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

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.

Risk factors for and estimated incidence of community-associated Clostridium difficile infection, North Carolina, USA

We determined estimated incidence of and risk factors for community-associated Clostridium difficile infection (CA-CDI) among patients treated at 6 North Carolina hospitals. CA-CDI case-patients were defined as adults (>18 years of age) with a positive stool test result for C. difficile toxin and no hospitalization within the prior 8 weeks. CA-CDI incidence was 21 and 46 per 100,000 person-years in Veterans Affairs (VA) outpatients and Durham County populations, respectively. VA case-patients were more likely than controls to have received antimicrobial drugs (adjusted odds ratio [aOR] 17.8, 95% confidence interval [CI] 6.6-48] and to have had a recent outpatient visit (aOR 5.1, 95% CI 1.5-17.9). County case-patients were more likely than controls to have received antimicrobial drugs (aOR 9.1, 95% CI 2.9-28.9), to have gastroesophageal reflux disease (aOR 11.2, 95% CI 1.9-64.2), and to have cardiac failure (aOR 3.8, 95% CI 1.1-13.7). Risk factors for CA-CDI overlap with those for healthcare-associated infection.

The occurrence and high diversity of Clostridium difficile genotypes in rivers

Clostridium difficile is mainly associated with nosocomial infections but can be present also in other environments. In this study we compared three methods (culturing with and without ethanol shock and real-time PCR) for detection of C. difficile in water and have used them on a series of river water samples. C. difficile was present in 17 of 25 rivers tested (68.0%) and in 42 of 69 water samples tested (60.9%). Positive sampling sites correlated with increased population densities. Isolates were distributed into 34 PCR ribotypes, of which more than half are present also in humans and animals. PCR ribotype 014 was the predominate type (16.2% of all isolates).

Review of medical and surgical management of Clostridium difficile infection

Clostridium difficile infection (CDI) has become an important area in our daily clinical practice. C. difficile is known to cause a broad spectrum of conditions ranging from asymptomatic carriage, through mild or moderately severe disease with watery diarrhoea, to the life-threatening pseudomembranous colitis (PMC), with toxic megacolon and ileus. Peoples who have been treated with broad-spectrum antibiotics, patients with serious underlying co-morbidities and the elderly are at greatest risk. Over 80% of CDIs reported are in people aged over 65. Due to the alarming increase in its frequency, appearance of more virulent strains and occasional need for life-saving surgical intervention, a more coherent multidisciplinary approach is needed. Combination of rapid turn round time and accurate diagnosis will result in a better management of CDI and a timely implementation of infection control measure. Discontinuation of causative agents such as antibiotic treatment is often curative. In more serious cases, oral administration of metronidazole or vancomycin is the treatment of choice. Relapses of CDI have been reported in about 20-25% of cases, this may increase to 45-60% after the first recurrence. Patients should be treated as soon as possible when the diagnosis of Clostridium difficile colitis is made to avoid sepsis or bowel perforation. Colectomy may improve the outcome of the patient with systemic or complicated Clostridium difficile colitis. This article reviews the changing epidemiological picture, microbiology, histopathology and both medical and surgical managements.

Clostridium difficile in food--innocent bystander or serious threat?

Clostridium difficile is a critically important cause of disease in humans, particularly in hospitalized individuals. Three major factors have raised concern about the potential for this pathogen to be a cause of foodborne disease: the increasing recognition of community-associated C. difficile infection, recent studies identifying C. difficile in food animals and food, and similarities in C. difficile isolates from animals, food and humans. It is clear that C. difficile can be commonly found in food animals and food in many regions, and that strains important in human infections, such as ribotype 027/NAP1/toxinotype III and ribotype 078/toxinotype V, are often present. However, it is currently unclear whether ingestion of contaminated food can result in colonization or infection. Many questions remain unanswered regarding the role of C. difficile in community-associated diarrhoea: its source when it is a food contaminant, the infective dose, and the association between ingestion of contaminated food and disease. The significant role of this pathogen in human disease and its potential emergence as an important community-associated pathogen indicate that careful evaluation of different sources of exposure, including food, is required, but determination of the potential role of food in C. difficile infection may be difficult.

