Contamination of a hospital environment byClostridium difficile

Multidrug-Resistant Bacteria Contaminating Plumbing Components and Sanitary Installations of Hospital Restrooms

Antimicrobial resistance (AMR) poses several issues concerning the management of hospital-acquired infections, leading to increasing morbidity and mortality rates and higher costs of care. Multidrug-resistant (MDR) bacteria can spread in the healthcare setting by different ways. The most important are direct contact transmission occurring when an individual comes into physical contact with an infected or colonized patient (which can involve healthcare workers, patients, or visitors) and indirect contact transmission occurring when a person touches contaminated objects or surfaces in the hospital environment. Furthermore, in recent years, toilets in hospital settings have been increasingly recognised as a hidden source of MDR bacteria. Different sites in restrooms, from toilets and hoppers to drains and siphons, can become contaminated with MDR bacteria that can persist there for long time periods. Therefore, shared toilets may play an important role in the transmission of nosocomial infections since they could represent a reservoir for MDR bacteria. Such pathogens can be further disseminated by bioaerosol and/or droplets potentially produced during toilet use or flushing and be transmitted by inhalation and contact with contaminated fomites. In this review, we summarize available evidence regarding the molecular features of MDR bacteria contaminating toilets of healthcare environments, with a particular focus on plumbing components and sanitary installation. The presence of bacteria with specific molecular traits in different toilet sites should be considered when adopting effective managing and containing interventions against nosocomial infections potentially due to environmental contamination. Finally, here we provide an overview of traditional and new approaches to reduce the spreading of such infections.

Clostridioides difficile spores tolerate disinfection with sodium hypochlorite disinfectant and remain viable within surgical scrubs and gown fabrics

Clostridioides difficile is the most common cause of antibiotic-associated diarrhoea globally. Its spores have been implicated in the prevalence of C. difficile infection due to their resistance and transmission ability between surfaces. Currently, disinfectants such as chlorine-releasing agents (CRAs) and hydrogen peroxide are used to decontaminate and reduce the incidence of infections in clinical environments. Our previous research demonstrated the ability of C. difficile spores to survive exposure to recommended concentrations of sodium dichloroisocyanurate in liquid form and within personal protective fabrics such as surgical gowns; however, the present study examined the spore response to clinical in-use concentrations of sodium hypochlorite. Spores were exposed to a 10 min contact time of 1000, 5000 and 10 000 p.p.m. sodium hypochlorite, and spore recovery was determined. To understand whether biocide-exposed spores transmitted across clinical surfaces in vitro , biocide-exposed spores were spiked onto surgical scrubs and patient gowns and recovery was determined by a plate transfer assay. Scanning electron microscopy was used to establish if there were any morphological changes to the outer spore coat. The results revealed that viable biocide-exposed C. difficile spores can be recovered from surgical scrubs and patient gowns, with no observable changes to spore morphology, highlighting the potential of these fabrics as vectors of spore transmission. This study demonstrates that alternative strategies should be urgently sought to disinfect C. difficile spores to break the chain of transmission in clinical environments.

The Hospital Environment as a Potential Source for Clostridioides difficile Transmission Based on Spore Detection Surveys Conducted at Paediatric Oncology and Gastroenterology Units

Clostridioides difficile is an anaerobic, Gram-positive bacterium widely present in the hospital environment due to its ability to generate spores. The transfer of spores to patients through the hands of medical personnel is one of the most frequent paths of C. difficile transmission. In paediatric patients burdened with a serious primary illness requiring long-term hospitalisation and antibiotic therapy, C. difficile may be a significant risk factor for antibiotic-associated diarrhoea. The goal of the study was to assess the state of hospital environments as a potential source of C. difficile spores and to establish the share of hyperepidemic strains at the two paediatric units. The survey for C. difficile was conducted with a C. diff Banana BrothTM medium, used to detect spores and to recover vegetative forms of the bacteria. Environmental samples (n = 86) and swabs from the clothing of medical personnel (n = 14) were collected at two units of a paediatric hospital, where the cases of antibiotic-associated diarrhoea with a C. difficile aetiology constitute a significant clinical problem. In 17 samples, a change in the broth's colour was observed, indicating the presence of spores. Out of seven samples, C. difficile strains were cultured. The pathogenic isolates of C. difficile were obtained from swabs collected from elements of beds, a toilet, a door handle and a doctor's uniform. In our study, we indicated points of increased risk of pathogen transmission, which could constitute a source of infection. The clothing of medical personnel may be a dangerous carrier of pathogenic spores. Periodical surveys of hospital environments with the use of specialist microbiological mediums successfully indicate the direction of corrective actions to be undertaken by the medical facility in order to increase patient safety.

Survival of Clostridioides difficile spores in thermal and chemo-thermal laundering processes and influence of the exosporium on their adherence to cotton bed sheets

Clostridioides difficile spores were previously demonstrated to survive industrial laundering. Understanding interactions between heat, disinfectants and soiling (e.g. bodily fluids) affecting C. difficile spore survival could inform the optimization of healthcare laundry processes. Reducing spore attachment to linen could also enhance laundering efficacy. This study aimed to compare the sensitivity of C. difficile spores to heat and detergent, with and without soiling and to investigate adherence to cotton. Survival of C. difficile spores exposed to industrial laundering temperatures (71-90°C), reference detergent and industrial detergent was quantified with and without soiling. The adherence to cotton after 0 and 24 h air drying was determined with the exosporium of C. difficile spores partially or fully removed. Clostridioides difficile spores were stable at 71°C for 20 min (≤0·37 log₁₀ reduction) while 90°C was sporicidal (3 log₁₀ reduction); soiling exerted a protective effect. Industrial detergent was more effective at 71°C compared to 25°C (2·81 vs 0·84 log₁₀ reductions), however, specifications for sporicidal activity (>3 log₁₀ reduction) were not met. Clostridioides difficile spores increasingly adhered to cotton over time, with 49% adherence after 24 h. Removal of the exosporium increased adherence by 19-23% compared to untreated spores. Further understanding of the role of the exosporium in attachment to cotton could enhance spore removal and aid decontamination of linen.

