Update on Clostridium difficile infection

Prevalence of Clostridium Difficile Infection (CDI) among Inflammatory Bowel Disease (IBD) Patients in Comparison to Non-IBD Patients in King Abdulaziz Medical City in Jeddah

Background

The prevalence of Clostridium difficile infection (CDI) as a common complication among inflammatory bowel disease (IBD) has been reported to increase worldwide and has been associated with a poor IBD outcome.

Objectives

In this study, our aim was to report on the prevalence of CDI among IBD vs. non-IBD patients in King Abdulaziz Medical City (KAMC).

Methods

This retrospective descriptive study was carried out between 2016 and 2020. Data of 89 patients reported with CDI in KAMC were analyzed for demographics and correlations between various characteristics such as BMI, personal/family history of IBD, infection with CDI, diagnosis, method of diagnosis, and treatment modalities.

Results

Of the total 89 CDI patients, 59 (66.3%) were adults and 30 (33.7%) were pediatric, of which 36 (40.4%) were females and 53 (59.6%) were males. PCR was the main method of choice for the diagnosis of CDI (89.9%) followed by a positive-culture result (10.0%). Seventy-eight (87.6%) CDI patients were found to be immunocompromised, with two patients diagnosed with IBDs, one with UC, and one with CD. The recurrence rate was 38.4 (30 patients) among the immunocompromised group in comparison to 27.2 (3 patients) in the immunocompetent group (p=0.584).

Conclusion

In this study, we found that adults were more prone to CDI infection, especially within hospital settings, and most of the CDI infections occurred in immunocompromised individuals, with cancer as the most common cause of it.

Microbial Resistance to Antibiotics and Effective Antibiotherapy

Currently, the efficacy of antibiotics is severely affected by the emergence of the antimicrobial resistance phenomenon, leading to increased morbidity and mortality worldwide. Multidrug-resistant pathogens are found not only in hospital settings, but also in the community, and are considered one of the biggest public health concerns. The main mechanisms by which bacteria develop resistance to antibiotics include changes in the drug target, prevention of entering the cell, elimination through efflux pumps or inactivation of drugs. A better understanding and prediction of resistance patterns of a pathogen will lead to a better selection of active antibiotics for the treatment of multidrug-resistant infections.

Prevalence of Detection of Clostridioides difficile Among Asymptomatic Children: A Systematic Review and Meta-analysis

IMPORTANCE

Detection of Clostridioides difficile has frequently been described in asymptomatic infants and children, but accurate estimates across the age spectrum are unavailable.

OBJECTIVE

To assess the prevalence of C difficile detection among asymptomatic children across the age spectrum.

DATA SOURCES

This systematic review and meta-analysis included a search of the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, CINAHL, Scopus, and Web of Science for articles published from January 1, 1990, to December 31, 2020. Search terms included Clostridium difficile, Peptoclostridium difficile, Clostridioides difficile, CDF OR CDI OR c diff OR c difficile, Clostridium infections OR cd positive diarrhea OR cd positive diarrhea OR Clostridium difficile OR Peptoclostridium difficile OR pseudomembranous colitis OR pseudomembranous enterocolitis, enterocolitis, and pseudomembranous. These were combined with the following terms: bacterial colonization and colonization OR colonized OR colonizing OR epidemiology OR prevalence OR seroprevalence.

STUDY SELECTION

Studies were screened independently by 2 authors. Studies were included if they reported testing for C difficile among asymptomatic children (ie, children without diarrhea) younger than 18 years.

DATA EXTRACTION AND SYNTHESIS

Data were extracted independently and in duplicate by 2 reviewers. Preferred Reporting Items for a Systematic Review and Meta-analysis (PRISMA) guidelines were used. Data were pooled using a random-effects model.

MAIN OUTCOMES AND MEASURES

The primary outcome was prevalence of C difficile detection among asymptomatic children. Secondary outcomes included prevalence of toxigenic vs nontoxigenic strains of C difficile and prevalence of C difficile detection stratified by geographic region, income status, testing method, and year of testing.

RESULTS

A total of 95 studies with 19 186 participants were included. Rates of detection of toxigenic or nontoxigenic C difficile were greatest among infants aged 6 to 12 months (41%; 95% CI, 32%-50%) and decreased to 12% (95% CI, 7%-18%) among children aged 5 to 18 years. The prevalence of toxigenic C difficile colonization was lower, peaking at 14% (95% CI, 8%-21%) among infants aged 6 to 12 months and decreasing to 6% (95% CI, 2%-11%) among children older than 5 years. Although prevalence differed by geographic region (ie, North and South America vs Europe: β, -0.151, P = .001; North and South America vs Western Pacific: β, 0.136, P = .007), there was no difference by testing method (ie, culture vs polymerase chain reaction: β, 0.069, P = .052; culture vs enzyme immunoassay: β, -0.178, P = .051), income class (low-middle income vs high income: β, -0.144, P = .23; upper-middle vs high income: β, -0.020, P = .64), or period (before 1990 vs 2010-2020: β, -0.125, P = .19; 1990-1999 vs 2010-2020: β, -0.037, P = .42; 2000-2009 vs 2010-2020: β, -0.006, P = .86).

CONCLUSIONS AND RELEVANCE

In this systematic review and meta-analysis, C difficile colonization rates among children were greatest at 6 to 12 months of age and decreased thereafter. These estimates may provide context for interpreting C difficile test results among young children.

