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

Detection of Clostridium difficile diarrhoea in Harare, Zimbabwe

BACKGROUND

Clostridium difficile is associated with nosocomial and community-acquired diarrhoea and pseudomembranous colitis in humans. Little information is available on the importance of C. difficile as a causative agent of diarrhoea in developing countries such as Zimbabwe. The current study was carried out to determine the prevalence of C. difficile in diarrhoeal stools of outpatients over 2 years of age presenting at healthcare centres in Harare, Zimbabwe, and to determine the antimicrobial susceptibility of the isolates.

METHODS

Toxigenic stool culture was used in this study. Diarrhoeal stool specimens were cultured for C. difficile, followed by direct immunoassay on colonies of positive cultures with significant growth to detect toxins A or B.

RESULTS

C. difficile was detected in 8.6% (n=23) of the 268 diarrhoeal stool specimens. All C. difficile isolates were susceptible to metronidazole, vancomycin, chloramphenicol and doxycyline, and resistant to clindamycin, ciprofloxacin, gentamicin and cefotaxime. About 70% of the isolates were resistant to co-trimoxazole.

CONCLUSIONS

C. difficile was observed to be an important diarrhoeal pathogen and metronidazole was effective in treating diarrhoea caused by the bacterium. Co-trimoxazole, which is widely used as prophylaxis against opportunistic infections in HIV/AIDS patients, was not very effective in preventing diarrhoea caused by C. difficile.

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.

Antimicrobial use in Hungarian long-term care facilities: high proportion of quinolone antibacterials

The aim of this survey was to estimate the burden of antimicrobial use and to describe the determinants for antimicrobial use in Hungarian long-term care facilities (LTCFs) in order to increase the attention given to the proper prescription for this vulnerable population. A one-day point-prevalence study was undertaken between April and May 2013. Data on resident treated with an antibacterial, antimycotic or tuberculostatic for systemic use were collected prospectively on a single day in each participating LTCF with over 50 beds. Descriptive statistics were used to present the data. 91 LTCFs with 11,823 residents participated in this survey. 156 residents (1.3%) were given antimicrobials. 96.8% of antimicrobials were mostly prescribed for therapy included urinary tract infections (40.3%), respiratory tract infections (38.4%) and skin and soft tissue infections (13.2%). The most common therapeutic antimicrobials (97.5%) belonged to the ATC J01 class of 'antibacterials for systemic use'. The most important J01 subclasses were J01M quinolone antibacterials (32.7%), J01C beta-lactam antibacterials (25.2%), J01D other beta-lactam antibacterials (11.3%) and J01F macrolides, lincosamides and streptogramins (11.3%). Antimicrobials were mostly prescribed empirically whereas 3.8% was microbiologically documented treatments. 3.2% of all prescribed antimicrobials were prescribed for the prophylaxis of urinary tract infections (60%) and ear, nose, mouth infections (40%). Our results emphasize the need of a national recommendation for good practice in LTCFs in order to avoid inappropriate antimicrobial therapy leading to spread of multidrug resistant pathogens. In addition, continuing education of prescribers on antimicrobial treatment is essential.

Control of Clostridium difficile infection in the hospital setting

Clostridium difficile infection (CDI) has emerged as a leading challenge in the control of healthcare-associated infection (HCAI). The epidemiology of CDI has changed dramatically, this is associated with emergence of 'hypervirulent' strains, particularly PCR ribotype 027. Despite the epidemic spread of these strains, there are recent reports of decreasing incidence from healthcare facilities where multi-facetted targeted control programs have been implemented. We consider these changes in epidemiology and reflect on the tools available to control CDI in the hospital setting. The precise repertoire of measures adopted and emphasis on different interventions will vary, not only between healthcare systems, but also within different institutions within the same healthcare system. Finally, we consider both the sustainability of reductions already achieved, and the potential to reduce CDI further. This takes account of newly emerging data on more recent changes in the epidemiology of CDI, and the potential of novel interventions to decrease the burden of disease.

Fidaxomicin in Clostridium difficile infection: latest evidence and clinical guidance

The incidence of Clostridium difficile infection (CDI) has risen 400% in the last decade. It currently ranks as the third most common nosocomial infection. CDI has now crossed over as a community-acquired infection. The major failing of current therapeutic options for the management of CDI is recurrence of disease after the completion of treatment. Fidaxomicin has been proven to be superior to vancomycin in successful sustained clinical response to therapy. Improved outcomes may be due to reduced collateral damage to the gut microflora by fidaxomicin, bactericidal activity, inhibition of Clostridial toxin formation and inhibition of new sporulation. This superiority is maintained in groups previously reported as being at high risk for CDI recurrence including those: with relapsed infection after a single treatment course; on concomitant antibiotic therapy; aged >65 years; with cancer; and with chronic renal insufficiency. Because the acquisition cost of fidaxomicin far exceeds that of metronidazole or vancomycin, in order to rationally utilize this agent, it should be targeted to those populations who are at high risk for relapse and in whom the drug has demonstrated superiority. In this manuscript is reviewed the changing epidemiology of CDI, current treatment options for this infection, proposed benefits of fidaxomicin over currently available antimicrobial options, available analysis of cost effectiveness of the drug, and is given recommendations for judicious use of the drug based upon the available published literature.

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.

Prevalence of Clostridium difficile in raw beef, cow, sheep, goat, camel and buffalo meat in Iran

Background

Clostridium difficile has been shown to be a nosocomial pathogen associated with diarrhoea and pseudomembranous colitis in hospitalised patients and the infection is believed to be acquired nosocomially. Recent studies have shown the occurrence of C. difficile in food animals which may act as a source of infection to humans.The aim of this study was to determine the occurrence of C. difficile in retail raw beef, cow, sheep, goat, camel and buffalo meat in Iran.

Method

From April to October 2012, a total of 660 raw meat samples from beef, cow, sheep, goat, camel and buffalo were purchased from 49 butcheries in Isfahan and Khuzestan provinces, Iran, and were evaluated for the presence of C. difficile using a method including selective enrichment in C. difficile broth, subsequent alcohol shock-treatment and plating onto C. difficile selective medium. C. difficile isolates were tested for the presence of toxin genes and were typed using PCR ribotyping.

