Staphylococcal enterocolitis--treatment with oral vancomycin

Clostridioides difficile infection: history, epidemiology, risk factors, prevention, clinical manifestations, treatment, and future options

SUMMARYClostridioides difficile infection (CDI) is one of the major issues in nosocomial infections. This bacterium is constantly evolving and poses complex challenges for clinicians, often encountered in real-life scenarios. In the face of CDI, we are increasingly equipped with new therapeutic strategies, such as monoclonal antibodies and live biotherapeutic products, which need to be thoroughly understood to fully harness their benefits. Moreover, interesting options are currently under study for the future, including bacteriophages, vaccines, and antibiotic inhibitors. Surveillance and prevention strategies continue to play a pivotal role in limiting the spread of the infection. In this review, we aim to provide the reader with a comprehensive overview of epidemiological aspects, predisposing factors, clinical manifestations, diagnostic tools, and current and future prophylactic and therapeutic options for C. difficile infection.

A worldwide systematic review and meta-analysis of bacteria related to antibiotic-associated diarrhea in hospitalized patients

INTRODUCTION

Antibiotic-associated diarrhea (AAD) is a major hospital problem and a common adverse effect of antibiotic treatment. The aim of this study was to investigate the prevalence of the most important bacteria that cause AAD in hospitalized patients.

MATERIALS AND METHODS

PubMed, Web of Science and Scopus databases were searched using multiple relevant keywords and screening carried out based on inclusion/exclusion criteria from March 2001 to October 2021. The random-effects model was used to conduct the meta-analysis.

RESULTS

Of the 7,377 identified articles, 56 met the inclusion criteria. Pooling all studies, the prevalence of Clostridioides (Clostridium) difficile, Clostridium perfringens, Klebsiella oxytoca, and Staphylococcus aureus as AAD-related bacteria among hospitalized patients were 19.6%, 14.9%, 27%, and 5.2%, respectively. The prevalence of all four bacteria was higher in Europe compared to other continents. The highest resistance of C. difficile was estimated to ciprofloxacin and the lowest resistances were reported to chloramphenicol, vancomycin, and metronidazole. There was no or little data on antibiotic resistance of other bacteria.

CONCLUSIONS

The results of this study emphasize the need for a surveillance program, as well as timely public and hospital health measures in order to control and treat AAD infections.

Zeolite-containing mixture alleviates microbial dysbiosis in dextran sodium sulfate-induced colitis in mice

Inflammatory bowel disease (IBD) is a multifactorial immunomodulatory disorder. In relative nosogenesis, gut microbiota has been the focus of research on IBD. In our previous study, we demonstrated the ameliorating effect of zeolite-containing mixture (Hydryeast®, HY) on dextran sodium sulfate (DSS)-induced colitis, through transcriptomics and proteomics. In the present study, we performed further investigation from the perspective of metagenomics using the gut microbiota. C57BL6 mice were provided an AIN-93G basal diet or a 0.8% HY-containing diet, and sterilized tap water for 11 days. Thereafter, colitis was induced by providing 1.5% (w/v) DSS-containing water for 9 days. DNA was extracted from the cecal contents and pooled into libraries in a single Illumina MiSeq run. The resulting sequences were analyzed using Quantitative Insights Into Microbial Ecology (QIIME) software. According to the alterations in the relative abundance of certain bacteria, and the related gene and protein expressions, HY supplementation could improve the gut microbiota composition, ameliorate the degree of inflammation, inhibit the colonic mucosal microbial growth, and, to some extent, promote energy metabolism in the colon compared with the DSS treatment. Thus, we believe that HY may be a candidate to prevent and treat IBD.

Effective Dosage of Oral Vancomycin in Treatment for Initial Episode of Clostridioides difficile Infection: A Systematic Review and Meta-Analysis

Background: Oral vancomycin is a first line treatment for an initial episode of Clostridioides difficile infection. However, the comparative efficacy of different dosing regimens is lacking evidence in the current literature. Methods: We searched PubMed, Embase, Cochrane Library, and ClinicalTrials.gov. from inception to May 2019. Only articles published in English are reviewed. This meta-analysis compares the effects of low dose oral vancomycin (<2 g per day) versus high dose vancomycin (2 g per day) for treatment of initial Clostridioides difficile infection. Results: One randomized controlled trial and two retrospective cohort studies are included. A total of 137 patients are identified, 53 of which were treated with low dose oral vancomycin (39%) and 84 with high dose oral vancomycin (61%). There is no significant reduction in recurrence rates with high dose vancomycin compared to low dose vancomycin for treating initial episodes of non-fulminant Clostridioides difficile infection ((odds ratio (OR) 2.058, 95%, confidence interval (CI): 0.653 to 6.489). Conclusions: Based on limited data in the literature, low dose vancomycin is no different than high dose vancomycin for treatment of an initial episode of Clostridioides difficile infection in terms of recurrence rate. Additional large clinical trials comparing the different dosages of vancomycin in initial Clostridioides difficile infection are warranted.

