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

Can patient-reported room cleanliness measures predict hospital-acquired C. difficile infection? A study of acute care facilities in New York state

BACKGROUND

Patient experience measures, like those form the Hospital Consumer Assessment of Healthcare providers and Systems survey, are increasingly used in healthcare policy decisions. However, it remains unclear if these reflect quality of care, like rates of hospital-acquired infections (HAIs). This study examined the relationship between patient-reported room cleanliness, from the Hospital Consumer Assessment of Healthcare providers and Systems survey, and hospital-acquired C. difficile infection (HA-CDI) rates in NYS acute care hospitals.

METHODS

A random-effects regression analysis compared the percentage of patients indicating their room was "always" and "sometimes/never" kept clean to that facility's average HA-CDI rates, controlling for known predictors.

RESULTS

A higher percentage of patients reporting their room was "always" kept clean was associated with significantly lower rates of HA-CDI. Facilities experience 0.031 fewer cases of HA-CDI/1,000 discharges for every percentage point increase in the number of patients rating their room as "always" clean (P = .006). A higher percentage of patients reporting their room was "sometimes/never" kept clean was associated with higher rates of HA-CDI (β = 0.033), but this was not significant (P = .096).

CONCLUSIONS

These findings suggest patient perceptions of cleanliness may reflect microbial cleanliness and these measures could assist in the prevention of HAIs. However, further research is needed.

Patient Experiences with Clostridioides difficile Infection: Results of a Canada-Wide Survey

PURPOSE

Clostridioides difficile infection (CDI) is the most prevalent cause of nosocomial infectious diarrhea in Canada and is highly correlated with antibiotic use and contact with health care facilitates. The often-severe symptoms of CDI include diarrhea, dehydration, and abdominal pain. Patients often relapse following symptom resolution, resulting in increased morbidity. Previous research on the impact of CDI centered around the health-care system, clinician perspectives and economic burden, but not on patient experiences. The purpose of this study was to understand the impact of CDI on patients in Canada.

METHODS

The Gastrointestinal Society conducted online surveys and gathered data from 167 qualifying participants, who were either patients or their non-treating caregivers. Quantitative parameters were analyzed by descriptive and comparative statistics and contextualized with qualitative insights derived from thematic analysis of open-ended questions.

RESULTS

Our findings, which focused on clinical parameters such as prior exposure to health-care settings, antibiotic use, and patients' symptoms, mirrored findings from previous research. Interestingly, most surveyed respondents experienced delays in diagnosis and treatment; 29% waited 6-30 days and 10% over 30 days. This delayed diagnosis was further complicated by the report that 62% of respondents did not experience symptom resolution within 7 days of initiating treatment. Importantly, our results suggest a lasting impact after the resolution of CDI and we saw a reduction of self-assessed quality of life from prior to post CDI. Patients' priorities regarding their experience with CDI focused around concerns about the health-care system, particularly time to diagnosis and treatment, concerns about antibiotic usage and needs from health-care providers.

CONCLUSION

This is the first Canadian report on patients' experience with CDI. Our data highlight the symptom-related impact on patients and the long-lasting effect on the quality of life including emotional impact. Reducing time to diagnosis and improving patient education are important priorities to attenuate the impact on patients.

Regional differences in temporal incidence of Clostridium difficile infection: a systematic review and meta-analysis

BACKGROUND

Previous decades have witnessed a change in the epidemiology of Clostridium difficile infections. This study aimed to determine temporal trends in the incidence of C difficile infection across geographic regions.

METHODS

An initial search of the relevant literature was conducted from date inception to October 2018 without language restriction. We estimated the pooled incidences using logit transformation, weighted by inverse variance. The Joinpoint Regression Analysis Program was used to explore its temporal trend.

RESULTS

Globally, the estimated incidence of C difficile infection increased from 6.60 per 10,000 patient-days in 1997 to 13.8 per 10,000 patient-days in 2004. Thereafter, a significant downward trend was observed, at -8.75% annually until 2015. From 2005 to 2015, the incidences in most European countries decreased at a rate between 1.97% and 4.11% per annum, except in France, where an increasing incidence was observed (β = 0.16; P < .001). The incidences have stabilized in North America over the same period; however, in Asia, the incidence increased significantly from 2006 to 2014 (annualized percentage change = 14.4%; P < .001). The increase was greatest in Western Asian countries, including Turkey and Israel (β > 0.10; P < .004).

CONCLUSIONS

This study revealed rapid changes in the incidence of C difficile infection. This meta-analysis should inform the allocation of resources for controlling C difficile infection and future surveillance efforts in countries where epidemiologic information on C difficile infection remains sparse.

Trends in the use of laboratory tests for the diagnosis of Clostridium difficile infection and association with incidence rates in Quebec, Canada, 2010-2014

BACKGROUND

Several Clostridium difficile infection (CDI) surveillance programs do not specify laboratory strategies to use. We investigated the evolution in testing strategies used across Quebec, Canada, and its association with incidence rates.

METHODS

Cross-sectional study of 95 hospitals by surveys conducted in 2010 and in 2013-2014. The association between testing strategies and institutional CDI incidence rates was analyzed via multivariate Poisson regressions.

RESULTS

The most common assays in 2014 were toxin A/B enzyme immunoassays (EIAs) (61 institutions, 64%), glutamate dehydrogenase (GDH) EIAs (51 institutions, 53.7%), and nucleic acid amplification tests (NAATs) (34 institutions, 35.8%). The most frequent algorithm was a single-step NAAT (20 institutions, 21%). Between 2010 and 2014, 35 institutions (37%) modified their algorithm. Institutions detecting toxigenic C difficile instead of C difficile toxin increased from 14 to 37 (P < .001). Institutions detecting toxigenic C difficile had higher CDI rates (7.9 vs 6.6 per 10,000 patient days; P = .01). Institutions using single-step NAATs, GDH plus toxigenic cultures, and GDH plus cytotoxicity assays had higher CDI rates than those using an EIA-based algorithm (P < .05).

CONCLUSIONS

Laboratory detection of CDI has changed since 2010. There is an association between diagnostic algorithms and CDI incidence. Mitigation strategies are warranted.

Epidemiological Patterns and Hospital Characteristics Associated with Increased Incidence ofClostridium difficileInfection in Quebec, Canada, 1998–2006

Objective.

To explore epidemiological patterns of the incidence ofClostridium difficileinfection (CDI) and hospital characteristics associated with increased incidence during nonepidemic and epidemic years.

Design.

Retrospective and prospective ecological study.

Setting.

Eighty-three acute care hospitals participating in CDI surveillance in the province of Quebec, Canada.

Methods.

A Serfling-type regression model applied to data obtained from an administrative database (1998-2006) and prospective Quebec CDI surveillance (2004-2006) was used to calculate expected CDI baseline incidence and to detect incidence exceeding the defined epidemic threshold at the provincial and hospital level. Multivariable Poisson regression was used to determine hospital characteristics associated with increased incidence during nonepidemic (1998-2001) and epidemic (2003-2005) periods.

Results.

During the study period (1998-2006), 4,525,847 discharges, including 45,508 with a CDI in any diagnosis field, were reported by 83 hospitals. During 1998-2001, the average Quebec incidence of CDI was 10,304 cases in 1,775,822 discharges (5.8 cases per 1,000 discharges) and presented a pattern of seasonality, with similar patterns at the hospital level for some hospitals. The Quebec epidemic started in October-November 2002 and peaked in March 2004 at 845 cases in 40,852 discharges (20.7 cases per 1,000 discharges). In multivariable analysis, higher incidence was associated with location in Montreal and surrounding regions, greater hospital size, larger proportion of hospitalized elderly patients, longer length of stay, and greater proportion of comorbidities in patients, whereas teaching profile was associated with decreased incidence during both nonepidemic and epidemic periods. The effect of geographical location on incidence was greater during the epidemic.

