complex lipid profile, and induced oxidative stress, protein degradation, and DNA damage. The brain metabolism was also disturbed by the aldicarb exposure. These findings may provide a novel understanding of the toxicity of carbamate insecticides.

Do preoperative oral antibiotics increase Clostridium difficile infection rates? An analysis of 13 959 colectomy patients

AIM

The aim of this study was to determine whether or not preoperative oral antibiotic preparation (POAP) increases the rate of Clostridium difficile colitis (CDC) in patients undergoing colectomy.

METHOD

In 2015, data for colectomies had been collected prospectively and recorded in the targeted colectomy option of the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP). This was available for retrospective analysis. Data available for analysis included elective and emergency status, POAP, surgical approach, primary anastomosis and CDC status. The effect of POAP on CDC was analysed and risk adjusted for 14 separate preoperative variables.

RESULTS

In all, 13 959 adult patients underwent a colectomy in 2015 (POAP group 5311 and non- POAP group 8648). The overall rate of CDC in colectomy patients was 1.6% (227/13 959). On univariate analysis, CDC was significantly less common in the POAP group than in the non-POAP group (1.2% vs 1.9%, P = 0.003). Univariate analysis of a further 41 preoperative variables revealed 14 to be associated with CDC. However, after risk adjustment with these 14 variables, POAP lost its statistical significance (adjusted OR 0.902, 95% CI 0.584-1.486, P = 0.685). Only patients with pre-existing systemic inflammatory response syndrome appeared to be at increased risk of CDC (adjusted OR 2.154, 95% CI 1.139-4.074, P = 0.018).

CONCLUSION

At the very least this study suggests it is safe to use POAP in colectomy patients without increasing the rate of CDC unless they have pre-existing systemic inflammatory response syndrome.

Evolutionary clade affects resistance of Clostridium difficile spores to Cold Atmospheric Plasma

Clostridium difficile is a spore forming bacterium and the leading cause of colitis and antibiotic associated diarrhoea in the developed world. Spores produced by C. difficile are robust and can remain viable for months, leading to prolonged healthcare-associated outbreaks with high mortality. Exposure of C. difficile spores to a novel, non-thermal atmospheric pressure gas plasma was assessed. Factors affecting sporicidal efficacy, including percentage of oxygen in the helium carrier gas admixture, and the effect on spores from different strains representing the five evolutionary C. difficile clades was investigated. Strains from different clades displayed varying resistance to cold plasma. Strain R20291, representing the globally epidemic ribotype 027 type, was the most resistant. However all tested strains displayed a ~3 log reduction in viable spore counts after plasma treatment for 5 minutes. Inactivation of a ribotype 078 strain, the most prevalent clinical type seen in Northern Ireland, was further assessed with respect to surface decontamination, pH, and hydrogen peroxide concentration. Environmental factors affected plasma activity, with dry spores without the presence of organic matter being most susceptible. This study demonstrates that cold atmospheric plasma can effectively inactivate C. difficile spores, and highlights factors that can affect sporicidal activity.

Management of Inflammatory Bowel Disease in the Elderly

OPINION STATEMENT

A substantial and growing proportion of patients with inflammatory bowel disease (IBD) are elderly, and these patients require tailored treatment strategies. However, significant challenges exist in the management of this population due to the paucity of data. Establishing the initial diagnosis and assessing the etiology of future symptoms and flares can be challenging as several other prevalent diseases can masquerade as IBD, such as ischemic colitis, diverticular disease, and infectious colitis. Important pharmacologic considerations include reduced glomerular filtration rate and drug-drug interactions in the elderly. No drug therapy is absolutely contraindicated in this population; however, special risk and benefit assessments should be made. Older patients are more susceptible to side effects of steroids such as delirium, fractures, and cataracts. Budesonide can be an appropriate alternative for mild to moderate ulcerative colitis (UC) or Crohn's disease (CD) as it has limited systemic absorption. Pill size and quantity, nephrotoxicity, and difficulty of administration of rectal preparations should be considered with 5-aminosalicylic (5-ASA) therapy. Biologics are very effective, but modestly increase the risk of infection in a susceptible group. Based on their mechanisms, integrin receptor antagonists (e.g., vedolizumab) may reduce these risks. Use of antibiotics for anorectal or fistulizing CD or pouchitis in UC increases the risk of Clostridium difficile infection. Pre-existing comorbidities, functional status, and nutrition are important indicators of surgical outcomes. Morbidity and mortality are increased among IBD patients undergoing surgery, often due to postoperative complications or sepsis. Elderly adults with IBD, particularly UC, have very high rates of venous thromboembolism (VTE). Colonoscopy appears safe, but the optimal surveillance interval has not been well defined. Should the octogenarian, nonagenarian, and centurion undergo colonoscopy? The length of surveillance should likely account for the individual's overall life expectancy. Specific health maintenance should emphasize administering non-live vaccines to patients on thiopurines or biologics and regular skin exams for those on thiopurines. Smoking cessation is crucial to overall health and response to medical therapy, even among UC patients. This article will review management of IBD in the elderly.