Clostridioides difficile therapeutics: guidelines and beyond

Clostridioides difficile infection (CDI) has become an increasingly common infection both within and outside of the hospital setting. The management of this infection has been evolving as we learn more about the role of the human microbiota in protecting us from this gastrointestinal opportunist. For many years the focus of treatment had been on eradication of the vegetative, toxin-producing form of the organism, with little regard for its collateral impact on the host's microbiota or risk of recurrence. With the marked increase in C. difficile disease, and, particularly, recurrent disease in the last decade, new guidelines are more focused on targeting and reducing collateral damage to the colonic microbiota. Immune-based strategies that manipulate the microbiota and provide a humoral response to toxins have now become mainstream. Newer strategies are needed to look beyond simply resolving the primary episode but are focused on delayed outcomes such as cure at 90 days, reduced morbidity and mortality, and patient quality of life. The purpose of this review is to familiarize readers with the most recent evidence-based guidelines for C. difficile management, and to describe the role of newer antimicrobials, immunological-, and microbiota-based therapeutics to prevent recurrence and improve the outcomes of people with CDI.

Proton pump inhibitors and risk of Clostridium difficile infection: association or causation?

PURPOSE OF REVIEW

The rising burden of Clostridium difficile infection (CDI) requires urgent identification of preventable risk factors. Observational studies suggest an association between proton-pump inhibitor (PPI) use and CDI risk.

RECENT FINDINGS

Key historical literature on PPI and CDI associations is reviewed as a prelude to evaluating the plausibility of a causative association. Impactful literature from the past 18 months is examined in detail and critically appraised through the lens of the Bradford Hill Criteria for determination of causality. The PPI and CDI association has been studied extensively and is valid. Nonetheless, causality is not proven due to extensive and difficult to control confounding in observational studies of CDI patient populations with complex comorbidities.

SUMMARY

In the authors' opinion, systematic discontinuation of PPIs in patients at risk for CDI is not warranted based on current evidence. Well controlled prospective human studies are needed. Careful and repeated consideration should be given to all PPI prescriptions to avoid potential adverse effects.

Clostridium difficile infection: Evolution, phylogeny and molecular epidemiology

Over the recent decades, Clostridium difficile infection (CDI) has emerged as a global public health threat. Despite growing attention, C. difficile remains a poorly understood pathogen, however, the exquisite sensitivity offered by next generation sequencing (NGS) technology has enabled analysis of the genome of C. difficile, giving us access to massive genomic data on factors such as virulence, evolution, and genetic relatedness within C. difficile groups. NGS has also demonstrated excellence in investigations of outbreaks and disease transmission, in both small and large-scale applications. This review summarizes the molecular epidemiology, evolution, and phylogeny of C. difficile, one of the most important pathogens worldwide in the current antibiotic resistance era.

Vancomycin treatment and butyrate supplementation modulate gut microbe composition and severity of neointimal hyperplasia after arterial injury

Gut microbial metabolites are increasingly recognized as determinants of health and disease. However, whether host–microbe crosstalk influences peripheral arteries is not understood. Neointimal hyperplasia, a proliferative and inflammatory response to arterial injury, frequently limits the long‐term benefits of cardiovascular interventions such as angioplasty, stenting, and bypass surgery. Our goal is to assess the effect of butyrate, one of the principal short chain fatty acids produced by microbial fermentation of dietary fiber, on neointimal hyperplasia development after angioplasty. Treatment of male Lewis Inbred rats with oral vancomycin for 4 weeks changed the composition of gut microbes as assessed by 16S rRNA‐based taxonomic profiling and decreased the concentration of circulating butyrate by 69%. In addition, rats treated with oral vancomycin had exacerbated neointimal hyperplasia development after carotid angioplasty. Oral supplementation of butyrate reversed these changes. Butyrate also inhibited vascular smooth muscle cell proliferation, migration, and cell cycle progression in a dose‐dependent manner in vitro. Our results suggest for the first time that gut microbial composition is associated with the severity of arterial remodeling after injury, potentially through an inhibitory effect of butyrate on VSMC.

Predictive values of models of Clostridium difficile infection

In vivo and in vitro models are widely used to simulate Clostridium difficile infection (CDI). They have made considerable contributions in the study of C difficile pathogenesis, antibiotic predisposition to CDI, and population dynamics as well as the evaluation of new antimicrobial and immunologic therapeutics. Although CDI models have greatly increased understanding of this complicated pathogen, all have limitations in reproducing human disease, notably their inability to generate a truly reflective immune response. This review summarizes the most commonly used models of CDI and discusses their pros and cons and their predictive values in terms of clinical outcomes.