Conclusion.

Baseline incidence from nonepidemic years and hospital characteristics associated with CDI incidence should be taken into account when estimating the efficacy of interventions.

Prevention of Clostridium difficile infection in rural hospitals

BACKGROUND

Prevention of Clostridium difficile infection (CDI) remains challenging across the spectrum of health care. There are limited data on prevention practices for CDI in the rural health care setting.

METHODS

An electronic survey was administered to 21 rural facilities in Wisconsin, part of the Rural Wisconsin Health Cooperative. Data were collected on hospital characteristics and practices to prevent endemic CDI.

RESULTS

Fifteen facilities responded (71%). Nearly all respondent facilities reported regular use of dedicated patient care items, use of gown and gloves, private patient rooms, hand hygiene, and room cleaning. Facilities in which the infection preventionist thought the support of his/her leadership to be "Very good" or "Excellent" employed significantly more CDI practices (13.3 ± 2.4 [standard deviation]) compared with infection preventionists who thought there was less support from leadership (9.8 ± 3.0, P = .033). Surveillance for CDI was highly variable. The most frequent barriers to implementation of CDI prevention practices included lack of adequate resources, lack of a physician champion, and difficulty keeping up with new recommendations.

CONCLUSION

Although most rural facilities in our survey reported using evidence-based practices for prevention of CDI, surveillance practices were highly variable, and data regarding the impact of these practices on CDI rates were limited. Future efforts that correlate CDI prevention initiatives and CDI incidence will help develop evidence-based practices in these resource-limited settings.

Isolation and characterization of Clostridium difficile associated with beef cattle and commercially produced ground beef

The incidence of Clostridium difficile infection has recently increased in North American and European countries. This pathogen has been isolated from retail pork, turkey, and beef products and reported associated with human illness. This increase in infections has been attributed to the emergence of a toxigenic strain designated North America pulsed-field gel electrophoresis type 1 (NAP1). The NAP1 strain has been isolated from calves as well as ground meat products, leading to speculation of illness from consumption of contaminated meat products. However, information on C. difficile associated with beef cattle during processing and commercially produced ground beef is limited. To address this data gap, samples from various steps during beef production were collected. Samples from hides (n = 525), preevisceration carcasses (n = 475), postintervention carcasses (n = 471), and 956 commercial ground beef samples were collected from across the United States. The prevalence of C. difficile spores on hides was 3.2%. C. difficile spores were not detected on preevisceration and postintervention carcasses or in commercially produced ground beef. Phenotypic and genetic characterizations were carried out for all 18 isolates collected from hide samples. Twenty-two percent of the isolates were nontoxigenic strains, while 78% of the isolates were toxigenic. Toxinotyping and PCR ribotyping patterns revealed that 6 and 33% of the isolates were identified as NAP1 and NAP7 strains, respectively. This article evidences that the prevalence of C. difficile, specifically pathogenic strains, in the U.S. beef production chain is low.

The undiagnosed cases of Clostridium difficile infection in a whole nation: where is the problem?

Underdiagnosis of Clostridium difficile infection (CDI) because of lack of clinical suspicion or the use of non-sensitive diagnostic techniques is a known problem whose real magnitude has not yet been quantified. In order to estimate the extent of this underdiagnosis, we performed C. difficile cultures on all unformed stool specimens sent-irrespective of the type of request-to a series of laboratories in Spain on a single day. The specimens were cultured, and isolates were characterized at a central reference laboratory. A total of 807 specimens from 730 patients aged ≥ 2 years were selected from 118 laboratories covering 75.4% of the Spanish population. The estimated rate of hospital-acquired CDI was 2.4 episodes per 1000 admissions or 3.8 episodes per 10,000 patient-days. Only half of the episodes occurred in patients hospitalized for >2 days. Two of every three episodes went undiagnosed or were misdiagnosed, owing to non-sensitive diagnostic tests (19.0%) or lack of clinical suspicion and request (47.6%; mostly young people or non-hospitalized patients). The main ribotypes were 014/020 (20.5%), 001 (18.2%), and 126/078 (18.2%). No ribotype 027 strains were detected. Strains were fully susceptible to metronidazole and vancomycin. CDI was underdiagnosed in diarrhoeic stools in a high proportion of episodes, owing to the use of non-sensitive techniques or lack of clinical suspicion, particularly in people aged <65 years or patients with community-acquired diarrhoea. C. difficile toxins should be routinely sought in unformed stools of any origin sent for microbiological diagnosis. The ribotype 027 clone has not yet disseminated in Spain.

Michigan Clostridium difficile hospital discharges: frequency, mortality, and charges, 2002-2008

OBJECTIVE

Clostridium difficile (C. difficile) causes an intestinal bacterial infection of increasing importance in Michigan residents and health-care facilities. The specific burden and health-care costs of C. difficile infection (CDI) were previously unknown. We evaluated the frequency, mortality, and health-care charges of CDI from Michigan hospital discharge data.

METHODS

The Michigan Department of Community Health purchased discharge data from all Michigan acute care hospitals from the Michigan Health and Hospital Association. We extracted all hospital discharges from 2002 through 2008 containing the International Classification of Diseases, Ninth Revision code for intestinal infection due to C. difficile. Discharges were stratified by principle diagnosis and comorbidity level. Total hospitalization charges were standardized to the 2008 U.S. dollar.

RESULTS

From 2002 through 2008, 68,686 hospital discharges with CDI occurred. The annual rate increased from 463.1 to 1096.5 CDI discharges per 100,000 discharges. CDI discharge rates were substantially higher among the elderly, females, and black people. Of all CDI discharges, 5,924 (8.6%) patients died. The mean total health-care charge for the time period was $67,149, and the annual mean increased 35% from 2002 to 2008. Hospital charges varied significantly by race/ethnicity and age. People with Medicaid insurance accrued the highest charges.

CONCLUSION

Across Michigan, the CDI burden is growing substantially and affecting vulnerable populations. Surveillance utilizing hospital discharge data can illuminate trends and inform intervention targets. To reduce disease and health-care charges, increased prevention and infection-control efforts should be directed toward high-risk populations, such as the elderly.

Prevalence and molecular characterization of Clostridium difficile isolated from feedlot beef cattle upon arrival and mid-feeding period

BACKGROUND

The presence of indistinguishable strains of Clostridium difficile in humans, food animals and food, as well as the apparent emergence of the food-animal-associated ribotype 078/toxinotype V as a cause of community-associated C. difficile infection have created concerns about the potential for foodborne infection. While studies have reported C. difficile in calves, studies of cattle closer to the age of harvest are required. Four commercial feedlots in Alberta (Canada) were enrolled for this study. Fecal samples were collected at the time of arrival and after acclimation (< 62, 62-71 or > 71 days on feed). Selective culture for Clostridium difficile was performed, and isolates were characterized by ribotyping and pulsed-field gel electrophoresis. A logistic regression model was built to investigate the effect of exposure to antimicrobial drugs on the presence of C. difficile.

RESULTS

Clostridium difficile was isolated from 18 of 539 animals at the time of feedlot arrival (CI = 2.3-6.1) and from 18 of 335 cattle at mid-feeding period (CI = 2.9-13.1). Overall, there was no significant difference in the prevalence of C. difficile shedding on arrival versus mid-feeding period (P = 0.47). No association between shedding of the bacterium and antimicrobial administration was found (P = 0.33). All the isolates recovered were ribotype 078, a toxinotype V strain with genes encoding toxins A, B and CDT. In addition, all strains were classified as NAP7 by pulsed field gel electrophoresis (PFGE) and had the characteristic 39 base pairs deletion and upstream truncating mutation on the tcdC gene.

CONCLUSIONS

It is apparent that C. difficile is carried in the intestinal tracts of a small percentage of feedlot cattle arriving and later in the feeding period and that ribotype 078/NAP7 is the dominant strain in these animals. Herd management practices associated with C. difficile shedding were not identified, however further studies of the potential role of antimicrobials on C. difficile acquisition and shedding are required.

An overview of the diagnosis and management of Clostridium difficile infection

The diagnosis and treatment of Clostridium difficile infection are becoming increasingly complex with the introduction of novel diagnostic techniques and new pharmacologic and nonpharmacologic treatments. The integration of these new approaches with older, established methods is a challenge to individual clinicians and hospital systems. This article provides an overview of the current methods for the diagnosis and treatment of C difficile infection.

The insect peptide coprisin prevents Clostridium difficile-mediated acute inflammation and mucosal damage through selective antimicrobial activity

Clostridium difficile-associated diarrhea and pseudomembranous colitis are typically treated with vancomycin or metronidazole, but recent increases in relapse incidence and the emergence of drug-resistant strains of C. difficile indicate the need for new antibiotics. We previously isolated coprisin, an antibacterial peptide from Copris tripartitus, a Korean dung beetle, and identified a nine-amino-acid peptide in the α-helical region of it (LLCIALRKK) that had antimicrobial activity (J.-S. Hwang et al., Int. J. Pept., 2009, doi:10.1155/2009/136284). Here, we examined whether treatment with a coprisin analogue (a disulfide dimer of the nine peptides) prevented inflammation and mucosal damage in a mouse model of acute gut inflammation established by administration of antibiotics followed by C. difficile infection. In this model, coprisin treatment significantly ameliorated body weight decreases, improved the survival rate, and decreased mucosal damage and proinflammatory cytokine production. In contrast, the coprisin analogue had no apparent antibiotic activity against commensal bacteria, including Lactobacillus and Bifidobacterium, which are known to inhibit the colonization of C. difficile. The exposure of C. difficile to the coprisin analogue caused a marked increase in nuclear propidium iodide (PI) staining, indicating membrane damage; the staining levels were similar to those seen with bacteria treated with a positive control for membrane disruption (EDTA). In contrast, coprisin analogue treatment did not trigger increases in the nuclear PI staining of Bifidobacterium thermophilum. This observation suggests that the antibiotic activity of the coprisin analogue may occur through specific membrane disruption of C. difficile. Thus, these results indicate that the coprisin analogue may prove useful as a therapeutic agent for C. difficile infection-associated inflammatory diarrhea and pseudomembranous colitis.

Surveillance for Clostridium difficile infection: ICD-9 coding has poor sensitivity compared to laboratory diagnosis in hospital patients, Singapore

Introduction

Clostridium difficile infection (CDI) is an increasingly recognized nosocomial infection in Singapore. Surveillance methods include laboratory reporting of Clostridium difficile toxin assays (CDTA) or use of International Classification of Diseases, 9^th Revision (ICD-9) discharge code 008.45. Previous US studies showed good correlation between CDTA and ICD-9 codes. However, the use of ICD-9 codes for CDI surveillance has not been validated in other healthcare settings.

Methods

We compared CDI rates based on CDTA to ICD-9 codes for all discharges in 2007 from our hospital to determine sensitivity and specificity of ICD-9 codes. Demographic and hospitalization data were analyzed to determine predictors for missing ICD-9 codes.

Results

During 2007, there were 56,352 discharges. Of these, 268 tested CDTA-positive but only 133 were assigned the CDI ICD-9 code. A total of 141 discharges had the ICD-9 code; 8 were CDTA-negative, the rest were CDTA-positive. Community-acquired CDI accounted for only 3.2% of cases. The sensitivity and specificity of ICD-9 codes compared to CDTA were 49.6% and 100% respectively. Concordance between CDTA and ICD-9 codes was 0.649 (p<.001). Comparing concordant patients (CDTA+/ICD9+) to discordant patients (CDTA+/ICD9−), concordant patients were more likely to be over 50 years of age (OR 3.49, 95% CI 1.66–7.34, p = .001) and have shorter time from admission to testing (OR 0.98, 95% CI 0.97–0.99, p = .009).

Discussion

Unlike previous studies in the US, ICD-9 codes substantially underestimate CDI in Singapore compared to microbiological data. Older patients with shorter time to testing were less likely to have missing ICD-9 codes.

Clostridium difficile infection in an endemic setting in the Netherlands

The purpose of this investigation was to study risk factors for Clostridium difficile infection (CDI) in an endemic setting. In a 34-month prospective case-control study, we compared the risk factors and clinical characteristics of all consecutively diagnosed hospitalised CDI patients (n = 93) with those of patients without diarrhoea (n = 76) and patients with non-CDI diarrhoea (n = 64). The incidence of CDI was 17.5 per 10,000 hospital admissions. C. difficile polymerase chain reaction (PCR) ribotype 014 was the most frequently found type (15.9%), followed by types 078 (12.7%) and 015 (7.9%). Independent risk factors for endemic CDI were the use of second-generation cephalosporins, previous hospital admission and previous stay at the intensive care unit (ICU). The use of third-generation cephalosporins was a risk factor for diarrhoea in general. We found no association of CDI with the use of fluoroquinolones or proton pump inhibitors (PPIs). The overall 30-day mortality among CDI patients, patients without diarrhoea and patients with non-CDI diarrhoea was 7.5%, 0% and 1.6%, respectively. In this endemic setting, risk factors for CDI differed from those in outbreak situations. Some risk factors that have been ascribed to CDI earlier were, in this study, not specific for CDI, but for diarrhoea in general. The 30-day mortality among CDI patients was relatively high.

Does the handling time of unrefrigerated human fecal specimens impact the detection of Clostridium difficile toxins in a hospital setting?

BACKGROUND

The stability of Clostridium difficile toxins is an important factor in determining the accuracy of the enzyme immunoassay (EIA). The Centers for Disease Control has stated that C. difficile toxins may become undetectable in unrefrigerated stool specimens within 2 h after collection.

PURPOSE

The purpose of our study was to determine how the unrefrigerated handling time of human fecal specimens affects the results of C. difficile infection (CDI) testing.

METHODS

A retrospective review of CDI testing with Premier™ Toxins A and B kit was conducted in northern New Jersey, USA. Stool collection times and receiving times were recorded for each specimen. The unrefrigerated handling time was calculated for each.

RESULTS

A total of 1126 fecal specimens were submitted. We excluded 72 fecal specimens due to incomplete documentation. We included 1054 fecal specimens collected from 636 hospitalized patients. A total of 132 out of 1054 specimens (12.5%) tested positive for C. difficile toxins. Nine hundred and fifty-four specimens were unrefrigerated for 13 h or less, of which 127 (13.3%) tested positive. Five (5%) of the 100 specimens that were unrefrigerated for more than 13 h tested positive (p = 0.02).

CONCLUSION

C. difficile toxins can still be detected up to 13 h after collection in unrefrigerated human fecal specimens. However, fecal specimens should be processed according to the current recommendations to ensure the reliability of EIA testing until the results of our study are confirmed with prospective studies.

Clostridium difficile PCR ribotype 027: assessing the risks of further worldwide spread

Highly virulent strains of Clostridium difficile have emerged since 2003, causing large outbreaks of severe, often fatal, colitis in North America and Europe. In 2008–10, virulent strains spread between continents, with the first reported cases of fluoroquinolone-resistant C difficile PCR ribotype 027 in three Asia-Pacific countries and Central America. We present a risk assessment framework for assessing risks of further worldwide spread of this pathogen. This framework first requires identification of potential vehicles of introduction, including international transfers of hospital patients, international tourism and migration, and trade in livestock, associated commodities, and foodstuffs. It then calls for assessment of the risks of pathogen release, of exposure of individuals if release happens, and of resulting outbreaks. Health departments in countries unaffected by outbreaks should assess the risk of introduction or reintroduction of C difficile PCR ribotype 027 using a structured risk-assessment approach.

Motility and flagellar glycosylation in Clostridium difficile

In this study, intact flagellin proteins were purified from strains of Clostridium difficile and analyzed using quadrupole time of flight and linear ion trap mass spectrometers. Top-down studies showed the flagellin proteins to have a mass greater than that predicted from the corresponding gene sequence. These top-down studies revealed marker ions characteristic of glycan modifications. Additionally, diversity in the observed masses of glycan modifications was seen between strains. Electron transfer dissociation mass spectrometry was used to demonstrate that the glycan was attached to the flagellin protein backbone in O linkage via a HexNAc residue in all strains examined. Bioinformatic analysis of C. difficile genomes revealed diversity with respect to glycan biosynthesis gene content within the flagellar biosynthesis locus, likely reflected by the observed flagellar glycan diversity. In C. difficile strain 630, insertional inactivation of a glycosyltransferase gene (CD0240) present in all sequenced genomes resulted in an inability to produce flagellar filaments at the cell surface and only minor amounts of unmodified flagellin protein.

Clostridium difficile and inflammatory bowel disease

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

Laboratory diagnosis of Clostridium difficile-associated disease in the Republic of Ireland: a survey of Irish microbiology laboratories

The Health Protection Surveillance Centre (HPSC) established a group to produce national guidelines for Clostridium difficile in Ireland in 2006. A laboratory questionnaire was distributed to determine current C. difficile diagnostic practices. Twenty-nine out of 44 laboratories providing C. difficile diagnostic services to 34 hospitals responded. Twenty-five out of 29 (86%) laboratories processed specimens for C. difficile and four (13.8%) forwarded specimens to another laboratory. Sixteen laboratories (64%) processed specimens for other healthcare facilities. None routinely examined stool for C. difficile, seven (28%) examined specimens only when requested to do so and 18 (72%) used specific selection criteria, including testing all liquid stools (39%), all nosocomial diarrhoea (44%), specific clinical criteria (28%) and history of antibiotic therapy (22%). All tested stool directly for C. difficile toxin with a variety of enzyme immunoassays, with 24 (96%) detecting both toxin A and B and one detecting toxin A only. Three (12%) laboratories used cytotoxicity assays; none used polymerase chain reaction and six (24%) laboratories performed C. difficile culture but only under specific circumstances. Seven (28%) laboratories had isolates typed during outbreaks, but none had the facilities to do so on-site. The HPSC group will produce national recommendations for laboratory diagnosis, surveillance and management of C. difficile infection. Since there are marked differences in diagnostic practices throughout the country and no national reference laboratory, the implementation of these recommendations will have cost implications that will need to be addressed.

[Update on Clostridium difficile infections]

PURPOSE

Clostridium difficile is an anaerobic gram positive, spore-forming bacterium which is responsible for 15-25% of antibiotic-associated diarrhea and for more than 95% of pseudomembranous colitis (PMC). This paper will review the main knowledge on C. difficile-associated infections and their recent evolution.

CURRENT KNOWLEDGE AND KEY POINTS

Since 2003, outbreaks of severe C. difficile-associated diarrhea (CDAD) have been increasingly reported in Canada and the United States. This trend is assumed to be associated with the rapid emergence and spread of a specific clone of C. difficile belonging to PCR-ribotype 027 or North American Pulsotype 1, pulsotype (NAP1). This clone is characterized by the overproduction of toxins A and B and is positive for a third toxin named binary toxin. This clone has spread in UK, in Belgium, in the Netherlands, and, more recently, in France where it has been responsible for large outbreaks mainly in northern France.

FUTURE PROSPECTS AND PROJECTS

A systematic reporting of C. difficile incidence by health facilities should enable a better assessment of this pathology in France.

Impact of emergency colectomy on survival of patients with fulminant Clostridium difficile colitis during an epidemic caused by a hypervirulent strain

OBJECTIVES

To determine whether emergency colectomy reduces mortality in patients with fulminant Clostridium difficile-associated disease (CDAD), and to identify subgroups of patients more likely to benefit from the procedure.

SUMMARY BACKGROUND DATA

Many hospitals in Quebec, Canada, have noted since 2003 a dramatic increase in CDAD incidence and in the proportion of cases severe enough to require intensive care unit (ICU) admission. The decision to perform an emergency colectomy remains largely empirical.

METHODS

Retrospective observational cohort study of 165 cases of CDAD that required ICU admission or prolongation of ICU stay between January 2003 and June 2005 in 2 tertiary care hospitals of Quebec. Multivariate analysis was performed through logistic regression; adjusted odds ratios (AOR) and their 95% confidence intervals (CI) were calculated. The primary outcome was mortality within 30 days of ICU admission.

RESULTS

Eighty-seven (53%) cases resulted in death within 30 days of ICU admission, almost half (38 of 87, 44%) within 48 hours of ICU admission. The independent predictors of 30-day mortality were: leukocytosis >or=50 x 10(9)/L (AOR, 18.6; 95% CI, 3.7-94.7), lactate >or=5 mmol/L (AOR, 12.4; 95% CI, 2.4-63.7), age >or=75 years (AOR, 6.5; 95% CI, 1.7-24.3), immunosuppression (AOR, 7.9; 95% CI, 2.3-27.2) and shock requiring vasopressors (AOR, 3.4; 95% CI, 1.3-8.7). After adjustment for these confounders, patients who had an emergency colectomy were less likely to die (AOR, 0.22; 95% CI, 0.07-0.67, P = 0.008) than those treated medically. Colectomy seemed more beneficial in patients aged 65 years or more, in those immunocompetent, those with a leukocytosis >or=20 x 10(9)/L or lactate between 2.2 and 4.9 mmol/L.

CONCLUSION

Emergency colectomy reduces mortality in some patients with fulminant CDAD.

Clostridium difficile PCR ribotypes in calves, Canada

C. difficile, including epidemic PCR ribotypes 017 and 027, were isolated from dairy calves in Canada.

We investigated Clostridium difficile in calves and the similarity between bovine and human C. difficile PCR ribotypes by conducting a case-control study of calves from 102 dairy farms in Canada. Fecal samples from 144 calves with diarrhea and 134 control calves were cultured for C. difficile and tested with an ELISA for C. difficile toxins A and B. C. difficile was isolated from 31 of 278 calves: 11 (7.6%) of 144 with diarrhea and 20 (14.9%) of 134 controls (p = 0.009). Toxins were detected in calf feces from 58 (56.8%) of 102 farms, 57 (39.6%) of 144 calves with diarrhea, and 28 (20.9%) of 134 controls (p = 0.0002). PCR ribotyping of 31 isolates showed 8 distinct patterns; 7 have been identified in humans, 2 of which have been associated with outbreaks of severe disease (PCR types 017 and 027). C. difficile may be associated with calf diarrhea, and cattle may be reservoirs of C. difficile for humans.

Clostridium difficile-associated disease in Oregon: increasing incidence and hospital-level risk factors

BACKGROUND

The incidence of Clostridium difficile-associated disease (CDAD) appears to be increasing. Population-based estimates of disease have been limited, and analyses of hospital-level risk factors for CDAD are lacking. We sought to determine the incidence and trends of CDAD in Oregon and to identify hospital-level factors associated with increases in disease.

METHODS

We analyzed hospital discharge data to calculate the incidence and to describe trends of CDAD in Oregon from 1995 through 2002. We administered questionnaires to hospital laboratory directors, infection control practitioners, and pharmacists to determine the status of laboratory, infection control, and pharmacy policies over time.

RESULTS

The overall incidence of CDAD in Oregon was 3.5 case patients per 10,000 residents in 2002. Incidence increased from 1.4 to 3.3 cases per 1,000 hospital discharges from 1995 to 2002. Rates of disease increased most in hospitals with licensed bed capacity of more than 250 beds and more than 5 intensive care unit beds. Few laboratories, infection control practitioners, and pharmacists were able to identify changes in specific policies over the study period.

CONCLUSIONS

This is the first study to determine a statewide population-based incidence of CDAD. Incidence of CDAD in Oregon has more than doubled over the past decade; larger hospitals experienced the greatest increase in disease rates. We did not identify hospital-level policies that could explain the increase. A study of patients with CDAD at the hospitals with the largest increases is underway to further identify risk factors.

Nosocomial diarrhoea

Toroviruses have been reported as a new cause of nosocomial viral diarrhoea, and the role of astroviruses has been further elucidated. Polymerase chain reaction methods promise to improve the diagnosis and understanding of the aetiology and control of hospital-acquired viral gastroenteritis. A clearer picture of the impact and extent of Clostridium difficile diarrhoea has emerged, and several control measures have been described. An epidemic Clostridium difficile strain and toxin A-deficient strains have been reported. There is growing evidence that enterotoxin-producing Clostridium perfringens can also cause antibiotic-associated diarrhoea.

Colonic abnormalities on CT in adult hospitalized patients with Clostridium difficile colitis: prevalence and significance of findings

OBJECTIVE

The purpose of this study was to determine the prevalence of an abnormal colon on CT in adult inpatients with Clostridium difficile colitis, compare the clinical presentation of these patients, and determine whether CT findings predicted the need for surgical treatment.

MATERIALS AND METHODS

Over a 21-month period, 152 of 572 inpatients with C. difficile colitis were identified and had CT scans performed within 2 weeks of the diagnosis. These were independently and retrospectively reviewed by two reviewers. Those with colonic wall thickness greater than 4 mm were considered positive (CT-positive patients) and were further reviewed for specific findings in the colon. All 152 patients with CT scans were also retrospectively reviewed using the hospital information system for certain clinical parameters, admitting diagnoses, and reasons for scanning. The following were compared using several statistical tests: clinical parameters in CT-positive and CT-negative patients and surgical and nonsurgical groups to determine if positive scans or surgical treatment could be clinically predicted; specific CT findings in CT-positive patients to see if an association was found with clinical parameters or surgical treatment; and admitting diagnoses and reasons for scanning in scanned and unscanned populations to see which patients were more likely to undergo CT.

RESULTS

Seventy-six (50%) of 152 scanned hospitalized patients with C. difficile colitis were CT-positive. These patients most often had segmental involvement (50 [66%] of 76 patients), with the rectum (60 [82%] of 73 patients) and sigmoid colon (61 [82%] of 74 patients) most often affected. Positive scans were associated with increased WBC, abdominal pain, and diarrhea. Patients with signs and symptoms of infection or abdominal complaints were more likely to be scanned. No statistical correlation was found between specific CT findings and clinical parameters or clinical parameters and patients requiring surgery. There was no predictive value of specific CT findings for surgical treatment.

CONCLUSION

Half of the patients scanned had an abnormal CT, with segmental colonic disease more common than diffuse. Positive scans were more likely in patients with leukocytosis, abdominal pain, and fever. Specific CT findings did not correlate with clinical parameters and could not predict surgical treatment.

Mortality attributable to nosocomial Clostridium difficile-associated disease during an epidemic caused by a hypervirulent strain in Quebec

BACKGROUND

Since 2002 an epidemic of Clostridium difficile-associated disease (CDAD) caused by a hypervirulent toxinotype III ribotype 027 strain has spread to many hospitals in Quebec. The strain has also been found in the United States, the United Kingdom and the Netherlands. The effects of this epidemic on mortality and duration of hospital stay remain unknown. We measured these effects among patients admitted to a hospital in Quebec during 2003 and 2004.

METHODS

We compared mortality and total length of hospital stay among inpatients in whom nosocomial CDAD developed and among control subjects without CDAD matched for sex, age, Charlson Comorbidity Index score and length of hospital stay up to the diagnosis of CDAD in the corresponding case.

RESULTS

Thirty days after diagnosis 23.0% (37/161) of the patients with CDAD had died, compared with 7.0% (46/656) of the matched control subjects (p < 0.001). Twelve months after diagnosis, mortality was 37.3% (60/161) among patients with CDAD and 20.6% (135/656) among the control subjects (p < 0.001), for a cumulative attributable mortality of 16.7% (95% confidence interval 8.6%-25.2%). Each case of nosocomial CDAD led, on average, to 10.7 additional days in hospital.

INTERPRETATION

This study documented a high attributable mortality among elderly patients with CDAD mostly caused by a hypervirulent strain, which represents a dramatic change in the severity of this infection.

Emergence of fluoroquinolones as the predominant risk factor for Clostridium difficile-associated diarrhea: a cohort study during an epidemic in Quebec

BACKGROUND

Since 2002, an epidemic of Clostridium difficile-associated-diarrhea (CDAD) associated with a high case-fatality rate has involved >30 hospitals in the province of Quebec, Canada. In 2003, a total of 55% of patients with CDAD at our hospital had received fluoroquinolones in the preceding 2 months. It has been suggested that massive use of proton pump inhibitors might have facilitated this epidemic.

METHODS

To delineate the risk of CDAD associated with specific classes of antibiotics and whether this is modulated by concomitant use of proton pump inhibitors and other drugs altering gastric acidity or gastrointestinal motility, we conducted a retrospective cohort study of patients hospitalized in a teaching hospital in Sherbrooke, Canada, during the period of January 2003 through June 2004. We obtained data on 7421 episodes of care corresponding to 5619 individuals. Patients were observed until they either developed CDAD or died or for 60 days after discharge from the hospital. Adjusted hazard ratios (AHRs) were calculated using Cox regression.

RESULTS

CDAD occurred in 293 patients. Fluoroquinolones were the antibiotics most strongly associated with CDAD (AHR, 3.44; 95% confidence interval [CI], 2.65-4.47). Almost one-fourth of all inpatients received quinolones, for which the population-attributable fraction of CDAD was 35.9%. All 3 generations of cephalosporins, macrolides, clindamycin, and intravenous beta-lactam/beta-lactamase inhibitors were intermediate-risk antibiotics, with similar AHRs (1.56-1.89). Proton pump inhibitors (AHR, 1.00, 95% CI, 0.79-1.28) were not associated with CDAD.

