Antibiotic-associated diarrhoea and Clostridium difficile in the community

Antibiotics Not Associated with Shorter Duration or Reduced Severity of Acute Lower Respiratory Tract Infection

BACKGROUND

Antibiotic use remains common for the treatment of lower respiratory tract infections. The objective of this study was to evaluate the impact of antibiotic use on the duration and severity of acute lower respiratory tract infection (LRTI).

PARTICIPANTS

Adult patients presenting to US primary or urgent care sites with a chief complaint of cough and symptoms consistent with LRTI.

MAIN MEASURES

Collected data included demographics, comorbidities, symptoms, and 48 viral and bacterial respiratory pathogens by PCR. Severity of signs/symptoms was reported for up to 28 days using diaries and text messages. Interpolation was used where data were missing.

KEY RESULTS

Of 718 patients with baseline data, 29% had an antibiotic prescribed at baseline. The most common antibiotics were amoxicillin-clavulanate, azithromycin, doxycycline, and amoxicillin in 85% of patients. Provision of an antibiotic had no effect on the duration or overall severity of cough, including in patients with viral, bacterial, and mixed infections. Receipt of an antibiotic did reduce the likelihood of a follow-up visit (14.1% vs 8.2%, aOR 0.47, 95% CI 0.26-0.84), perhaps by removing the motivation of getting an antibiotic at a follow-up visit. However, they were also more likely to receive a systemic corticosteroid (31.9% vs 4.5%, p < 0.001) and were also more likely to receive an albuterol inhaler (22.7% vs 7.6%, p < 0.001). Patients believed that receiving an antibiotic would reduce the duration of their illness by nearly 4 days.

CONCLUSIONS

In this large prospective study in the US primary and urgent care setting, antibiotics had no measurable impact on the severity or duration of cough due to acute LRTI. Patients had unrealistic expectations regarding the duration of LRTI and the effect of antibiotics which should be the target of antibiotic stewardship efforts.

Bifidobacterium animalis subsp. lactis BB-12 Protects against Antibiotic-Induced Functional and Compositional Changes in Human Fecal Microbiome

The administration of broad-spectrum antibiotics is often associated with antibiotic-associated diarrhea (AAD), and impacts gastrointestinal tract homeostasis, as evidenced by the following: (a) an overall reduction in both the numbers and diversity of the gut microbiota, and (b) decreased short-chain fatty acid (SCFA) production. Evidence in humans that probiotics may enhance the recovery of microbiota populations after antibiotic treatment is equivocal, and few studies have addressed if probiotics improve the recovery of microbial metabolic function. Our aim was to determine if Bifidobacterium animalis subsp. lactis BB-12 (BB-12)-containing yogurt could protect against antibiotic-induced fecal SCFA and microbiota composition disruptions. We conducted a randomized, allocation-concealed, controlled trial of amoxicillin/clavulanate administration (days 1-7), in conjunction with either BB-12-containing or control yogurt (days 1-14). We measured the fecal levels of SCFAs and bacterial composition at baseline and days 7, 14, 21, and 30. Forty-two participants were randomly assigned to the BB-12 group, and 20 participants to the control group. Antibiotic treatment suppressed the fecal acetate levels in both the control and probiotic groups. Following the cessation of antibiotics, the fecal acetate levels in the probiotic group increased over the remainder of the study and returned to the baseline levels on day 30 (-1.6% baseline), whereas, in the control group, the acetate levels remained suppressed. Further, antibiotic treatment reduced the Shannon diversity of the gut microbiota, for all the study participants at day 7. The magnitude of this change was larger and more sustained in the control group compared to the probiotic group, which is consistent with the hypothesis that BB-12 enhanced microbiota recovery. There were no significant baseline clinical differences between the two groups. Concurrent administration of amoxicillin/clavulanate and BB-12 yogurt, to healthy subjects, was associated with a significantly smaller decrease in the fecal SCFA levels and a more stable taxonomic profile of the microbiota over time than the control group.

The Intestinal Microbiota: Impacts of Antibiotics Therapy, Colonization Resistance, and Diseases

Trillions of microbes exist in the human body, particularly the gastrointestinal tract, coevolved with the host in a mutually beneficial relationship. The main role of the intestinal microbiome is the fermentation of non-digestible substrates and increased growth of beneficial microbes that produce key antimicrobial metabolites such as short-chain fatty acids, etc., to inhibit the growth of pathogenic microbes besides other functions. Intestinal microbiota can prevent pathogen colonization through the mechanism of colonization resistance. A wide range of resistomes are present in both beneficial and pathogenic microbes. Giving antibiotic exposure to the intestinal microbiome (both beneficial and hostile) can trigger a resistome response, affecting colonization resistance. The following review provides a mechanistic overview of the intestinal microbiome and the impacts of antibiotic therapy on pathogen colonization and diseases. Further, we also discuss the epidemiology of immunocompromised patients who are at high risk for nosocomial infections, colonization and decolonization of multi-drug resistant organisms in the intestine, and the direct and indirect mechanisms that govern colonization resistance to the pathogens.

A Clinical Decision Analysis for Use of Antibiotic Prophylaxis for Nonabsorbable Nasal Packing

OBJECTIVE

Nonabsorbable nasal packing is often placed for the treatment of epistaxis or after sinonasal or skull base surgery. Antibiotics are often prescribed to prevent toxic shock syndrome (TSS), a rare, potentially fatal occurrence. However, the risk of TSS must be balanced against the major risk of antibiotic use, specifically Clostridium difficile colitis (CDC). The purpose of this study is to evaluate in terms of cost-effectiveness whether antibiotics should be prescribed when nasal packing is placed.

STUDY DESIGN

A clinical decision analysis was performed using a Markov model to evaluate whether antibiotics should be given.

SETTING

Patients with nonabsorbable nasal packing placed.