Novel immunoassay for diagnosis of ongoing Clostridioides difficile infections using serum and medium enriched for newly synthesized antibodies (MENSA)

BACKGROUND

Clostridioides difficile infections (CDI) have been a challenging and increasingly serious concern in recent years. While early and accurate diagnosis is crucial, available assays have frustrating limitations.

OBJECTIVE

Develop a simple, blood-based immunoassay to accurately diagnose patients suffering from active CDI.

MATERIALS AND METHODS

Uninfected controls (N = 95) and CDI patients (N = 167) were recruited from Atlanta area hospitals. Blood samples were collected from patients within twelve days of a positive CDI test and processed to yield serum and PBMCs cultured to yield medium enriched for newly synthesized antibodies (MENSA). Multiplex immunoassays measured Ig responses to ten recombinant C. difficile antigens.

RESULTS

Sixty-six percent of CDI patients produced measurable responses to C. difficile antigens in their serum or MENSA within twelve days of a positive CDI test. Fifty-two of the 167 CDI patients (31%) were detectable in both serum and MENSA, but 32/167 (19%) were detectable only in MENSA, and 27/167 (16%) were detectable only in serum.

DISCUSSION

We describe the results of a multiplex immunoassay for the diagnosis of ongoing CDI in hospitalized patients. Our assay resolved patients into four categories: MENSA-positive only, serum-positive only, MENSA- and serum-positive, and MENSA- and serum-negative. The 30% of patients who were MENSA-positive only may be accounted for by nascent antibody secretion prior to seroconversion. Conversely, the serum-positive only subset may have been more advanced in their disease course. Immunocompromise and misdiagnosis may have contributed to the 34% of CDI patients who were not identified using MENSA or serum immunoassays.

IMPORTANCE

While there was considerable overlap between patients identified through MENSA and serum, each method detected a distinctive patient group. The combined use of both MENSA and serum to detect CDI patients resulted in the greatest identification of CDI patients. Together, longitudinal analysis of MENSA and serum will provide a more accurate evaluation of successful host humoral immune responses in CDI patients.

Multicenter Prevalence Study Comparing Molecular and Toxin Assays for Clostridioides difficile Surveillance, Switzerland

Public health authorities in the United States and Europe recommend surveillance for Clostridioides difficile infections among hospitalized patients, but differing diagnostic algorithms can hamper comparisons between institutions and countries. We compared surveillance based on detection of C. difficile by PCR or enzyme immunoassay (EIA) in a nationwide C. difficile prevalence study in Switzerland. We included all routinely collected stool samples from hospitalized patients with diarrhea in 76 hospitals in Switzerland on 2 days, 1 in winter and 1 in summer, in 2015. EIA C. difficile detection rates were 6.4 cases/10,000 patient bed-days in winter and 5.7 cases/10,000 patient bed-days in summer. PCR detection rates were 11.4 cases/10,000 patient bed-days in winter and 7.1 cases/10,000 patient bed-days in summer. We found PCR used alone increased reported C. difficile prevalence rates by <80% compared with a 2-stage EIA-based algorithm.

Management of difficult-to-treat Clostridioides difficile in a patient with chronic osteomyelitis

A 61-year-old male patient being treated with intravenous antibiotics for left foot osteomyelitis presented to the hospital septic, with several days of worsening abdominal pain, bloating and watery bowel movements. Investigation revealed that the patient had severe, treatment-resistant Clostridioides difficile colitis. He was initially treated with oral vancomycin and intravenous metronidazole, which was switched to oral fidaxomicin. After no improvement in the patient's symptoms, he was treated with two faecal microbiota transplants. He was offered a third faecal microbiota transplant but declined. The patient was placed back on oral fidaxomicin and saw ultimate resolution of his symptoms. This case provides an example of a treatment pathway for refractory C. difficile infection.

Characterization of Circulating Clostridium difficile Strains, Host Response and Intestinal Microbiome in Hospitalized Children With Diarrhea

BACKGROUND

Clostridium difficile is capable of causing severe enterocolitis in adults. The significance of toxin-producing C. difficile in children with diarrhea is unclear and practice differs on whether to institute treatment. We aimed to characterize the microbiome in relation to the presence of C. difficile and co-infection with other pathogens and to describe host response to infection.

METHODS

Participants were children with acute diarrhea, 0-16 years of age, from whom stool samples had been submitted to the hospital laboratory for routine microbiology/virology. Convenience sampling was used for 50 prospective and 150 retrospective samples. No participants were treated for C. difficile. Rates of culture positivity for C. difficile, presence of toxin and PCR-ribotype were compared between age groups. Presence of other potential pathogens, comorbidities and complications were recorded. Microbiotal diversity was measured by 16S profiling.

RESULTS

Nineteen of 77 (25%) children <2 years of age and 13 of 119 (11%) children >2 years of age were C. difficile positive, of whom 10 (53%) and 9 (69%), respectively, carried toxigenic strains. Increased Shannon diversity was seen in children carrying C. difficile, with altered milieu. Presence of C. difficile was not associated with adverse clinical outcomes. In stools containing both Norovirus and C. difficile, there was increased relative abundance of verrucomicrobia.

CONCLUSIONS

Children with diarrhea regularly carried toxigenic and non-toxigenic strains of C. difficile, demonstrating enhanced microbiotal diversity, and change in milieu, without apparent morbidity. This unexpected finding is contrary to that seen in adults with C. difficile disease.