Multilocus variable-number tandem-repeat analysis and multilocus sequence typing reveal genetic relationships among Clostridium difficile isolates genotyped by restriction endonuclease analysis

Numbers of Clostridium difficile infections have increased worldwide in the past decade. While infection with C. difficile remains predominantly a health care-associated infection, there may also be an increased incidence of community-associated infections. C. difficile strains of public health significance continue to emerge, and reliable genotyping methods for epidemiological investigations and global surveillance of C. difficile are required. In this study, multilocus sequence typing (MLST) and multilocus variable-number tandem-repeat analysis (MLVA) were performed on a set of 157 spatially and temporally diverse C. difficile isolates that had been previously genotyped by restriction endonuclease analysis (REA) to determine the concordance among these genotyping methods. In addition, sequence analysis of the tcdC genotype was performed to investigate the association of allelic variants with epidemic C. difficile isolates. Overall, the MLST and MLVA data were concordant with REA genotyping data. MLST was less discriminatory than either MLVA or REA, yet this method established C. difficile genetic lineage. MLVA was highly discriminatory and demonstrated relationships among the MLST genetic lineages and REA genotypes that were previously unrecognized. Several tcdC genotypes were specific to epidemic clones, highlighting the possible importance of toxin misregulation in C. difficile disease pathogenesis. This study demonstrates that a combination of MLST and MLVA may prove useful for the investigation and surveillance of emergent C. difficile clones of global public health concern.

Injudicious antibiotic use leading to fulminating Clostridium difficile infection: a case report

The case illustrates the myriad of fulminating complications due to Clostridium difficile infection in a previously healthy individual without any risk factors. Community acquired Clostridium difficile infection can occur even many weeks after the course of broad spectrum antibiotics. There is no definitive pattern or guidelines to predict who would develop the fulminating complications.

Comparison of nine commercially available Clostridium difficile toxin detection assays, a real-time PCR assay for C. difficile tcdB, and a glutamate dehydrogenase detection assay to cytotoxin testing and cytotoxigenic culture methods

The continuing rise in the incidence of Clostridium difficile infection is a cause for concern, with implications for patients and health care systems. Laboratory diagnosis largely relies on rapid toxin detection kits, although assays detecting alternative targets, including glutamate dehydrogenase (GDH) and toxin genes, are now available. Six hundred routine diagnostic diarrheal samples were tested prospectively using nine commercial toxin detection assays, cytotoxin assay (CYT), and cytotoxigenic culture (CYTGC) and retrospectively using a GDH detection assay and PCR for the toxin B gene. The mean sensitivity and specificity for toxin detection assays were 82.8% (range, 66.7 to 91.7%) and 95.4% (range, 90.9 to 98.8%), respectively, in comparison with CYT and 75.0% (range, 60.0 to 86.4%) and 96.1% (91.4 to 99.4%), respectively, in comparison with CYTGC. The sensitivity and specificity of the GDH assay were 90.1% and 92.9%, respectively, compared to CYT and 87.6% and 94.3%, respectively, compared to CYTGC. The PCR assay had the highest sensitivity of all the tests in comparison with CYT (92.2%) and CYTGC (88.5%), and the specificities of the PCR assay were 94.0% and 95.4% compared to CYT and CYTGC, respectively. All kits had low positive predictive values (range, 48.6 to 86.8%) compared with CYT, assuming a positive sample prevalence of 10% (representing the hospital setting), which compromises the clinical utility of single tests for the laboratory diagnosis of C. difficile infection. The optimum rapid single test was PCR for toxin B gene, as this had the highest negative predictive value. Diagnostic algorithms that optimize test combinations for the laboratory diagnosis of C. difficile infection need to be defined.

Characterisation of Clostridium difficile isolates by slpA and tcdC gene sequencing

The genotyping of Clostridium difficile is generally performed by the analysis of fragment- or amplification-length polymorphism by pulsed field gel electrophoresis (PFGE) or polymerase chain reaction (PCR) ribotyping. However, sequence-based methods allow typing technique standardisation and data comparison. In the present study 100 C. difficile isolates, obtained from various institutions in the state of Saarland, Germany, were prospectively analyzed by surface layer protein A single locus sequence typing (slpAST). A high proportion (52%) of isolates attributable to ribotype 027 (RT027) was found indicating that the new outbreak strain has become endemic, at least in parts of Germany. RT027 strains displayed characteristic mutations of the potential toxin repressor gene tcdC and antibiotic resistance to macrolides and fluoroquinolones. C. difficile isolates attributable to ribotypes RT001 (27%), RT014/066 (5%), RT078 (4%), to the smz genotype (3%), and to more sporadic genotypes were also identified. Overall, the prevalence of strains with resistance to macrolides or fluoroquinolones was >80%. slpAST allows the comprehensive identification of C. difficile strains by global data comparison, exemplified here by our identification of smz strains previously identified by slpAST of a Japanese outbreak. In conclusion, slpAST appears to be a powerful discriminative tool for the straightforward, standardised genotyping of C. difficile isolates.