CONCLUSIONS

Administration of fluoroquinolones emerged as the most important risk factor for CDAD in Quebec during an epidemic caused by a hypervirulent strain of C. difficile.

From stool to statistics: reporting of acute gastrointestinal illnesses in Canada

BACKGROUND

Limitations associated with the under-reporting of enteric illnesses have long been recognized but the extent and variation of this under-reporting in Canada has not been examined. Given the public health value of surveillance data, a closer examination of under-reporting of enteric illnesses in Canada was warranted.

METHODS

Paper-based surveys were administered (a) to all laboratories in Canada licensed to process stool specimens and (b) to all local public health authorities in two provinces.

RESULTS

Of the laboratories surveyed, 67% (n=274) conducted on-site testing of stool specimens for enteric bacteria, 31% (n=126) for parasites and 10% (n=42) for viruses. In the year 2000, these laboratories processed 459,982 stool specimens, of which 5%, 15%, 8% and 19% were positive for enteric bacteria (excluding C. difficile), C. difficile, parasites and viruses, respectively. Variations in laboratory testing and health authority reporting protocols and policies were identified. Of the laboratory-confirmed cases of AGI reported to local public health authorities, 5% (n=846) were not reported to provincial counterparts.

CONCLUSION

A significant proportion of AGI cases submitting stool specimens are not captured in Canada's passive surveillance system due to unknown etiology. A much smaller proportion of laboratory-confirmed cases reported to local public health authorities are not captured at the provincial or national level. Given that the number of laboratory-confirmed AGI cases represents such a small fraction of all community cases, strategies to compensate for under-reporting and efforts directed at harmonizing laboratory and local public health authority policies and practices would be welcomed.

Rifalazil treats and prevents relapse of clostridium difficile-associated diarrhea in hamsters

Although vancomycin and metronidazole effectively treat Clostridium difficile-associated diarrhea and colitis (CDAD), their use is associated with a high incidence of relapsing C. difficile infection. Rifalazil is a new benzoxazinorifamycin that possesses activity against Mycobacterium tuberculosis and gram-positive bacteria. Here we compared rifalazil and vancomycin for effectiveness in preventing or treating clindamycin-induced cecitis in a hamster model of CDAD. Golden Syrian hamsters were injected subcutaneously with clindamycin phosphate (10 mg/kg), followed 24 h later by C. difficile gavage. Hamsters received by gavage for 5 days vehicle, vancomycin (50 mg/kg), or rifalazil (20 mg/kg) either simultaneously with (prophylactic protocol) or 24 h after C. difficile administration (treatment protocol). While all vehicle-administered animals became moribund within 48 h of C. difficile administration, no rifalazil- or vancomycin-treated animals in either protocol showed signs of morbidity after 7 days. Ceca of rifalazil-treated animals showed absence of epithelial cell damage, significantly reduced congestion and edema, and less, but not statistically significantly less, neutrophil infiltration compared to those of vehicle-treated animals. In contrast, vancomycin-treated animals demonstrated severe epithelial cell damage and mildly reduced congestion and edema. Moreover, hamsters relapsed and tested C. difficile toxin positive (by enzyme-linked immunosorbent assay) 10 to 15 days after discontinuation of vancomycin treatment. None of the rifalazil-treated hamsters showed signs of disease or presence of toxins in their feces 30 days after discontinuation of treatment. Our results indicate that once daily rifalazil may be superior to vancomycin for curative treatment of CDAD.

Molecular epidemiology of hospital-associated and community-acquired Clostridium difficile infection in a Swedish county

All episodes of Clostridium difficile associated diarrhea (CDAD) diagnosed in a defined population of 274,000 including one tertiary and two primary hospitals and their catchment areas were studied during 12 months. The annual CDAD incidence in the county was 97 primary episodes per 100,000, and 78% of all episodes were classified as hospital associated with a mean incidence of 5.3 (range, 1.4 to 6.5) primary episodes per 1,000 admissions. The incidence among hospitalized individuals was 1,300-fold higher than that in the community (33,700 versus 25 primary episodes per 100,000 persons per year), reflecting a 37-fold difference in antibiotic consumption (477 versus 13 defined daily doses [DDD]/1,000 persons/day) and other risk factors. Three tertiary hospital wards with the highest incidence (13 to 36 per 1,000) had CDAD patients of high age (median age of 80 years versus 70 years for other wards, P < 0.001), long hospital stay (up to 25 days versus 4 days), or a high antibiotic consumption rate (up to 2,427 versus 421 DDD/1,000 bed days). PCR ribotyping of C. difficile isolates available from 330 of 372 CDAD episodes indicated nosocomial acquisition of the strain in 17 to 27% of hospital-associated cases, depending on the time interval between index and secondary cases allowed (2 months or up to 12 months), and only 10% of recurrences were due to a new strain of C. difficile (apparent reinfection). In other words, most primary and recurring episodes were apparently caused by the patient's endogenous strain rather than by one of hospital origin. Typing also indicated that a majority of C. difficile strains belonged to international serotypes, and the distribution of types was similar within and outside hospitals and in primary and relapsing CDAD. However, type SE17 was an exception, comprising 22% of hospital isolates compared to 6% of community isolates (P = 0.008) and causing many minor clusters and a silent nosocomial outbreak including 36 to 44% of the CDAD episodes in the three high-incidence wards.

Multicenter evaluation of a new screening test that detects Clostridium difficile in fecal specimens

Clostridium difficile causes approximately 25% of nosocomial antibiotic-associated diarrheas and most cases of pseudomembranous colitis. We evaluated C. DIFF CHEK, a new screening test that detects glutamate dehydrogenase of C. difficile. Our results showed that this test was comparable to PCR in sensitivity and specificity and outperformed bacterial culture.

From stool to statistics: reporting of acute gastrointestinal illnesses in Canada

BACKGROUND

Limitations associated with the under-reporting of enteric illnesses have long been recognized but the extent and variation of this under-reporting in Canada has not been examined. Given the public health value of surveillance data, a closer examination of under-reporting of enteric illnesses in Canada was warranted.

METHODS

Paper-based surveys were administered (a) to all laboratories in Canada licensed to process stool specimens and (b) to all local public health authorities in two provinces.

RESULTS

Of the laboratories surveyed, 67% (n=274) conducted on-site testing of stool specimens for enteric bacteria, 31% (n=126) for parasites and 10% (n=42) for viruses. In the year 2000, these laboratories processed 459,982 stool specimens, of which 5%, 15%, 8% and 19% were positive for enteric bacteria (excluding C. difficile), C. difficile, parasites and viruses, respectively. Variations in laboratory testing and health authority reporting protocols and policies were identified. Of the laboratory-confirmed cases of AGI reported to local public health authorities, 5% (n=846) were not reported to provincial counterparts.

CONCLUSION

A significant proportion of AGI cases submitting stool specimens are not captured in Canada's passive surveillance system due to unknown etiology. A much smaller proportion of laboratory-confirmed cases reported to local public health authorities are not captured at the provincial or national level. Given that the number of laboratory-confirmed AGI cases represents such a small fraction of all community cases, strategies to compensate for under-reporting and efforts directed at harmonizing laboratory and local public health authority policies and practices would be welcomed.