Results

In this study, 13 of 660 meat samples (2%) were contaminated with C. difficile. The highest prevalence of C. difficile was found in buffalo meat (9%), followed by goat meat (3.3%), beef meat (1.7%), cow (0.94%) and sheep meat (0.9%). Seven of the 13C. difficile strains (53.9%) were positive for tcdA, tcdB and cdtB toxin genes and were classified as ribotype 078. Four strains (30.8%) were positive tcdA, and tcdB, and one strain (7.7%) was possessed only tcdB. The remaining isolate was non-toxigenic. Susceptibilities of 13C. difficile isolates were determined for 11 antimicrobial drugs using the disk diffusion assay. Resistance to clindamycin, gentamycin, and nalidixic acid was the most common finding.

Conclusions

To our knowledge, the present study is the first report of the isolation of C. difficile from raw buffalo meat. This study indicates the potential importance of food, including buffalo meat, as a source of transmission of C. difficile to humans.

Parameters for the mathematical modelling of Clostridium difficile acquisition and transmission: a systematic review

INTRODUCTION

Mathematical modelling of Clostridium difficile infection dynamics could contribute to the optimisation of strategies for its prevention and control. The objective of this systematic review was to summarise the available literature specifically identifying the quantitative parameters required for a compartmental mathematical model of Clostridium difficile transmission.

METHODS

Six electronic healthcare databases were searched and all screening, data extraction and study quality assessments were undertaken in duplicate. Results were synthesised using a narrative approach.

RESULTS

Fifty-four studies met the inclusion criteria. Reproduction numbers for hospital based epidemics were described in two studies with a range from 0.55 to 7. Two studies provided consistent data on incubation periods. For 62% of cases, symptoms occurred in less than 4 weeks (3-28 days) after infection. Evidence on contact patterns was identified in four studies but with limited data reported for populating a mathematical model. Two studies, including one without clinically apparent donor-recipient pairs, provided information on serial intervals for household or ward contacts, showing transmission intervals of <1 week in ward based contacts compared to up to 2 months for household contacts. Eight studies reported recovery rates of between 75%-100% for patients who had been treated with either metronidazole or vancomycin. Forty-nine studies gave recurrence rates of between 3% and 49% but were limited by varying definitions of recurrence. No study was found which specifically reported force of infection or net reproduction numbers.

CONCLUSIONS

There is currently scant literature overtly citing estimates of the parameters required to inform the quantitative modelling of Clostridium difficile transmission. Further high quality studies to investigate transmission parameters are required, including through review of published epidemiological studies where these quantitative estimates may not have been explicitly estimated, but that nonetheless contain the relevant data to allow their calculation.

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

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

Intestinal inflammatory biomarkers and outcome in pediatric Clostridium difficile infections

OBJECTIVES

To identify specific fecal biomarkers for symptomatic Clostridium difficile infection and predictors of poor outcomes.

STUDY DESIGN

We enrolled 65 children with positive C difficile testing (cases) and 37 symptomatic controls. We also analyzed stool samples from colonized and non-colonized asymptomatic children. We performed enzyme immunoassays to determine fecal interleukin (IL)-8, lactoferrin, and phosphorylated-p38 protein concentrations, and quantitative polymerase chain reaction to determine IL-8 and chemokine ligand (CXCL)-5 RNA relative transcript abundances, and C difficile bacterial burden.

RESULTS

Of 68 asymptomatic controls, 16 were colonized with C difficile. Phosphorylated-p38 was specific for C difficile infection but lacked sensitivity. Fecal cytokines were elevated in samples from symptomatic children, whether cases or controls. In children with C difficile infection, fecal CXCL-5 and IL-8 messenger RNA abundances at diagnosis correlated with persistent diarrhea after 5 days of C difficile infection therapy and with treatment with vancomycin. When children with concomitant viral gastroenteritis were excluded, these correlations persisted. Time-to-diarrhea resolution was significantly longer in patients with elevated fecal cytokines at diagnosis. A logistic regression model identified high CXCL-5 messenger RNA abundance as the only predictor of persistent diarrhea. Conversely, fecal C difficile bacterial burden was not different in symptomatic and asymptomatic children and did not correlate with any clinical outcome measure.

CONCLUSIONS

Fecal inflammatory cytokines may be useful in distinguishing C difficile colonization from disease and identifying children with C difficile infection likely to have prolonged diarrhea.

Community-associated Clostridium difficile infection: how real is it?

Community-associated Clostridium difficile infection (CA-CDI) represents 32% of all CDI cases based on U.S. population-based data. The current epidemic strain, NAP1, is the most prevalent strain causing these infections. Although complications, recurrence and death are uncommon, one-fourth of the CA-CDI patients are hospitalized within 7 days after the diagnosis.

[Rational antibiotic prescribing. Challenges and successes]

Rational and prudent antibiotic prescribing strategies are important both for the hospital sector as well as for ambulatory medicine. Prerequisites are the availability of antibiotic use and antibiotic resistance data and of infrastructure and trained personnel needed for implementing and evaluating antibiotic policies. Currently, these requirements are not being met sufficiently in Germany. A major challenge in this country is the lack of adequately trained and experienced personnel. On the other hand there are several projects and initiatives supported in part within the national antibiotic resistance control program which have produced some progress and success. One example is GERMAP, the national antibiotic use and resistance atlas covering both human medicine and the veterinary field. Other examples are the recently improved program for continuous hospital antibiotic use, surveillance and feedback and the Antibiotic Stewardship (ABS) training program with establishment of an ABS expert network. Future perspectives include programs for evaluation of practice guideline adherence and the development and evaluation of quality of care indicators. Intermediate and long-term investment is needed in specialty training and certification of a sufficient number of infectious disease physicians, medical microbiologists and infection control doctors/hospital epidemiologists and hospital pharmacists.

Proton Pump Inhibitors and Clostridium Difficile Infection: Are We Propagating an Already Rapidly Growing Healthcare Problem?

Proton pump inhibitors (PPIs) have been associated with Clostridium difficile infection (CDI) in several recent studies. The exact mechanism through which PPIs may cause Clostridium difficile infection is not well understood. One potential mechanism to explain this association may be that elevated gastric pH levels facilitate the growth of potentially pathogenic upper and lower gastrointestinal tract flora. Although Clostridium difficile spores are acid resistant, vegetative forms are susceptible to acidity. Higher gastric PH therefore increases vegetative bacteria counts in the small and large intestine. Other potential mechanisms include impairment of leukocytes and other immune responses and antimicrobial properties of PPIs. In recent years, much research has been contributed to prove the relationship between PPIs and CDI as causal. Most studies however, fail to prove causality due to the use of antibiotics and other medications during time of initial diagnosis of CDI. PPIs continue to also be one of the most heavily prescribed drugs in our country. As primary and recurrent infection caused by Clostridium difficile continues to rise, more data must be collected to determine better treatment, overall management, and the role that PPIs may play in its propagation.

Toxin-producing Clostridium difficile strains as long-term gut colonizers in healthy infants

Clostridium difficile is a colonizer of the human gut, and toxin-producing strains may cause diarrhea if the infectious burden is heavy. Infants are more frequently colonized than adults, but they rarely develop C. difficile disease. It is not known whether strains of C. difficile differ in the capacity to colonize and persist in the human gut microbiota. Here, we strain typed isolates of C. difficile that had colonized 42 healthy infants followed from birth to ≥12 months of age by using PCR ribotyping of the 16S-23S rRNA intergenic spacer region. The isolates were also characterized regarding carriage of the toxin genes tcdA, tcdB, and cdtA/B and the capacity to produce toxin B in vitro. Most strains (71%) were toxin producers, and 51% belonged to the 001 or 014 ribotypes, which often cause disease in adults. These ribotypes were significantly more likely than others to persist for ≥6 months in the infant micobiota, and they were isolated from 13/15 children carrying such long-term-colonizing strains. Ribotype 001 strains were often acquired in the first week of life and attained higher population counts than other C. difficile ribotypes in newborn infants' feces. Several toxin-negative ribotypes were identified, two of which (GI and GIII) were long-term colonizers, each found in one infant. Our results suggest that the toxin-producing C. difficile ribotypes 001 and 014 have special fitness in the infantile gut microbiota. Toxin-producing strains colonizing young children for long time periods may represent a reservoir for strains causing disease in adults.

Epidemiology of Clostridium difficile infection

There has been dramatic change in the epidemiology of Clostridium difficile infection (CDI) since the turn of the 21st century noted by a marked increase in incidence and severity, occurring at a disproportionately higher frequency in older patients. Historically considered a nosocomial infection associated with antibiotic exposure, CDI has now also emerged in the community in populations previously considered low risk. Emerging risk factors and disease recurrence represent continued challenges in the management of CDI. The increased incidence and severity associated with CDI has coincided with the emergence and rapid spread of a previously rare strain, ribotype 027. Recent data from the United States and Europe suggest that the incidence of CDI may have reached a crescendo in the recent years and is perhaps beginning to plateau. The acute care direct costs of CDI were estimated to be US$4.8 billion in 2008. However, nearly all the published studies have focused on CDI diagnosed and treated in the acute care hospital setting and fail to measure the burden outside the hospital, including recently discharged patients, outpatients, and those in long-term care facilities. Enhanced surveillance methods are needed to monitor the incidence, to identify populations at risk, and to characterize the molecular epidemiology of strains causing CDI.

Risk factors for Clostridium difficile infection in the community: a case-control study in patients in general practice, Denmark, 2009-2011

To identify risk factors for Clostridium difficile infection (CDI) in Danish patients consulting general practice with gastrointestinal symptoms, a prospective matched case-control study was performed; cases (N = 259) had positive cultures for toxigenic C. difficile and controls (N = 455) negative cultures. Data were analysed by conditional logistic regression. In patients aged ⩾2 years (138 cases), hospitalization [odds ratio (OR) 8·4, 95% confidence interval (CI) 3·1-23], consumption of beef (OR 5·5, 95% CI 2·0-15), phenoxymethylpenicillin (OR 15, 95% CI 2·7-82), dicloxacillin (OR 27, 95% CI 3·6-211), and extended spectrum penicillins (OR 9·2, 95% CI 1·9-45) were associated with CDI. In patients aged <2 years none of these were associated with CDI, but in a subgroup analysis contact with animals was associated with CDI (OR 8·1, 95% CI 1·0-64). This study emphasizes narrow-spectrum penicillins, and suggests beef consumption, as risk factors for CDI in adults, and indicates a different epidemiology of CDI in infants.

Reprint of New opportunities for improved ribotyping of C. difficile clinical isolates by exploring their genomes

Clostridium difficile causes outbreaks of infectious diarrhoea, most commonly occurring in healthcare institutions. Recently, concern has been raised with reports of C. difficile disease in those traditionally thought to be at low risk i.e. community acquired rather than healthcare acquired. This has increased awareness for the need to track outbreaks and PCR-ribotyping has found widespread use to elucidate epidemiologically linked isolates. PCR-ribotyping uses conserved regions of the 16S rRNA gene and 23S rRNA gene as primer binding sites to produce varying PCR products due to the intergenic spacer (ITS1) regions of the multiple operons. With the explosion of whole genome sequence data it became possible to analyse the start of the 23S rRNA gene for a more accurate selection of regions closer to the end of the ITS1. However the following questions must still be asked: (i) Does the chromosomal organisation of the rrn operon vary between C. difficile strains? and (ii) just how conserved are the primer binding regions? Eight published C. difficile genomes have been aligned to produce a detailed database of indels of the ITS1's from the rrn operon sets. An iPad Filemaker Go App has been constructed and named RiboTyping (RT). It contains detail such as sequences, ribotypes, strain numbers, GenBank numbers and genome position numbers. Access to various levels of the database is provided so that details can be printed. There are three main regions of the rrn operon that have been analysed by the database and related to each other by strain, ribotype and operon: (1) 16S gene (2) ITS1 indels (3) 23S gene. This has enabled direct intra- and inter-genomic comparisons at the strain, ribotype and operon (allele) levels in each of the three genomic regions. This is the first time that such an analysis has been done. By using the RT App with search criteria it will be possible to select probe combinations for specific strains/ribotypes/rrn operons for experiments to do with diagnostics, typing and recombination of operons. Many more incomplete C. difficile whole genome sequencing projects are recorded in GenBank as underway and the rrn operon information from these can also be added to the RT App when available. The RT App will help simplify probe selection because of the complexity of the ITS1 in C. difficile even in a single genome and because other allele-specific regions (16S and 23S genes) of variability can be relationally compared to design extra probes to increase sensitivity.

Clostridium difficile infection in the twenty-first century

Clostridium difficile is a spore-forming gram-positive bacillus, and the leading cause of antibiotic-associated nosocomial diarrhea and colitis in the industrialized world. With the emergence of a hypervirulent strain of C. difficile (BI/NAP1/027), the epidemiology of C. difficile infection has rapidly changed in the last decade. C. difficile infection, once thought to be an easy to treat bacterial infection, has evolved into an epidemic that is associated with a high rate of mortality, causing disease in patients thought to be low-risk. In this review, we discuss the changing face of C .difficile infection and the novel treatment and prevention strategies needed to halt this ever growing epidemic.

Contamination of ready-to-eat raw vegetables with Clostridium difficile in France

The presence of Clostridium difficile in food like shellfish, vegetables and meat has been reported in several publications during the past few years. The objective of this study was to assess the prevalence of ready-to-eat raw vegetables contaminated with C. difficile in France. One hundred and four ready-to-eat salads and vegetables were studied. Toxigenic C. difficile strains were isolated in three samples (2.9 %): two ready-to-eat salads (one heart of lettuce and one lamb's lettuce salad) and one portion of pea sprouts. The strains belonged to three different PCR ribotypes: 001, 014/020/077 and 015. The detection thresholds for vegetative cells and spores cells varied between 1 and 3 c.f.u. in 20 g salad and between 6 and 15 c.f.u. in 20 g salad, respectively, for the method employed.

Clostridium difficile infection in children: a comprehensive review

OBJECTIVE

To provide a comprehensive review of the literature relating to Clostridium difficile (C. difficile) infection (CDI) in the pediatric population.

METHODS

Two investigators conducted independent searches of PubMed, Web of Science, and Scopus until March 31st, 2013. All databases were searched using the terms 'Clostridium difficile infection', 'Clostridium difficile associated diarrhea' 'antibiotic associated diarrhea', 'C. difficile', in combination with 'pediatric' and 'paediatric'. Articles which discussed pediatric CDI were reviewed and relevant cross references also read and evaluated for inclusion. Selection bias could be a possible limitation of this approach.

FINDINGS

There is strong evidence for an increased incidence of pediatric CDI. Increasingly, the infection is being acquired from the community, often without a preceding history of antibiotic use. The severity of the disease has remained unchanged. Several medical conditions may be associated with the development of pediatric CDI. Infection prevention and control with antimicrobial stewardship are of paramount importance. It is important to consider the age of the child while testing for CDI. Traditional therapy with metronidazole or vancomycin remains the mainstay of treatment. Newer antibiotics such as fidaxomicin appear promising especially for the treatment of recurrent infection. Conservative surgical options may be a life-saving measure in severe or fulminant cases.

CONCLUSIONS

Pediatric providers should be cognizant of the increased incidence of CDI in children. Early and judicious testing coupled with the timely institution of therapy will help to secure better outcomes for this disease.

Presence of Clostridium difficile PCR ribotype clusters related to 033, 078 and 045 in diarrhoeic calves in Germany

This study provides data on the distribution and relationship of C. difficile PCR ribotypes in diarrhoeic calves in Germany. C. difficile was isolated from 176 of 999 (17.6 %) faecal samples or swabs of diarrhoeic calves from 603 farms collected between January 2010 and August 2012 by eight federal laboratories of six states. Strains were assigned to 17 PCR ribotypes. PCR ribotypes 033 (57 %), 078 (17 %) and 045/FLI01 (closest match to 045 in the WEBRIBO database; 9 %) were found the most frequently. Nine per cent of all culture-positive tested animals shed more than one multiple locus variable number tandem repeat analysis (MLVA) or PCR ribotype. Eight PCR ribotypes with related profiles (including 033, 078 and 045/FLI01) representing 92 % of all isolates were grouped into three clusters. Molecular relatedness was supported by the absence of the MLVA locus A6 Cd only in clustered strains and identical toxin gene profiles for strains within each cluster. Previously reported mulitilocus sequence typing analysis for PCR ribotypes that were also recovered in this study found identical sequence types and a tcdC deletion (Δ39 bp) for 033, 045, 078 and 126 (ST-11), confirming this clustering. A different geographical occurrence of PCR ribotypes was shown for cluster 033 (found more frequently in southern Germany) and 045 (found more frequently in northern Germany). This study showed that clusters of C. difficile PCR ribotypes related to 033, 078 and 045 are predominant in diarrhoeic calves in Germany. The high number of strains belonging to PCR ribotype 078 demonstrated that diarrhoeic calves are also potential reservoirs for human pathogenic C. difficile strains.

Outpatient healthcare settings and transmission of Clostridium difficile

BACKGROUND

Recent reports suggest that community-associated Clostridium difficile infection (CDI) (i.e., no healthcare facility admission within 90 days) may be increasing in frequency. We hypothesized that outpatient clinics could be an important source for acquisition of community-associated CDI.

METHODS

We performed a 6-month prospective study of CDI patients to determine frequency of and risk factors for skin and environmental shedding during outpatient visits and to derive a prediction rule for positive cultures. We performed a point-prevalence culture survey to assess the frequency of C. difficile contamination in outpatient settings and evaluated the frequency of prior outpatient visits in patients with community-associated CDI.

RESULTS

Of 67 CDI patients studied, 54 (81%) had 1 or more outpatient visits within 12 weeks after diagnosis. Of 44 patients cultured during outpatient visits, 14 (32%) had skin contamination and 12 (27%) contaminated environmental surfaces. Decreased mobility, fecal incontinence, and treatment with non-CDI antibiotics were associated with positive cultures, whereas vancomycin taper therapy was protective. In patients not on CDI therapy, a prediction rule including incontinence or decreased mobility was 90% sensitive and 79% specific for detection of spore shedding. Of 84 clinic and emergency department rooms cultured, 12 (14%) had 1 or more contaminated environmental sites. For 33 community-associated CDI cases, 31 (94%) had an outpatient visit during the 12 weeks prior to onset of diarrhea.

CONCLUSIONS

Patients with recent CDI present a significant risk for transmission of spores during outpatient visits. The outpatient setting may be an underappreciated source of community-associated CDI cases.

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.

Epidemiology, diagnosis and treatment of Clostridium difficile infection

Clostridium difficile infection (CDI) is considered to be the main cause of bacterial infectious diarrhea in nosocomial settings. Since the beginning of the new century a continuous rise in the incidence of severe CDI has been observed worldwide. Even though some CDI cases are not associated with previous antibiotic exposure, this remains as the principal risk factor for the development of CDI. The rate of recurrences represents perhaps one the most challenging aspect on the management of CDI. There are several microbiological tests available, but glutamate dehydrogenase antigen test can be selected as the first screening step in a diagnostic algorithm, with positive samples then confirmed using a toxin(s) test, to distinguish toxinogenic from nontoxinogenic CDI. Although metronidazole and vancomycin are and have been the mainstay treatment options for CDI, there are some unmet medical and therapeutical needs. Usually oral metronidazole is recommended for initial treatment of nonsevere CDI and vancomycin for treatment of severe disease. Fidaxomicin may be considered in patients who cannot tolerate vancomycin, although more data are needed. For treatment of a nonsevere initial recurrence of CDI, oral metronidazole should be used, but for treatment of subsequent recurrences or more severe cases fidaxomicin may be helpful.

The impact of pseudomembrane formation on the outcome of Clostridium difficile-associated disease

PURPOSE

Although pseudomembranes are the hallmark manifestation of Clostridium difficile-associated diarrhea (CDAD), there are scant data specifically addressing their impact on the clinical outcome. We investigated whether the formation of pseudomembranes predicts a worse CDAD outcome.

METHODS

CDAD patients hospitalized during 2010 underwent sigmoidoscopy and were followed prospectively. In addition, all hospitalized CDAD patients in the period 01/2000-12/2009 who underwent lower endoscopy were retrospectively identified and their charts reviewed. Patients with detectable pseudomembranes on endoscopy were compared to those in whom pseudomembranes were absent. Thirty-day mortality and a composite outcome comprised of mortality within 30 days of diagnosis, admission to the intensive care unit (ICU), colectomy, peritonitis, hemodynamic instability, or respiratory insufficiency were addressed. Additional clinical outcomes used for comparison between the two groups were 60-day mortality, duration of hospitalization, and the failure of metronidazole and vancomycin.

RESULTS

A total of 117 CDAD patients (mean age 62.9 ± 19 years) who underwent lower endoscopy were included; 46 with pseudomembranes and 71 without. Seven out of the 46 patients with pseudomembranes died within 30 days compared to 9/71 in the non-pseudomembrane group [odds ratio (OR) 1.2, 95% confidence interval (CI) 0.4-3.6, P = 0.8]. Similarly, there was no correlation between the occurrence of pseudomembranes and the rate of the composite adverse outcome (P = 0.6). In contrast, acute renal insufficiency (OR 15, 95% CI 3.2-72, P < 0.001) and hypoalbuminemia (OR 5.7, 95% CI 1.8-18, P = 0.002) were both independently predictive of a severe clinical outcome.

CONCLUSIONS

Our findings suggest that the presence of pseudomembranes is not associated with an adverse outcome in CDAD patients.

Indications and safety of proton pump inhibitor drug use in patients with cancer

INTRODUCTION

Although the exact prevalence of proton pump inhibitor (PPI) use in cancer patients is not known, it is generally perceived to be widespread. PPIs are generally well tolerated and carry an excellent safety profile. However, increasing and longer term PPI use has raised concerns about the risk of pneumonia, bone fractures and enteric infections, and a possible interaction with clopidogrel that could increase the risk of cardiovascular events.

AREAS COVERED

We conducted a PubMed search of English language articles addressing the safety and adverse events associated with PPI use with particular emphasis in cancer patients.

EXPERT OPINION

PPIs, frequently used in cancer patients, are generally well tolerated and carry an excellent safety profile. PPI-induced acid suppression may increase the risk of Clostridium difficile or other enteric infections, nutritional deficiencies and community acquired pneumonia, all particularly important in cancer patients. The indications for PPI use in cancer patients should be carefully reviewed prior to use.

Clostridium difficile as a cause of acute diarrhea: a prospective study in a tertiary care center

INTRODUCTION

Clostridium difficile-associated diarrhea (CDAD) is an increasing problem. Recent reports suggest presence of community acquired CDAD (CA CDAD). Studies in India have shown varied results.

AIMS

The following are the aims of this study: (a) the prevalence of CDAD and CA CDAD in patients with acute diarrhea; (b) the incremental yield of second stool sample for the diagnosis of C. difficile infection (CDI); and (c) the risk factors for CDI.

PATIENTS AND METHODS

Patients with acute diarrhea (<4 weeks) between April 2009 and December 2010 had two stool sample tested for C. difficile toxin (CDT) by enzyme-linked immunofluorescent assay. Demographic, clinical data, risk factors, clinical course, complications, treatment, and response were noted.

RESULTS

Of 150 patients (mean age, 47.3 years; 76 males), 12 (8 %) had their first stool sample positive for CDT. Two patients (1.3 %) had community acquired CDI. The study group was compared with 138 patients ("control group", stool samples negative for CDT). Compared to the controls, the study group were more likely to have had intensive care unit (ICU) stay (p = 0.018) and tube feeding (p = 0.035). Eleven patients were treated with metronidazole. One patient did not respond to metronidazole and was treated with vancomycin. No patient developed complications of CDAD.

CONCLUSIONS

The prevalence of CDAD in our population was 8 % and of CA CDAD was 1.3 %. There was no advantage of testing two samples. ICU stay and tube feeding were major risk factors for the CDAD. Metronidazole was an effective first-line therapy.

Community-associated Clostridium difficile infection and antibiotics: a meta-analysis

OBJECTIVES

Antibiotic exposure is the most important risk factor for Clostridium difficile infection (CDI). Most evaluations of antimicrobial risk factors have been conducted in healthcare settings. The objective of this meta-analysis was to evaluate the association between antibiotic exposure and community-associated CDI (CA-CDI) (i.e. symptom onset in the community with no healthcare facility admission within 12 weeks) and to determine the classes of antibiotics posing the greatest risk.

METHODS

We searched four electronic databases for subject headings and text words related to CA-CDI and antibiotics. Studies that investigated the risk of CA-CDI associated with antibiotic usage were considered eligible. Data from the identified studies were combined using a random-effects model and ORs were calculated.

RESULTS

Of 910 citations identified, eight studies (n = 30 184 patients) met our inclusion criteria. Antibiotic exposure was associated with an increased risk of CA-CDI (OR 6.91, 95% CI 4.17-11.44, I(2) = 95%). The risk was greatest with clindamycin (OR 20.43, 95% CI 8.50-49.09) followed by fluoroquinolones (OR 5.65, 95% CI 4.38-7.28), cephalosporins (OR 4.47, 95% CI 1.60-12.50), penicillins (OR 3.25, 95% CI 1.89-5.57), macrolides (OR 2.55, 95% CI 1.91-3.39) and sulphonamides/trimethoprim (OR 1.84, 95% CI 1.48-2.29). Tetracyclines were not associated with an increased CDI risk (OR 0.91, 95% CI 0.57-1.45).

CONCLUSIONS

Antibiotic exposure was an important risk factor for CA-CDI, but the risk was different amongst different antibiotic classes. The risk was greatest with clindamycin followed by fluoroquinolones and cephalosporins, whereas tetracyclines were not associated with an increased risk.

New opportunities for improved ribotyping of C. difficile clinical isolates by exploring their genomes

Clostridium difficile causes outbreaks of infectious diarrhoea, most commonly occurring in healthcare institutions. Recently, concern has been raised with reports of C. difficile disease in those traditionally thought to be at low risk i.e. community acquired rather than healthcare acquired. This has increased awareness for the need to track outbreaks and PCR-ribotyping has found widespread use to elucidate epidemiologically linked isolates. PCR-ribotyping uses conserved regions of the 16S rRNA gene and 23S rRNA gene as primer binding sites to produce varying PCR products due to the intergenic spacer (ITS1) regions of the multiple operons. With the explosion of whole genome sequence data it became possible to analyse the start of the 23S rRNA gene for a more accurate selection of regions closer to the end of the ITS1. However the following questions must still be asked: (i) Does the chromosomal organisation of the rrn operon vary between C. difficile strains? and (ii) just how conserved are the primer binding regions? Eight published C. difficile genomes have been aligned to produce a detailed database of indels of the ITS1's from the rrn operon sets. An iPad Filemaker Go App has been constructed and named RiboTyping (RT). It contains detail such as sequences, ribotypes, strain numbers, GenBank numbers and genome position numbers. Access to various levels of the database is provided so that details can be printed. There are three main regions of the rrn operon that have been analysed by the database and related to each other by strain, ribotype and operon: (1) 16S gene (2) ITS1 indels (3) 23S gene. This has enabled direct intra- and inter-genomic comparisons at the strain, ribotype and operon (allele) levels in each of the three genomic regions. This is the first time that such an analysis has been done. By using the RT App with search criteria it will be possible to select probe combinations for specific strains/ribotypes/rrn operons for experiments to do with diagnostics, typing and recombination of operons. Many more incomplete C. difficile whole genome sequencing projects are recorded in GenBank as underway and the rrn operon information from these can also be added to the RT App when available. The RT App will help simplify probe selection because of the complexity of the ITS1 in C. difficile even in a single genome and because other allele-specific regions (16S and 23S genes) of variability can be relationally compared to design extra probes to increase sensitivity.

Clostridium difficile infection is associated with increased risk of death and prolonged hospitalization in children

BACKGROUND

Clostridium difficile infection (CDI) is associated with significant morbidity and mortality among adults. However, outcomes are poorly defined among children.

METHODS

A retrospective cohort study was performed among hospitalized children at 41 children's hospitals between January 2006 and August 2011. Patients with CDI (exposed) were matched 1:2 to patients without CDI (unexposed) based on the probability of developing CDI (propensity score derived from patient characteristics). Exposed subjects were stratified by C. difficile test date, suggestive of community-onset (CO) versus hospital-onset (HO) CDI. Outcomes were analyzed for matched subjects.

RESULTS

We identified 5107 exposed and 693 409 unexposed subjects. Median age was 6 years (interquartile range [IQR], 2-13 years) for exposed and 8 years (IQR, 3-14 years) for unexposed subjects. Of these, 4474 exposed were successfully matched to 8821 unexposed by propensity score. In-hospital mortality differed significantly (CDI, 1.43% vs matched unexposed, 0.66%; P < .001). Mortality rates were similar between CO-CDI and matched subjects. However, mortality rates were significantly greater among HO-CDI compared with matched unexposed (odds ratio, 6.73 [95% confidence interval {CI}, 3.77-12.02]). Mean differences in length of stay (LOS) and total cost were significant: 5.55 days (95% CI, 4.54-6.56 days) and $18 900 (95% CI, $15 100-$22 700) for CO-CDI, and 21.60 days (95% CI, 19.29-23.90 days) and $93 600 (95% CI, $80 000-$107 200) for HO-CDI.

CONCLUSIONS

Pediatric CDI is associated with increased mortality, longer LOS, and higher costs. These findings underscore the importance of antibiotic stewardship and infection control programs to prevent this disease in children.

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

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

Meta-analysis of antibiotics and the risk of community-associated Clostridium difficile infection

The rising incidence of Clostridium difficile infection (CDI) could be reduced by lowering exposure to high-risk antibiotics. The objective of this study was to determine the association between antibiotic class and the risk of CDI in the community setting. The EMBASE and PubMed databases were queried without restriction to time period or language. Comparative observational studies and randomized controlled trials (RCTs) considering the impact of exposure to antibiotics on CDI risk among nonhospitalized populations were considered. We estimated pooled odds ratios (OR) for antibiotic classes using random-effect meta-analysis. Our search criteria identified 465 articles, of which 7 met inclusion criteria; all were observational studies. Five studies considered antibiotic risk relative to no antibiotic exposure: clindamycin (OR = 16.80; 95% confidence interval [95% CI], 7.48 to 37.76), fluoroquinolones (OR = 5.50; 95% CI, 4.26 to 7.11), and cephalosporins, monobactams, and carbapenems (CMCs) (OR = 5.68; 95% CI, 2.12 to 15.23) had the largest effects, while macrolides (OR = 2.65; 95% CI, 1.92 to 3.64), sulfonamides and trimethoprim (OR = 1.81; 95% CI, 1.34 to 2.43), and penicillins (OR = 2.71; 95% CI, 1.75 to 4.21) had lower associations with CDI. We noted no effect of tetracyclines on CDI risk (OR = 0.92; 95% CI, 0.61 to 1.40). In the community setting, there is substantial variation in the risk of CDI associated with different antimicrobial classes. Avoidance of high-risk antibiotics (such as clindamycin, CMCs, and fluoroquinolones) in favor of lower-risk antibiotics (such as penicillins, macrolides, and tetracyclines) may help reduce the incidence of CDI.