METHODS

Utility scores, probabilities, and costs were obtained from the literature. We assess the cost-effectiveness of antibiotic use when the risk of community-acquired CDC is balanced against the risk of TSS from nasal packing. Sensitivity analysis was performed for assumptions used in the model.

RESULTS

The incremental cost-effectiveness ratio for antibiotic use was 334,493 US dollars (USD)/quality-adjusted life year (QALY). Probabilistic sensitivity analysis showed that not prescribing antibiotics was cost-effective in 98.0% of iterations at a willingness to pay of 50,000 USD/QALY. Sensitivity analysis showed that when the risk of CDC from antibiotics was greater than 910/100,000 or when the incidence of TSS after nasal packing was less than 49/100,000 cases, the decision to withhold antibiotics was cost-effective.

CONCLUSIONS

Routine antibiotic prophylaxis in the setting of nasal packing is not cost-effective and should be reconsidered. Even if antibiotics are assumed to prevent TSS, the risk of complications from antibiotic use is of greater consequence.

LEVEL OF EVIDENCE

3a.

Antibiotics as Major Disruptors of Gut Microbiota

Advances in culture-independent research techniques have led to an increased understanding of the gut microbiota and the role it plays in health and disease. The intestine is populated by a complex microbial community that is organized around a network of metabolic interdependencies. It is now understood that the gut microbiota is vital for normal development and functioning of the human body, especially for the priming and maturation of the adaptive immune system. Antibiotic use can have several negative effects on the gut microbiota, including reduced species diversity, altered metabolic activity, and the selection of antibiotic-resistant organisms, which in turn can lead to antibiotic-associated diarrhea and recurrent Clostridioides difficile infections. There is also evidence that early childhood exposure to antibiotics can lead to several gastrointestinal, immunologic, and neurocognitive conditions. The increase in the use of antibiotics in recent years suggests that these problems are likely to become more acute or more prevalent in the future. Continued research into the structure and function of the gut microbiota is required to address this challenge.

Beneficial effects of Saccharomyces boulardii CNCM I-745 on clinical disorders associated with intestinal barrier disruption

Intestinal barrier defects lead to "leaky gut syndrome", defined as an increase in intestinal permeability that allows the passage of luminal content into intestinal tissue and the bloodstream. Such a compromised intestinal barrier is the main factor underlying the pathogenesis of inflammatory bowel disease, but also commonly occurs in various systemic diseases such as viral infections and metabolic syndrome. The non-pathogenic yeast Saccharomyces boulardii CNCM I-745 has demonstrated its effectiveness as a probiotic in the prevention and treatment of antibiotic-associated, infectious and functional diarrhea. Via multiple mechanisms of action implicated in intestinal barrier function, S. boulardii has beneficial effects on altered intestinal microbiota and epithelial barrier defects in different pathologies. The well-studied probiotic yeast S. boulardii plays a crucial role in the preservation and/or restoration of intestinal barrier function in multiple disorders. This could be of major interest in diseases characterized by alterations in intestinal barrier function.

The Microbiome and Tuberculosis: Early Evidence for Cross Talk

Tuberculosis (TB) is an ancient infectious disease of humans that has been extensively studied both clinically and experimentally. Although susceptibility to Mycobacterium tuberculosis infection is clearly influenced by factors such as nutrition, immune status, and both mycobacterial and host genetics, the variable pathogenesis of TB in infected individuals remains poorly understood.

Tuberculosis (TB) is an ancient infectious disease of humans that has been extensively studied both clinically and experimentally. Although susceptibility to Mycobacterium tuberculosis infection is clearly influenced by factors such as nutrition, immune status, and both mycobacterial and host genetics, the variable pathogenesis of TB in infected individuals remains poorly understood. During the past two decades, it has become clear that the microbiota—the trillion organisms that reside at mucosal surfaces within and on the body—can exert a major influence on disease outcome through its effects on host innate and adaptive immune function and metabolism. This new recognition of the potentially pleiotropic participation of the microbiome in immune responses has raised the possibility that the microbiota may influence M. tuberculosis infection and/or disease. Similarly, treatment of TB may alter the healthy steady-state composition and function of the microbiome, possibly affecting treatment outcome in addition to other host physiological parameters. Herein, we review emerging evidence for how the microbiota may influence the transition points in the life cycle of TB infection, including (i) resistance to initial infection, (ii) initial infection to latent tuberculosis (LTBI), (iii) LTBI to reactivated disease, and (iv) treatment to cure. A major goal of this review is to frame questions to guide future scientific and clinical studies in this largely unexplored but increasingly important area of TB research.

Epidemiological and genomic characterization of community-acquired Clostridium difficile infections

BACKGROUND

Clostridium difficile infection (CDI) is a major cause of morbidity and mortality in North America and Europe. The aim of this study was to identify epidemiologically-confirmed cases of community-acquired (CA)-CDI in a large North American urban center and analyze isolates using multiple genetic and phenotypic methods.

METHODS

Seventy-eight patients testing positive for C. difficile from outpatient clinics were further investigated by telephone questionnaire. CA-CDI isolates were characterized by antibiotic susceptibility, pulsed-field gel electrophoresis and whole genome sequencing. CA-CDI was defined as testing positive greater than 12 weeks following discharge or no previous hospital admission in conjunction with positive toxin stool testing.

RESULTS

51.3% (40/78) of the patients in this study were found to have bona fide CA-CDI. The majority of patients were female (71.8% vs. 28.2%) with 50-59 years of age being most common (21.8%). Common co-morbidities included ulcerative colitis (1/40; 2.5%), Crohn's disease (3/40; 7.5%), celiac disease (2/40; 5.0%) and irritable bowel syndrome (8/40; 20.0%). However, of 40 patients with CA-CDI, 9 (29.0%) had been hospitalized between 3 and 6 months prior and 31 (77.5%) between 6 and 12 months prior. The hypervirulent North American Pulostype (NAP) 1-like (9/40; 22.5%) strain was the most commonly identified pulsotype. Whole genome sequencing of CA-CDI isolates confirmed that NAP 1-like pulsotypes are commonplace in CA-CDI. From a therapeutic perspective, there was universal susceptibility to metronidazole and vancomycin.