Faecal microbiota transplantation for Clostridium difficile infection using a lyophilized inoculum from non-related donors: A case series involving 19 patients

Faecal microbiota transplantation (FMT) has been reported to be effective in treating relapsing of refractory Clostridium difficile infections, although some practical barriers are limiting its widespread use. In this study, our objective was to evaluate the rate of resolution of diarrhea following administration of lyophilized and resolved FMT via a nasogastric (NG) tube. We recruited 19 patients suffered from laboratory-confirmed C. difficile infection. Each of them was treated by lyophilized and resolved inoculum through a NG tube. One participant succumbed following the procedure due to unrelated diseases. Out of 18 cases, 15 patients reportedly experienced a resolution of the symptoms. One patient was treated with another course of antibiotics, and two of the non-responders were successfully retreated with another course of FMT utilizing a lyophilized inoculum. Notably, no significant adverse activities were observed. In accordance to our clinical experiences, a patient will likely benefit from FMT treatment including lyophilized inoculum.

Clostridium difficile-associated Diarrhea in Developing Countries: A Systematic Review and Meta-Analysis

INTRODUCTION

The prevalence of Clostridium difficile infection is rapidly increasing worldwide, but prevalence is difficult to estimate in developing countries where awareness, diagnostic resources, and surveillance protocols are limited. As diarrhea is the hallmark symptom, we conducted a systematic review and meta-analysis to determine the prevalence and incidence of C. difficile infection in patients in these regions who presented with diarrhea.

METHODS

We conducted a systematic literature search of MEDLINE/PubMed, Scopus, and Latin-American and Caribbean Health Sciences Literature databases to identify and analyze data from recent studies providing prevalence or incidence rates of C. difficile-associated diarrhea in developing countries within four regions: Africa-Middle East, developing Asia, Latin America, and China. Our objectives were to determine the current prevalence and incidence density rates of first episodes of C. difficile-associated diarrhea in developing countries.

RESULTS

Within the regions included in our analysis, prevalence of C. difficile infection in patients with diarrhea was 15% (95% CI 13-17%) (including community and hospitalized patients), with no significant difference across regions. The incidence of C. difficile infection in 17 studies including this information was 8.5 per 10,000 patient-days (95% CI 5.83-12.46). Prevalence was significantly higher in hospitalized patients versus community patients (p  = 0.0227).

CONCLUSION

Our prevalence estimate of 15% is concerning; however, low awareness and inconsistent diagnostic and surveillance protocols suggest this is markedly underestimated. Enhanced awareness and management of C. difficile infection in patients with diarrhea, along with improvements in infection control and surveillance practices, should be implemented to reduce prevalence of C. difficile-associated diarrhea in developing countries.

FUNDING

Pfizer Inc.

The first isolation of Clostridium difficile RT078/ST11 from pigs in China

We investigated the molecular characteristics and antimicrobial susceptibility of Clostridium difficile isolated from animals in China. We obtained 538 rectal swabs from pigs, chickens and ducks in 5 provinces during 2015 and 2016. C. difficile isolates were characterized by detection of toxin genes, multilocus sequence typing and ribotyping. And antimicrobial susceptibility testing was performed using the agar dilution method. Out of 538 samples, 44 (8.2%) were C. difficile positive with high prevalence in pigs (n = 31). Among these, 39 (88.6%) were toxigenic including 14 (31.8%) that were A+B+CDT+ and 13 (29.5%) A+B+. The remaining 12 (27.3%) were A-B+. We identified 7 ST types and 6 PCR ribotypes. The most predominant type was ST11/RT078 with toxin profile A+B+CDT+ and all were isolated from piglets with diarrhea. ST109 isolates possessed two different toxigenic profiles (A-B-CDT- and A-B+CDT-) and although it was not the most prevalent sequence type, but it was widely distributed between chickens, ducks and pigs in the 5 provinces. All C. difficile isolates were fully susceptible to vancomycin, metronidazole, fidaxomicin, amoxicillin/clavulanate and meropenem but retained resistance to 4 or 5 of the remaining antibiotics, especially cefotaxime, tetracycline, ciprofloxacin, cefoxitin. The RT078/ST11 isolates were simultaneously resistant to cefotaxime, tetracycline, cefoxitin, ciprofloxacin and imipenem. This is the first report of the molecular epidemiology of C. difficile isolated from food animals in China. We identified the epidemic strain RT078/ST11 as the predominate isolate among the animals we screened in our study.

Oral Immunization with Nontoxigenic Clostridium difficile Strains Expressing Chimeric Fragments of TcdA and TcdB Elicits Protective Immunity against C. difficile Infection in Both Mice and Hamsters

The symptoms of Clostridium difficile infection (CDI) are attributed largely to two C. difficile toxins, TcdA and TcdB. Significant efforts have been devoted to developing vaccines targeting both toxins through parenteral immunization routes. However, C. difficile is an enteric pathogen, and mucosal/oral immunization would be particularly useful to protect the host against CDI, considering that the gut is the main site of disease onset and progression. Moreover, vaccines directed only against toxins do not target the cells and spores that transmit the disease. Previously, we constructed a chimeric vaccine candidate, mTcd138, comprised of the glucosyltransferase and cysteine proteinase domains of TcdB and the receptor binding domain of TcdA. In this study, to develop an oral vaccine that can target both C. difficile toxins and colonization/adhesion factors, we expressed mTcd138 in a nontoxigenic C. difficile (NTCD) strain, resulting in strain NTCD_mTcd138. Oral immunization with spores of NTCD_mTcd138 provided mice full protection against infection with a hypervirulent C. difficile strain, UK6 (ribotype 027). The protective strength and efficacy of NTCD_mTcd138 were further evaluated in the acute CDI hamster model. Oral immunization with spores of NTCD_mTcd138 also provided hamsters significant protection against infection with 2 × 10⁴ UK6 spores, a dose 200-fold higher than the lethal dose of UK6 in hamsters. These results imply that the genetically modified, nontoxigenic C. difficile strain expressing mTcd138 may represent a novel mucosal vaccine candidate against CDI.