Genetically related Clostridium difficile from water sources and human CDI cases revealed by whole-genome sequencing

Clostridium difficile isolates from the environment are closely related to those from humans, indicating a possible environmental transmission route for C. difficile infection (CDI). In this study, C. difficile was isolated from 47.3% (53/112) of lake/pond, 23.0% (14/61) of river, 20.0% (3/15) of estuary and 0.0% (0/89) of seawater samples. The most common toxigenic strain isolated was C. difficile PCR ribotype (RT) 014/020 (10.5%, 8/76). All water isolates were susceptible to fidaxomicin, metronidazole, rifaximin, amoxicillin/clavulanic acid, moxifloxacin and tetracycline. Resistance to vancomycin, clindamycin, erythromycin and meropenem was detected in 5.3% (4/76), 26.3% (20/76), 1.3% (1/76) and 6.6% (5/76) of isolates, respectively. High-resolution core-genome analysis was performed on RT 014/020 isolates of water origin and 26 clinical RT 014/020 isolates from the same year and geographical location. Notably, both human and water strains were intermixed across three sequence types (STs), 2, 13 and 49. Six closely related groups with ≤10 core-genome single nucleotide polymorphisms were identified, five of which comprised human and water strains. Overall, 19.2% (5/26) of human strains shared a recent genomic relationship with one or more water strains. This study supports the growing hypothesis that environmental contamination by C. difficile plays a role in CDI transmission.

The future of Clostridioides difficile diagnostics

PURPOSE OF REVIEW

Although the epidemiology of Clostridioides difficile has changed, this organism continues to cause significant morbidity and mortality. This review addresses current and future approaches to the diagnosis of C. difficile disease.

RECENT FINDINGS

Over the last several years, large prospective studies have confirmed that there is no single optimal test for the diagnosis of C. difficile disease. The pendulum has swung from a focus on rapid molecular diagnosis during the years of the ribotype 027 epidemic, to a call for use of algorithmic approaches that include a test for toxin detection. In addition, diagnostic stewardship has been shown to improve test utilization, especially with molecular methods. Advances in testing include development of ultrasensitive toxin tests and an expansion of biomarkers that may be more C. difficile specific. Microbiome research may be leveraged to inform novel diagnostic approaches based on measurements of volatile and nonvolatile organic compounds in stool.

SUMMARY

As rates of C. difficile infection decline, emphasis is now on improving test utilization and a quest for improved diagnostic approaches. These approaches may involve implementation of technologies that improve toxin testing, predict patients likely to have disease and/or a severe outcome, and harnessing research on changes in the microbiome to advance metabolomics.

Advances and required improvements in methods to diagnosing Clostridioides difficile infections in the healthcare setting

INTRODUCTION

Clostrididioides difficile is associated with adverse clinical outcomes and increased morbidity, mortality, length of hospital stay, and health-care costs.Areas Covered: We searched relevant papers in PubMed for the last 10 years. In major papers, we scanned the bibliographies to ensure that important articles were included. This review addresses the evolving epidemiology of Clostridioides difficile infection (CDI) and discusses novel methods/approaches for improving the diagnosis of this important disease.

EXPERT OPINION

No single diagnostic test to date has demonstrated optimum sensitivity and specificity for detection of CDI. Many institutions have developed multi-step algorithms consistent with guidelines established by various professional societies. Some institutions have successfully tried to improve the pretest probability of molecular assays by implementing appropriate sample rejection criteria and establishing best practice alerts at the time of electronic order entry. Others have established PCR cycle threshold cutoffs to attempt to differentiate symptomatic patients from asymptomatic carriers or to make predictions about severity of disease with variable success. As research advances our understanding of C. difficile pathogenesis and pathophysiology, more information on CDI specific biomarkers is emerging. Finally, assessments of the microbiome and metabolome may expand the diagnostic armamentarium with advances in mass spectrometry and sequencing technologies.

An Analysis of Clostridium difficile Environmental Contamination During and After Treatment for C difficile Infection

Background

Lower Clostridium difficile spore counts in feces from C difficile infection (CDI) patients treated with fidaxomicin versus vancomycin have been observed. We aimed to determine whether environmental contamination is lower in patients treated with fidaxomicin compared with those treated with vancomycin/metronidazole.

Methods

The CDI cases were recruited at 4 UK hospitals (Leeds, Bradford, and London [2 centers]). Environmental samples (5 room sites) were taken pretreatment and at 2–3, 4–5, 6–8, and 9–12 days of treatment, end of treatment (EOT), and post-EOT. Fecal samples were collected at diagnosis and as often as produced thereafter. Swabs/feces were cultured for C difficile; percentage of C difficile-positive samples and C difficile bioburden were compared between different treatment arms at each time point.

Results

Pre-EOT (n = 244), there was a significant reduction in environmental contamination (≥1 site positive) around fidaxomicin versus vancomycin/metronidazole recipients at days 4–5 (30% vs 50% recipients, P = .04) and at days 9–12 (22% vs 49%, P = .005). This trend was consistently seen at all other timepoints, but it was not statistically significant. No differences were seen between treatment groups post-EOT (n = 76). Fidaxomicin-associated fecal positivity rates and colony counts were consistently lower than those for vancomycin/metronidazole from days 4 to 5 of treatment (including post-EOT); however, the only significant difference was in positivity rate at days 9–12 (15% vs 55%, P = .03).

Conclusions

There were significant reductions in C difficile recovery from both feces and the environment around fidaxomicin versus vancomycin/metronidazole recipients. Therefore, fidaxomicin treatment may lower the C difficile transmission risk by reducing excretion and environmental contamination.