CONCLUSIONS

All CA-CDI cases had some history of hospitalization if the definition were modified to health care facility exposure in the last 12 months and is supported by the genomic analysis. This raises the possibility that even CA-CDI may have nosocomial origins.

Prolonged Mechanical Ventilation Assistance Interacts Synergistically with Carbapenem for Clostridium difficile Infection in Critically Ill Patients

Objectives: Interactions between mechanical ventilation (MV) and carbapenem interventions were investigated for the risk of Clostridium difficile infection (CDI) in critically ill patients undergoing concurrent carbapenem therapy. Methods: Taiwan’s National Intensive Care Unit Database (NICUD) was used in this analytical, observational, and retrospective study. We analyzed 267,871 intubated patients in subgroups based on the duration of MV support: 7–14 days (n = 97,525), 15–21 days (n = 52,068), 22–28 days (n = 35,264), and 29–60 days (n = 70,021). The primary outcome was CDI. Results: Age (>75 years old), prolonged MV assistance (>21 days), carbapenem therapy (>15 days), and high comorbidity scores were identified as independent risk factors for developing CDI. CDI risk increased with longer MV support. The highest rate of CDI was in the MV 29–60 days subgroup (adjusted hazard ratio (AHR) = 2.85; 95% confidence interval (CI) = 1.46–5.58; p < 0.02). Moreover, higher CDI rates correlated with the interaction between MV and carbapenem interventions; these CDI risks were increased in the MV 15–21 days (AHR = 2.58; 95% CI = 1.12–5.91) and MV 29–60 days (AHR = 4.63; 95% CI = 1.14–10.03) subgroups than in the non-MV and non-carbapenem subgroups. Conclusions: Both MV support and carbapenem interventions significantly increase the risk that critically ill patients will develop CDI. Moreover, prolonged MV support and carbapenem therapy synergistically induce CDI. These findings provide new insights into the role of MV support in the development of CDI.

Clostridium difficile, the Difficult "Kloster" Fuelled by Antibiotics

Clostridium difficile is normally present in low numbers in a healthy adult gastro-intestinal tract (GIT). Drastic changes in the microbial population, e.g., dysbiosis caused by extensive treatment with antibiotics, stimulates the growth of resistant strains and the onset of C. difficile infection (CDI). Symptoms of infection varies from mild diarrhea to colitis (associated with dehydration and bleeding), pseudomembranous colitis with yellow ulcerations in the mucosa of the colon, to fulminant colitis (perforation of the gut membrane), and multiple organ failure. Inflamed epithelial cells and damaged mucosal tissue predisposes the colon to other opportunistic pathogens such as Clostridium perfringens, Staphylococcus aureus, Klebsiella oxytoca, Candida spp., and Salmonella spp. This may lead to small intestinal bacterial overgrowth (SIBO), sepsis, toxic megacolon, and even colorectal cancer. Many stains of C. difficile are resistant to metronidazole and vancomycin. Vaccination may be an answer to CDI, but requires more research. Success in treatment with probiotics depends on the strains used. Oral or rectal fecal transplants are partly effective, as spores in the small intestine may germinate and colonize the colon. The effect of antibiotics on C. difficile and commensal gut microbiota is summarized and changes in gut physiology are discussed. The need to search for non-antibiotic methods in the treatment of CDI and C. difficile-associated disease (CDAD) is emphasized.

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.

A Prospective, Case Control Study Evaluating the Association between Clostridium Difficile Toxins in the Colon of Neonatal Swine and Gross and Microscopic Lesions

Clostridium difficile infection in swine has most often been described in suckling pigs, where it has been associated with mesocolonic edema and typhlocolitis. This prospective study was designed to assess the correlation between the presence of C. difficile toxins (TCd) in the colon contents of neonatal pigs and a number of parameters, including gross evidence of diarrhea, mesocoloninc edema, typhlitis, and colitis. C. difficile was isolated from 51% (66/129) of large intestines and TCd was detected in the colon contents of 50% (65/129) of the piglets. Fifty-eight percent (38/65) of TCd-positive piglets had normal to pelleted colon and rectal contents, whereas 75% (48/64) of TCd-negative pigs had gross evidence of diarrhea. Clostridium difficile toxin-positive animals were significantly more likely to have normal to pelleted feces. Edema of the mesocolon was observed in 38/65 (59%) of TCd-positive piglets. Because a high number of TCd-positive piglets (41%) lacked edema of the mesocolon and a high number of TCd-negative pigs had mesocolonic edema (51%), a statistically significant association between TCd and mesocolonic edema was not identified. Seventy-five percent (49/65) of TCd-positive piglets had colitis and 47/65 (72%) had typhlitis. The association between TCd and both colitis and typhlitis was statistically significant. Apparently healthy piglets were obtained from 5 separate sites. Because TCd was detected in the colon contents of 23/29 (79%) apparently healthy piglets obtained from 5 separate sites, and 70% of TCd-positive control pigs had colitis, C. difficile may represent an important subclinical issue in neonatal swine.

