Diarrheal disease due to Clostridium difficile in general practice

Toxigenic Clostridium difficile carriage in general practice: results of a laboratory-based cohort study

OBJECTIVES

Reported rates of community-acquired Clostridium difficile infections (CDIs) have been increasing. However, the true burden of the disease in general practice is unknown in France. Our objective was to determine the incidence of toxigenic C. difficile carriage and the percentage of stool samples prescribed by general practitioners (GPs) which contained free C. difficile toxins.

METHODS

During an 11-month period, all stool samples submitted for any enteric pathogen detection to 15 different private laboratories in Paris and the surrounding areas were tested for C. difficile, irrespective of the GPs' request. A clinical questionnaire was completed for each patient. Stool samples were screened using a rapid simultaneous glutamate dehydrogenase and toxins A/B detection test: any positive result (glutamate dehydrogenase or toxin) was further confirmed by the stool cytotoxicity assay (CTA) on MRC-5 cells and by toxigenic culture (TC) at a central laboratory. The C. difficile isolates were characterized by PCR ribotyping.

RESULTS

A total of 2541 patients (1295 female, 1246 male) were included. The incidences of patients with a positive toxigenic culture and a positive CTA were 3.27% (95% CI 2.61%-4.03%) and 1.81% (95% CI 1.33%-2.41%), respectively. GPs requested C. difficile testing in only 12.93% of the stool samples, detecting 52.30% of all TC-positive patients. The 83 toxigenic C. difficile strains belonged to 36 different PCR ribotypes.

CONCLUSIONS

Toxigenic C. difficile carriage is frequent in general practice but remains under-recognized. It may affect young patients without previous antimicrobial therapy or hospitalization.

Epidemiology and Risk Factors for Community-Associated Clostridium difficile Infection: A Narrative Review

Clostridium difficile infection (CDI) was once considered a primarily nosocomial concern. Emerging evidence from the last 20 years has highlighted a drastic shift in the known epidemiology of CDI, with disease outside of hospitals apparently occurring more frequently and causing severe disease in populations that were thought to be at low risk. This narrative review summarises potential pathways for infection outside of the hospital environment and highlights likely routes of transmission. Further, evidence is presented on potential risk factors for development of disease. Understanding the epidemiology of CDI outside of hospitals is essential to the ability to prevent and control disease in vulnerable populations.

The incidence and clinical symptomatology of Clostridium difficile infections in a community setting in a cohort of Danish patients attending general practice

Clostridium difficile infection (CDI) is gradually being recognised as a cause of morbidity in the community. We investigated the incidence and clinical characteristics of CDI in a community setting and characterised the C. difficile strains by toxin gene profiling and polymerase chain reaction (PCR) ribotyping. Patients included in the study had attended general practice, primarily because of diarrhoea; CDI patients (259 patients; 121 <2 years of age) had positive cultures for toxigenic C. difficile and non-CDI patients (455 patients) were culture-negative. Outcome variables included the frequency and duration of diarrhoea, vomiting, stomach ache, fever >38 °C, weight loss and sick leave. Data were analysed by logistic regression. CDI patients <2 and ≥2 years of age with C. difficile as the only enteropathogen in the faecal sample reported slimy stools (65% vs. 62%), stomach ache (60% vs. 75%), weight loss (50% vs. 76%) and duration of diarrhoea >15 days (59% vs. 73%) as the predominant symptoms. CDI patients ≥2 years old reported duration of diarrhoea >15 days more often compared to non-CDI patients (73% vs. 27 %, p < 0.0001). The annual incidence of CDI was 518 and 23/100,000 for patients <2 and ≥2 years of age, respectively, and 46/100,000 in the subgroup of patients ≥60 years of age. CDI was characterised by stomach ache and persistent diarrhoea, often leading to weight loss. This emphasises the importance of diagnosing CDI not only in hospitalised patients, but also in individuals ≥2 years of age attending general practice because of gastrointestinal symptoms, especially in the elderly, where the incidence of CDI is high.