Facilely accessible quinoline derivatives as potent antibacterial agents

Quinoline compounds have been extensively explored as anti-malaria and anti-cancer agents for decades and show profound functional bioactivities, however, the studies of these compounds in other medicinal fields have lagged dramatically. In this study, we report the development of a series of facilely accessible quinoline derivatives that display potent antibacterial activity against a panel of multidrug-resistant Gram-positive bacterial strains, especially C. difficile. We also demonstrated that these molecules are effective in vivo against C. difficile. These results revealed that these types of quinoline compounds could serve as prototypes for the development of an appealing class of antibiotic agents used to combat Gram-positive drug-resistant bacterial strains, including C. difficile.

Role of intestinal Clostridium in pathogenesis and treatment of diarrhea

Clostridium is a group of facultative anaerobic bacteria in the intestinal tract and is closely related to many diseases. By producing toxins and gas, Clostridium difficile and Clostridium perfringens can induce diarrhea. Clostridium butyricum, Faecalibacterium prausnitzii and other probiotics, Clostridium toxin vaccine, antibiotics, fecal bacteria transplantation, and other means are the main methods which are clinically used to inhibit the proliferation of harmful Clostridium and restore the balance of intestinal flora. In this paper, we will review the role of intestinal Clostridium in the pathogenesis and treatment of diarrhea to promote the exploration of new therapeutic methods for diarrhea caused by intestinal Clostridium infection.

Clostridium difficile Infections: A Global Overview of Drug Sensitivity and Resistance Mechanisms

Clostridium difficile (C. difficile) is the most prevalent causative pathogen of healthcare-associated diarrhea. Notably, over the past 10 years, the number of Clostridium difficile outbreaks has increased with the rate of morbidity and mortality. The occurrence and spread of C. difficile strains that are resistant to multiple antimicrobial drugs complicate prevention as well as potential treatment options. Most C. difficile isolates are still susceptible to metronidazole and vancomycin. Incidences of C. difficile resistance to other antimicrobial drugs have also been reported. Most of the antibiotics correlated with C. difficile infection (CDI), such as ampicillin, amoxicillin, cephalosporins, clindamycin, and fluoroquinolones, continue to be associated with the highest risk for CDI. Still, the detailed mechanism of resistance to metronidazole or vancomycin is not clear. Alternation in the target sites of the antibiotics is the main mechanism of erythromycin, fluoroquinolone, and rifamycin resistance in C. difficile. In this review, different antimicrobial agents are discussed and C. difficile resistance patterns and their mechanism of survival are summarized.

Clostridium difficile infection in hospitalized patients with inflammatory bowel disease: Prevalence, risk factors, and prognosis

To evaluate the frequency, possible risk factors, and outcome of Clostridium difficile infection (CDI) in inflammatory bowel disease (IBD) patients.There has been an upsurge of CDI in patients with IBD who has been associated with increased morbidity and mortality. Various risk factors have been found to predispose IBD patients to CDI.A retrospective case-control study on IBD patients admitted with exacerbation and tested for CDI at the Tel Aviv Medical Center in 2008 to 2013. Epidemiologic, laboratory, and prognostic data were retrieved from electronic files and compared between patients who tested positive (CDI+) or negative (CDI-) for CDI.CDI was identified in 28 of 311 (7.31%) IBD patients hospitalized with diarrhea. IBD-specific risk factors (univariate analysis) for CDI included: use of systemic steroids therapy (odds ratio [OR] = 3.6, 95% confidence interval [CI] 1.2-10.6) and combinations of ≥2 immunomodulator medications (OR = 2.6, 95% CI 1.1-6.3). Additional risk factors for CDI that are common in the general population were hospitalization in the preceding 2 months (OR = 6.0, 95% CI 2.6-14.1), use of antacids (OR = 3.8, 95% CI 1.7-8.4), and high Charlson comorbidity score (OR = 2.5, 95% CI 1.1-5.7). A multivariate analysis confirmed that only hospitalization within the preceding 2 months and use of antacids were significant risk factors for CDI. The prognosis of CDI+ patients was similar to that of CDI- patients.Hospitalized IBD patients with exacerbation treated with antacids or recently hospitalized are at increased risk for CDI and should be tested and empirically treated until confirmation or exclusion of the infection.