Clostridium difficile heterogeneously impacts intestinal community architecture but drives stable metabolome responses

Clostridium difficile-associated diarrhoea (CDAD) is caused by C. difficile toxins A and B and represents a serious emerging health problem. Yet, its progression and functional consequences are unclear. We hypothesised that C. difficile can drive major measurable metabolic changes in the gut microbiota and that a relationship with the production or absence of toxins may be established. We tested this hypothesis by performing metabolic profiling on the gut microbiota of patients with C. difficile that produced (n=6) or did not produce (n=4) toxins and on non-colonised control patients (n=6), all of whom were experiencing diarrhoea. We report a statistically significant separation (P-value <0.05) among the three groups, regardless of patient characteristics, duration of the disease, antibiotic therapy and medical history. This classification is associated with differences in the production of distinct molecules with presumptive global importance in the gut environment, disease progression and inflammation. Moreover, although severe impaired metabolite production and biological deficits were associated with the carriage of C. difficile that did not produce toxins, only previously unrecognised selective features, namely, choline- and acetylputrescine-deficient gut environments, characterised the carriage of toxin-producing C. difficile. Additional results showed that the changes induced by C. difficile become marked at the highest level of the functional hierarchy, namely the metabolic activity exemplified by the gut microbial metabolome regardless of heterogeneities that commonly appear below the functional level (gut bacterial composition). We discuss possible explanations for this effect and suggest that the changes imposed by CDAD are much more defined and predictable than previously thought.

Clostridium difficile-associated infection: a disease of varying severity

Clostridium difficile-associated infection (CDI) can have varying severity from asymptomatic carriage to fulminant colitis. Its incidence and virulence in North America are increasing. The increase in virulence is associated with emergence of the highly toxigenic North American pulsed field gel electrophoresis-1 strain. The major risk factor for CDI is exposure to antibiotics. Another major risk factor is hospitalization. The spectrum of CDI ranges from asymptomatic carriers to fulminant disease. Although asymptomatic carriers require no treatment, fulminant disease carries a substantial mortality regardless of management strategy.

Evaluation of the diagnostic algorithm consisting of enzyme immunoassay for toxins and polymerase chain reaction, for the diagnosis of Clostridium difficile-associated diarrhoea

A total of 1631 stool specimens were tested for Clostridium difficile toxins A and B using an enzyme immunoassay (EIA). C. difficile toxin was detected in 191 (11.7%, 191/1631) cases by EIA. Among the remaining 1440 cases, 102 cases in patients with either antibiotic-associated diarrhoea or hospitalized patients with unexplained leukocytosis (> 15,000/mm³) and fever (≥ 38°C) even though they did not meet the criteria for diarrhoea, were further assessed using a polymerase chain reaction (PCR) for the toxin B gene (tcdB). Thirty-four cases were tcdB-positive (33.3%, 34/102). A total of 225 cases (13.8%, 225/1631) had a stool test result positive for C. difficile toxins. Among these, 145 cases were diagnosed with C. difficile-associated diarrhoea (CDAD): 80.7% (117/145) using the EIA and 19.3% (28/145) using the PCR. In our study, the 2-test algorithm including EIA-toxin assay and PCR test made a more accurate diagnosis of CDAD. Furthermore, the application of clinical situations may be effective in the selection of patients who need confirmatory testing.