Association between NSAIDs and Clostridium difficile-Associated Diarrhea: A Systematic Review and Meta-Analysis

Objective. Clostridium difficile infection is a leading cause of nosocomial diarrhea in developed countries. Studies evaluating the associations of increased risk of community-acquired CDAD and the use of nonsteroidal anti-inflammatory drugs (NSAIDs) have yielded inconclusive results. We conducted a systematic review and meta-analysis to compare the odds of NSAID exposure in patients with CDAD versus patients without CDAD in both community-based and healthcare-associated settings. Methods. Relevant observational studies indexed in PubMed/MEDLINE and EMBASE up to February 2015 were analyzed and data were extracted from nine studies. Of these, eight studies were included in the meta-analysis. Results. A search of the databases resulted in 987 articles. The nine studies from which data were extracted involved over 39,000 subjects. The pooled odds ratio for history of NSAID use in participants with CDAD compared with controls was 1.41 (95% CI 1.06-1.87; p < 0.01), indicating a significant increased odds of CDAD among patients exposed to NSAIDs. Conclusions. To the best of our knowledge, this is the first study of its nature to demonstrate the association between the use of NSAIDs and increased risk of CDAD. Further studies to evaluate if any specific types of NSAIDs can increase the risk of CDAD are warranted.

Inhibiting Microbial Toxins Using Plant-Derived Compounds and Plant Extracts

Many pathogenic bacteria and fungi produce potentially lethal toxins that cause cytotoxicity or impaired cellular function either at the site of colonization or other locations in the body through receptor-mediated interactions. Various factors, including biotic and abiotic environments, competing microbes, and chemical cues affect toxin expression in these pathogens. Recent work suggests that several natural compounds can modulate toxin production in pathogenic microbes. However, studies explaining the mechanistic basis for their effect are scanty. This review discusses the potential of various plant-derived compounds for reducing toxin production in foodborne and other microbes. In addition, studies highlighting their anti-toxigenic mechanism(s) are discussed.

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.

Potential sources of Clostridium difficile in human infection

The view of Clostridium difficile infection as a hospital-acquired infection transmitted only by symptomatic patients is changing. Although C difficile is present in food for human consumption, food-borne infection caused by C difficile has never been confirmed. More information on the infective dose and the level of contamination is needed to determine the risk for food-borne exposure to C difficile in humans. The emergence of C difficile polymerase chain reaction (PCR) ribotype 078 in humans is epidemiologically linked to its presence in piglets and calves and their environment, suggesting zoonotic transmission.

[NET WATER TRANSPORT VIA RAT COLON EPITELIUM UNDER THE EXPERIMENTAL DYSBIOSIS]

The aim of the present study was to investigate the effect of cephalosporin antibiotic ceftriaxone (50 mg/kg, i/m) and mac- rolide antibiotic azithromycin (15 mg/kg, per.os.) on net water transport across rat colonic epithelium. Study was done on male Wistar rats (180-250 g). Azithromycin or ceftriaxone was injected daily for 5 days. Net water transport was evaluated on the 6th day by isolated colonic loop perfusion technique in vivo on anaesthetized rats. Treatment with azithromycin increased 2,4-fold the absorption of water, while ceftriaxone caused decrease 1,9-fold water absorption. The antibiotics treatment within five days didn't change the composition of the fecal and colonic parietal microbiota. Azithromycin-induced increase in water absorption was associated with upregulation of AQP 8 water channel expression (P < 0.05) in colonic mucosa. Ceftriaxone treatment didn't change protein level of AQP8 but induced pro-inflammatory changes in colonic mucosa structure and mast cells degranulation. We showed for the first time the opposite effects ofmacrolide and cephalosporin antibiotics on net water transport across rat colonic epithelium.

Gastrointestinal microbiota-mediated control of enteric pathogens

The gastrointestinal (GI) microbiota is a complex community of microorganisms residing within the mammalian gastrointestinal tract. The GI microbiota is vital to the development of the host immune system and plays a crucial role in human health and disease. The composition of the GI microbiota differs immensely among individuals yet specific shifts in composition and diversity have been linked to inflammatory bowel disease, obesity, atopy, and susceptibility to infection. In this review, we describe the GI microbiota and its role in enteric diseases caused by pathogenic Escherichia coli, Salmonella enterica, and Clostridium difficile. We discuss the central role of the GI microbiota in protective immunity, resistance to enteric pathogens, and resolution of enteric colitis.

Effects of antibiotics on human microbiota and subsequent disease

Although antibiotics have significantly improved human health and life expectancy, their disruption of the existing microbiota has been linked to significant side effects such as antibiotic-associated diarrhea, pseudomembranous colitis, and increased susceptibility to subsequent disease. By using antibiotics to break colonization resistance against Clostridium, Salmonella, and Citrobacter species, researchers are now exploring mechanisms for microbiota-mediated modulation against pathogenic infection, revealing potential roles for different phyla and family members as well as microbiota-liberated sugars, hormones, and short-chain fatty acids in regulating pathogenicity. Furthermore, connections are now being made between microbiota dysbiosis and a variety of different diseases such as rheumatoid arthritis, inflammatory bowel disease, type 1 diabetes, atopy, and obesity. Future advances in the rapidly developing field of microbial bioinformatics will enable researchers to further characterize the mechanisms of microbiota modulation of disease and potentially identify novel therapeutics against disease.

Community-acquired Clostridium difficile infection: an increasing public health threat

There has been a startling shift in the epidemiology of Clostridium difficile infection over the last decade worldwide, and it is now increasingly recognized as a cause of diarrhea in the community. Classically considered a hospital-acquired infection, it has now emerged in populations previously considered to be low-risk and lacking the traditional risk factors for C. difficile infection, such as increased age, hospitalization, and antibiotic exposure. Recent studies have demonstrated great genetic diversity for C. difficile, pointing toward diverse sources and a fluid genome. Environmental sources like food, water, and animals may play an important role in these infections, apart from the role symptomatic patients and asymptomatic carriers play in spore dispersal. Prospective strain typing using highly discriminatory techniques is a possible way to explore the suspected diverse sources of C. difficile infection in the community. Patients with community-acquired C. difficile infection do not necessarily have a good outcome and clinicians should be aware of factors that predict worse outcomes in order to prevent them. This article summarizes the emerging epidemiology, risk factors, and outcomes for community-acquired C. difficile infection.