Surveillance of antibiotic resistance among common Clostridium difficile ribotypes in Hong Kong

Incidence of Clostridium difficile infection (CDI) is rapidly increasing and it poses a major health burden globally. However, data regarding the epidemiology of CDI in Asia are limited. We aimed to characterize the antimicrobial susceptibility patterns of common ribotypes of toxigenic C. difficile in Hong Kong. Fifty-three PCR ribotypes were identified among 284 toxigenic C. difficile clinical isolates. The five most prevalent ribotypes were 002 (13%), 017 (12%), 014 (10%), 012 (9.2%), and 020 (9.5%). All tested C. difficile strains remained susceptible to metronidazole, vancomycin, meropenem and piperacillin/tazobactam, but highly resistant to cephalosporins. Of the fluoroquinolones, highest resistance to ciprofloxacin was observed (99%), followed by levofloxacin (43%) and moxifloxacin (23%). The two newly emerged PCR ribotypes, 017 and 002, demonstrated high levels of co-resistance towards clindamycin, tetracycline, erythromycin and moxifloxacin. PCR ribotypes 017 and 002 with multi-drug resistance are rapidly emerging and continuous surveillance is important to monitor the epidemiology of C. difficile to prevent outbreaks of CDI.

Genome characterization of a novel binary toxin-positive strain of Clostridium difficile and comparison with the epidemic 027 and 078 strains

Background

Clostridium difficile is an anaerobic Gram-positive spore-forming gut pathogen that causes antibiotic-associated diarrhea worldwide. A small number of C. difficile strains express the binary toxin (CDT), which is generally found in C. difficile 027 (ST1) and/or 078 (ST11) in clinic. However, we isolated a binary toxin-positive non-027, non-078 C. difficile LC693 that is associated with severe diarrhea in China. The genotype of this strain was determined as ST201. To understand the pathogenesis-basis of C. difficile ST201, the strain LC693 was chosen for whole genome sequencing, and its genome sequence was analyzed together with the other two ST201 strains VL-0104 and VL-0391 and compared to the epidemic 027/ST1 and 078/ST11 strains.

Results

The project finally generated an estimated genome size of approximately 4.07 Mbp for strain LC693. Genome size of the three ST201 strains ranged from 4.07 to 4.16 Mb, with an average GC content between 28.5 and 28.9%. Phylogenetic analysis demonstrated that the ST201 strains belonged to clade 3. The ST201 genomes contained more than 40 antibiotic resistance genes and 15 of them were predicted to be associated with vancomycin-resistance. The ST201 strains contained a larger PaLoc with a Tn6218 element inserted than the 027/ST1 and 078/ST11 strains, and encoded a truncated TcdC. In addition, the ST201 strains contained intact binary toxin coding and regulation genes which are highly homologous to the 027/ST1 strain. Genome comparison of the ST201 strains with the epidemic 027 and 078 strain identified 641 genes specific for C. difficile ST201, and a number of them were predicted as fitness and virulence associated genes. The presence of those genes also contributes to the pathogenesis of the ST201 strains.

Conclusions

In this study, the genomic characterization of three binary toxin-positive C. difficile ST201 strains in clade 3 was discussed and compared to the genomes of the epidemic 027 and the 078 strains. Our analysis identified a number fitness and virulence associated genes/loci in the ST201 genomes that contribute to the pathogenesis of C. difficile ST201.

Electronic supplementary material

The online version of this article (doi:10.1186/s13099-017-0191-z) contains supplementary material, which is available to authorized users.

Update on Antimicrobial Resistance in Clostridium difficile: Resistance Mechanisms and Antimicrobial Susceptibility Testing

Oral antibiotics such as metronidazole, vancomycin and fidaxomicin are therapies of choice for Clostridium difficile infection. Several important mechanisms for C. difficile antibiotic resistance have been described, including the acquisition of antibiotic resistance genes via the transfer of mobile genetic elements, selective pressure in vivo resulting in gene mutations, altered expression of redox-active proteins, iron metabolism, and DNA repair, as well as via biofilm formation. This update summarizes new information published since 2010 on phenotypic and genotypic resistance mechanisms in C. difficile and addresses susceptibility test methods and other strategies to counter antibiotic resistance of C. difficile.

The Association between GABA-Modulators and Clostridium difficile Infection - A Matched Retrospective Case-Control Study

OBJECTIVE

Recently, metabolomics studies have suggested that the neurotransmitter γ-amino butyric acid (GABA) may modulate C. difficile infection (CDI) pathogenesis. In the present study, we investigated the association between GABA-modulating pharmaceuticals and CDI development.

METHODS

In July-December 2013, we performed a matched, retrospective case-control study in Skåne county, Sweden, to assess the association between the use of GABA-modulators (defined as regular use of at least one of the following: zolpidem, zopiclone, benzodiazepines, gabapentin, pregabalin or baclofen) and CDI. Multivariate regression models, adjusted for known risk factors for CDI, were fitted to assess the associations and a propensity score-adjusted analysis was performed.

RESULTS

The study included 292 cases and 292 matched controls. In a multivariate regression model only recent antibiotic use (clindamycin, cephalosporins and fluoroquinolones) and nursing home residency was significantly associated with CDI. The regular use of any GABA-modulator was not associated with CDI (OR = 1.07, 95%CI 0.69-1.66, p = 0.76). The association between regular use of the selective GABA-agonist zolpidem and CDI trended towards significance (OR = 2.31, 95%CI 0.91-5.86, p = 0.078). These associations remained when only cases treated with antibiotics were included. Corresponding findings for zolpidem was observed in a propensity-score adjusted analysis (OR = 2.52, 95% CI 0.91-6.97, p = 0.075). Severe initial CDI was significantly associated with CDI recurrence (OR = 3.77, 95% CU 1.20-11.86, p = 0.023).