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

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

Examination of potential mechanisms to explain the association between proton pump inhibitors and Clostridium difficile infection

Proton pump inhibitors (PPIs) have been associated with Clostridium difficile infection (CDI) in several recent studies. However, other studies have not shown this association, and the mechanism by which PPIs might promote CDI has not been elucidated. We hypothesized two possible mechanisms of causation: first, by raising pH, PPIs may prevent gastric contents from killing C. difficile spores; second, gastric contents of PPI-treated patients may promote germination and outgrowth of C. difficile spores. Survival rates of spores from six different strains of C. difficile in acidic gastric contents were assessed using quantitative cultures on selective media. Germination and outgrowth of spores were assessed by heat shock at 80 degrees C, phase-contrast microscopy, and ethanol shock after incubation for 24 h in the gastric contents of patients and in the gastric, small intestinal, and cecal contents of mice. C. difficile spores survived and remained dormant in nonbilious gastric contents with acidic pH. Germination did not occur in unmodified gastric contents of patients but did occur with the addition of taurocholic acid and amino acids. In mice, germination did not occur in gastric contents but did occur in small intestinal and cecal contents. In summary, C. difficile spores survived in acidic gastric contents and did not undergo germination and outgrowth in gastric contents, probably due to lack of essential germinants, such as taurocholic acid. Our results suggest that the effects of PPIs in the stomach do not contribute to the pathogenesis of CDI.

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.

Diagnostic trends in Clostridium difficile detection in Finnish microbiology laboratories

Due to increased interest directed to Clostridium difficile-associated infections, a questionnaire survey of laboratory diagnostics of toxin-producing C. difficile was conducted in Finland in June 2006. Different aspects pertaining to C. difficile diagnosis, such as requests and criteria used for testing, methods used for its detection, yearly changes in diagnostics since 1996, and the total number of investigations positive for C. difficile in 2005, were asked in the questionnaire, which was sent to 32 clinical microbiology laboratories, including all hospital-affiliated and the relevant private clinical microbiology laboratories in Finland. The situation was updated by phone and email correspondence in September 2008. In June 2006, 28 (88%) laboratories responded to the questionnaire survey; 24 of them reported routinely testing requested stool specimens for C. difficile. Main laboratory methods included toxin detection (21/24; 88%) and/or anaerobic culture (19/24; 79%). In June 2006, 18 (86%) of the 21 laboratories detecting toxins directly from feces, from the isolate, or both used methods for both toxin A (TcdA) and B (TcdB), whereas only one laboratory did so in 1996. By September 2008, all of the 23 laboratories performing diagnostics for C. difficile used methods for both TcdA and TcdB. In 2006, the number of specimens processed per 100,000 population varied remarkably between different hospital districts. In conclusion, culturing C. difficile is common and there has been a favorable shift in toxin detection practice in Finnish clinical microbiology laboratories. However, the variability in diagnostic activity reported in 2006 creates a challenge for national monitoring of the epidemiology of C. difficile and related diseases.

Clostridium difficile strains from community-associated infections

Clostridium difficile isolates from presumed community-associated infections (n = 92) were characterized by toxinotyping, pulsed-field gel electrophoresis, tcdC and cdtB PCR, and antimicrobial susceptibility. Nine toxinotypes (TOX) and 31 PFGE patterns were identified. TOX 0 (48, 52%), TOX III (18, 20%), and TOX V (9, 10%) were the most common; three isolates were nontoxigenic.

The clinical safety of long-term lansoprazole for the maintenance of healed erosive oesophagitis

BACKGROUND

The clinical safety of long-term lansoprazole therapy for the maintenance of healed erosive oesophagitis has not been extensively studied in clinical trials.

AIM

To assess the long-term clinical safety of dose-titrated lansoprazole as maintenance therapy for up to 82 months in subjects with healed erosive oesophagitis.

METHODS

Clinical safety was assessed by monitoring adverse events (AEs), laboratory data including serum gastrin levels, and endoscopy.

RESULTS

Mean duration (+/- s.d.) of lansoprazole treatment during the titrated open-label period was 56 +/- 24 months (range <1-82 months). Overall, 189 of 195 (97%) subjects experienced a total of 2825 treatment-emergent AEs. Most AEs occurred during the first year of treatment, were mild-to-moderate in severity and resolved while on treatment. Of 155 serious AEs (in 74 subjects), only two (colitis and rectal haemorrhage in one subject) were considered treatment-related. Sixty-nine of 195 subjects (35%) experienced 187 treatment-related AEs, with diarrhoea (10%), headache (8%) and abdominal pain (6%) being the most common. Gastrin levels > or = 400 pg/mL were seen in 9% of subjects; hypergastrinemia was not associated with gastro-intestinal AEs or nodules/polyps.

CONCLUSIONS

Lansoprazole maintenance therapy for up to 6 years is safe and well tolerated in subjects with healed erosive oesophagitis.