Diagnosis and management of Clostridium difficile infection

Clostridium difficile infection (CDI) is increasing in frequency and severity in and out of the hospital, with a high probability of recurrence after treatment. The recent literature on CDI was reviewed using PubMed to include recent publications dealing with diagnosis and therapy. Real-time polymerase chain reaction is a sensitive and useful diagnostic test for CDI but there are growing concerns of false-positive test results if the rate of CDI is low in the patient population providing samples and/or if the population being studied commonly includes people with C difficile colonization. Recommended therapy of CDI includes oral metronidazole for milder cases of CDI and oral vancomycin or fidaxomicin for more severe cases, each given for 10 days. Colectomy is being performed more frequently in patients with fulminant CDI. For treatment of first recurrences the drug used in the first bout can be used again and for second recurrences longer courses of vancomycin often are given in a tapered dose or intermittently to allow gut flora reconstitution, or other treatments including fidaxomicin may be used. Bacteriotherapy with fecal transplantation is playing an increasing role in therapy of recurrent cases. Metagenomic studies of patients with CDI during successful therapy are needed to determine how best to protect the flora from assaults from antibacterial drugs and to develop optimal therapeutic approaches. Immunotherapy and immunoprophylaxis offer opportunities to prevent CDI, to speed up recovery from CDI, and to eliminate recurrent infection. Humanized monoclonal antitoxin antibodies and active immunization with vaccines against C difficile or its toxins are both in development and appear to be of potential value.

Biology of Clostridium difficile: implications for epidemiology and diagnosis

Clostridium difficile is an anaerobic, spore-forming, gram-positive rod that causes a spectrum of antibiotic-associated colitis through the elaboration of two large clostridial toxins and other virulence factors. Since its discovery in 1978 as the agent responsible for pseudomembranous colitis, the organism has continued to evolve into an adaptable, aggressive, hypervirulent strain. Advances in molecular methods and improved animal models have facilitated an understanding of how this organism survives in the environment, adapts to the gastrointestinal tract of animals and humans, and accomplishes its unique pathogenesis. The advances in microbiology have been accompanied by some important clinical observations including increased rates of C. difficile infection, increased virulence, and multiple outbreaks. The major new risk is fluoroquinolone use; there is also an association with proton pump inhibitors and increased recognition of cases in outpatients, pediatric patients, and patients without recent antibiotic use. The combination of more aggressive strains with mobile genomes in a setting of an expanded pool of individuals at risk has refocused attention on and challenged assumptions regarding diagnostic gold standards. Future research is likely to build upon the advancements in phylogenetics to create novel strategies for diagnosis, treatment, and prevention.

Genetic manipulation of Clostridium difficile

Clostridium difficile is a Gram-positive, spore forming, anaerobic, intestinal bacterium and is the most common cause of antibiotic-associated colitis. For many years this organism was considered genetically intractable, but in the past 10 years, multiple methods have been developed or adapted for genetic manipulation of C. difficile. This unit describes the molecular techniques used for genetic modification of this organism, including methods for gene disruption, complementation, plasmid introduction and integration, and cross-species conjugations.

Clostridium difficile and the disease it causes

Clostridium difficile is a spore-forming, toxin-producing, anaerobic bacterium abundant in soils and water. Frequent and early colonization of the human intestinal flora is common and often asymptomatic. Antimicrobials given commonly disrupt the intestinal microflora and through proliferation in colon and production of toxin A and B it precipitates C. difficile infection (CDI). The enterocytic detachment and bowel inflammation provoke C. difficile-associated diarrhoea (CDAD) sometimes developing into severe pseudomembranous colitis (PMC) and paralytic ileus. Infection is acquired from an endogenous source or from spores in the environment, most easily facilitated during hospital stay. In the elderly, comorbidity, hospitalization and antimicrobial treatment present as major risk factors and the slow recolonization of the normal flora likely responsible for single or multiple recurrences of CDI (25-50%) post therapy. The key procedure for diagnosis is toxin detection from stool specimens and sometimes in combination with culture to increase sensitivity. In mild cases stopping the offending antimicrobial will lead to resolution (25%) but standard therapy still consist of either oral metronidazole or vancomycin. Alternative agents are presently being developed and fidaxomicin, as well as nitrothiazolide are promising. Furthermore, host factors like low antitoxin A levels in serum relates to increased risk of recurrence and small numbers of patients have received immunoglobulin with good results. An immunogenic toxoid vaccine has been developed and human colostrum rich in specific secretory Ig A also support the future use of immunotherapy. Today we experience a tenfold increase of CDI incidence in the western world and both epidemics and therapeutic failure of metronidazole is contributing to morbidity and mortality. The current epidemic of the C. difficile strain NAP1/027 emerging in 2002 in Canada and the USA has now spread to most parts of Europe and virulence factors like high toxin production and sporulation challenge the therapeutic situation and cause great concern among infection control workers. Excessive use of modern fluoroquinolones is thought to play an important role in facilitating this epidemic since NAP1/027 was shown to have acquired moxifloxacin resistance compared to historical strains of the same genotype. Both the current epidemic like this and other local outbreaks from resistant or virulent strains warrant culture to be routinely performed enabling susceptibility testing and typing of the pathogen. Genotyping is most commonly done today by pulse-field gel electrophoresis (PFGE) or PCR ribotyping but multilocus variable-number tandem-repeat analysis (MLVA) seems promising. Epidemiological surveillance using all these tools will help us to better understand the global spread of C. difficile.