Clostridium difficile-associated disease acquired in the cardiothoracic intensive care unit

OBJECTIVES

To determine the prevalence, severity, and outcome associated with Clostridium difficile-associated disease (CDAD) acquired while in the cardiothoracic intensive care unit (CTICU).

DESIGN

A 5-year retrospective study.

SETTING

The CTICU.

PARTICIPANTS

All CTICU patients with a positive C difficile stool toxin assay 48 hours after admission.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The results of all CTICU patients with a positive C difficile stool toxin assay were obtained from the Microbiology Department. Each patient's medical notes and charts then were reviewed in turn. A total of 27 of 5,199 (0.5%) CTICU patients acquired CDAD. The median age was 74 years (IQR 68-77), and 17 (63%) patients were male. There were 21 (78%) surgical patients; 13 (62%) were elective admissions. The most frequent diagnosis on admission was valvular heart disease (10 [37%] patients). Sixteen (59%) patients underwent coronary artery bypass graft (CABG) surgery and/or valvular heart surgery. The median interval between CTICU admission and CDAD diagnosis was 10 days (IQR 5-18). Previously identified risk factors for ICU-acquired CDAD included age >65 years (23), antibiotic use (26), and medical device requirements (27). At the time of diagnosis, 14 (52%) patients had moderate CDAD. After treatment initiation, 8 (30%) patients developed worsening CDAD. The 30-day in-hospital mortality rate for CTICU-acquired CDAD was 26% (7 patients).

CONCLUSIONS

C difficile-associated disease rarely is acquired in the CTICU. Approximately one third of patients may experience disease progression, and just over a quarter may die within 30 days of diagnosis. The implementation of recommended severity definitions and treatment algorithms may reduce complication rates and merits prospective evaluation.

Clostridium difficile Infection and Inflammatory Bowel Disease: A Review

The incidence of Clostridium difficile infection (CDI) has significantly increased in the last decade in the United States adding to the health care burden of the country. Patients with inflammatory bowel disease (IBD) have a higher prevalence of CDI and worse outcomes. In the past, the traditional risk factors for CDI were exposure to antibiotics and hospitalizations in elderly people. Today, it is not uncommon to diagnose CDI in a pregnant women or young adult who has no risk factors. C. difficile can be detected at the initial presentation of IBD, during a relapse or in asymptomatic carriers. It is important to keep a high index of suspicion for CDI in IBD patients and initiate prompt treatment to minimize complications. We summarize here the changing epidemiology, pathogenesis, risk factors, clinical features, and treatment of CDI in IBD.

Safety of the long-term use of proton pump inhibitors

The proton pump inhibitors (PPIs) as a class are remarkably safe and effective for persons with peptic ulcer disorders. Serious adverse events are extremely rare for PPIs, with case reports of interstitial nephritis with omeprazole, hepatitis with omeprazole and lansoprazole, and disputed visual disturbances with pantoprazole and omeprazole. PPI use is associated with the development of fundic gland polyps (FGP); stopping PPIs is associated with regression of FGP. In the absence of Helicobacter pylori infection, the long-term use of PPIs has not been convincingly proven to cause or be associated with the progression of pre-existing chronic gastritis or gastric atrophy or intestinal metaplasia. Mild/modest hypergastrinemia is a physiological response to the reduction in gastric acid secretion due to any cause. The long-term use of PPIs has not been convincingly proven to cause enterochromaffin-like cell hyperplasia or carcinoid tumors. PPIs increase the risk of community acquired pneumonia, but not of hospital acquired (nosocomial) pneumonia. There is no data to support particular care in prescribing PPI therapy due to concerns about risk of hip fracture with the long-term use of PPIs. Long-term use of PPIs does not lead to vitamin B12 deficiencies, except possibly in the elderly, or in persons with Zollinger-Ellison Syndrome who are on high doses of PPI for prolonged periods of time. There is no convincingly proven data that PPIs increase the risk of Clostridium difficile-associated diarrhea in persons in the community. The discontinuation of PPIs may result in rebound symptoms requiring further and even continuous PPI use for suppression of symptoms. As with all medications, the key is to use PPIs only when clearly indicated, and to reassess continued use so that long-term therapy is used judiciously. Thus, in summary, the PPIs are a safe class of medications to use long-term in persons in whom there is a clear need for the maintenance of extensive acid inhibition.