Epidemiology and outcomes of community-acquired Clostridium difficile infections in Medicare beneficiaries

BACKGROUND

The incidence of community-acquired Clostridium difficile (CACD) is increasing in the United States. Many CACD infections occur in the elderly, who are predisposed to poor outcomes. We aimed to describe the epidemiology and outcomes of CACD in a nationally representative sample of Medicare beneficiaries.

STUDY DESIGN

We queried a 5% random sample of Medicare beneficiaries (2009-2011 Part A inpatient and Part D prescription drug claims; n = 864,604) for any hospital admission with a primary ICD-9 diagnosis code for C difficile (008.45). We examined patient sociodemographic and clinical characteristics, preadmission exposure to oral antibiotics, earlier treatment with oral vancomycin or metronidazole, inpatient outcomes (eg, colectomy, ICU stay, length of stay, mortality), and subsequent admissions for C difficile.

RESULTS

A total of 1,566 (0.18%) patients were admitted with CACD. Of these, 889 (56.8%) received oral antibiotics within 90 days of admission. Few were being treated with oral metronidazole (n = 123 [7.8%]) or vancomycin (n = 13 [0.8%]) at the time of admission. Although 223 (14%) patients required ICU admission, few (n = 15 [1%]) underwent colectomy. Hospital mortality was 9%. Median length of stay among survivors was 5 days (interquartile range 3 to 8 days). One fifth of survivors were readmitted with C difficile, with a median follow-up time of 393 days (interquartile range 129 to 769 days).

CONCLUSIONS

Nearly half of the Medicare beneficiaries admitted with CACD have no recent antibiotic exposure. High mortality and readmission rates suggest that the burden of C difficile on patients and the health care system will increase as the US population ages. Additional efforts at primary prevention and eradication might be warranted.

Community-associated Clostridium difficile infection among older people in Tayside, Scotland, is associated with antibiotic exposure and care home residence: cohort study with nested case-control

OBJECTIVES

To estimate the risks of community-associated Clostridium difficile infection (CA-CDI) among the population aged ≥ 65 years associated with antibiotic exposure and care home residence.

POPULATION AND METHODS

We linked cases from a prospective study in Tayside, Scotland from 1 November 2008 to 31 October 2009 to population datasets to conduct a cohort study and a nested, matched (1 : 10 by age and gender) case-control study.

RESULTS

There were 79,039 eligible residents. CA-CDI incidence was 20.3/10,000 person years. In the cohort study, after adjustment, we found a significantly increasing risk of CA-CDI with increasing age and comorbidity, prior hospital admission, care home residence [hazard ratio (HR) 1.96, 95% CI 1.14-3.34] and baseline antibiotic exposure (1.94, 1.35-2.77). In separate adjusted models, '4C' antibiotics (clindamycin, co-amoxiclav, cephalosporins, ciprofloxacin; 2.75, 1.78-4.26) and fluoroquinolones (3.33, 1.95-5.67) had higher associated risks. We matched 62 CA-CDI cases without recent (prior 3 months) hospital admission to 620 controls. In adjusted logistic regression models, exposure to any antibiotics increased the risk of CA-CDI (OR 6.04, 95% CI 3.19-11.43). Exposure to 4C antibiotics or fluoroquinolones had higher associated risks: adjusted OR 11.60 (95% CI 5.57-24.15) and 13.04 (4.91-34.64), respectively. Risk of CA-CDI increased with cumulative antibiotic exposure. Subgroup analysis of 42 cases with C. difficile cultured and 420 controls amplified all associations between antibiotic exposure and CA-CDI. Care home residence independently increased the risk of CA-CDI in all models.

CONCLUSIONS

Our results have two important implications. First, they validate the classification of 4C antibiotics and fluoroquinolones in primary care as high risk for CA-CDI. Second, they demonstrate the importance of prior antibiotic exposure and place of residence for risk assessment by primary care prescribers.

Non-steroidal anti-inflammatory drugs and the risk of Clostridium difficile-associated disease

AIM

Several case reports have linked diclofenac, a non-steroidal anti-inflammatory drug (NSAID), with Clostridium difficile associated disease (CDAD). We assessed whether NSAID use in general, and diclofenac use in particular, is associated with an increased risk of CDAD.

METHODS

We used the United Kingdom's General Practice Research Database (GPRD) to conduct a population-based case-control study. All cases of CDAD occurring between 1994 and 2005 were identified and were matched to 10 controls each. Conditional logistic regression was used to estimate the odds ratio of CDAD associated with current NSAID use, adjusting for covariates.

RESULTS

We identified 1360 CDAD cases and 13 072 controls. We found an increased risk of CDAD associated with diclofenac (adjusted odds ratio (RR) 1.35, 95% confidence interval (CI) 1.10, 1.67). We did not observe an increased risk of CDAD with use of any other NSAID. No dose-response for diclofenac exposure was found. When we analyzed only patients who were not hospitalized in the year before the index date, we found diclofenac to have a similar effect on CDAD risk (adjusted RR 1.43, 95% CI 1.11, 1.84).

CONCLUSION

Diclofenac use is associated with a modest increase in the risk of CDAD. In patients at risk of CDAD, other NSAIDs could be prescribed.

Overview of strategies for overcoming the challenge of antimicrobial resistance

The discovery of penicillin undoubtedly transformed the management of life-threatening bacterial infections. However, a less comfortable aspect of the antibiotic revolution was that within 10 years, over 80% of patients with acute bronchitis were receiving antibiotics without any evidence of clinical benefit. Antibiotic use inevitably causes collateral damage to the normal human flora and increases the risk of infection with antibiotic-resistant bacteria and Clostridium difficile. The twin aims of antibiotic stewardship are first to ensure effective treatment for patients with bacterial infection and second to provide convincing evidence and information to educate and support professionals and patients to reduce unnecessary use and minimize collateral damage. We review evidence of progress with these aims in Europe and nationally in Scotland.