Historical perspectives on studies of Clostridium difficile and C. difficile infection

The initial period of studies on Clostridium difficile (published during 1978-1980) appeared to provide a nearly complete portfolio of criteria for diagnosing and treating C. difficile infection (CDI). The putative pathogenic role of C. difficile was established using Koch's postulates, risk factors were well-defined, use of a cell cytotoxicity assay as the diagnostic test provided accurate results, and treatment with oral vancomycin was highly effective and rapidly incorporated into practice. During the next 10 years, enzyme immunoassays (EIAs) were introduced as diagnostic tests and became the standard for most laboratories. This was not because EIAs were as good as the cell cytotoxicity assay; rather, EIAs were inexpensive and yielded results quickly. Similarly, metronidazole became the favored treatment because it was less expensive and quelled fears of colonization with vancomycin-resistant organisms, not because it was better than vancomycin therapy. Cephalosporins replaced clindamycin as the major inducers of CDI because they were so extensively used, rather than because they incurred the same risk. Some serious issues remained unresolved during this period: the major challenges were to determine ways to treat seriously ill patients for whom it was not possible to get vancomycin into the colon and to find methods that stop persistent relapses. These concerns persist today.

An update on diagnosis, treatment, and prevention of Clostridium difficile-associated disease

Clostridium difficile is an important cause of nosocomial morbidity and mortality and is implicated in recent epidemics. Data support the treatment of colitis with oral metronidazole in a dose of 1.0 to 1.5 g/d, with oral vancomycin as a second-line agent, not because its efficacy is questioned but because of environmental concerns. Nitazoxanide and other drugs are currently under intense study as alternatives. Treatment of asymptomatic patients is not recommended. Current management strategies appear to be increasingly ineffective, especially for patients who experience multiple recurrences. Biotherapy and vaccination are currently being explored as treatment options for patients who have recurrent disease. Greater attention should be paid to hospital infection control policies and restriction of broad-spectrum antibiotics.

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

Clostridium difficile colitis is a major complication of antibiotic therapy. Antibiotics cause a reduction in bacteria that normally reside in the colon. If an antibiotic-treated patient ingests C. difficile bacteria, this organism may proliferate in the colon because it is resistant to most antibiotics and because it does not have to compete with the normal bacteria for nutrients. If the C. difficile organism has the gene for toxin production, the toxin can produce a colitis. In addition to antibiotics, other proposed risk factors for development of C. difficile colitis include advanced age, contact with infected patients and with their health care providers, impaired immune function, suppression of gastric acid secretion by a proton pump inhibitor, and postpyloric tube feeding. Many of the risk factors become simultaneously focused on patients admitted to the hospital. The incidence of C. difficile disease has been rising, and strains have become more virulent. In some forms of the disease, the patient doesn't have diarrhea, and in such patients C. difficile can be deadly but difficult to diagnose. The standard treatment, with metronidazole or vancomycin, fails to work in up to 25% of patients with the fulminant form of colitis. Since C. difficile causes only 20% of cases of antibiotic-associated diarrhea, a specific test is needed to diagnose this organism. Toxigenic cultureis highly specific but not available at most institutions. The tests that are available--enzyme-linked immunosorbent assay and fecal cytotoxicity assay--have high false-negative rates, even in patients with severe clinical disease, creating a diagnostic dilemma. The only proven way to reduce the risk of C. difficile disease is implementation of an antibiotic management program in conjunction with enhanced infection control procedures.