CONCLUSION

This study did not identify a general association between GABA-modulators and CDI. A trend towards a significant association between zolpidem and CDI was observed, an association that should be re-assessed in a study appropriately powered for this particular hypothesis.

Clostridium difficile Infections in Children: Impact of the Diagnostic Method on Infection Rates

BACKGROUND

Polymerase chain reaction (PCR) assays based on the detection of the toxin B gene are replacing enzyme-linked immunosorbent assay (ELISA)–based toxin production detection or cell cytotoxicity assay in most laboratories.

OBJECTIVE

To determine the proportion of pediatric patients diagnosed withClostridium difficile infection by PCR who would have also been diagnosed by ELISA and to compare the clinical characteristics of PCR+/ELISA+ vs PCR+/ELISA− patients.

METHODS

Using the microbiology laboratory information system, stool samples positive for C. difficile by PCR between October 2010 and July 2014 were identified. Using frozen stool specimens, an ELISA for toxin A and B was performed. A retrospective medical chart review was conducted to obtain demographic and clinical data. Duplicate samples were excluded.

RESULTS

A total of 136 PCR-positive samples underwent ELISA testing: 54 (40%) were positive for toxin A or B. The mean (SD) age of the entire cohort was 8.5 (6.2) years. There was no difference in age, gender, clinical manifestation, previous medical problems, and management between patients positive or negative by ELISA. However, patients positive by ELISA were more likely to have had a recent exposure to antibiotics (67.9% vs 50%; crude odds ratio, 2.1 [95% CI, 1.03–4.28]).

CONCLUSION

In our pediatric population, 60% of patients with C. difficile diagnosed by PCR had no toxin detectable by ELISA. ELISA-negative patients were less likely to have received an antibiotic recently compared with ELISA-positive patients. These results highlight the need to standardize laboratory criteria for the diagnosis of C. difficile infections in children.

Infect Control Hosp Epidemiol 2016;37:1087–1093

The role of Clostridium difficile in the paediatric and neonatal gut - a narrative review

Clostridium difficile is an important nosocomial pathogen in adults. Its significance in children is less well defined, but cases of C. difficile infection (CDI) appear to be increasingly prevalent in paediatric patients. This review aims to summarize reported Clostridium difficile carriage rates across children of different age groups, appraise the relationship between CDI and factors such as method of delivery, type of infant feed, antibiotic use, and co-morbidities, and review factors affecting the gut microbiome in children and the host immune response to C. difficile. Searches of PubMed and Google Scholar using the terms 'Clostridium difficile neonates' and 'Clostridium difficile children' were completed, and reference lists of retrieved publications screened for further papers. In total, 88 papers containing relevant data were included. There was large inter-study variation in reported C. difficile carriage rates. There was an association between CDI and recent antibiotic use, and co-morbidities such as immunosuppression and inflammatory bowel disease. C. difficile was also found in stools of children with diarrhoea attributed to other pathogens (e.g. rotavirus). The role of C. difficile in the paediatric gut remains unclear; is it an innocent bystander in diarrhoeal disease caused by other organisms, or a pathogen causing subclinical to severe symptoms? Further investigation of the development of serological and local host response to C. difficile carriage may shed new light on disease mechanisms. Work is underway on defining a framework for diagnosis and management of paediatric CDI.

Development of Photodynamic Antimicrobial Chemotherapy (PACT) for Clostridium difficile

BACKGROUND

Clostridium difficile is the leading cause of antibiotic-associated diarrhoea and pseudo membranous colitis in the developed world. The aim of this study was to explore whether Photodynamic Antimicrobial Chemotherapy (PACT) could be used as a novel approach to treating C. difficile infections.

METHODS

PACT utilises the ability of light-activated photosensitisers (PS) to produce reactive oxygen species (ROS) such as free radical species and singlet oxygen, which are lethal to cells. We screened thirteen PS against C. difficile planktonic cells, biofilm and germinating spores in vitro, and cytotoxicity of effective compounds was tested on the colorectal adenocarcinoma cell-line HT-29.

RESULTS

Three PS were able to kill 99.9% of bacteria in both aerobic and anaerobic conditions, both in the planktonic state and in a biofilm, after exposure to red laser light (0.2 J/cm2) without harming model colon cells. The applicability of PACT to eradicate C. difficile germinative spores indirectly was also shown, by first inducing germination with the bile salt taurocholate, followed by PACT.

CONCLUSION

This innovative and simple approach offers the prospect of a new antimicrobial therapy using light to treat C. difficile infection of the colon.

Flooding and Clostridium difficile Infection: A Case-Crossover Analysis

Clostridium difficile is a bacterium that can spread by water. It often causes acute gastrointestinal illness in older adults who are hospitalized and/or receiving antibiotics; however, community-associated infections affecting otherwise healthy individuals have become more commonly reported. A case-crossover study was used to assess emergency room (ER) and outpatient visits for C. difficile infection following flood events in Massachusetts from 2003 through 2007. Exposure status was based on whether or not a flood occurred prior to the case/control date during the following risk periods: 0-6 days, 7-13 days, 14-20 days, and 21-27 days. Fixed-effects logistic regression was used to estimate the risk of diagnosis with C. difficile infection following a flood. There were 129 flood events and 1575 diagnoses of C. difficile infection. Among working age adults (19-64 years), ER and outpatient visits for C. difficile infection were elevated during the 7-13 days following a flood (Odds Ratio, OR = 1.69; 95% Confidence Interval, CI: 0.84, 3.37). This association was more substantial among males (OR = 3.21; 95% CI: 1.01-10.19). Associations during other risk periods were not observed (p < 0.05). Although we were unable to differentiate community-associated versus nosocomial infections, a potential increase in C. difficile infections should be considered as more flooding is projected due to climate change.