Outcomes in community-acquired Clostridium difficile infection

BACKGROUND

Community-acquired Clostridium difficile infection (CA-CDI) is an increasingly appreciated condition. It is being described in populations lacking traditional predisposing factors that have been previously considered at low-risk for this infection. As most studies of CDI are hospital-based, outcomes in these patients are not well known.

AIM

To examine outcomes and their predictors in patients with CA-CDI.

METHODS

A sub-group analysis of a population-based epidemiological study of CDI in Olmsted county, Minnesota from 1991-2005 was performed. Data regarding outcomes, including severity, treatment response, need for hospitalisation and recurrence were analysed.

RESULTS

Of 157 CA-CDI cases, the median age was 50 years and 75.3% were female. Among all CA-CDI cases, 40% required hospitalisation, 20% had severe and 4.4% had severe-complicated infection, 20% had treatment failure and 28% had recurrent CDI. Patients who required hospitalisation were significantly older (64 years vs. 44 years, P < 0.001), more likely to have severe disease (33.3% vs. 11.7%, P = 0.001), and had higher mean Charlson comorbidity index scores (2.06 vs. 0.84, P = 0.001). They had similar treatment failure and recurrence rates as patients who did not require hospitalisation.

CONCLUSIONS

Community-acquired Clostridium difficile infection can be associated with complications and poor outcomes, including hospitalisation and severe Clostridium difficile infection. As the incidence of community-acquired Clostridium difficile infection increases, clinicians should be aware of risk factors (increasing age, comorbid conditions and disease severity) that predict the need for hospitalisation and complications in patients with community-acquired Clostridium difficile infection.

The epidemiology of community-acquired Clostridium difficile infection: a population-based study

OBJECTIVES

Clostridium difficile infection (CDI) is a common hospital-acquired infection with increasing incidence, severity, recurrence, and associated morbidity and mortality. There are emerging data on the occurrence of CDI in nonhospitalized patients. However, there is a relative lack of community-based CDI studies, as most of the existing studies are hospital based, potentially influencing the results by referral or hospitalization bias by missing cases of community-acquired CDI.

METHODS

To better understand the epidemiology of community-acquired C. difficile infection, a population-based study was conducted in Olmsted County, Minnesota, using the resources of the Rochester Epidemiology Project. Data regarding severity, treatment response, and outcomes were compared in community-acquired vs. hospital-acquired cohorts, and changes in these parameters, as well as in incidence, were assessed over the study period.

RESULTS

Community-acquired CDI cases accounted for 41% of 385 definite CDI cases. The incidence of both community-acquired and hospital-acquired CDI increased significantly over the study period. Compared with those with hospital-acquired infection, patients with community-acquired infection were younger (median age 50 years compared with 72 years), more likely to be female (76% vs. 60%), had lower comorbidity scores, and were less likely to have severe infection (20% vs. 31%) or have been exposed to antibiotics (78% vs. 94%). There were no differences in the rates of complicated or recurrent infection in patients with community-acquired compared with hospital-acquired infection.

CONCLUSIONS

In this population-based cohort, a significant proportion of cases of CDI occurred in the community. These patients were younger and had less severe infection than those with hospital-acquired infection. Thus, reports of CDI in hospitalized patients likely underestimate the burden of disease and overestimate severity.

The epidemiology of community-acquired Clostridium difficile infection: a population-based study

OBJECTIVES

Clostridium difficile infection (CDI) is a common hospital-acquired infection with increasing incidence, severity, recurrence, and associated morbidity and mortality. There are emerging data on the occurrence of CDI in nonhospitalized patients. However, there is a relative lack of community-based CDI studies, as most of the existing studies are hospital based, potentially influencing the results by referral or hospitalization bias by missing cases of community-acquired CDI.

METHODS

To better understand the epidemiology of community-acquired C. difficile infection, a population-based study was conducted in Olmsted County, Minnesota, using the resources of the Rochester Epidemiology Project. Data regarding severity, treatment response, and outcomes were compared in community-acquired vs. hospital-acquired cohorts, and changes in these parameters, as well as in incidence, were assessed over the study period.

RESULTS

Community-acquired CDI cases accounted for 41% of 385 definite CDI cases. The incidence of both community-acquired and hospital-acquired CDI increased significantly over the study period. Compared with those with hospital-acquired infection, patients with community-acquired infection were younger (median age 50 years compared with 72 years), more likely to be female (76% vs. 60%), had lower comorbidity scores, and were less likely to have severe infection (20% vs. 31%) or have been exposed to antibiotics (78% vs. 94%). There were no differences in the rates of complicated or recurrent infection in patients with community-acquired compared with hospital-acquired infection.

CONCLUSIONS

In this population-based cohort, a significant proportion of cases of CDI occurred in the community. These patients were younger and had less severe infection than those with hospital-acquired infection. Thus, reports of CDI in hospitalized patients likely underestimate the burden of disease and overestimate severity.

Increased health burden associated with Clostridium difficile diarrhoea in patients with inflammatory bowel disease

BACKGROUND

Clostridium difficile (C. difficile) infection in hospitals in developed countries continues to be a major public health hazard despite increased control measures including review of antibiotic policies and hygiene measures. Patients with colitis are thought to be particularly vulnerable to C. difficile associated diarrhoea (CDAD). Identifying the clinical burden among hospitalised patients admitted with inflammatory bowel disease is an essential first step towards identifying and treating severe C. difficile infection in such individuals.