Treatment of Clostridium difficile-associated disease: old therapies and new strategies

Clostridium difficile-associated disease (CDAD) causes substantial morbidity and mortality. The pathogenesis is multifactorial, involving altered bowel flora, production of toxins, and impaired host immunity, often in a nosocomial setting. Current guidelines recommend treatment with metronidazole; vancomycin is a second-line agent because of its potential effect on the hospital environment. We present the data that led to these recommendations and explore other therapeutic options, including antimicrobials, antibody to toxin A, probiotics, and vaccines. Treatment of CDAD has increasingly been associated with failure and recurrence. Recurrent disease may reflect relapse of infection due to the original infecting organism or infection by a new strain. Poor antibody responses to C difficile toxins have a permissive role in recurrent infection. Hospital infection control and pertinent use of antibiotics can limit the spread of CDAD. A vaccine directed against C difficile toxin may eventually offer a solution to the CDAD problem.

Effectiveness and safety of enteral vancomycin to control endemicity of methicillin-resistant Staphylococcus aureus in a medical/surgical intensive care unit

A prospective trial was undertaken to assess the effectiveness and safety of enteral vancomycin in controlling methicillin-resistant Staphylococcus aureus (MRSA) in an endemic setting. Over the 49 month period patients aged >14 years were enrolled, following admission to a medical/surgical intensive care unit (ICU) and expected to require ventilation for three days or more. A total of 799 patients were included in the trial. Period one, 1 July 1996-30 April 1997, (N=140), was observational. During period two, 1 May 1997-30 September 1998, (N=258), surveillance samples were obtained. MRSA carriers were isolated and received enteral vancomycin. During period three, 1 October 1998-31 July 2000, (N=400), all ventilated patients were given selective digestive decontamination (SDD) with polymyxin E, tobramycin, amphotericin B and vancomycin and four days of intravenous cefotaxime. The primary endpoints were: (1) incidence of patients with diagnostic samples positive for MRSA acquired on the ICU; (2) incidence of patients with vancomycin-resistant enterococci (VRE) in surveillance or diagnostic samples; (3) incidence of patients with samples positive for S. aureus with intermediate sensitivity to glycopeptides (GISA). The incidence of patients with MRSA in diagnostic samples were 31%, 14%, and 2% in periods one, two and three, respectively (P<0.001). There was a VRE outbreak involving 13 patients during period three. VRE disappeared with no change in policy. GISA was not detected. These findings support the effectiveness and safety of enteral vancomycin in the control of MRSA.

Methicillin-resistant Staphylococcus aureus in children with cystic fibrosis: An eradication protocol

A retrospective 12-year study (May 1988-July 2000) was undertaken in children with cystic fibrosis (CF) to evaluate 1) the magnitude of methicillin-resistant Staphylococcus aureus (MRSA) in these children; 2) the clinical impact of MRSA on CF; and 3) the efficacy of an MRSA protocol aimed at the eradication of the carrier state. The study maneuver comprised of 1) surveillance cultures of throat/rectum to detect the MRSA carrier state; 2) life-long cephradine rather than flucloxacillin to lift selection pressure; 3) topical application of oral and nebulized vancomycin for 5 days to clear the carriage of MRSA; and 4) a strict antistaphylococcal hygiene program, including handwashing and device policy. Fifteen children with CF (11 boys, with median age 117 months) positive for MRSA were enrolled. The current prevalence of MRSA among children with CF in our hospital is 6.5%. Of 15 children identified, only 12 (18 episodes of MRSA colonization) were treated according to protocol. Median age of MRSA acquisition was 73 months (interquartile range, 43-134 months). In 7 patients (55%), MRSA was eradicated. Of a total of 18 MRSA episodes, the protocol was successful in 10 episodes. The mean period of MRSA-free status was 12 months (range, 6-36 months). Pulmonary function (measured by FEV(1)) was not affected (68% of predicted before treatment, and 68% of predicted after treatment). All children were oropharyngeal carriers of both MRSA and ceftazidime-resistant P. aeruginosa. We believe that an effort has to be made to limit MRSA in CF clinics for the following reasons: 1) MRSA carriage in any individual is an abnormal condition; 2) limitation of systemic vancomycin use is desirable; 3) MRSA carriage may be a contraindication for lung transplantation; and 4) epidemiologically, a CF unit with a substantial MRSA problem functions as a source of dissemination for other patients.

Clostridium difficile-associated Enteric Disease

Clostridium difficile was identified as the putative agent of antibiotic-associated pseudomembranous colitis in 1978 and is now recognized as the major identifiable cause of antibiotic-associated diarrhea. This microbe causes a spectrum of enteric disease ranging from nuisance diarrhea to life-threatening colitis. Risk factors include increasing age, exposure to antibiotics, colonization or acquisition of toxin-producing strains of C. difficile, and lack of circulating antibody to C. difficile toxin A. Detection is relatively simple by stool assay for C. difficile toxin--usually an enzyme immunoassay that will detect toxin A and B. Most nonsevere cases will respond with discontinuation of the implicated antibiotic. More severe cases require metronidazole and supportive care. The major complications include ileus, toxic megacolon, relapsing disease after antibiotic treatment, and nosocomial epidemics.