Improved detection of gastrointestinal pathogens using generalised sample processing and amplification panels

We aimed to streamline the diagnosis of gastrointestinal disease by producing multiplexed real time polymerase chain reaction (PCR) panels employing universal sample processing for DNA and RNA containing pathogens. A total of 487 stored, previously characterised stool samples comprising bacterial, viral, protozoan and Clostridium difficile positive samples were tested using four multiplexed real time PCR panels. A further 81 pre-selected clinical samples from a teaching hospital were included to provide an independent validation of assay performance. Improved sensitivity was achieved using the protozoan panels and 16 more mixed infections were observed compared to tests with conventional methods. Using the C. difficile panels, 100% sensitivity was achieved when compared to the gold standard of toxigenic culture. In addition, hypervirulent strains including ribotype 027 could be identified directly from primary sample without the need for ribotyping methods. Bacterial and viral panels detecting Salmonella, Shigella, Campylobacter, Yersinia enterocolitica, Listeria monocytogenes, norovirus groups I and II, rotavirus A, astrovirus, sapovirus, rotavirus B, adenovirus and adenovirus 40/41 performed as well as conventional methods, whilst allowing detection in 3 hours from processing to result. Multiplex real time PCR panels with universal sample preparation allow streamlined, rapid diagnosis of gastrointestinal pathogens whilst extending the characterisation of pathogens present in stool samples from affected patients.

Protein composition of the outermost exosporium-like layer of Clostridium difficile 630 spores

Clostridium difficile spores are considered the morphotype of infection, transmission and persistence of C. difficile infections. There is a lack of information on the composition of the outermost exosporium layer of C. difficile spores. Using recently developed exosporium removal methods combined with MS/MS, we have established a gel-free approach to analyze the proteome of the exosporium of C. difficile spores of strain 630. A total of 184 proteins were found in the exosporium layer of C. difficile spores. We identified 7 characterized spore coat and/or exosporium proteins; 6 proteins likely to be involved in spore resistance; 6 proteins possibly involved in pathogenicity; 13 uncharacterized proteins; and 146 cytosolic proteins that might have been encased into the exosporium during assembly, similarly as reported for Bacillus anthracis and Bacillus cereus spores. We demonstrate through Flag-fusions that CotA and CotB are mainly located in the spore coat, while the exosporium collagen-like glycoproteins (i.e. BclA1, BclA2 and BclA3), the exosporium morphogenetic proteins CdeC and CdeM, and the uncharacterized exosporium proteins CdeA and CdeB are mainly located in the exosporium layer of C. difficile 630 spores. This study offers novel candidates of C. difficile exosporium proteins as suitable targets for detection, removal and spore-based therapies.

BIOLOGICAL SIGNIFICANCE

This study offers a novel strategy to identify proteins of the exosporium layer of C. difficile spores and complements previous proteomic studies on the entire C. difficile spores and spore coat since it defines the proteome of the outermost layer of C. difficile spores, the exosporium. This study suggests that C. difficile spores have several proteins involved in protection against environmental stress as well as putative virulence factors that might play a role during infection. Spore exosporium structural proteins were also identified providing the ground basis for further functional studies of these proteins. Overall this work provides new protein target for the diagnosis and/or therapeutics that may contribute to combat C. difficile infections.

Development of microbeads of chicken yolk antibodies against Clostridium difficile toxin A for colonic-specific delivery

The incidence of Clostridium difficile infection has increased in Western world in the past 10 years, similar infection rates are also reported in developing countries such as China. Current antibiotics treatments have recurrence rates between 15% and 30%. IgY antibodies against toxin A of C. difficile could protect animal models from the challenge of lethal dose of C. difficile spores. However, IgY is sensitive to the low pH environment of the stomach and proteinases in the intestine. The objective of this study was to prepare colonic-specific delivery system of toxin A antigen-specific IgY to block the recognition of toxin A to the colon mucosa cells. Egg-laying hens were immunized with purified C. difficile toxin A C-terminal domain for 3 times, then egg IgY against the recombinant ToxA-C protein was purified from immunized egg yolk and frozen dried. IgY-loaded microbeads were prepared using mini fluid bed system; the loading efficiency was 21%. The pH and temperature stabilities of the microbeads were assayed. The IgY-loaded microbeads coated with 35% Eudragit S100 had colonic-specific IgY release specificity both in vitro and in vivo, the colonic-specific release of biological active IgY was 87.5% in the rat. Our study provides a new option for the biological treatment C. difficile infection.