Intestinal epithelial restitution after TcdB challenge and recovery from Clostridium difficile infection in mice with alanyl-glutamine treatment

BACKGROUND

Clostridium difficile is an anaerobic bacterium that causes antibiotic-associated diarrhea. It produces toxin A and toxin B (TcdB), which cause injury to the gut epithelium. Glutamine is a fundamental fuel for enterocytes, maintaining intestinal mucosal health. Alanyl-glutamine (AQ) is a highly soluble dipeptide derivative of glutamine. We studied whether administration of AQ ameliorates the effects of TcdB in the intestinal cells and improves the outcome of C. difficile infection in mice.

METHODS

WST-1 proliferation and cell-wounding-migration assays were assessed in IEC-6 cells exposed to TcdB, with or without AQ. Apoptosis and necrosis were assessed using Annexin V and flow cytometry. C57BL/6 mice were infected with VPI 10463 and treated with either vancomycin, AQ, or vancomycin with AQ. Intestinal tissues were collected for histopathologic analysis, apoptosis staining, and determination of myeloperoxidase activity.

RESULTS

AQ increased proliferation in intestinal cells exposed to TcdB, improved migration at 24 and 48 hours, and reduced apoptosis in intestinal cells challenged with TcdB. Infected mice treated with vancomycin and AQ had better survival and histopathologic findings than mice treated with vancomycin alone.

CONCLUSIONS

AQ may reduce intestinal mucosal injury in C. difficile-infected mice by partially reversing the effects of TcdB on enterocyte proliferation, migration, and apoptosis, thereby improving survival from C. difficile infection.

Clostridium difficile Infection in travelers--a neglected pathogen?

BACKGROUND

Until recently, Clostridium difficile infection (CDI) has been mostly diagnosed in hospitalized elderly patients treated with antibacterial agents. The epidemiology of C difficile is changing as the ribotype 027 strain is spreading worldwide, and more infections are diagnosed in patients residing in the community. Although only few data about the epidemiology of CDI in developing countries are available, a number of reports seem to indicate that the incidence of CDI may be high in some such countries. Transmission of CDI may be more common in hospitals that lack the resources for efficient infection control programs. Theoretically, travelers to low-income countries may be exposed to C difficile both in the community and within hospitals.

METHODS

Data for this article were identified by searches of PubMed and MEDLINE, and references from relevant articles using the search terms "clostridium" and "travel." Abstracts were included when related to previously published work.

RESULTS AND CONCLUSIONS

A total of 48 cases of travelers with CDI were located. CDI among travelers was more commonly acquired in low- and medium-income countries, although 20% of all reported cases occurred in travelers returning from high-income countries. All travelers with CDI for whom a detailed history was available acquired the infection in the community. CDI in travelers occurred in relatively young patients and was frequently associated with the empiric use of antibacterial agents, notably fluoroquinolones. A sizable minority of travelers with CDI had no exposure to antibacterial agents at all. The incidence of travel-related CDI is unknown, but may be higher than previously suspected. A prospective study among travelers with unexplained acute or chronic diarrhea is warranted.

Five years experience of Clostridium difficile infection in children at a UK tertiary hospital: proposed criteria for diagnosis and management

Background

Clostridium difficile infection (CDI) is associated with significant morbidity and mortality in adults. There is increasing evidence of the pathogenic role of C. difficile in the paediatric population. We sought to ascertain the clinical presentation and severity of CDI in children at our institution and develop criteria to aid management.

Methods

Clinical data was retrospectively collected from all children (0–16 yrs) with a positive C. difficile toxin result over a 5-year period. National adult guidelines were used to assess the severity and management of CDI.

Results

Seventy-five patients were included with a mean age of 2.97 years. Forty-nine were hospital onset, 22 community onset and 4 healthcare-associated. The most common co-morbidity among the hospital onset infections was malignancy. Gastrointestinal conditions were most common among community onset infections. Fifty-five cases (73.3%) had received antibiotics in the preceding month, 7 (9.3%) had cow’s milk intolerance and 9 (12%) had co-infection with another gut pathogen. According to national adult guidelines 57 cases (76%) were categorised as severe. Thirty cases received oral metronidazole, two patients required intensive care and one patient had a sub-total colectomy for pseudomembranous colitis. No mortality was observed.

Discussion

We confirm the association of paediatric CDI with co-morbidities such as haematological and solid organ malignancies, recent antibiotic use and hospitalisation. We observed an association between cows milk protein intolerance and C. difficile. The use of adult criteria overestimated severity of disease in this cohort, as most cases experienced a mild course of illness with low morbidity and no mortality. This indicates that adult scoring criteria are not useful in guiding management and we propose specific criteria for children.

Microevolutionary analysis of Clostridium difficile genomes to investigate transmission

BACKGROUND

The control of Clostridium difficile infection is a major international healthcare priority, hindered by a limited understanding of transmission epidemiology for these bacteria. However, transmission studies of bacterial pathogens are rapidly being transformed by the advent of next generation sequencing.

RESULTS

Here we sequence whole C. difficile genomes from 486 cases arising over four years in Oxfordshire. We show that we can estimate the times back to common ancestors of bacterial lineages with sufficient resolution to distinguish whether direct transmission is plausible or not. Time depths were inferred using a within-host evolutionary rate that we estimated at 1.4 mutations per genome per year based on serially isolated genomes. The subset of plausible transmissions was found to be highly associated with pairs of patients sharing time and space in hospital. Conversely, the large majority of pairs of genomes matched by conventional typing and isolated from patients within a month of each other were too distantly related to be direct transmissions.