Clostridium difficile contamination of public tap water distribution system during a waterborne outbreak in Finland

Aims: In November through December 2007, the drinking water distribution system in the town of Nokia, Finland, was contaminated with treated sewage effluent that resulted in a large gastroenteritis outbreak in the community. The aim of the present study was to investigate if the contaminated water in this outbreak was also a potential source of Clostridium difficile infections. Methods: Samples from the contaminated tap water and treated sewage effluent were collected. Stool samples from a portion of patients that fell ill during the outbreak were examined for C. difficile. PCR ribotyping was performed on toxin positive C. difficile isolates and the genetic profiles of the water and patient isolates were compared. Results: Twelve toxin-positive C. difficile isolates were found in water samples: five from contaminated tap water and seven from treated sewage effluent. Among these, four and five distinct PCR ribotype profiles were identified, respectively. Four PCR ribotype profiles were found among nine human faecal C. difficile isolates. Two isolates, one from tap water and one from a patient, had an indistinguishable PCR ribotype profile. Conclusions: Our findings demonstrate for the first time C. difficile contamination of a tap water distribution system and waterborne transmission of toxigenic C. difficile seems possible.

Systematic review: Clostridium difficile and inflammatory bowel disease

BACKGROUND

There is increasing concern about the apparently rising incidence and worsening outcome of Clostridium difficile infection (CDI) associated with inflammatory bowel disease (IBD). We have systematically reviewed the literature to evaluate the incidence, risk factors, endoscopic features, treatment and outcome of CDI complicating IBD.

AIM

To systematically review: clostridium difficile & inflammatory bowel disease.

METHODS

Structured searches of Pubmed up to September 2010 for original, cross-sectional, cohort and case-controlled studies were undertaken.

RESULTS

Of 407 studies, 42 met the inclusion criteria: their heterogeneity precluded formal meta-analysis. CDI is commoner in active IBD, particularly ulcerative colitis, than in controls. Certainty about a temporal trend to its increasing incidence in IBD is compromised by possible detection bias and miscoding. Risk factors include immunosuppressants and antibiotics, the latter less commonly than in controls. Endoscopy rarely shows pseudomembranes and is unhelpful for diagnosing CDI in IBD. There are no controlled therapeutic trials of CDI in IBD. In large studies, outcome of CDI in hospitalised IBD patients appears worse than in controls.

CONCLUSIONS

The complication of IBD by Clostridium difficile infection has received increasing attention in the past decade, but whether its incidence is really increasing or its outcome worsening remains unproven. Therapeutic trials of Clostridium difficile infection in IBD are lacking and are needed urgently.

The changing epidemiology of Clostridium difficile infections

The epidemiology of Clostridium difficile infection (CDI) has changed dramatically during this millennium. Infection rates have increased markedly in most countries with detailed surveillance data. There have been clear changes in the clinical presentation, response to treatment, and outcome of CDI. These changes have been driven to a major degree by the emergence and epidemic spread of a novel strain, known as PCR ribotype 027 (sometimes referred to as BI/NAP1/027). We review the evidence for the changing epidemiology, clinical virulence and outcome of treatment of CDI, and the similarities and differences between data from various countries and continents. Community-acquired CDI has also emerged, although the evidence for this as a distinct new entity is less clear. There are new data on the etiology of and potential risk factors for CDI; controversial issues include specific antimicrobial agents, gastric acid suppressants, potential animal and food sources of C. difficile, and the effect of the use of alcohol-based hand hygiene agents.

The changing epidemiology of Clostridium difficile infections

The epidemiology of Clostridium difficile infection (CDI) has changed dramatically during this millennium. Infection rates have increased markedly in most countries with detailed surveillance data. There have been clear changes in the clinical presentation, response to treatment, and outcome of CDI. These changes have been driven to a major degree by the emergence and epidemic spread of a novel strain, known as PCR ribotype 027 (sometimes referred to as BI/NAP1/027). We review the evidence for the changing epidemiology, clinical virulence and outcome of treatment of CDI, and the similarities and differences between data from various countries and continents. Community-acquired CDI has also emerged, although the evidence for this as a distinct new entity is less clear. There are new data on the etiology of and potential risk factors for CDI; controversial issues include specific antimicrobial agents, gastric acid suppressants, potential animal and food sources of C. difficile, and the effect of the use of alcohol-based hand hygiene agents.

Clinical and microbiological characteristics of community-onset Clostridium difficile infection in The Netherlands

To elucidate the prevalence, characteristics and risk factors of community-onset Clostridium difficile infection (CO-CDI), an uncontrolled prospective study was performed. For 3 months in 2007-2008, three laboratories in The Netherlands tested all unformed stool samples submitted by general practitioners (GPs) for C. difficile by enzyme immunoassay for toxins A and B, irrespective of whether GPs specifically requested this. Patients with positive results were asked to complete a questionnaire. Positive stool samples were cultured for C. difficile, and isolates were characterized. In all, 2443 stool samples from 2423 patients were tested, and 37 patients (1.5%) with positive toxin test results were identified. Mixed infections were not found. Age varied from 1 to 92 years, and 18% were under the age of 20 years. Diarrhoea was typically frequent and watery, sometimes with admixture of blood or fever. Eight of 28 patients (29%) suffered recurrences. Among 31 patients with toxin-positive stool samples for whom information was available, 20 (65%) had not been admitted to a healthcare institution in the year before, 13 (42%) had not used antibiotics during the 6 months before, and eight (26%) had neither risk factor. A separate analysis for patients whose samples were both toxin-positive and culture-positive produced similar results. Cultured C. difficile isolates belonged to 13 different PCR ribotypes, and 24% of the isolates were non-typeable (rare or new) PCR ribotypes. In conclusion, CO-CDI can affect all age groups, and many patients do not have known risk factors. Several PCR ribotypes not encountered in hospital-associated outbreaks were found, suggesting the absence of a direct link between outbreaks and community-onset cases.

A case-control study of community-associated Clostridium difficile infection

OBJECTIVES

The aim of this study was to determine the incidence of and risk factors for community-associated Clostridium difficile infection (CDI).

METHODS

Prospective surveillance of community-derived faecal samples for C. difficile cytotoxin, followed by a questionnaire-based case-control study in two distinct patient cohorts (one semi-rural and the other urban).

RESULTS

The proportion of randomly selected faecal samples positive for C. difficile cytotoxin was 2.1% in both patient cohorts (median ages 73 and 45 years for the urban and semi-rural cohorts, respectively). Exposure to antibiotics in the previous 4 weeks, particularly multiple agents (P < 0.001), aminopenicillins (P < 0.05) and oral cephalosporins (P < 0.05), was significantly more frequent among cases than controls. Hospitalization in the preceding 6 months was significantly associated with CDI (45% versus 23%; P = 0.022). However, almost half the cases had not received antibiotic therapy in the month before C. difficile detection, and approximately one-third neither had exposure to antibiotics nor recent hospitalization. Contact with infants aged < or =2 years was significantly associated with CDI (14% versus 2%; P = 0.02). Prior exposure to gastrointestinal-acting drugs (proton pump inhibitor, H2 antagonist or non-steroidal anti-inflammatory) was not significantly more common in CDI cases. C. difficile PCR ribotype 001 caused 60% and 13% of urban and semi-rural community-associated CDI cases, respectively.

CONCLUSIONS

Reliance on antibiotic history and age (> or =65 years) will contribute to missed diagnoses of community-associated CDI. Potential risk factors for community-associated CDI should be explored further to explain the large proportion of cases not linked to recent antibiotic therapy or hospitalization.

Clostridium difficile in broiler chickens sold at market places in Zimbabwe and their antimicrobial susceptibility

Clostridium difficile has been shown to be a nosocomial pathogen associated with diarrhoea and pseudomembranous colitis in hospitalised patients and the infection is believed to be acquired nosocomially. Community-acquired C. difficile-associated diarrhoea has also been reported. Recent studies have shown the occurrence of C. difficile in food animals which may act as a source of infection to humans. The aim of this study was to determine the occurrence of C. difficile in broiler chickens sold at market places in an urban area in Zimbabwe. Faeces of broiler chickens were collected from the cages at the market places and soils were collected from areas around the market places. The chicken faeces and soil samples were cultured for C. difficile. The C. difficile isolates were tested for toxins A or B production as well as for their susceptibility to antimicrobial drugs. C. difficile was isolated from 29.0% of 100 chicken faeces samples and 22.0% of 100 soil samples. Some of the C. difficile isolates from chickens (89.7%) and soils (95.5%) were toxigenic. All the isolates were susceptible to metronidazole, vancomycin, doxycycline, chloramphenicol and tetracycline. Over 70% of the isolates were susceptible to erythromycin, co-trimoxazole and ampicillin. They were all resistant to cefotaxime, gentamicin, ciprofloxacin, norfloxacin and nalidixic acid. The results of the present study suggest that broiler chickens sold at market places in the urban area are an important source of C. difficile, which may infect humans through consumption of chicken meat.

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.

Risk factors for acquisition of Clostridium difficile-associated diarrhea among outpatients at a cancer hospital

BACKGROUND

Clostridium difficile-associated diarrhea (CDAD) is an important infection in hospital settings. Its impact on outpatient care has not been well defined.

OBJECTIVE

To examine risk factors of ambulatory cancer patients with CDAD.

DESIGN

Case-control study.

SETTING

Memorial Sloan-Kettering Cancer Center, a tertiary-care hospital.

METHODS

Cases of CDAD among oncology outpatients from January 1999 through December 2000 were'identified via positive C. difficile toxin assay results on stool specimens sent from clinics or the emergency department. A 1:3 matched case-control study examined exposures associated with CDAD.

RESULTS

Forty-eight episodes of CDAD were identified in cancer outpatients. The mean age was 51 years; 44% were female. Forty-one (85%) had received antibiotics within 60 days of diagnosis, completing courses a median of 16.5 days prior to diagnosis. Case-patients received longer courses of first-generation cephalosporins (4.8 vs 3.2 days; P = .03) and fluoroquinolones (23.6 vs 8 days; P < .01) than did control-patients. Those receiving clindamycin were 3.9-fold more likely to develop CDAD (P < .01). For each additional day of clindamycin or third-generation cephalosporin exposure, patients were 1.29- and 1.26-fold more likely to develop CDAD (P < .01 and .04, respectively). The 38 CDAD patients hospitalized during the risk period (79.2%) spent more time as inpatients than did control-patients (19.3 vs 9.7 days; P < .001).

CONCLUSIONS

Antibiotic use, especially with cephalosporins and clindamycin, and prolonged hospitalization contributed to the development of CDAD. Outpatient CDAD appears to be most strongly related to inpatient exposures; reasons for the delayed development of symptoms are unknown.

Pathogenesis and treatment of Clostridium difficile infection

This paper reviews the pathogenesis and management of Clostridium difficile diarrhoea, in particular the management of recurrent episodes.

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.