Human neutrophils are activated by a peptide fragment of Clostridium difficile toxin B presumably via formyl peptide receptor

Clostridium difficile may induce antibiotic-associated diarrhoea and, in severe cases, pseudomembranous colitis characterized by tremendous neutrophil infiltration. All symptoms are caused by two exotoxins: TcdA and TcdB. We describe here the activation of isolated human blood neutrophils by TcdB and, moreover, by toxin fragments generated by limited proteolytical digestion. Kinetics and profiles of TcdB-induced rise in intracellular-free Ca(2+) and reactive oxygen species production were similar to that induced by fMLF, which activates the formyl peptide receptor (FPR) recognizing formylated bacterial peptide sequences. Transfection assays with the FPR-1 isoform hFPR26 in HEK293 cells, heterologous desensitization experiments and FPR inhibition via cyclosporine H strongly suggest activation of cells via FPR-1. Domain analyses revealed that the N-terminal glucosyltransferase domain of TcdB is a potent activator of FPR pointing towards an additional mechanism that might contribute to pathogenesis. This pro-inflammatory ligand effect can be triggered even by cleaved and, thus, non-cytotoxic toxin. In summary, we report (i) a ligand effect on neutrophils as completely new molecular mode of action, (ii) pathogenic potential of truncated or proteolytically cleaved 'non-cytotoxic' fragments and (iii) an interaction of the N-terminal glucosyltransferase domain instead of the C-terminal receptor binding domain of TcdB with target cells.

Impact of Clostridium difficile infection on inflammatory bowel disease outcome: A review

Although a considerable number of studies support a substantial increase in incidence, severity, and healthcare costs for Clostridium difficile infection (CDI) in inflammatory bowel disease (IBD), only few evaluate its impact on IBD outcome. Medline and several other electronic databases from January 1993 to October 2013 were searched in order to identify potentially relevant literature. Most of the studies showed that IBD patients with CDI present a greater proportion of worse outcomes than those without CDI. These patients have longer length of hospital stay, higher rates of colectomies, and increased mortality. Patients with ulcerative colitis are more susceptible to CDI and have more severe outcomes than those with Crohn’s disease. However, studies reported variable results in both short- and long-term outcomes. Contrasting results were also found between studies using nationwide data and those reporting from single-center, or between some North-American and European studies. An important limitation of all studies analyzed was their retrospective design. Due to contrasting data often provided by retrospective studies, further prospective multi-center studies are necessary to evaluate CDI impact on IBD outcome. Until then, a rapid diagnosis and adequate therapy of infection are of paramount importance to improve IBD patients’ outcome. The aim of this article is to provide up to date information regarding CDI impact on outcome in IBD patients.

The changes of PCR ribotype and antimicrobial resistance of Clostridium difficile in a tertiary care hospital over 10 years

The aims of this study were to investigate any change in PCR ribotypes and to determine the antimicrobial resistance of common PCR ribotypes over a 10-year period in a tertiary care hospital. We conducted PCR ribotyping, antimicrobial susceptibility testing and DNA gyrase sequencing to identify changes in 1407 Clostridium difficile non-duplicated isolates obtained between 2000 and 2009. A total of 74 different ribotypes were found. The most prevalent ribotype was ribotype 001 (26.1 %). The prevalence of ribotype 017 was 17 % and that of ribotype 014/020 was 9.6 %. Ribotyping showed that the prevalence of ribotype 001 decreased and the prevalence of ribotypes 017, 014/020 and 018 increased over the 10 years. Antimicrobial resistance rates in prevalent ribotypes were: clindamycin, 81 %; cefotetan, 19 %; moxifloxacin, 42 %; imipenem, 8 %; ciprofloxacin, 100 % and erythromycin, 80 %. Ribotype 018 showed greater antimicrobial resistance than other ribotypes. All ribotype 018 strains showing moxifloxacin resistance had a substitution of a gyrA coding amino acid (Thr82 to Ile). This study will help the understanding of PCR ribotype trends and antimicrobial resistance of C. difficile in Korea.

Fidaxomicin: a minimally absorbed macrocyclic antibiotic for the treatment of Clostridium difficile infections

Fidaxomicin was approved for the treatment of Clostridium difficile infections in 2011. It has a novel mechanism of action and narrow spectrum of activity that makes it unique among the currently used therapies for this disease. Phase III clinical studies demonstrated a benefit of fidaxomicin over vancomycin for the outcomes of recurrence and global cure or sustained clinical response. This observation was confirmed within specific populations, including those of older age, immunocompromised due to active cancers, and patients taking concomitant antibiotics. Additionally, fidaxomicin significantly reduced recurrence rates compared to vancomycin among patients receiving treatment for recurrent C. difficile episodes. Fidaxomicin represents an advance in therapy for the treatment of C. difficile infections.

Food Safety: Emerging Pathogens

This article presents information related to emerging pathogens that are foodborne or have the potential to be foodborne including bacteria, viruses, and parasites. The phenotypic characteristics of these pathogens, their epidemiology, prevalence in foods, and transmission routes to humans as well as means for their control are also discussed.

Pseudomembranous colitis associated with a triple therapy for Helicobacter pylori eradication

Helicobacter pylori (H. pylori) is one of the most common chronic bacterial infections in humans, affecting half of world’s population. Therapy for H. pylori infection has proven to be both effective and safe. The one-week triple therapy including proton pump inhibitor, clarithromycin, and amoxicillin or metronidazole is still recommended as a first-line treatment to eradicate H. pylori infection in countries with low clarithromycin resistance. Generally, this therapy is well-tolerated, with only a few and usually minor side effects. However, rare but severe adverse effects such as pseudomembranous colitis have been reported, Clostridium difficile (C. difficile) infection being the main causative factor in all cases. We report the cases of two women who developed pseudomembranous colitis after a 1-wk triple therapy consisting of pantoprazole 20 mg bid, clarithromycin 500 mg bid, and amoxicillin 1 g bid to eradicate H. pylori infection. A limited colonoscopy showed typical appearance of pseudomembranous colitis, and the stool test for C. difficile toxins was positive. