Clostridium difficile in general practice and community health

Present and past perspectives on Clostridium difficile infection

Clostridium difficile is a Gram-positive bacillus that has become one of the main hospital-acquired human gastrointestinal infections in recent years. Its incidence is on the rise, involving more virulent strains, affecting new and previously uncontemplated groups of patients, and producing changes in clinical presentation and treatment response that influence disease outcome. Early diagnosis and disease stratification based on the severity of C.difficile infection are essential for therapeutic management and the implementation of containment measures. However, the speed at which new strains with greater pathogenicity are developing is surpassing that of the development of new drugs, making it necessary to validate other therapeutic options. The present article is a review of the epidemiologic, pathophysiologic, diagnostic, and therapeutic aspects of C.difficile infection, from its first isolation to the present date, that aims to contribute to the preparation of general physicians and specialists, so that patients with this infection receive opportune and quality medical attention.

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.

Risk and Severity of Hospital-Acquired Clostridium difficile Infection in Patients Taking Proton Pump Inhibitors

STUDY OBJECTIVE

To compare the rates and severity of hospital-acquired Clostridium difficile infection (CDI) among patients taking proton pump inhibitors (PPIs) versus those not taking PPIs.

DESIGN

Retrospective, single-center, cohort study.

SETTING

Tertiary community hospital with a teaching service.

PATIENTS

A total of 41,663 patients with CDI who were hospitalized between January 2013 and May 2014; of those, 17,471 patients (41.9%) had received at least one dose of a PPI (PPI group), and 24,192 patients (58.1%) had no PPI exposure (control group).

MEASUREMENTS AND MAIN RESULTS

A total of 348 patients had CDI during the study period, with 269 cases present on admission. Hospital-acquired CDI was defined as CDI diagnosis occurring on or after the third calendar day of admission. After excluding those patients with CDI on admission, 65 (0.38%) of 17,302 patients later developed CDI in the hospital in the PPI group compared with only 14 (0.058%) of 24,092 patients in the control group. Of these patients, 36 patients (0.21%) in the PPI group met the definition of severe CDI compared with 8 (0.03%) in the control group. This demonstrated an unadjusted relative risk (RR) of 6.46 (95% confidence interval [CI] 3.63-11.51, p<0.0001) of developing hospital-acquired CDI and an unadjusted RR of 6.27 (95% CI 2.91-13.48, p<0.0001) of developing severe CDI while taking a PPI. When evaluating only patients who developed severe-complicated CDI, there were 22 cases in the PPI group and 2 cases in the control group, demonstrating an unadjusted RR of 15.3 (95% CI 3.6-65.13, p=0.0002) of developing severe-complicated CDI. Confounding variables were similar between groups.

CONCLUSION

PPI use was associated with an increase in both the rate and severity of hospital-acquired CDI.

Emergence of community-acquired Clostridium difficile infection: the experience of a French hospital and review of the literature

BACKGROUND

Clostridium difficile infection (CDI) is a common cause of nosocomial diarrhoea. People in the general community are not usually considered to be at risk of CDI. CDI is associated with a high risk of morbidity and mortality. The risk of severity is defined by the Clostridium Severity Index (CSI).

METHODS

The cases of 136 adult patients with CDI treated at the University Hospital of Tours, France between 2008 and 2012 are described. This was a retrospective study.

RESULTS

Among the 136 patients included, 62 were men and 74 were women. Their median age was 64.4 years (range 18-97 years). Twenty-six of the 136 (19%) cases were community-acquired (CA) and 110 (81%) were healthcare-acquired (HCA). The major risk factors for both groups were long-term treatment with proton pump inhibitors (54% of CA, 53% of HCA patients) and antibiotic treatment within the 2.5 months preceding the CDI (50% of CA, 91% of HCA). The CSI was higher in the CA-CDI group (1.56) than in the HCA-CDI group (1.39). Intensive care was required for 8% of CA-CDI and 16.5% of HCA-CDI patients.

CONCLUSIONS

CDI can cause community-acquired diarrhoea, and CA-CDI may be more severe than HCA-CDI. Prospective studies of CDI involving people from the general community without risk factors are required to confirm this observation.

A prospective study of community-associated Clostridium difficile infections: the role of antibiotics and co-infections

OBJECTIVES

This prospective study was performed to determine the incidence, risk factors, severity and outcomes of community-associated Clostridium difficile infection (CA-CDI) in the SE of Scotland.

METHODS

All patients (335) diagnosed with laboratory confirmed CDI in the city of Edinburgh, East Lothian and Midlothian regions of Scotland between August 2010 and July 2011 were followed up for one year after diagnosis. Clinical details and laboratory markers were recorded. Stool samples were tested for C. difficile, other bacterial pathogens and norovirus. Molecular epidemiology of C. difficile isolates was studied by PCR-ribotyping.

RESULTS

Of the total 335 confirmed CDI cases, PCR-ribotype 001 was the commonest (14.1%), followed by PCR-ribotypes 078 (12.9%) and 015 (11.7%), respectively. CA-CDI represented 12.5% of the cases. In these, PCR-ribotype 078 was the commonest (19.0%), followed by PCR-ribotypes 014/020 (16.7%), PCR-ribotype 015 (14.3% and PCR-ribotype 001 (11.9%). A lower Charlson co-morbidity index and a lower age was observed in the CA-CDI group as was total number of different antibiotic classes whereas age >75 was more common in the HA-CDI group. On multivariable analysis presence of PCR-ribotype 078 was significantly associated with community acquisition (p = 0.006) whereas a greater proportion of immunosuppressed patients and those on antibiotics 8 weeks preceding diagnosis (p = 0.035 and p = 0.005 respectively) were found among HA-CDI cases. Charlson co-morbidity index, number of different antibiotics given in the eight weeks preceding onset, severity of infection and rural residence were not significantly different between the two groups.

CONCLUSION

This study demonstrates that patients with CA-CDI may also present with severe infection, are less likely to receive antibiotics prior to CDI, more likely to be younger in age and have a greater proportion of PCR-ribotype 078 compared with CDI acquired in a hospital setting. Hence a high level of vigilance must be maintained to detect CDI cases which present in the community without the traditional predisposing factors.

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.

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.

Proton Pump Inhibitors and Hospitalization for Clostridium Difficile--Associated Disease: A Population-Based Study

BACKGROUND

Previous studies have examined the association between proton pump inhibitor (PPI) use and the risk of Clostridium difficile-associated disease (CDAD), with conflicting results. Whether outpatient PPI use influences the risk of hospital admission for CDAD among older patients who have recently been treated with antibiotics is unknown.

METHODS

We conducted a population-based, nested case-control study of linked health care databases in Ontario, Canada, from 1 April 2002 through 31 March 2005. We identified patients aged > or = 66 years who were hospitalized for CDAD within 60 days of receiving outpatient antibiotic therapy. Each case patient with CDAD was matched with 10 control subjects on the basis of age, sex, and details of antibiotic use (antibiotic class, timing, and number of antibiotics used). PPI use by case patients and control subjects was categorized as current (within 90 days), recent (91-180 days), or remote (181-365 days). We used conditional logistic regression to estimate the odds ratio for the association between outpatient PPI use and risk of hospitalization for CDAD.

RESULTS

We identified 1389 case patients and 12,303 matched control subjects. Case patients were no more likely than control subjects to have received a PPI in the preceding 90 days (adjusted odds ratio, 0.9; 95% confidence interval, 0.8-1.1). Similarly, we found no association between hospitalization for CDAD and more remote use of PPIs.

CONCLUSIONS

Among community-dwelling older patients, PPI use is not a risk factor for hospitalization with CDAD.

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.

Improvement of Clostridium difficile isolation by heat-shock and typing of the isolated strains by SDS-PAGE

Clostridium difficile plays an essential role in causing pseudomembranous colitis. We looked for the presence of these bacteria in the stools of 169 hospitalized patients and 38 nurses from wards with cases of diarrhea (207 subjects). The study was divided into three parts. In the first part, we compared three methods for isolating Clostridium difficile from stool samples: pre-selection with heat-shock, direct plating on Cycloserine-Cefotaxime-Fructose Agar (CCFA) and culturing in a selective broth medium. Final identification of Clostridium difficile was achieved by gas-chromatography and ApiZym. From the 207 consecutively obtained stool specimens, Clostridium difficile was isolated in 108 (52%) when pre-treated by heat-shock compared to only 26 (13%) when plated on modified CCFA and 23 (11%) when cultured in selective broth medium. Pre-selection significantly increases the isolation rate for Clostridium difficile and should be used in further epidemiological research. In the second part of our study, a retrospective review of subjects' records showed that the heat-shock method detected Clostridium difficile in all age groups at a higher rate than the other methods. In the third part of our study, we typed the 157 isolates of Clostridium difficile strains by protein patterns using SDS-PAGE, and 16 distinct groups were identified. In 19 cases different Clostridium difficile strains were found in the same subject by SDS-PAGE. Finally, the isolated strains were compared with strains from Brussels and Freiburg. Matching patterns were noted in only three cases.