Incidence and importance of Clostridium difficile in paediatric diarrhoea in Brazil

Clostridium difficile strains were detected in 14 of 210 (6.7 %) faecal samples from children in Rio de Janeiro, Brazil, by cultivating faeces on cycloserine/cefoxitin/fructose agar after alcohol-shock. Two main groups of children were studied: inpatients (n = 96) and outpatients (n = 114). The inpatient group consisted of children on antibiotics or immunosuppressors who presented with diarrhoea and other children who did not present with diarrhoea and were not under an antibiotic or chemotherapeutic regimen. Among the outpatients, two groups were examined: namely, a group that comprised children who presented with diarrhoea and were occasionally under an antibiotic regimen and another group that comprised patients who were not taking antibiotics. After cytotoxic assay, toxigenic C. difficile (Cd tox+) strains were detected in 4.2 % of inpatients and 3.5 % of outpatients. Exclusion of other infectious causes of diarrhoea indicated a typical case of C. difficile-associated paediatric diarrhoea in the community. Among Cd tox+ isolates, no variations were detected by PCR for toxin A that employed primers NK9 and NKVO11. No resistance was found to metronidazole or vancomycin among strains that were isolated from children who presented with diarrhoea, but the MIC(50) and MIC(90) values for clindamycin were 6-8 and 16 microg ml(-1), respectively. Resistance to clindamycin seems to be more disseminated in strains from outpatients than in those from inpatients (P < 0.05). In conclusion, these data suggest that investigation for C. difficile infection should be taken into account in paediatric diarrhoea in both inpatients and outpatients in developing countries.

Detection of Clostridium difficile cytotoxin and Clostridium perfringens enterotoxin in cases of diarrhoea in the community

Faecal specimens from 843 cases of diarrhoea in the community were tested for the presence of Clostridium difficile cytotoxin and Clostridium perfringens enterotoxin. C. difficile cytotoxin was detected in faecal specimens from 0.6 % of cases aged at least 2 years by using a Vero cell assay. Factors associated with detection of C. difficile cytotoxin were antibiotic therapy, age over 60 years and living in a home with other elderly people. Three methods were used for the detection of C. perfringens enterotoxin: a Vero cell assay, a commercial (TechLab) enzyme immunoassay (EIA) and an in-house EIA. The lower level of detection of pure C. perfringens enterotoxin in buffer was 0.01 micro g ml(-1) by the TechLab EIA and 1.0 micro g ml(-1) by the Vero cell assay. C. perfringens enterotoxin was detected by using the TechLab EIA in faecal specimens from 2.5 % of cases. This commercial EIA was less sensitive than the in-house EIA, detecting only 31 % of positive cases, but was specific and could be used for outbreak investigation by routine diagnostic laboratories. Age over 60 years was a factor associated with C. perfringens enterotoxin detection; this age group may be targeted for testing.

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.

Should all stool specimens be routinely tested for Clostridium difficile?

OBJECTIVE: To determine the frequency with which Clostridium difficile was detected in stool specimens from outpatients and patients hospitalized for less than 4 days to assess the usefulness of routine laboratory screening for detecting this enteric pathogen. METHODS: Seven hundred and forty-one specimens from 398 patients were cultured over a 6-month period for Salmonella, Shigella, Yersinia, Escherichia coli O157:H7, Campylobacter and Clostridium difficile. Clostridium difficile culture-positive samples were further tested for cytotoxin production. RESULTS: Campylobacter, Salmonella, Shigella and E. coli O157:H7 were isolated in 50 (6.7%) specimens from 35 (8.8%) patients. Clostridium difficile was cultured from 88 (11.9%) specimens from 35 (8.8%) patients and its cytotoxin detected in 35 (4.7%) specimens of 12 (3%) patients. Clostridium difficile was the second most frequent enteric pathogen after Campylobacter. Of 178 (24%) specimens submitted with a specific request for Clostridium difficile testing, 13 (7.3%) were cytotoxin positive (three patients); of 563 specimens for which Clostridium difficile was not requested, 22 (3.9%) were cytotoxin positive (nine patients). CONCLUSIONS: Nine of 12 patients with cytotoxin-positive specimens would have gone undiagnosed in the laboratory had all stool samples submitted not been tested. These results suggest that Clostridium difficile disease is under-recognized and that testing all stool samples for Clostridium difficile may be warranted in our community of patients.