Ridinilazole for the treatment of Clostridioides difficile infection

INTRODUCTION

Ridinilazole is a novel antibiotic being developed for the treatment of Clostridioides difficile infection (CDI). Ridinilazole has completed two phase II trials and phase III trials which are denoted Ri-CoDIFy 1 and 2, are planned (ClinicalTrials.gov identifiers: NCT03595553 and NCT03595566). Areas covered: This article covers the chemistry, mechanism of action, in vitro microbiology versus C. difficile and host microbiota, pre-clinical and clinical efficacy, pharmacokinetics, pharmacodynamics and safety and tolerability of ridinilazole. Expert opinion: Ridinilazole is a novel antibiotic with ideal properties for the treatment of CDI. Given the promising results from the phase II clinical trial, ridinilazole may have the capability to lower the risk for CDI recurrence thus improving sustained clinical response rates - a current unmet medical need. Assuming a positive phase III trial, ridinilazole will enter a market with heightened awareness on the importance of prevention of CDI. This along with further research into the economic consequences and decreased patient quality of life associated with recurrent CDI, should provide clinicians with further evidence for the need for therapy that limits CDI recurrence and improves sustained clinical cure.

Clostridium difficile -Associated Disease in Long-Term Care Facilities

Clostridium difficile is a major cause of gastrointestinal infections. In 1978, Bartlett and colleagues identified C difficile and its toxin as the cause of the antibiotic-associated pseudomembranous colitis (PMC). Within a few years, there was the development of a diagnostic assay, a description of a clinical and pathological spectrum of the disease, a definition of risk factors and characterization of the two toxins that account for the pathological event. Additional information regarding the microbiology, pathogenesis, clinical manifestations, diagnosis and treatment has rapidly developed. These features are beyond the scope of this report, and the reader is referred to several recent reviews.

Risk Factors for Clostridium difficile Toxin-Associated Diarrhea

The hospital-wide attack rate for Clostridium difficile-associated diarrhea at our tertiary-care university hospital was 0.02 per 100 patient discharges (0.02%) in 1982, but 0.41% and 1.47% in 1986 and 1987, respectively, with a peak incidence of 2.25% in the fourth quarter of 1987. Hospital antibiotic usage patterns showed concurrent increased use of third-generation cephalosporins, and intravenous vancomycin and metronidazole. Thirty-seven cases selected for study were older than 37 control patients, more likely to have an underlying malignancy and less likely hospitalized on the obstetrics/gynecology service. Their mean duration of hospitalization prior to diagnosis was 21 days, versus a mean total length of stay of eight days for controls. All cases received antibiotics, compared to 24 of the controls. Cases were given more antibiotics for longer periods, and more often received clindamycin, third-generation cephalosporins, aminoglycosides and vancomycin. Gender, race, duration of hospitalization, prior surgery and antiulcer therapy were not significant by logistic regression analysis. Epidemiologic variables with significantly different adjusted odds ratios (95% confidence intervals) were age greater than 65 years (14.1, 1.4-141), intensive care unit residence (39.2, 2.2-713), gastrointestinal procedure (23.2, 2.1-255) and more than ten antibiotic days (summation of days of each antibiotic administered) (16.1, 2.2-117). Control measures included encouraging earlier isolation and treatment of suspected cases and formulary restriction of clindamycin, with use of metronidazole for therapy of anaerobic infections. By the second half of 1988, the attack rate had dropped progressively to 0.74%.

Aerosol-Transmitted Infections-a New Consideration for Public Health and Infection Control Teams

Since the emergence of the 2003 severe acute respiratory syndrome (SARS), the 2003 reemergence of avian A/H5N1, the emergence of the 2009 pandemic influenza A/H1N1, the 2012 emergence of Middle East respiratory syndrome (MERS), the 2013 emergence of avian A/H7N9 and the 2014 Ebola virus outbreaks, the potential for the aerosol transmission of infectious agents is now routinely considered in the investigation of any outbreak. Although many organisms have traditionally been considered to be transmitted by only one route (e.g. direct/indirect contact and/or faecal-orally), it is now apparent that the aerosol transmission route is also possible and opportunistic, depending on any potentially aerosol-generating procedures, the severity of illness and the degree and duration of pathogen-shedding in the infected patient, as well as the environment in which these activities are conducted.This article reviews the evidence and characteristics of some of the accepted (tuberculosis, measles, chickenpox, whooping cough) and some of the more opportunistic (influenza, Clostridium difficile, norovirus) aerosol-transmitted infectious agents and outlines methods of detecting and quantifying transmission.

The epidemiology of Clostridium difficile infection inside and outside health care institutions

This article describes the global changes in Clostridium difficile epidemiology since the late twentieth century and into the twenty-first century when the new epidemic strain BI/NAP1/027 emerged. The article provides an overview of how understanding of C difficile epidemiology has rapidly evolved since its initial association with colitis in 1974. It also discusses how C difficile has spread across the globe, the role of asymptomatic carriers in disease transmission, the increased recognition of C difficile outside health care settings, the changes in epidemiology of C difficile infection in children, and the risk factors for disease.

Extraction and sensitive detection of toxins A and B from the human pathogen Clostridium difficile in 40 seconds using microwave-accelerated metal-enhanced fluorescence

Clostridium difficile is the primary cause of antibiotic associated diarrhea in humans and is a significant cause of morbidity and mortality. Thus the rapid and accurate identification of this pathogen in clinical samples, such as feces, is a key step in reducing the devastating impact of this disease. The bacterium produces two toxins, A and B, which are thought to be responsible for the majority of the pathology associated with the disease, although the relative contribution of each is currently a subject of debate. For this reason we have developed a rapid detection assay based on microwave-accelerated metal-enhanced fluorescence which is capable of detecting the presence of 10 bacteria in unprocessed human feces within 40 seconds. These promising results suggest that this prototype biosensor has the potential to be developed into a rapid, point of care, real time diagnostic assay for C. difficile.

In Vitro Evaluation of Antimicrobial Activity of Lactic Acid Bacteria against Clostridium difficile

Clostridium difficile infection (CDI) has become a significant threat to public health. Although broad-spectrum antibiotic therapy is the primary treatment option for CDI, its use has evident limitations. Probiotics have been proved to be effective in the treatment of CDI and are a promising therapeutic option for CDI. In this study, 4 strains of lactic acid bacteria (LAB), namely, Lactobacillus rhamnosus (LR5), Lactococcuslactis (SL3), Bifidobacterium breve (BR3), and Bifidobacterium lactis (BL3) were evaluated for their anti-C. difficile activity. Co-culture incubation of C. difficile (10(6) and 10(10) CFU/ml) with each strain of LAB indicated that SL3 possessed the highest antimicrobial activity over a 24-hr period. The cell-free supernatants of the 4 LAB strains exhibited MIC50 values between 0.424 mg/ml (SL3) and 1.318 (BR3) mg/ml. These results may provide a basis for alternative therapies for the treatment of C. difficile-associated gut disorders.

A systematic evaluation of a peracetic-acid-based high performance disinfectant

The importance of environmental contamination in the spread of healthcare associated infections (HAI) has generated a need for high performance disinfectants. Currently chlorine-based disinfectants are the products of choice, a position reflected in UK guidance. The aim of this research was to evaluate a peracetic acid (PAA) generating disinfectant to determine if it provided a realistic alternative to commonly used chlorine-based disinfectants. The European standards framework was employed in this study and enhanced where appropriate by reducing the contact times, increasing the organic and microbial challenge, and changing the organisms involved. When tested against bacteria and spores PAA provided similar or better performance than currently employed levels of chlorine. This was particularly the case in the presence of an organic challenge or dried surface contamination. The chlorine disinfectants only demonstrated superior performance in the case of fungal spores. These results suggest that PAA generating products provide an effective alternative to chlorine-based products up to 10,000 ppm free available chlorine. These products have superior performance in situations with spore borne, surface contamination and high organic challenge. In cases where filamentous fungi are a concern, high levels of PAA (>5,000 ppm) would be required to match the performance of chlorine based disinfectants.

Improved recovery of Clostridium difficile spores with the incorporation of synthetic taurocholate in cycloserine-cefoxitin-fructose agar (CCFA)

AIM

Culture remains important for the detection and typing of Clostridium difficile. Culture of C. difficile spores can be enhanced on media supplemented with a germinant. Despite this, unsupplemented media continues to be used in some laboratories. The aim of this study was to quantify the effect of the known germinant sodium taurocholate on recovery of C. difficile spores and to determine if the supplement impacts on the recovery of vegetative C. difficile.

METHODS

The recovery on cycloserine-cefoxitin-fructose agar (CCFA) with and without taurocholate, of spore, vegetative, and total cell fractions of broth cultures of eight C. difficile isolates was compared.

RESULTS

Taurocholate in CCFA did not inhibit growth of vegetative C. difficile and significantly increased recovery of spores (p = 0.04).

CONCLUSIONS

The routine incorporation of taurocholate in CCFA is recommended for improved sensitivity in C. difficile culture from specimens.

Evaluation of the sporicidal activity of different chemical disinfectants used in hospitals against Clostridium difficile

Decontamination of surfaces and medical equipment is integral to the control of Clostridium difficile transmission, and many products claim to inactivate this bacterium effectively. Thirty-two disinfectants were tested against spores of C. difficile in a suspension test based on European Standard BS EN 13704:2002, with contact times of 1 and 60 min in simulations of clean (0.3% albumin) and dirty (3% albumin) conditions. The addition of a 1-min contact time was chosen as a more realistic simulation of probable real-life exposures in the situation being modelled than the 60 min specified by the Standard. The manufacturer's lowest recommended concentrations for use were tested. Sixteen products achieved >10(3) reduction in viability after 60 min (the pass criterion for the Standard) under both clean and dirty conditions. However, only eight products achieved >10(3) reduction in viability within 1 min under dirty conditions. Three products failed to reduce the viability of the C. difficile spores by a factor of 10(3) in any of the test conditions. This study highlights that the application of disinfectants claiming to be sporicidal is not, in itself, a panacea in the environmental control of C. difficile, but that carefully chosen environmental disinfectants could form part of a wider raft of control measures that include a range of selected cleaning strategies.

Clostridium difficile 30 years on: what has, or has not, changed and why?

The report of clindamycin-associated colitis in 1974 by Tedesco et al. [Ann Intern Med 81: 429-33] stimulated an intense search for the cause of this severe complication of antibiotic use. The search culminated in early 1978 in the publication of a series of papers within 3 months that identified the causative agent as Clostridium difficile and its accompanying toxins. Thirty years later we are in the midst of a resurgence of C. difficile infection (CDI) in North America and Europe that is greater than ever previously reported and for which morbidity and mortality appear to be higher than ever seen in the past. The purpose of this review is to highlight the discoveries of the past 30 years that, in my view, have brought us to our current level of understanding of the pathogenesis, prevention and treatment of CDI, and to suggest why a disease thought to be managed so well 30 years ago could now be causing more morbidity and mortality than ever before. In the 21st century the focus should be on better understanding the relationship between the C. difficile organism and the host at the mucosal level, so that biotherapeutic and vaccine strategies for the prevention of CDI can be developed.

Recent advances in Clostridium difficile-associated disease

The main purpose of this article is to review recent developments in the management of acute and recurrent Clostridium difficile-associated disease, with consideration of existing and new antibiotic and non-antibiotic agents for treatment. Details of the current developmental stage of new agents are provided and the role of surgery in the management of severe disease is discussed. Infection control measures considered comprise prudent use of antimicrobials, prevention of cross-infection and surveillance. Other topics that are covered include the recent emergence of an epidemic hypervirulent strain, pathogenesis, clinical presentation and approaches to rapid diagnosis and assessment of the colonic disease.

Antimicrobial activity of lacticin 3,147 against clinical Clostridium difficile strains

Clostridium difficile-associated diarrhoea (CDAD) is the most common hospital-acquired diarrhoea, and is a major type of gastroenteritis infection in nursing homes and facilities for the elderly. In this study the antimicrobial activity of the two-component lantibiotic, lacticin 3,147, against a range of genetically distinct C. difficile isolates was studied. The bacteriocin exhibited an MIC(50) of 3.6 microg ml(-1) for 10 genetically distinct C. difficile strains isolated from healthy subjects, inflammatory bowel disease patients and culture collection strains. In time-kill studies, 10(6) c.f.u. ml(-1) C. difficile ATCC 42,593 and CDAD isolate DPC 6,220 were killed within 120 or 20 min incubation, respectively, at a concentration of 6 microg lacticin ml(-1). Interestingly, addition of lacticin 3,147 to exponentially growing cells of C. difficile ATCC 43,593 caused rapid lysis of the cells after an initial lag phase, as measured by the concomitant release of the intracellular enzyme, acetate kinase. The addition of a food-grade, milk-based lacticin containing powder to faecal fermentation demonstrated that lacticin is effective in completely eliminating 10(6) c.f.u. C. difficile ml(-1) from a model faecal environment within 30 min when present at concentrations as low as 18 microg ml(-1). While other culturable microflora such as total anaerobes, bacteroides, total non-spore-forming anaerobes and total Gram-negative anaerobes were unaffected, populations of lactobacilli and bifidobacteria were reduced by 3 log cycles at bacteriocin levels sufficient to eliminate over 10(6) C. difficile. In light of these findings, the potential of lacticin 3,147 for treatment of CDAD is discussed.

Prevalence of Clostridium difficile in the environment in a rural community in Zimbabwe

Clostridium difficile has been shown to be a nosocomial pathogen associated with diarrhoea and pseudomembranous colitis in hospitalised patients, but very little is known about its prevalence outside the hospital environment. The aim of this study was to determine the prevalence of C. difficile in faeces of domestic animals, soil and drinking water in a rural community. Water, animal faeces and soil were collected from homesteads in a rural community and the samples were cultured for C. difficile. Clostridium difficile isolates that produced toxins A or B were tested for their susceptibility to antimicrobial drugs. Clostridium difficile was isolated from 37.0% of 146 soil samples, 17.4% of 115 chicken faeces samples, 6.0% of 234 water samples and 4.3% of 161 faecal samples of other animals. Some of the C. difficile isolates from chickens (55.0%), soil (66.7%) and water (14.3%) were toxigenic. All toxigenic isolates were susceptible to metronidazole, vancomycin, doxycycline, chloramphenicol and tetracycline and all were resistant to cefotaxime, gentamicin, ciprofloxacin, norfloxacin and nalidixic acid. The results of the present study suggest that chickens kept by villagers are an important reservoir of C. difficile, which may act as a source of human infection.

Laboratory diagnosis of Clostridium difficile-associated diarrhoea: a plea for culture

A routine protocol for diagnosing Clostridium difficile-associated diarrhoea (CDAD) based on both faecal-cytotoxin detection and toxigenic culture was adopted by the microbiology laboratory of the St Luc-UCL University Hospital in Brussels in 1997. A toxigenic culture is a faecal culture followed, in the case of positivity, by a direct immunoassay on colonies to detect toxin A production. The results obtained over the past 7 years in the hospital are reviewed here. A total of 10,552 diarrhoeal stools from 7042 patients were analysed, of which 9494 were negative for all tests. A total of 1058 samples (10 %) from 794 patients were culture-positive, of which 460 (4.4 %) were positive for a faecal cytotoxin. The remaining 598 cultures were tested for toxin A on colonies; 355 of them were positive, which is 3.4 % of the total, and the remaining 243 (2.3 %) were negative. The positivity of the faecal-cytotoxin assay was statistically linked to the number of colonies observed on the culture plate. In conclusion, over a 7 year period, toxigenic culture allowed the diagnosis of 355 cases of CDAD that would have been missed by a protocol using a faecal-cytotoxin assay alone. In terms of both patient care, prevention of environmental contamination and prevention of risk of a hospital outbreak, it is proposed that these results justify the recommendation to perform both faecal-toxin assay and culture in routine medical practice.

Gastrointestinal disorders and the critically ill. Clostridium difficile infection and pseudomembranous colitis

Clostridium difficile causes a spectrum of diseases ranging from diarrhoea to pseudomembranous colitis, primarily in the hospitalized elderly, although community-acquired infection is probably under-documented. Host factors are increasingly recognized as critical determinants of disease expression. Exposure to antibiotics, particularly those adversely affecting anaerobic gut flora, appears to create a niche which is exploited by C. difficile. Several retrospective and intervention studies have indicated that third-generation cephalosporins have a high propensity to induce C. difficile diarrhoea. Conversely, some broad-spectrum antibiotics, including ureidopenicillins (e.g. piperacillin-tazobactam) and ciprofloxacin, are less likely to induce C. difficile infection. Effective control of C. difficile in the hospital requires both antibiotic control and prevention of environmental seeding and bacterial spread. Epidemic C. difficile strains are widely distributed in the hospital environment, both as a cause and result of nosocomial diarrhoea. Current treatment options are antibiotic-based, which is less than ideal. Although many biotherapeutic approaches have been tried few have shown real benefit.

Clostridium difficile infections in animals with special reference to the horse. A review

In human medicine, Clostridium (C.) difficile is since many years a well-known cause of nosocomial diarrhea induced by antibiotic treatment. In horses, C. difficile was recently suggested as a possible enteric pathogen. The bacterium is associated with acute colitis in mature horses following treatment with antibiotics. C. difficile, and/or its cytotoxin, is also associated with acute colitis in mares when their foals are being treated with erythromycin and rifampicin for Rhodococcus equi pneumonia. The colitis can have resulted from an accidental ingestion of erythromycin by the mares. In an experimental study it was also demonstrated in mature horses that erythromycin can induce severe colitis associated with proliferation of C. difficile. A new interesting finding was that in healthy foals younger than 14 days, C. difficile was isolated from every third foal whereas older foals proved negative. In this paper the current state of knowledge of C. difficile infections in animals, especially in horses, is reviewed. A short description is given of the historical background of Clostridium difficile and the antibiotic-associated colitis and diarrhea caused by infection with this bacterium. The taxonomy of Clostridium difficile is described extensively. A summary is given of the diseases associated with clostridia infections in animals. Special attention is paid to the pathogenesis, epidemiology, clinical symptoms, laboratory diagnosis, and pathology of Clostridium difficile infections in horses. Finally, some other bacterial causes of colitis in horses are discussed shortly.

Value of lysozyme agar incorporation and alkaline thioglycollate exposure for the environmental recovery of Clostridium difficile

Clostridium difficile is an increasingly prevalent nosocomial pathogen. Environmental contamination by spores is believed to be a major factor propagating the spread of C. difficile. Various approaches including the use of bile salts have been described to enhance the recovery of C. difficile from clinical and environmental specimens. We found that lysozyme (5 mg/L) incorporated into a selective medium containing bile salts significantly increased the recovery of C. difficile from swabs of 197 environmental sites (11% versus 24% samples positive, P< 0.01). Furthermore, in a separate series of experiments additional use of cooked meat broth enrichment significantly enhanced the recovery of C. difficile (35% versus 45%, P = 0.009). Conversely, we found that pre-exposure to alkaline thioglycollate did not improve the yield of C. difficile. Lysozyme incorporation markedly increases the recovery of C. difficile from environmental samples probably by stimulation of spore germination. Our findings suggest that previous attempts to determine the level of environmental C. difficile contamination have markedly underestimated the true prevalence of this pathogen.

Survey of incidence of Clostridium difficile infection in Canadian hospitals and diagnostic approaches

A questionnaire relating to Clostridium difficile disease incidence and diagnostic practices was sent to 380 Canadian hospitals (all with > 50 beds). The national questionnaire response rate was 63%. In-house testing was performed in 17.6, 61.5, and 74.2% of the hospitals with < 300, 300 to 500, and > 500 beds, respectively. The average test positivity rates were 17.2, 15.3, and 13.2% for hospitals with < 300, 300 to 500, and > 500 beds, respectively. The average disease incidences were 23.5, 30.8, and 40.3 cases per 100,000 patient days in the hospitals with < 300, 300 to 500, and > 500 beds, respectively. In the 81 hospitals where in-house testing was performed, cytotoxin testing utilizing tissue culture was most common (44.4%), followed by enzyme-linked immunosorbent assay (38.3%), culture for toxigenic C. difficile (32.1%), and latex agglutination (13.6%). The clinical criteria for C. difficile testing were variable, with 85% of hospitals indicating that a test was done automatically if ordered by a doctor. Our results show that C. difficile-associated diarrhea is a major problem in hospitals with > or = 200 beds. Despite a lower disease incidence in smaller hospitals, there was a higher diagnostic test positivity rate. This may reflect the preference of smaller hospitals for culture and latex agglutination tests.

Determination and validation of a predictive model for Clostridium difficile diarrhea in hospitalized oncology patients

BACKGROUND

Clostridium difficile colitis in the cancer patient receiving chemotherapy is a frequent cause of morbidity which may prolong hospitalization. Techniques for identifying infection often delay the initiation of therapy.

PATIENTS AND METHODS

In this retrospective case-control analysis, we identified predictors for C. difficile-associated diarrhea in 29 patients hospitalized from 1988 to 1993 on a hematologic malignancy/bone marrow transplant unit (hospital A). We then validated our model with 58 C. difficile cases and 74 controls admitted to an oncology unit from a different institution (hospital B).

RESULTS

We found that low intensity of chemotherapy (P < 0.001), lack of parenteral vancomycin use (P = 0.03) and hospitalization within the past two months (P = 0.05) were independently predictive of C. difficile colitis by multivariate analysis. These variables were weighted for predictive capability using a receiver operator characteristic score; low intensity chemotherapy was assigned two points, lack of parenteral vancomycin received one point and prior hospitalization one point (P < 0.001 by chi 2 for trend). The receiver operating characteristic (ROC) curve areas were 0.78 for patients at hospital A and 0.70 at hospital B indicating moderate drop off in discrimination. Compared to hospital A patients, hospital B patients hospitalized between 1989 and 1994 were more often women (P = 0.04), received less systemic vancomycin (P = 0.01), were less frequently neutropenic (P < 0.05), and received less intense chemotherapy regimens (P < 0.05). Despite these differences in demographics in patients between these institutions, our predictive model was validated in hospital B patients (P = 0.02 by chi 2 for trend).

CONCLUSIONS

The results of this study may help clinicians predict the risk of C. difficile disease in the hospitalized immunocompromised oncology patient and may help guide empiric therapy while awaiting results of stool toxin assays.

Primary symptomless colonisation by Clostridium difficile and decreased risk of subsequent diarrhoea

BACKGROUND

Little is known about whether patients who develop Clostridium-difficile-associated diarrhoea (CDAD) are culture-positive or culture-negative before illness. The most important risk factor is antibiotic exposure. We aimed to find out whether patients identified as primary symptom-free C difficile carriers are at higher risk of developing CDAD than patients who are culture-negative.

METHOD

We reviewed four longitudinal studies in which 810 patients admitted to hospital were followed up by prospective rectal-swab culture. At least two consecutive weekly cultures were obtained. We calculated the difference in risk of CDAD between colonised and non-colonised patients in each study and combined the results of the four studies in a random-effects model.

FINDINGS

Of 618 non-colonised patients (mean follow-up 1.7 weeks [SD 1.3]), 22 (3.6%) developed CDAD, whereas only two (1.0%) of 192 primary symptom-free carriers (1.5 [1.5]) developed CDAD (pooled risk difference -2.3% [95% CI 0.3-4.3], p=0.021). Of patients who received antibiotics, the risk difference was increased: 22 (4.5%) of 491 non-colonised patients compared with two (1.1%) of 176 colonised patients developed CDAD (-3.2% [0.4-6.0], p=0.024). Of the primary symptom-free C difficile carriers, 95 were colonised with toxigenic strains, 76 with non-toxigenic strains, 12 with both toxigenic and non-toxigenic strains (non-concurrently), and nine with strains of undetermined toxigenicity. Nine of the 12 toxogenic strains of C difficile isolates that cause CDAD were also recovered from stools of symptom-free patients.