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.

Relapse versus reinfection with Clostridium difficile

Relapse of Clostridium difficile-associated diarrhoea occurs in 15-20% of patients; however, whether relapse is due to an endogenous source of the organism or reinfection from the environment remains unclear. Restriction enzyme analysis (REA) of chromosomal DNA was used to type multiple isolates from ten patients who had experienced apparent relapses. More than half the relapses were due to infection with a new strain of C. difficile. The remaining patients were infected with the same strain, but whether this strain was acquired from the environment or from endogenous sources could not be determined. Relapses with a different strain of C. difficile could occur if an individual harboured more than one strain in their gastrointestinal tract. To investigate this possibility ten other patients were assessed for carriage of multiple strains. Ten colonies from a primary culture plate from each patient were typed by REA and tested for their ability to produce cytotoxin. All isolates from the same patient were identical by both methods, indicating that multiple carriage of strains may be a rare event.

Diarrheal disease due to Clostridium difficile in general practice

A total of 288 stool samples from patients attending their general practitioners was examined for the presence of Clostridium difficile. C. difficile or its cytotoxin was found in 16 patients (5.5%) and was the most common enteric pathogen detected. Most patients had only mild to moderate diarrhea but in the majority of patients the diarrhea was protracted. Eleven of the 16 patients had received antimicrobial agents in the 3 mths preceding onset of diarrhea and there was good circumstantial evidence that 2 other patients had also been exposed. None of the patients had a history of any inflammatory bowel disease or possible occupational exposure. The prescribing habits of general practitioners with regard to antimicrobial agents were monitored for a 1 yr period. Tetracyclines and amoxycillin accounted for approximately 25% each of all prescriptions dispensed. Ten of the 16 patients were treated with antimicrobials (mainly metronidazole) and in most cases the diarrhea resolved. We conclude that C. difficile may be a significant cause of community-acquired diarrhea.

Evaluation of a latex agglutination test for Clostridium difficile in two nursing home outbreaks

The Culturette Brand Clostridium difficile test (CDT; Marion Laboratories, Inc., Kansas City, Mo.) is a latex agglutination test for C. difficile. The recent controversy involving the identity of antigens detected by CDT has made decisions on its use difficult. We compared the test results with those of selective culture and stool cytotoxin assays in investigations of two nursing home outbreaks of C. difficile-associated disease in order to formulate usage recommendations. Selective culture for C. difficile identified 27 (19%) of 142 subjects as carriers. CDT and the stool cytotoxin assay identified only 52 and 48% of these carriers, respectively. Compared with the stool cytotoxin assay, CDT had a high sensitivity (92%) and specificity (89%) for the detection of C. difficile disease, but the positive predictive value of the test was only 17% when the prevalence of disease was 2%. We conclude that the CDT should not be used to identify carriers but that it is a sufficiently sensitive and specific screening test for diagnosing C. difficile disease. However, since the positive predictive value of the CDT is low when the prevalence of disease is low, positive test results should be confirmed by the stool cytotoxin assay.

Laboratory diagnosis of Clostridium difficile-associated diarrhoea

This paper reviews the various laboratory procedures available for the isolation and identification of Clostridium difficile and the detection of toxins produced by this organism. Laboratories should be selective in determining which patients require investigation for Clostridium difficile-associated diarrhoea. Transport and storage of stool specimens at 4 degrees C is recommended when delays in processing may occur. Tissue culture techniques are still the best method for detection of cytotoxin and a variety of cell lines can be used. Other methods for detecting cytotoxin, and methods for detecting other toxins are not sufficiently developed yet to warrant introduction into diagnostic laboratories. Culture techniques remain the most sensitive for diagnosis, particularly since the development of a variety of enrichment techniques. Cycloserine cefoxitin fructose agar is still adequate, although reduced concentrations of antimicrobial agents are necessary, and improvements, such as the addition of sodium taurocholate, increase the recovery of spores. Enrichment cultures have markedly increased isolation rates for Clostridium difficile but the significance of these isolates needs to be carefully evaluated. Until simpler and more reliable tests are available in clinical laboratories for the detection of toxins, the isolation of Clostridium difficile from patients with diarrhoeal disease should be considered paramount.