Multiple intestinal ulcerations and perforations secondary to methicillin-resistant Staphylococcus aureus enteritis in infants

PURPOSE

The aim of this study was to define a distinctive clinical entity of multiple intestinal ulcerations and perforations in infants.

METHODS

Two infants underwent abdominal exploration for surgical abdomen and were noted to have multiple intestinal ulcerations and perforations. A peculiar and unique surgical finding, numerous transverse linear ulcerations scattered along the entire small intestine, prompted us to search for similar instances. Five similar cases were additionally identified by members of the Korean Association of Pediatric Surgeons. The clinical courses, the surgical findings, and the results of bacterial cultures were reviewed. As well, the tissues of resected intestines were examined histopathologically.

RESULTS

The characteristics of this entity are as follows. (1) It usually occurs in infants who have been treated with broad-spectrum antibiotics. (2) Despite broad-spectrum antibiotic treatment, diarrhea and abdominal distension developed progressively and deteriorated. (3) Histological evaluation showed mucosal ulcers with neutrophil infiltration, submucosal microabscesses, and colonies of Gram-positive cocci. (4) Methicillin-resistant Staphylococcus aureus (MRSA) was the predominant organism cultured from the body fluid. (5) Only two cases, the completely resected one and the one immediately treated postoperatively with vancomycin, survived.

CONCLUSIONS

This entity is caused by multiple intestinal ulcerations and perforations secondary to MRSA enteritis in infants. It has a high mortality rate because of its difficult diagnosis. However, early recognition of this entity can lead to successful treatment.

Comparison of four laboratory tests for diagnosis of Clostridium difficile-associated diarrhea

Four different laboratory tests for diagnosis of Clostridium difficile-associated diarrhea were compared to determine the optimal one for management of patients with hospital-acquired diarrhea. Stool samples from 231 patients with diarrhea were tested by the following methods: culture for Clostridium difficile with subsequent determination of exotoxin production, with a toxigenic Clostridium difficile positive (TCP) result considered truly positive; enzyme immunoassay (EIA); latex agglutination test; and an immunobinding blot assay. The rates of positive results were as follows: EIA 5.5%, TCP 7.3%, latex agglutination 16.7%, and immunobinding blot assay 26.1%. Compared to the TCP results, the sensitivity and specificity were, respectively, 61 and 98% for EIA, 47 and 85% for latex agglutination, and 60 and 76% for the immunobinding blot assay. Samples from patients with > or = 6 stools/day were TCP and EIA positive in 27 and 17% of cases, respectively, whereas in patients with < 6 stools/day, these percentages decreased to 2 and 3%, respectively (p < 0.001). In hospitalized patients with > or = 6 stools/day, EIA appears to be the optimal test for diagnosis of Clostridium difficile-associated diarrhea, with a 73% positive predictive value and a 97% negative predictive value. However, in patients with < 6 stools/day, the prevalence of Clostridium difficile is low, and laboratory detection of this organism remains problematic.

Diagnosis and management of Clostridium difficile infection

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Review article: antibiotics and the gut

Antibiotics have an important place in the management of gastrointestinal disease. Recent studies have demonstrated efficacy in acute bacterial gastroenteritis caused by salmonellae and campylobacteriaceae, shigellae and enterotoxigenic strains of E coli (ETEC). Tetracycline remains effective in cholera. Antibiotic resistance is widespread amongst the enteric pathogens and can quickly spread during epidemics of infective diarrhoeas. It is important that antibiotics are reserved for the treatment of serious infections lest their effectiveness in these conditions be lost. Campylobacter pylori appears to be an important cause of chronic active gastritis and is amenable to treatment with antibiotics and bismuth salts. The role of C. pylori in the pathogenesis of peptic ulcer disease is not yet established but there is mounting evidence that antibiotic treatment will have a place in the treatment of this common condition. The effect of antibiotics on the normal intestinal microflora can have serious consequences. It is a major cause of resistance in urinary tract pathogens, can result in outbreaks of hospital infection with resistant organisms and frequently results in C. difficile associated diarrhoea.