Piglet models of acute or chronic Clostridium difficile illness

We examined the piglet model of Clostridium difficile illness (CDI) in humans, because swine are naturally susceptible to C. difficile. The piglet is a reproducible model of acute or chronic CDI with characteristic pseudomembranous colitis. Germ-free piglets were consistently and extensively colonized after oral challenge with the human strain 027/BI/NAP1, establishing an infectious dose-age relationship. This allowed a demarcation between acute fatal and chronic models. The clinical manifestations of disease inclusive of gastrointestinal and systemic symptoms and characteristic mucosal lesions of the large bowel (including pseudomembranous colitis) are described. Additionally, we demonstrate the presence of toxins in feces, body fluids, and serum and a significant elevation in interleukin 8 levels in animals with severe disease. We conclude that piglets infected with C. difficile mimic many of the key characteristics observed in humans with CDI and are suitable animals in which to investigate the role played by virulence attributes, drug efficacy, and vaccine candidates.

Clostridium difficile colitis

Clostridium difficile is the most common cause of infectious diarrhea in hospitalized patients. Its effects are mediated by C difficile toxins A and B. Recent outbreaks of severe colitis have been associated with a new strain of the bacterium that produces large amounts of the toxins. Although oral metronidazole and oral vancomycin can be used to treat C difficile-associated disease, intraluminal vancomycin is preferable for more severe C difficile colitis. Early surgical intervention can improve outcomes with fulminant colitis, although overall mortality remains high.

Evaluation of repeat Clostridium difficile enzyme immunoassay testing

Clostridium difficile is the leading cause of antibiotic-associated diarrhea and pseudomembranous colitis, which have significant morbidity and mortality. Accurate and timely diagnosis is critical. Repeat enzyme immunoassay testing for C. difficile toxin has been recommended because of <100% sensitivity. All C. difficile tests between 1 January 2006 and 31 December 2006 were retrospectively analyzed for results and testing patterns. The Wampole C. difficile Tox A/B II enzyme immunoassay kit was used. There were a total of 8,256 tests from 3,112 patients; 49% of tests were repeated. Of the 3,749 initially negative patient tests, 96 were positive upon repeat testing within 10 days of the first test. Of repeat tests, 0.9% repeated on day 0 (same day as the first test), 1.8% on day 1, 3.8% on day 2, 2.6% on day 3, 5.4% on days 4 to 6, and 10.6% on days 7 to 10 were positive. Thirty-eight patients had a positive test within 48 h of an initial negative test, and based on chart review, 18 patients were treated empirically while 16 were treated following the new result. None had evidence of medical complications. Of initially positive patients, 91% were positive upon repeat testing on day 0, 75% on day 1, and 58% on day 2, to a low of 14% on days 7 to 10. Depending on the clinical setting, these data support not repeating C. difficile tests within 2 days of a negative result and limiting repeat testing to >/=1 week of a positive result.

Treatment of Clostridium difficile infection

Recent outbreaks of Clostridium difficile infection (CDI) in North America have been due to a more virulent, possibly more resistant strain that causes more-severe disease, making prompt recognition of cases and optimal management of infection essential for a successful therapeutic outcome. Treatment algorithms are presented to help guide the management of patients with CDI. Metronidazole has been recommended as initial therapy since the late 1990s and continues to be the first choice for all but seriously ill patients and those with complicated or fulminant infections or multiple recurrences of CDI, for whom vancomycin is recommended. Other options for recurrent CDI, such as probiotics and currently available anion-exchange resins, have limited efficacy and are potentially harmful. Intravenous immunoglobulin may benefit patients with refractory, recurrent, or severe disease, but no controlled data are available. Two antimicrobials available in the United States for other indications, nitazoxanide and rifaximin, have been used successfully for CDI treatment but, like metronidazole, lack United States Food and Drug Administration approval for this indication. Experimental treatments currently in clinical development include a toxin-binding polymer, tolevamer; 2 poorly absorbed antimicrobials, OPT-80 (formerly known as Difimicin) and ramoplanin; monoclonal antibodies; and a C. difficile vaccine.