Treatment of Clostridium difficile-associated disease

Clostridium difficile infection is an increasing burden to the health care system, totaling more than $1 billion/year in the United States. Treatment of patients with C difficile infection with metronidazole or vancomycin reduces morbidity and mortality, although the number of patients that do not respond to metronidazole is increasing. Despite initial response rates of greater than 90%, 15%-30% of patients have a relapse in symptoms after successful initial therapy, usually in the first few weeks after treatment is discontinued. Failure to develop specific antibody response has recently been identified as a critical factor in recurrence. The review discusses the different management strategies for initial and recurrent symptomatic C difficile infections.

Proton pump inhibitor use and enteric infections

Proton pump inhibitors (PPIs) and H2 receptor antagonists (H2RAs) are very commonly prescribed drugs and are routinely used in the chronic management of gastro-esophageal reflux disease. Concerns have been raised about the possible association of PPIs with enteric infections. This article reviews the studies that have examined the associations of proton pump inhibitors in particular, and enteric infections.

Patterns of antibiotic use and risk of hospital admission because of Clostridium difficile infection

BACKGROUND

Previous observations have indicated that infection with Clostridium difficile occurs almost exclusively after exposure to antibiotics, but more recent observations have suggested that prior antibiotic exposure may be less frequent among cases of community-acquired disease.

METHODS

We used 2 linked health databases to perform a matched, nested case-control study of elderly patients admitted to hospital with community-acquired C. difficile infection. For each of 836 cases among people 65 years of age or older, we selected 10 controls. We determined the proportion of cases that occurred without prior antibiotic exposure and estimated the risk related to exposure to different antibiotics and the duration of increased risk.

RESULTS

Of the 836 cases, 442 (52.9%) had no exposure to antibiotics in the 45-day period before the index date, and 382 (45.7%) had no exposure in the 90-day period before the index date. Antibiotic exposure was associated with a rate ratio (RR) of 10.6 (95% confidence interval [CI] 8.9-12.8). Clindamycin (RR 31.8, 95% CI 17.6-57.6), cephalosporins (RR 14.9, 95% CI 10.9-20.3) and gatifloxacin (RR 16.7, 95% CI 8.3-33.6) were associated with the highest risk. The RR for C. difficile infection associated with antibiotic exposure declined from 15.4 (95% CI 12.2-19.3) by about 20 days after exposure to 3.2 (95% CI 2.0-5.0) after 45 days. Use of a proton pump inhibitor was associated with increased risk (RR 1.6, 95% CI 1.3-2.0), as were concurrent diagnoses of inflammatory bowel disease (RR 4.1, 95% CI 2.6-6.6), irritable bowel syndrome (RR 3.4, 95% CI 2.3-5.0) and renal failure (RR 1.7, 95% CI 1.2-2.2).

INTERPRETATION

Community-acquired C. difficile infection occurred in a substantial proportion of individuals with no recent exposure to antibiotics. Among patients who had been exposed to antibiotics, the risk declined markedly by 45 days after discontinuation of use.

Patterns of antibiotic use and risk of hospital admission because of Clostridium difficile infection

BACKGROUND

Previous observations have indicated that infection with Clostridium difficile occurs almost exclusively after exposure to antibiotics, but more recent observations have suggested that prior antibiotic exposure may be less frequent among cases of community-acquired disease.

METHODS

We used 2 linked health databases to perform a matched, nested case-control study of elderly patients admitted to hospital with community-acquired C. difficile infection. For each of 836 cases among people 65 years of age or older, we selected 10 controls. We determined the proportion of cases that occurred without prior antibiotic exposure and estimated the risk related to exposure to different antibiotics and the duration of increased risk.

RESULTS

Of the 836 cases, 442 (52.9%) had no exposure to antibiotics in the 45-day period before the index date, and 382 (45.7%) had no exposure in the 90-day period before the index date. Antibiotic exposure was associated with a rate ratio (RR) of 10.6 (95% confidence interval [CI] 8.9-12.8). Clindamycin (RR 31.8, 95% CI 17.6-57.6), cephalosporins (RR 14.9, 95% CI 10.9-20.3) and gatifloxacin (RR 16.7, 95% CI 8.3-33.6) were associated with the highest risk. The RR for C. difficile infection associated with antibiotic exposure declined from 15.4 (95% CI 12.2-19.3) by about 20 days after exposure to 3.2 (95% CI 2.0-5.0) after 45 days. Use of a proton pump inhibitor was associated with increased risk (RR 1.6, 95% CI 1.3-2.0), as were concurrent diagnoses of inflammatory bowel disease (RR 4.1, 95% CI 2.6-6.6), irritable bowel syndrome (RR 3.4, 95% CI 2.3-5.0) and renal failure (RR 1.7, 95% CI 1.2-2.2).

INTERPRETATION

Community-acquired C. difficile infection occurred in a substantial proportion of individuals with no recent exposure to antibiotics. Among patients who had been exposed to antibiotics, the risk declined markedly by 45 days after discontinuation of use.