Clostridium difficile: its disease and toxins

Clostridium difficile is the etiologic agent of pseudomembranous colitis, a severe, sometimes fatal disease that occurs in adults undergoing antimicrobial therapy. The disease, ironically, has been most effectively treated with antibiotics, although some of the newer methods of treatment such as the replacement of the bowel flora may prove more beneficial for patients who continue to relapse with pseudomembranous colitis. The organism produces two potent exotoxins designated toxin A and toxin B. Toxin A is an enterotoxin believed to be responsible for the diarrhea and mucosal tissue damage which occur during the disease. Toxin B is an extremely potent cytotoxin, but its role in the disease has not been as well studied. There appears to be a cascade of events which result in the expression of the activity of these toxins, and these events, ranging from the recognition of a trisaccharide receptor by toxin A to the synergistic action of the toxins and their possible dissemination in the body, are discussed in this review. The advantages and disadvantages of the various assays, including tissue culture assay, enzyme immunoassay, and latex agglutination, currently used in the clinical diagnosis of the disease also are discussed.

Cefazolin-induced pseudomembranous colitis resulting in perforation of the sigmoid colon

The seventh case of probable cefazolin-induced pseudomembranous colitis is reported. Perforation of the colon necessitated sigmoid resection. The postoperative course was protracted, and illustrates the difficulty of managing advanced pseudomembranous colitis when the oral route of antibiotic administration is not available. Although rare, pseudomembranous colitis related to cefazolin administration is a potentially fatal complication. The routine use of prophylactic antibiotics must be weighed against this possibility.

Double blind controlled trial of oral vancomycin as adjunctive treatment in acute exacerbations of idiopathic colitis

A prospective double blind trial of vancomycin vs placebo was undertaken in 40 consecutive adult patients with exacerbation of idiopathic colitis (33 ulcerative colitis, seven Crohn's disease). Vancomycin or placebo (500 mg six hourly) was given for seven days in addition to routine medical therapy. Although there was no significant overall difference in outcome between the two groups, there was a trend towards a reduction in the need for operative intervention in patients with ulcerative colitis treated with vancomycin compared with controls. The efficacy of vancomycin was not attributable to its known action against C difficile, which was not isolated from any of the patients. The data suggest that microbiological factors may play a part in the pathogenesis of ulcerative colitis and that further studies using antimicrobials are desirable.

Medical management of antimicrobial-associated diarrhea and colitis

Gastrointestinal complications, including diarrhea, may occur with virtually all antimicrobial agents. Such diarrhea may represent either a common, nonspecific adverse effect, or it may be one of the manifestations of antimicrobial-associated colitis (AAC), a potentially fatal complication. Clostridium difficile and a cytotoxin neutralized by Clostridium sordellii antitoxin has been isolated from the stools of nearly all patients with antibiotic-associated pseudomembranous colitis, many patients with AAC, and approximately 20% of those with antimicrobial-induced diarrhea. Demonstration that C. difficile is responsible for cytotoxin production has allowed for specific therapy for these disorders. General treatment measures include discontinuation of the causative antimicrobial agent(s), bowel rest, and supportive care with fluids, electrolytes and colloids, if necessary. Antiperistaltic agents and corticosteroids are not recommended. Various antimicrobials demonstrate potential efficacy in treating AAC in humans. Oral vancomycin is the most widely tested and is currently the treatment of choice. It achieves high concentrations in the feces and is very active against C. difficile in doses of 125-500 mg by mouth every six hours. Other potentially useful but inadequately tested antimicrobials include metronidazole (500 mg by mouth every eight hours) and bacitracin (25,000 units by mouth every six hours). Tetracycline has been employed with some success in nonspecific antibiotic-associated diarrhea, although it is as yet untested in humans with AAC and may induce diarrhea itself. Both miconazole and rifampin are highly effective against C. difficile in vitro but have not been evaluated in AAC. Anion-exchange resins bind the cytotoxin found in stools of patients with AAC. Cholestyramine has been used with variable response in oral doses of 4 g every six to eight hours. Since these resins may also bind vancomycin, resulting in lowered vancomycin concentrations in the stool, combination therapy should be used cautiously. With specific therapy directed against the toxin and aggressive supportive therapy, surgical intervention is rarely necessary. More recently, investigations have been directed at using bacterial preparations to suppress C. difficile by restoring the normal flora. The development of immunological agents (i.e., vaccines, toxoids, antitoxins) for the prevention or treatment of AAC would be a significant advance in therapy.

Vancomycin

While vancomycin is thus not as nephrotoxic as once feared, its use by the parenteral route should be avoided if possible when other nephrotoxic drugs are being given. Used properly, vancomycin appears efficacious and can be given with safety to infants, children, and adults. Vancomycin is incompatible with many other drugs in intravenous solutions, especially chloramphenicol, adrenocorticosteroids, and methicillin.