AIM

To determine excess morbidity and in-hospital mortality associated with hospital acquired CDAD in patients with inflammatory bowel disease (IBD-CDAD-HAI) admitted to NHS hospitals in England compared with those admitted for inflammatory bowel disease alone.

METHODS

Time trends study of all admissions to NHS hospitals between 2002/03 and 2007/08. We developed case definitions for IBD-CDAD-HAI patients. The primary outcomes were in-hospital mortality and length of stay. The secondary outcome was gastrointestinal surgery.

RESULTS

Patients in the IBD-CDAD-HAI group were more likely to die in hospital (adjusted OR 6.32), had 27.9 days longer in-patient stays and higher gastrointestinal surgery rates (adjusted OR 1.87) than patients admitted for inflammatory bowel disease alone.

CONCLUSION

Patients with inflammatory bowel disease admitted to NHS hospitals in England with co-existent C. difficile infection are at risk of greater in-hospital mortality and morbidity than patients admitted for inflammatory bowel disease alone.

Protection against increased intestinal permeability and bacterial translocation induced by intestinal obstruction in mice treated with viable and heat-killed Saccharomyces boulardii

BACKGROUND

There are substantial evidences suggesting that probiotics can protect the gastrointestinal tract against inflammatory or infectious episodes. The effects of oral treatment with viable or heat-killed cells of Saccharomyces boulardii (Sb) on bacterial translocation, intestinal permeability, histological aspect of the ileum, and some immunological parameters were evaluated in a murine intestinal obstruction (IO) model.

RESULTS

Bacterial translocation and intestinal permeability in the IO group were significantly higher when compared to a Sham group (p < 0.05). Pretreatment with both viable and heat-killed S. boulardii prevented these increases, and the data obtained for IO + Sb and IO + heat-killed Sb groups were similar to those observed in the Sham group (p > 0.05). Histological analysis showed preservation of the ileum mucosa in mice that received both forms of the yeast when compared to the lesions observed in the IO group. The levels of serum interleukin (IL)-10 and intestinal secretory immunoglobulin A (sIgA) were higher in the animals that received both yeast treatments when compared to those from IO and Sham groups.

CONCLUSION

Oral treatment with viable or heat-killed cells of S. boulardii maintained intestinal integrity and modulated the immune system in a murine IO model, preventing bacterial translocation and intestinal lesions.

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.

Real-time multiplex polymerase chain reaction assay for rapid detection of Clostridium difficile toxin-encoding strains

Clostridium difficile is considered an important emerging pathogen capable of causing disease in humans and animal species. In our study, we developed and evaluated a multiplex real-time polymerase chain reaction (PCR) assay for the detection of C. difficile genes encoding toxin A (tcdA), toxin B (tcdB), and binary toxin (cdtA and cdtB). The standardized real-time PCR assay for toxin genes of C. difficile was used to screen for toxigenic C. difficile in fecal samples from 71 preweaned calves, 53 retail ground meat samples, and 27 pasteurized milk samples. All samples were also examined for C. difficile using traditional culture techniques to validate the PCR assay. A total of 24 fecal samples (33.80%) were positive for toxigenic C. difficile using either multiplex real-time PCR or culture. Toxin-encoding C. difficile was detected in 23 enriched fecal samples using the multiplex real-time PCR assay and only 15 samples using culture techniques. C. difficile was not detected in ground meat or pasteurized milk by traditional culture or real-time PCR assay. Eleven fecal samples were positive for all 4 toxin genes, suggesting that preweaned calves may be a likely source for toxigenic C. difficile. On the basis of findings of our study, it can be concluded that multiplex real-time PCR carried out on samples enriched for C. difficile is a reliable, sensitive, and specific diagnostic tool for rapid screening and identification of samples contaminated with C. difficile.

The growing incidence and severity of Clostridium difficile infection in inpatient and outpatient settings

Clostridium difficile infection (CDI) is a leading cause of nosocomial infections, with disease severity ranging from mild diarrhea to fulminant colitis. The incidence and severity of CDI has been on the rise over the last 10-20 years, with CDI being increasingly described outside healthcare settings and in populations previously thought to be at low risk. There has also been an increase in the morbidity, mortality and economic burden associated with CDI in the last several years. This increasing incidence and severity is thought to be at least partially due to frequent antibiotic use and the emergence of a hypervirulent C. difficile strain.

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.

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.

Human intestinal microbiota gene risk factors for antibiotic-associated diarrhea: perspectives for prevention. Risk factors for antibiotic-associated diarrhea

Antibiotic-associated diarrhea (AAD) is associated with altered intestinal microflora and other symptoms that may lead to possibly death. In critically ill patients, diarrhea increases rates of morbimortality. Assessing diarrhea risks is thus important for clinicians. For this reason, we conducted a hypothesis-generating study focused on AAD to provide insight into methods of prevention. We evaluated the hypothesis of predisposing factors within the resident intestinal microbiota in a cohort of outpatients receiving antibiotherapy. Among the pool of tested variables, only those related to bacterial 16S rRNA genes were found to be relevant. Complex statistical analyses provided further information: amid the bacteria 16S rRNA genes, eight were determined to be essential for diarrhea predisposition and characterized from the most important to the least. Using these markers, AAD risk could be estimated with an error of 2%. This molecular analysis offers new perspectives for clinical applications at the level of prevention.

Intake of Lactobacillus plantarum reduces certain gastrointestinal symptoms during treatment with antibiotics

GOALS

To examine if intake of Lactobacillus plantarum can prevent gastrointestinal side effects in antibiotic-treated patients.

BACKGROUND

Diarrhea is a common side effect of treatment with antibiotics. Some studies indicate that the risk of antibiotic-associated diarrhea can be reduced by administration of certain probiotic microorganisms.