Discrepancies between clinical and autopsy diagnoses: a comparison of university, community, and private autopsy practices

Although it is known that autopsies often disclose unexpected findings, few studies have been published that address the effect of institutional setting, selection bias, and length of hospitalization. Records of medical autopsies from 3 institutional settings were studied for discrepancies between clinical and autopsy findings. The settings were university hospital (n = 85); community hospital (n = 146); and private autopsy (n = 60), which were referred from various community hospitals and paid for by family members. The same prosector performed the autopsies in the community and private settings. The overall rate of major discrepancy that involved the cause of death was 17.2%. Factors that increased the likelihood of missed diagnoses were private setting (P = .0005), community setting (P = .02), and short hospital stay before death (P = .02). Additional major findings were present in 28.5% of autopsies. Length of hospital stay before death, institution, and selection bias all affect the rate of major unexpected findings in hospital-based autopsies.

Epidemiology, pathogenesis, and management of Clostridium difficile infection

Clostridium difficile infection is an important health problem worldwide and leads to increased morbidity and mortality, particularly among the elderly population. Antibiotics, especially those with a broad spectrum, often trigger the infection; hence the use of unnecessary antibiotics should be avoided. Mild to moderate cases respond to metronidazole or vancomycin. Severe cases may require bowel resection. Chronic relapsing cases require a prolonged course of antibiotics, immunoglobulin, probiotics, and, occasionally, feces enema. This review provides a comprehensive update on pathogenesis and management of Clostridium difficile infection for health professionals all over the world.

Fulminant Clostridium difficile colitis

PURPOSE OF REVIEW

Clostridium difficile is the most common cause of nosocomial infectious diarrhea in adults. The purpose of this review is to increase awareness that infection from C. difficile is not always indolent, but with fulminant colitis, it can be lethal. The epidemiology, pathogenesis and treatment of C. difficile infection are discussed, with special emphasis on management of fulminant colitis.

RECENT FINDINGS

Clostridium difficile causes fulminant colitis in 3-8% of patients. Early predictors of disease include immunosuppression, hypotension, hypoalbuminemia, and a pronounced leukocytosis. In patients with fulminant colitis, early colectomy before vasopressor therapy is required and may improve survival.

SUMMARY

The incidence and virulence of C. difficile infection are increasing. Antibiotic use and length of hospital stay correlate strongly with infection. Oral or intravenous metronidazole is the recommended first-line therapy, with discontinuation of systemic antibiotics if possible. Forty percent of patients may have a prolonged course and 20% will relapse despite adequate therapy. Fulminant colitis develops in 3-8% of patients; diagnosis can be difficult with diarrhea absent in 20% of the subgroup. Once diagnosed, subtotal colectomy with ileostomy is usually required. In patients with a marked leukocytosis or bandemia, surgery is advisable because the leukocytosis frequently precedes hypotension and the requirement for vasopressor therapy, which carries a poor prognosis.

Implications of the changing face of Clostridium difficile disease for health care practitioners

Recent reported outbreaks of Clostridium difficile-associated disease in Canada have changed the profile of C difficile infections. Historically, C difficile disease was thought of mainly as a nosocomial disease associated with broad-spectrum antibiotics, and the disease was usually not life threatening. The emergence of an epidemic strain, BI/NAP1/027, which produces a binary toxin in addition to the 2 classic C difficile toxins A and B and is resistant to some fluoroquinolones, was associated with large numbers of cases with high rates of mortality. Recently, C difficile has been reported more frequently in nonhospital-based settings, such as community-acquired cases. The C difficile disease is also being reported in populations once considered of low risk (children and young healthy women). In addition, poor response to metronidazole treatment is increasing. Faced with an increasing incidence of C difficile infections and the changing profile of patients who become infected, this paper will reexamine the current concepts on the epidemiology and treatment of C difficile-associated disease, present new hypotheses for risk factors, examine the role of spores in the transmission of C difficile, and provide recommendations that may enhance infection control practices.