INTERPRETATION

Primary symptomless C difficile colonisation is associated with a decreased risk of CDAD. Although the mechanism is unknown, risk reduction is found in colonisation with non-toxigenic and toxigenic strains.

Treatment and Control of Colonization in the Prevention of Nosocomial Infections

Patients frequently develop nosocomial infections that are caused by normal flora colonizing the patient at the time of admission, or by exogenous pathogens that are acquired and subsequently colonize the patient after admission to the hospital. To prevent nosocomial infections, a variety of strategies have been used either to prevent colonization from occurring, to eradicate colonizing organisms, or to prevent the progression from colonization to infection. These strategies include implementation of infection control measures designed to prevent acquisition of exogenous pathogens, eradication of exogenous pathogens from patients or personnel who have become colonized, suppression of normal flora, prevention of colonizing flora from entering sterile body sites during invasive procedures, microbial interference therapy, immunization of high-risk patients, and modification of antibiotic utilization practices. Because strategies that require widespread use of antimicrobial agents to suppress or eradicate colonizing organisms tend to promote emergence of multidrug-resistant pathogens, greater emphasis should be given to those strategies that prevent colonization from occurring or employ techniques other than administration of prophylactic antibiotics to eradicate colonization. Restricting inappropriate use of antibiotics should reduce the frequency with which patients become colonized and infected with multidrug-resistant organisms.

Clostridium difficile-associated diarrhea and colitis

OBJECTIVES

To review and summarize the status of diagnosis, epidemiology, infection control, and treatment of Clostridium difficile-associated disease (CDAD).

DIAGNOSIS

A case definition of CDAD should include the presence of symptoms (usually diarrhea) and at least one of the following positive tests: endoscopy revealing pseudomembranes, stool cytotoxicity test for toxin B, stool enzyme immunoassay for toxin A or B, or stool culture for C difficile (preferably with confirmation of organism toxicity if a direct stool toxin test is negative or not done). Testing of asymptomatic patients, including those who are asymptomatic after treatment, is not recommended other than for epidemiologic purposes. Lower gastrointestinal endoscopy is the only diagnostic test for pseudomembranous colitis, but it is expensive, invasive, and insensitive (51% to 55%) for the diagnosis of CDAD. Stool culture is the most sensitive laboratory test currently in clinical use, but it is not as specific as the cell cytotoxicity assay.

EPIDEMIOLOGY

C difficile is the most frequently identified cause of nosocomial diarrhea. The majority of C difficile infections are acquired nosocomially, and most patients remain asymptomatic following acquisition. Antimicrobial exposure is the greatest risk factor for patients, especially clindamycin, cephalosporins, and penicillins, although virtually every antimicrobial has been implicated. Cases of CDAD unassociated with prior antimicrobial or antineoplastic use are very rare. Hands of personnel, as well as a variety of environmental sites within institutions, have been found to be contaminated with C difficile, which can persist as spores for many months. Contaminated commodes, bathing tubs, and electronic thermometers have been implicated as sources of C difficile. Symptomatic and asymptomatic infected patients are the major reservoirs and sources for environmental contamination. Both genotypic and phenotypic typing systems for C difficile are available and have enhanced epidemiologic investigation greatly.

INFECTION CONTROL

Successful infection control measures designed to prevent horizontal transmission include the use of gloves in handling body substances and replacement of electronic thermometers with disposable devices. Isolation, cohorting, handwashing, environmental disinfection, and treatment of asymptomatic carriers are recommended practices for which convincing data of efficacy are not available. The most successful control measure directed at reduction in symptomatic disease has been antimicrobial restriction.

TREATMENT

Treatment of symptomatic (but not asymptomatic) patients with metronidazole or vancomycin for 10 days is effective; metronidazole may be preferred to reduce risk of vancomycin resistance among other organisms in hospitals. Recurrence of symptoms occurs in 7% to 20% of patients and is due to both relapse and reinfection. Over 90% of first recurrences can be treated successfully in the same manner as initial cases. Combination treatment with vancomycin plus rifampin or the addition orally of the yeast Saccharomyces boulardii to vancomycin or metronidazole treatment has been shown to prevent subsequent diarrhea in patients with recurrent disease.

Use of pulsed-field gel electrophoresis for investigation of an outbreak of Clostridium difficile infection among geriatric patients

A six-month outbreak of Clostridium difficile infection among elderly residents of a middle-term-care facility was investigated. Pulsed-field gel electrophoresis was used to genotype 22 outbreak strains and 30 epidemiologically unrelated strains. A prospective case-control study was conducted to identify risk factors for epidemic Clostridium difficile-associated diarrhea. All epidemiologically unrelated Clostridium difficile strains of the same serogroup could be differentiated by their DNA patterns with two restriction enzymes (SmaI and KspI). Among clustered strains, two epidemic serogroups (C and K) were identified. Two different DNA patterns were identified among serogroup C strains and three among serogroup K strains. Multivariate analysis showed that the risk of Clostridium difficile infection increased with antimicrobial chemotherapy (beta-lactam agents and pristinamycin) and the presence of a feeding tube. This study confirms the high discriminative power of restriction fragment length polymorphism analysis by pulsed-field gel electrophoresis to describe Clostridium difficile epidemiology. The typing results confirm that infection was principally exogenous in this outbreak. Furthermore, they indicate the need to improve all measures limiting transmission of infection.

Chronic septic arthritis and osteomyelitis in a prosthetic knee joint due to Clostridium difficile

A case of chronic septic arthritis and osteomyelitis in a prosthetic knee joint due to Clostridium difficile is reported. A knee prosthesis was installed in a 16-year-old boy for surgical treatment of an osteosarcoma of the femur. Later, the patient suffered a traumatic closed fracture of his patella, and a sterile fluid was aspirated. One month later, the joint displayed inflammation. Culture of the articular fluid yielded a nontoxigenic Clostridium difficile strain. Despite several attempts using conservative medical treatment with penicillins and ornidazole, Clostridium difficile strains with the same antibiotic susceptibility pattern were repeatedly isolated from the joint over an eight-month period. The foreign material was then ablated, and finally, the patient's leg was amputated one year after Clostridium difficile was first isolated. The possible sources of contamination in our case and other reported cases of extraintestinal infection due to Clostridium difficile are discussed.

Epidemiological aspects of infections caused by Bacteroides fragilis and Clostridium difficile

Bacteroides fragilis and Clostridium difficile are two of the most common anaerobes associated with human disease. Studies on the epidemiology of Bacteroides fragilis are limited and are based predominantly on serogrouping, which suggests intraspecies differences. Further studies using newer techniques for typing are required to elucidate the epidemiological characteristics of this important pathogen. By contrast, numerous phenotypic, immunological and molecular methods have been developed for typing and fingerprinting of Clostridium difficile and applied in epidemiological studies to show conclusively that Clostridium difficile is nosocomially acquired and that there is transmission and cross-infection between hospital patients.

Clostridium difficile infection: responses, relapses and re-infections

Clostridium difficile infection is a common and potentially lethal complication of antibiotic usage. Since the aetiology of antibiotic-associated colitis was discovered 14 years ago, two antibiotics in particular, metronidazole and vancomycin, have been used to treat C. difficile infection. Studies comparing the efficacy of these antibiotics are reviewed. It is now apparent that many of the so-called 'relapses' of C. difficile infection following antibiotic treatment are, in fact, re-infections. Such findings have major infection control implications.

Clostridium difficile infection in a geriatric ward

In a prospective, longitudinal study we searched for the presence of Clostridium difficile in the stools of 100 consecutively hospitalized elderly patients (mean age: 82; SD: 9.5 years). C. difficile was found on admission in 6 patients, 3 of whom were asymptomatic carriers. Ten patients acquired C. difficile during hospitalization. Four different types of C. difficile were isolated. The various types were clustered in time, indicating that the infection was acquired from the environment.

Clostridium difficile-associated disease in long-term care facilities

Clostridium difficile is a major cause of gastrointestinal infections. In 1978, Bartlett and colleagues identified C difficile and its toxin as the cause of the antibiotic-associated pseudomembranous colitis (PMC). Within a few years, there was the development of a diagnostic assay, a description of a clinical and pathological spectrum of the disease, a definition of risk factors and characterization of the two toxins that account for the pathological event. Additional information regarding the microbiology, pathogenesis, clinical manifestations, diagnosis and treatment has rapidly developed. These features are beyond the scope of this report, and the reader is referred to several recent reviews.

Risk factors for Clostridium difficile toxin-associated diarrhea

The hospital-wide attack rate for Clostridium difficile-associated diarrhea at our tertiary-care university hospital was 0.02 per 100 patient discharges (0.02%) in 1982, but 0.41% and 1.47% in 1986 and 1987, respectively, with a peak incidence of 2.25% in the fourth quarter of 1987. Hospital antibiotic usage patterns showed concurrent increased use of third-generation cephalosporins, and intravenous vancomycin and metronidazole. Thirty-seven cases selected for study were older than 37 control patients, more likely to have an underlying malignancy and less likely hospitalized on the obstetrics/gynecology service. Their mean duration of hospitalization prior to diagnosis was 21 days, versus a mean total length of stay of eight days for controls. All cases received antibiotics, compared to 24 of the controls. Cases were given more antibiotics for longer periods, and more often received clindamycin, third-generation cephalosporins, aminoglycosides and vancomycin. Gender, race, duration of hospitalization, prior surgery and antiulcer therapy were not significant by logistic regression analysis. Epidemiologic variables with significantly different adjusted odds ratios (95% confidence intervals) were age greater than 65 years (14.1, 1.4-141), intensive care unit residence (39.2, 2.2-713), gastrointestinal procedure (23.2, 2.1-255) and more than ten antibiotic days (summation of days of each antibiotic administered) (16.1, 2.2-117). Control measures included encouraging earlier isolation and treatment of suspected cases and formulary restriction of clindamycin, with use of metronidazole for therapy of anaerobic infections. By the second half of 1988, the attack rate had dropped progressively to 0.74%.

Environmental diseases of the digestive system

Environmental factors are important mediators of many diseases of the digestive system, defined as the alimentary tract and the accessory organs of digestion, the liver and pancreas. In this review, we principally focus on the action of chemical agents which are classified as (1) naturally occurring compounds, (2) occupational hazards, (3) therapeutic drugs, and (4) constituents of substances of abuse. In addition, the putative role of dietary habits in the pathogenesis of malignant diseases of the digestive system is discussed.

Nosocomial acquisition of Clostridium difficile infection

We studied the acquisition and transmission of Clostridium difficile infection prospectively on a general medical ward by serially culturing rectal-swab specimens from 428 patients admitted over an 11-month period. Immunoblot typing was used to differentiate individual strains of C. difficile. Seven percent of the patients (29) had positive cultures at admission. Eighty-three (21 percent) of the 399 patients with negative cultures acquired C. difficile during their hospitalizations. Of these patients, 52 (63 percent) remained asymptomatic and 31 (37 percent) had diarrhea; none had colitis. Patient-to-patient transmission of C. difficile was evidenced by time-space clustering of incident cases with identical immunoblot types and by significantly more frequent and earlier acquisition of C. difficile among patients exposed to roommates with positive cultures. Of the hospital personnel caring for patients with positive cultures, 59 percent (20) had positive cultures for C. difficile from their hands. The hospital rooms occupied by symptomatic patients (49 percent) as well as those occupied by asymptomatic patients (29 percent) were frequently contaminated. Eighty-two percent of the infected cohort still had positive cultures at hospital discharge, and such patients were significantly more likely to be discharged to a long-term care facility. We conclude that nosocomial C. difficile infection, which was associated with diarrhea in about one third of cases, is frequently transmitted among hospitalized patients and that the organism is often present on the hands of hospital personnel caring for such patients. Effective preventive measures are needed to reduce nosocomial acquisition of C. difficile.