STUDY

Patients treated for infections at a university hospital infectious diseases clinic were randomized to daily intake of either a fruit drink with L. plantarum 299v (10(10) colony forming units/d) or a placebo drink, until a week after termination of antibiotic treatment. Subjects recorded the number and consistency of stools as well as gastrointestinal symptoms until up to 3 weeks after last intake of test drink. Fecal samples were collected before the first intake of test drink and after termination of antibiotic therapy and analyzed for Clostridium difficile toxin.

RESULTS

Clinical characteristics on admission were similar in the 2 groups. The overall risk of developing loose or watery stools was significantly lower among those receiving L. plantarum [odds ratio (OR), 0.69; 95% confidence interval (CI), 0.52-0.92; P=0.012], as was development of nausea (OR, 0.51; 95% CI, 0.30-0.85; P=0.0097). Diarrhea defined as > or =3 loose stools/24 h for > or =2 consecutive days was unaffected by the treatment (OR, 1.4; 95% CI, 0.33-6.0; P=0.86). No significant differences regarding carriage of toxin producing C. difficile were observed between the groups.

CONCLUSIONS

Our results indicate that intake of L. plantarum could have a preventive effect on milder gastrointestinal symptoms during treatment with antibiotics.

Toxic megacolon from hypervirulent Clostridium difficile infection (ribotype 027) following elective total knee replacement: an emerging challenge in modern health care

We present a rare case of community acquired (presenting in hospital on the day of admission or within 48 h of admission) Clostridium difficile infection (CDI) with the hypervirulent (ribotype 027) strain causing toxic megacolon in a patient, diagnosed on the third postoperative day following an elective total knee replacement. The patient did not have any of the commonly reported risk factors for CDI. The source of sepsis was initially presumed to be the operated prosthetic joint, and this caused a delay in the correct diagnosis and institution of appropriate antimicrobial treatment which may have contributed to a poorer outcome. This case highlights the risk of patients arriving from the community manifesting life threatening CDI in the hospital.

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.

Emerging Insights into Antibiotic-Associated Diarrhea and Clostridium difficile Infection through the Lens of Microbial Ecology

Antibiotics are the main, and often only, clinical intervention for prophylactic and active treatment of bacterial infections in humans. Perhaps it is not surprising that these drugs also shift the composition of commensal bacteria inside our bodies, especially those within the gut microbial community (microbiota). How these dynamics ultimately affect the function of the gut microbiota, however, is not fully appreciated. Likewise, how antibiotic induced changes facilitate the outgrowth and pathogenicity of certain bacterial strains remains largely enigmatic. Here, we discuss the merits of a microbial ecology approach toward understanding a common side effect of antibiotic use, antibiotic-associated diarrhea (AAD), and the opportunistic bacterial infections that sometimes underlie it. As an example, we discuss how this approach is being used to address complex disease dynamics during Clostridium difficile infection.

Effect of antibiotic therapy on human fecal microbiota and the relation to the development of Clostridium difficile

The gastrointestinal tract is a complex ecosystem. Recent studies have shown that the human fecal microbiota is composed of a consortium of microorganism. It is known that antibiotic treatment alters the microbiota, facilitating the proliferation of opportunists that may occupy ecological niches previously unavailable to them. It is therefore important to characterize resident microbiota to evaluate its latent ability to permit the development of pathogens such as Clostridium difficile. Using samples from 260 subjects enrolled in a previously published clinical study on antibiotic-associated diarrhea, we investigated the possible relationship between the fecal dominant resident microbiota and the subsequent development of C. difficile. We used molecular profiling of bacterial 16S rDNA coupled with partial least square (PLS) regression analysis. Fecal samples were collected on day 0 (D0) before antibiotic treatment and on day 14 (D14) after the beginning of the treatment. Fecal DNA was isolated, and V6-to-V8 regions of the 16S rDNA were amplified by polymerase chain reaction with general primers and analyzed by temporal temperature gradient gel electrophoresis (TTGE). Main bacteria profiles were compared on the basis of similarity (Pearson correlation coefficient). The characteristics of the microbiota were determined using PLS discriminant analysis model. Eighty-seven TTGE profiles on D0 have been analyzed. The banding pattern was complex in all cases. The subsequent onset of C. difficile was not revealed by any clustering of TTGE profiles, but was explained up to 46% by the corresponding PLS model. Furthermore, 6 zones out of the 438 dispatched from the TTGE profiles by the software happened to be specific for the group of patients who acquired C. difficile. The first approach in the molecular phylogenetic analysis showed related sequences to uncultured clones. As for the 87 TTGE profiles on D14, no clustering could be found either, but the subsequent onset of C. difficile was explained up to 74.5% by the corresponding PLS model, thus corroborating the results found on D0. The non exhaustive data of the microbiota we found should be taken as the first step to assess the hypothesis of permissive microbiota. The PLS model was used successfully to predict C. difficile development. We found that important criteria in terms of main bacteria could be markedly considered as predisposing factors for C. difficile development. Yet, the resident microbiota in case of antibiotic-associated diarrhea has still to be analyzed. Furthermore, these findings suggest that strategies reinforcing the ability of the fecal microbiota to resist to modifications would be of clinical relevance.

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.

Update on the changing epidemiology of Clostridium difficile-associated disease

In the past, Clostridium difficile-associated disease (CDAD) was thought of mainly as a nosocomial disease associated with the use of broad-spectrum antibiotics, but its epidemiology seems to be changing. Since 2002, outbreaks of severe CDAD associated with increased mortality and reduced effectiveness of treatment with metronidazole have focused attention on this challenging pathogen. A fluoroquinolone-resistant strain of C. difficile (BI/NAP1/027) has been predominantly associated with these outbreaks. Changes in the epidemiology of CDAD include the emergence of new at-risk populations and the increased incidence of the disease. Infection control programs and more effective treatments offer hope that future outbreaks of CDAD can be controlled.