Treatment of Clostridium difficile colitis and diarrhea with vancomycin

Toxigenic Clostridium difficle is the major cause of antibiotic-associated colitis and is susceptible to vancomycin at fecal concentrations achieved with oral therapy. The effect of oral vancomycin was studied in 16 patients with C. difficile-related diarrhea or colitis, 12 of whom had colitis documented by endoscopy, biopsy, and/or barium enema. Four patients had antibiotic-associated diarrhea and possibly antibiotic-associated colitis, because sigmoidoscopy either showed normal results (two patients) or was not performed (two patients). Nineteen episodes of diarrhea were treated with oral vancomycin in two dosage regimens for three to 14 days. Twelve patients received 2 g daily, and four patients initially received 1 g or less per day. Within 48 hours of the start of vancomycin therapy, 14 of 16 patients (87 percent) showed a decrease in temperature, abdominal pain and diarrhea. Diarrhea ceased completely within two days of the start of vancomycin in nine episodes, within three to seven days in six episodes, and within eight to 14 days in the remaining four episodes, and within eight to 14 days in the remaining four episodes. Diarrhea recurred in two of these patients (12 percent) when the drug inciting the initial episode of colitis was given again 42 days or more after vancomycin therapy was stopped; both patients responded again to retreatment with vancomycin. Oral vancomycin is an effective treatment of C. difficile-related colitis and diarrhea.

Pseudomembranous (antibiotic-associated) colitis

We have come to understand the cause of antibiotic-associated pseudomembranous colitis (PMC) only in the last decade. Clostridium difficile produces the intestinal dysfunction and the characteristic finding of exudative plaques on the mucosa by elaborating a toxin in the colon. This report reviews the development of our knowledge of this disease and the rapid adoption of a rational therapy once the cause was specified. C. difficile or its toxin can be cultured or isolated from the stools of 90% of the patients with PMC. This organism is almost never found in healthy people or in any other conditions except inflammatory bowel disease, where its significance is not yet known. The detection of pseudomembranes by sigmoidoscopy establishes the diagnosis. The laboratory technics that confirm the presence of C. difficile and its toxin are being incorporated into many laboratories around the country. Treatment of diagnosed PMC is relatively simple and usually completely effective. The offending antibiotic is stopped, a proper fluid and electrolyte balance maintained, and oral vancomycin begun, 125 to 500 mg four times a day. Cholestyramine can also be used as an adjunct to this regimen. Relapse can occur in patients treated with oral vancomycin, necessitating a repeat course of therapy.

[Antibiotic-associated diarrhoea and enterocolitis (author's transl)]

Many antibiotics, particularly the lincomycins, may cause diarrhoea with or without enterocolitis. The pathogenesis of antibiotic-associated diarrhoea without colitis is uncertain; colloidosmotic water binding in the colon by endogenous glycoproteins undegraded by colonic bacteria is considered. Antibiotic-associated enterocolitis is now known to be due to toxin-producing clostridia, proven for Cl. difficile. Improved methods for the detection of toxin and clostridia are presently being studied. Endoscopically, pseudomembranes are characteristic but not antibiotic-specific, they may be absent or missed diagnostically. A possible role of asymptomatic clostridia-carriers in enterocolitis clustering remains to be determined. The potentially lethal course of the disease requires rapid diagnosis and therapy, with discontinuation of the antibiotic, intensive supportive measures and, at least in severe disease, oral vancomycin.

Antibiotic-associated colitis--a review of 66 cases

We have reviewed 66 cases of antibiotic-associated colitis since March 1975, which have been associated with a 27 per cent mortality. We believe antibiotics may predispose patients to this condition which is caused by a toxin produced by Clostridium difficile. Although the disease is rare, it is more common than previously reported. The presentation, methods of diagnosis and treatment are discussed.

Necrotizing colitis in patients with cancer

Necrotizing lesions of the colon occur in patients with malignancy. We identified 26 patients with cancer (23 with acute leukemia and three with solid tumors) who died from necrotizing colitis. Autopsies revealed three pathologic categories: pseudomembranous colitis in 69 per cent, agranulocytic colitis in 19 per cent and ischemic colitis in 12 per cent. Most died from sepsis. A comparison of characteristics was made with a control population matched for diagnosis, age, cause of death and duration of neoplasia. Nearly all patients in both groups had fever and were granulocytopenic secondary to chemotherapy. Most received antineoplastic and antimicrobial regimens during the month prior to their terminal illness. Abdominal pain and distention, stomatitis and necrotizing pharyngitis were frequently associated with colitis. Hyperbilirubinemia was a frequent late complication in those with colitis and the control group. Single and multiorganism septicemia were found more frequently in patients with colitis. As antemortem diagnosis was unusual, aggressive attempts at diagnosis are necessary to assess the true incidence of this disorder and the best therapy.