Incidence and impact of Clostridium difficile infection in the UK, 1993-1996

Questionnaires were sent to 360 UK medical microbiologists to determine the incidence of Clostridium difficile infection in the UK between 1993-1996, and to establish the current laboratory testing protocols. Replies were received from 104 laboratories (29% response rate), 86, 7, 4 and 3% of which are in England, Scotland, Wales and Northern Ireland, respectively. The laboratories serve a total of approximately 90,000 hospital beds (median 750). C. difficile testing was performed by 83% of the laboratories, and 52, 45 and 31% used toxin A +/- B kits, cell cytotoxicity, and culture +/- isolate toxigenicity testing methods, respectively. Forty-seven percent of laboratories only performed testing when specifically requested, 19% if antibiotic use was stated, 15% tested all diarrhoeal specimens, and 14% examined all specimens except those from infants and community patients. The annual totals of positive C. difficile reports and cases increased from 3132 to 12,775, and from 1576 to 8211, respectively, between 1993-1996. In 1993 C. difficile infection caused ward closures in 5% of hospitals but 16% in 1996. Antibiotic policy changes, due to C. difficile infection, occurred in 21% of hospitals in 1996 compared with only 4% in 1993. C. difficile infection appears to be increasing markedly in the UK with major implications on hospital inpatient activity. Wide variations in laboratory selection and testing methods are likely to be masking the true epidemiology of C. difficile infection, and consensus is required on optimal protocols.

Dynamics of Clostridium difficile infection. Control using diet

Understanding the dynamics of the establishment of C. difficile within the gut is vital to effective prevention, control and therapy of disease due to this nosocomial pathogen. Factors affecting the establishment of C. difficile in the gut were investigated including the role of bacterial metabolic products (BMPs), the composition of colonic flora, diet, and properties of the infecting strain. Concentrations of 9/12 bacterial metabolic products (BMPs), both volatile and non-volatile were significantly higher in mice which eliminated oral challenge with 10(8) spores of C. difficile (E mice) than in mice harbouring the organism (H mice). Growth of C. difficile in vitro was inhibited 10(4) fold at combinations of BMPs at concentrations found in stools of E mice but not in stools of H mice. The in situ production and concentrations of BMPs were increased by augmenting the amount of fermentable fibre in the diet. This resulted in elimination of C. difficile from 6/7 C. difficile colonized mice within 6 days of beginning a diet containing 20% fermentable fibre. Whereas mice fed diets containing 2% fermentable fibre or 20% non-fermentable fibre continued excreting the organism. Elimination of C. difficile was associated with increased concentrations of BMPs and changes in the numbers of organisms already present within the colonic flora. Properties of two microbial phenotypes (smooth (S), and rough (R)) of one strain of C. difficile were examined in vitro and the ID50s determined. The S phenotype survived, germinated and grew in media containing higher concentrations of BMPs, acquired iron when grown under iron restriction, utilized haem and bound Congo red more readily than the R phenotype. In mice fed the 2% fermentable fibre diet the ID50 for the S phenotype was 10(3) spores and 10(8) spores for the R phenotype, whereas for mice fed the 20% fermentable fibre diet it was > 10(6) spores for the S phenotype. The ability of this opportunistic pathogen to adapt to changing environmental conditions is an important factor in determining whether the organism will colonize and cause disease. Diets supplemented with fermentable fibre may be a valuable method of preventing and treating C. difficile related disease.

Antibiotic use in the emergency department. II The aminoglycosides, macrolides, tetracyclines, sulfa drugs, and urinary antiseptics

The aminoglycoside, macrolide, tetracycline, and sulfa classes of antibiotics provide antimicrobial coverage pertinent to many infectious diseases diagnosed in the emergency department (ED). The aminoglycosides are parenteral agents that are useful in Gram-negative infections and as synergistic drugs in the management of some Gram-positive infections. The macrolides, of which erythromycin is the prototype, are used for a number of Gram-positive and atypical bacterial infections, while the tetracyclines are appropriate for ED treatment of a diverse group of infections such as chlamydiae, spirochetes, and rickettsiae. The sulfa agents are appropriate for many urinary and respiratory tract infections, and also have particular utility in some infections encountered primarily in patients with AIDS. The urinary antiseptics are a group of antimicrobials that may be effective for cystitis but have no systemic efficacy. This article, which is the second in a four-part series on antibiotic use in the ED, reviews the pharmacology and clinical utility of these diverse agents for the emergency physician.