CONCLUSIONS

Our results confirm that nosocomial transmission between symptomatic C. difficile cases contributes far less to current rates of infection than has been widely assumed, which clarifies the importance of future research into other transmission routes, such as from asymptomatic carriers. With the costs of DNA sequencing rapidly falling and its use becoming more and more widespread, genomics will revolutionize our understanding of the transmission of bacterial pathogens.

Changing epidemiology of Clostridium difficile-associated disease during stem cell transplantation

The incidence and severity of Clostridium difficile-associated disease (CDAD) within the general population has risen dramatically over the past decade, yet little data are available from hematopoietic stem cell transplantation (HSCT) centers. In the present study, we performed a chart review of 822 consecutive autologous and allogeneic HCST recipients treated at Northwestern Memorial Hospital between 2004 and 2008 to determine the incidence of CDAD at our institution. Variables including age, sex, diagnosis, chemotherapy regimen, transplantation type, microbial colonization, coinfections, diet, antibiotic use, neutropenic fever, comorbid conditions, time to engraftment, growth factor administration, and occurrence of graft-versus-host disease were assessed as potential risk factors for the development of CDAD. Eighty-five CDAD cases (10.3%) were identified. Bivariate analysis revealed a significant association between CDAD and neutropenic fever, administration of a neutropenic diet, ciprofloxacin and aztreonam use and duration of therapy, vancomycin and aztreonam use and duration of therapy, receipt of an allogeneic transplantation, bacterial coinfection, and vancomycin-resistant Entereococcus faecium (VRE) colonization. Cox regression analysis identified the following as factors associated with the development of CDAD: age >60 years, allogeneic transplantation, and prior VRE colonization. Allogeneic recipients with CDAD experienced increased higher rates of grades II to IV gastrointestinal graft-versus-host disease and nonrelapse mortality. A risk stratification model was developed to identify HSCT recipients at different levels of risk. With an incidence >10%, CDAD is a significant infectious complication of stem cell transplantation.

PPI therapy and albumin are better predictors of recurrent Clostridium difficile colitis than choice of antibiotics

BACKGROUND

Recurrent Clostridium difficile colitis (RCDC) is common, but data regarding recurrence rates and predisposing factors are sparse.

METHODS

A retrospective case-control study was performed, identifying all inpatients and outpatients ≥18 years of age with C. difficile colitis (CDC) confirmed by a positive stool sample collected at our institution from January 2008 to August 2011. Factors associated with RCDC, the number of RCDC episodes, and the need for admission for RCDC were sought.

RESULTS

A total of 739 patients (male, 47 %) were studied, of whom 527 (71 %) received inpatient treatment for their index episode of CDC. There was no difference (p = 0.53) between RCDC rates for inpatients (17.6 %) and outpatients (19.8 %). While severity score and albumin were associated with RCDC in our population, use of proton pump inhibitors (PPIs) correlated with decreased RCDC (p = 0.006) and decreased need for admission (p = 0.005). The addition of vancomycin to metronidazole therapy did not lower RCDC rates (p = 0.52) or decrease the need for admission (p = 0.78).

CONCLUSIONS

Hypoalbuminemia strongly correlated with higher recurrence rates, while PPI therapy actually reduced RCDC, representing previously underappreciated potential therapeutic targets for lowering CDC recurrence. The addition of vancomycin to metronidazole did not improve RCDC rates.

Current status of Clostridium difficile infection epidemiology

The dramatic changes in the epidemiology of Clostridium difficile infection (CDI) during recent years, with increases in incidence and severity of disease in several countries, have made CDI a global public health challenge. Increases in CDI incidence have been largely attributed to the emergence of a previously rare and more virulent strain, BI/NAP1/027. Increased toxin production and high-level resistance to fluoroquinolones have made this strain a very successful pathogen in healthcare settings. In addition, populations previously thought to be at low risk are now being identified as having severe CDI. Recent genetic analysis suggests that C. difficile has a highly fluid genome with multiple mechanisms to modify its content and functionality, which can make C. difficile adaptable to environmental changes and potentially lead to the emergence of more virulent strains. In the face of these changes in the epidemiology and microbiology of CDI, surveillance systems are necessary to monitor trends and inform public health actions.

Community-acquired Clostridium difficile NAP1/027-associated diarrhea in an eighteen month old child

Clostridium difficile infection (CDI), characterized by symptoms varying from diarrhea to life-threatening colitis, is a major complication of antibiotic therapy. Studies suggested that CDI is emerging as an important cause of childhood diarrhea in community and hospital settings. This work is the first report of a documented case of community-acquired CDI by a NAP1 hypervirulent strain in an eighteen month old child from Latin America.

Clostridium difficile: a European perspective

Clostridium difficile infection is the leading cause of diarrhoea in the industrialised world. First identified in 1935, our knowledge about the clonal population structure, toxins and PCR ribotypes is still increasing. New PCR ribotypes and sequence types are frequently added. In the last decade hypervirulent strains have emerged and been associated with increased severity of disease, high recurrence and significant mortality. Although previously a primarily hospital- or health-care acquired infection, since the 1990's C. difficile infections that are community-acquired have been increasingly reported. Risk factors include hospitalisation, advancing age and prior antibiotic use. The ubiquitous presence of C. difficile in the environment and asymptomatic intestinal colonisation may be important reservoirs for infection and the changing epidemiology of C. difficile infection. Although surveillance in Europe is now a requirement of the European Commission, reporting is not standardised or mandatory. Here we review the current literature, guidelines on diagnosis and treatment and conclude by highlighting a number of areas where further research would increase our understanding.

Clostridium difficile Infection in Children: Current State and Unanswered Questions

The incidence of Clostridium difficile infection (CDI) in children has increased over the past decade. In recent years, new and intriguing data on pediatric CDI have emerged. Community-onset infections are increasingly recognized, even in children who have not previously received antibiotics. A hypervirulent strain is responsible for up to 20% of pediatric CDI cases. Unique risk factors for CDI in children have been identified. Advances in diagnostic testing strategies, including the use of nucleic acid amplification tests, have raised new questions about the optimal approach to diagnosing CDI in children. Novel therapeutic options are available for adult patients with CDI, raising questions about the use of these agents in children. Updated recommendations about infection prevention and control measures are now available. We summarize these recent developments in pediatric CDI in this review and also highlight remaining knowledge gaps that should be addressed in future research efforts.