Epidemiology and molecular characterization of Clostridium difficile strains from patients with diarrhea: low disease incidence and evidence of limited cross-infection in a Swedish teaching hospital

We prospectively studied the epidemiology of Clostridium difficile-associated diarrhea (CDAD) in a 900-bed hospital over the course of 12 months by PCR-ribotyping of C. difficile isolates. A total of 304 cases were diagnosed, corresponding to an overall incidence of 7/1,000 admissions, with higher rates in nephrology, hematology, and organ transplantation wards (37, 30, and 21/1,000), and 72% were classified as hospital associated (onset in hospital or onset at home but after a hospital stay within 2 months). All 382 isolates from 227 of 304 (75%) patients available for PCR-ribotyping were typeable, yielding 70 PCR-ribotypes. The three most common types comprised 30% of hospital-associated and 34% of community-associated cases, indicating import via admitted patients as a major source of C. difficile strains occurring in the hospital. Of the 227 patients studied, 38% each contributed 2 to 13 fecal samples positive for C. difficile over the course of the study period. Repeat isolates of the same PCR-ribotype as the first isolate were found in 79% of these patients and in 95% of specimens delivered within 30 days, compared to 63% of those obtained at 31 to 204 days. Nosocomial acquisition of CDAD, defined as the proportion of cases sharing C. difficile type and admitted to the same ward within 2 or 12 months, was 20% and 32% of hospital-associated cases and 14% and 23% of all cases, respectively. Thus, most CDAD cases diagnosed over the course of the study period, including those associated with hospitalization, appeared to be caused by endogenous C. difficile strains rather than by strains truly being acquired in the hospital.

Clostridium difficile in long-term-care facilities for the elderly

Antimicrobial agents are among the most frequently prescribed medications in long-term-care facilities (LTCFs). Therefore, it is not surprising that Clostridium difficile colonization and C. difficile-associated diarrhea (CDAD) occur commonly in elderly LTCF residents. C. difficile has been identified as the most common cause of non-epidemic acute diarrheal illness in nursing homes, and outbreaks of CDAD in LTCFs have also been recognized. This position paper reviews the epidemiology and clinical features of CDAD in elderly residents of LTCFs and, using available evidence, provides recommendations for the management of C. difficile in this setting.

Adjunctive intracolonic vancomycin for severe Clostridium difficile colitis: case series and review of the literature

Successful treatment of severe Clostridium difficile colitis has been reported with the use of adjunctive intracolonic vancomycin (ICV) therapy. We report a descriptive case series and review the literature on patients with C. difficile colitis who received adjunctive ICV therapy. Nine patients received antibiotics within 6 weeks prior to presentation. Complete resolution of the clinical presentation occurred in 8 patients (88.9%), and eradication of C. difficile cytotoxin production was documented in 3 (75%) of 4 patients who were tested after the completion of adjunctive ICV therapy. One patient (11.1%) died as a result of progressive multisystem organ failure. In the 6 weeks after the completion of treatment for C. difficile colitis, no patient had recurrent disease, required surgical intervention, or experienced complications from adjunctive ICV therapy. In this case series, administration of adjunctive ICV therapy appeared to be a safe, practical, and effective adjunctive therapy for severe C. difficile colitis.

Reassessment of Clostridium difficile susceptibility to metronidazole and vancomycin

Clostridium difficile is the most frequently identified enteric pathogen in patients with nosocomially acquired, antibiotic-associated diarrhea. The drugs most commonly used to treat diseases associated with C. difficile are metronidazole and vancomycin. Most clinical laboratories assume that all C. difficile isolates are susceptible to metronidazole and vancomycin. We report on the antimicrobial susceptibilities of 415 C. difficile isolates to metronidazole and vancomycin over an 8-year period (1993 to 2000). The overall rate of resistance to metronidazole at the critical breakpoint (16 microg/ml) was 6.3%. Although full resistance to vancomycin was not observed, the overall rate of intermediate resistance was 3.1%. One isolate had a combination of resistance to metronidazole and intermediate resistance to vancomycin. Rates of resistance to metronidazole and vancomycin were higher among isolates from human immunodeficiency virus-infected patients. Molecular typing methods proved the absence of clonality among the isolates with decreased susceptibilities to the antimicrobials tested.

Clostridium difficile

Clostridium difficile is a major cause of antibiotic-associated diarrhea and colitis. The incidence of infection with this organism is increasing in hospitals worldwide, consequent to the widespread use of broad-spectrum antibiotics. Pathogenic strains of C. difficile produce two protein exotoxins, toxin A and toxin B, that cause colonic mucosal injury and inflammation. Many patients who are colonized are asymptomatic, and recent evidence indicates that diarrhea and colitis occur in those individuals who lack a protective antitoxin immune response. In patients who do develop symptoms, the spectrum of C. difficile disease ranges from mild diarrhea to fulminant pseudomembranous colitis. Prevention of nosocomial C. difficile infection involves judicious use of antibiotics and multidisciplinary infection control measures to reduce environmental contamination and patient cross-infection. Ultimately, active or passive immunization against C. difficile may be an effective means of controlling the growing problem of nosocomial C. difficile diarrhea and colitis.

Evaluation of methods for detection of toxins in specimens of feces submitted for diagnosis of Clostridium difficile-associated diarrhea

Clostridium difficile is the principal pathogen associated with hospital-acquired acute diarrheal disease. We have evaluated the performances of six approaches for diagnosis of C. difficile-associated diarrhea (CDAD). Consecutive stool specimens (n = 200) from 133 patients were examined by cytotoxin assay, by culture of C. difficile on cycloserine-cefoxitin-fructose agar, and by toxin detection using four rapid immunoassay systems (Oxoid Toxin A test, ImmunoCard Toxin A test, TechLab Tox A/B II test, and Premier Toxins A&B test). A diagnosis of CDAD was established for 35 (27%) patients (representing 29% of specimens). The adjusted sensitivity and specificity of the methods were, respectively, 98 and 99% for the cytotoxin assay, 54 and 99% for ImmunoCard, 50 and 98% for Oxoid, 79 and 98% for TechLab, 80 and 98% for Premier, and 57 and 100% for culture. The TechLab and Premier assays are acceptable tests for diagnosis of CDAD but are not equivalent to the cytotoxin assay.

Evaluating the CT diagnosis of Clostridium difficile colitis: should CT guide therapy?

OBJECTIVE

The purpose of this study was to further characterize the CT findings of Clostridium difficile colitis and to provide for the first time a diagnostic sensitivity, specificity, positive predictive value, and negative predictive value to help clinicians decide whether antibiotic treatment is warranted on the basis of CT findings while awaiting stool test results (which may take as long as 48 hr).

MATERIALS AND METHODS

A retrospective review covering a 4-year period was performed of the charts and CT scans of 54 symptomatic patients with stool test results positive for C. difficile and of a control group of 56 patients with antibiotic-associated diarrhea with stool test results negative for C. difficile.

RESULTS

At our institution, C. difficile colitis was explicitly diagnosed at CT in these patients with a sensitivity of 52%, specificity of 93%, positive predictive value of 88%, and negative predictive value of 67%. The sensitivity can be raised to 70% with no change in specificity with more rigid adherence to diagnostic criteria of colon wall thickening of greater than 4 mm combined with any one or more findings of pericolonic stranding, colon wall nodularity, the "accordion" sign, or otherwise unexplained ascites.

CONCLUSION

Although routine CT screening of antibiotic-associated diarrhea is not advocated, the 88% positive predictive value of a diagnosis of C. difficile colitis in those who are scanned may merit consideration of treatment by clinicians on the basis of the CT results alone.

Characterization of a toxin A-negative, toxin B-positive strain of Clostridium difficile responsible for a nosocomial outbreak of Clostridium difficile-associated diarrhea

Clostridium difficile-associated diarrhea (CAD) is a very common nosocomial infection that contributes significantly to patient morbidity and mortality as well as to the cost of hospitalization. Previously, strains of toxin A-negative, toxin B-positive C. difficile were not thought to be associated with clinically significant disease. This study reports the characterization of a toxin A-negative, toxin B-positive strain of C. difficile that was responsible for a recently described nosocomial outbreak of CAD. Analysis of the seven patient isolates from the outbreak by pulsed-field gel electrophoresis indicated that this outbreak was due to transmission of a single strain of C. difficile. Our characterization of this strain (HSC98) has demonstrated that the toxin A gene lacks 1.8 kb from the carboxy repetitive oligopeptide (CROP) region but apparently has no other major deletions from other regions of the toxin A or toxin B gene. The remaining 1.3-kb fragment of the toxin A CROP region from strain HSC98 showed 98% sequence homology with strain 1470, previously reported by M. Weidmann in 1997 (GenBank accession number Y12616), suggesting that HSC98 is toxinotype VIII. The HSC98 strain infecting patients involved in this outbreak produced the full spectrum of clinical illness usually associated with C. difficile-associated disease. This pathogenic spectrum was manifest despite the inability of this strain to alter tight junctions as determined by using in vitro tissue culture testing, which suggested that no functional toxin A was produced by this strain.

Antibiotics and Clostridium difficile diarrhea in the ambulatory care setting

OBJECTIVE

The goal of this study was to determine the prevalence of Clostridium difficile diarrhea (CDD) and the risk for CDD associated with different oral antibiotics commonly used in the ambulatory care setting.

METHODS

The prevalence of CDD was determined for enrollees in 4 UnitedHealth Group-affiliated health plans between January 1, 1992, and December 31, 1994. Cases were identified based on the presence of an inpatient or outpatient claim with a primary diagnosis of diarrhea, a pharmacy claim for a prescription drug used to treat CDD, or a physician or facility claim for the C. difficile toxin test, and were confirmed using full-text medical records. Within a retrospective cohort design, periods of risk for CDD were defined on the basis of duration of antibiotic therapy. To control for potential selection bias created by heterogeneous rates of C. difficile testing and to limit confounding due to multiple antibiotic exposures, we used a nested case-control design, restricting eligibility to subjects who underwent screening for C. difficile and who had been exposed to only 1 antibiotic risk period with a single antibiotic.

RESULTS

The global prevalence of CDD in 358,389 ambulatory care enrollees was 12 per 100,000 person-years. In the nested case-control study, after controlling for other risk factors, 2 antibiotics demonstrated an increased association with CDD: cephalexin (odds ratio [OR] = 7.5, 95% CI = 1.8 to 34.7) and cefixime (OR = 6.4, 95% CI = 1.2 to 39.0).

CONCLUSIONS

Although CDD is thought to occur primarily in hospitalized patients, it was found to be present in an ambulatory care population, but at a low frequency. In this population, it appeared to be associated with 2 cephalosporins but not with other types of antibiotics usually linked with nosocomial CDD. Because the frequency of C. difficile testing was shown to be more common with high-risk antibiotics, CDD may be underdiagnosed in the ambulatory care setting.

Epidemiology of nosocomial clostridium difficile diarrhoea

Clostridium difficile is a frequent and clinically important cause of diarrhoea that has been strongly but not exclusively associated with the hospital setting. The vast majority of cases of C. difficile diarrhoea are associated with antecedent treatment with antibiotics, of which cephalosporins and clindamycin appear to pose the highest risk. Within hospitals and chronic-care facilities, cross-infection of C. difficile has been related to transient carriage on hands of healthcare workers and contamination of diverse environmental surfaces, including electronic rectal thermometers. Prospective epidemiologic studies have demonstrated that acquisition of C. difficile is common in hospitalized patients. Although colonized patients contribute to nosocomial transmission of C. difficile, symptom-free carriage of C. difficile appears to reduce risk of subsequent development of C. difficile diarrhoea. Antimicrobial treatment with oral metronidazole or vancomycin to attempt to eradicate symptomless carriage is not recommended. Measures to control nosocomial C. difficile diarrhoea have focused on improved handwashing, use of barrier precautions with single rooms for symptomatic patients, reduction of environmental contamination, and antibiotic restriction. Restricting clindamycin has been particularly successful in terminating outbreaks of C. difficile diarrhoea associated with its use. The epidemiologic features of C. difficile and strategies for control are similar to those for micro-organisms that have acquired antimicrobial resistance. C. difficile may be indirectly or directly contributing to spread of resistant organisms, for instance, by causing diarrhoea and thereby enhancing environmental contamination with other gastrointestinal flora such as vancomycin-resistant enterococci. Thus, a consideration of C. difficile in the larger context of the world-wide spread of antibiotic resistance offers useful insights that may help form the basis for the development of more effective control measures.

Detection of Clostridium difficile toxin A by reversed passive latex agglutination

A reversed passive latex agglutination (RPLA) assay for detecting Clostridium difficile toxin A is presented. Purified monoclonal antibody (mAb 37B5) was used for latex sensitization. The culture supernatants of 93 strains of C. difficile were tested by RPLA assay and the results compared with those of a commercially available latex agglutination test, PCR and cytotoxin assay with Vero cells. There was agreement between RPLA, cytotoxicity and PCR assays, but 29 strains were positive in the RPLA assay while 35 were positive in the cytotoxicity test and PCR using primer pair NK3-NK2 directed to the nonrepeating portion of the C. difficile toxin A gene. The 6 cytotoxic but RPLA-negative strains were demonstrated to be toxin A-negative/toxin B-positive strains in the PCR assay by using primer pair NK11-NK9 directed to the repeating portion of the C. difficile toxin A gene. There were no cross-reactions with culture supernatants of the other clostridial strains except for two strains of C. sordelli that produced hemorrhagic toxin (which is immunologically related to C. difficile toxin A).

Winner of the Best Paper Award from the Gold Medal Forum: Clinical Characteristics and Antibiotic Utilization in Surgical Patients with Clostridium difficile-Associated Diarrhea

Clostridium difficile-associated diarrhea (CDAD) remains a significant problem in surgical patients. To address this, we prospectively studied all episodes of treated CDAD in surgical inpatients at the University of Virginia hospital from December 1996 through March 1998. CDAD accounted for 3.2 per cent (32) of 1000 total infections. Compared with a randomly selected control group with other nosocomial infections, patients with CDAD had a longer period from the time of admission to diagnosis of infection (19 ± 4 versus 9 ± 1; P = 0.01), were more likely to be female (66% versus 37%; P = 0.009), and had a higher overall crude mortality (31% versus 11%; P = 0.01), although there were no deaths directly attributable to CDAD. Ciprofloxacin (19%) and cefoxitin (16%) were the most common individual antibiotics prescribed before the diagnosis of CDAD. The average time from completion of antibiotic therapy to diagnosis of CDAD was 7 ± 2 days (range, 0-58). Sixteen per cent (5 of 32) developed CDAD after administration of prophylactic perioperative antibiotics only. The high crude mortality rate associated with CDAD suggests that this may be a significant predictor of poor outcome among infected surgical patients. Antibiotics used commonly but not classically associated with CDAD frequently precipitate this infection. Finally, the use of prophylactic antibiotics is not without risk, as demonstrated by the significant percentage of CDAD occurring after routine administration of these agents.