Differentiation of Clostridium difficile, Clostridium bifermentans, Clostridium sordellii, and Clostridium perfringens from diarrheal stool by API ZYM and API LRA oxidase test

A simple, rapid and reliable outline for identification of clostridia isolates from human infections was developed. It consists of a combination of API ZYM and API LRA Oxidase tests. The enzymatic activities were performed with strains sub-cultured onto carbohydrate-free medium (Columbia blood agar). Fifty-five strains of Clostridium difficile, C. bifermentans, C. sordellii, and C. perfringens from clinical specimens and eight reference standard strains representing different species of the same genus were analyzed. The accuracy of the new method was evaluated by comparison with the results obtained by DNA/DNA analysis.

Fecal shedding of Clostridium difficile in dogs: a period prevalence survey in a veterinary medical teaching hospital

The goal of this study was to determine the fecal prevalence of Clostridium difficile in dogs who were patients at a veterinary medical teaching hospital. Stool specimens collected from 152 dogs (in- and outpatients) were analyzed for the presence of C. difficile. An additional 42 stool specimens were collected and examined from dogs recently housed at local animal shelters. Following culture on selective medium, C. difficile was identified by a latex agglutination test, and the presence of the toxin A and B genes was determined individually by polymerase chain reaction. Clostridium difficile was isolated from the feces of 28 of the veterinary hospital patients (18.4%); isolates from 14 of these patients (50.0%) were toxigenic. Diarrhea was a clinical finding in 5 (35.7%) of the dogs carrying toxigenic isolates of C. difficile, whereas diarrhea was noted in only 2 of 14 dogs (14.3%) shedding nontoxigenic isolates. Three of 14 dogs (21.4%) shedding toxigenic isolates of C. difficile were receiving antibiotics at the time of stool collection, whereas 5 of 14 dogs (37.5%) shedding nontoxigenic strains of C. difficile were receiving antibiotics. The carriage rate of C. difficile was significantly higher for animals categorized as inpatients of the veterinary hospital. The carriage rate also provided evidence for an increased risk for fecal shedding with increasing age. Clostridium difficile was not isolated from any of the 42 dogs recently housed at local animal shelters. This study confirms the presence of toxigenic C. difficile in dogs at a veterinary teaching hospital.(ABSTRACT TRUNCATED AT 250 WORDS)

Gastrointestinal carriage of Clostridium difficile in cats and dogs attending veterinary clinics

Cats and dogs being treated at two veterinary clinics were investigated for gastrointestinal carriage of Clostridium difficile using selective solid and enrichment media. Thirty-two (39.5%) of 81 stool samples yielded C. difficile. There were significant differences in isolation rates between clinics, 61.0% of animals being positive at one clinic compared to 17.5% at the other (Chi-square, P less than 0.005). Of 29 animals receiving antibiotics, 15 (52.0%) harboured C. difficile while 11 (23.9%) of 46 animals not receiving antibiotics were positive (Chi-square, P less than 0.01). There was no difference in carriage rate between cats (38.1%) and dogs (40.0%). The environment at both veterinary clinics was surveyed for the presence of C. difficile. Fifteen of 20 sites at one clinic were positive compared to 6 of 14 sites at the other clinic. Both cytotoxigenic and noncytotoxigenic isolates of C. difficile were recovered from animals and environmental sites. These findings suggest that household pets may be a potentially significant reservoir of infection with C. difficile.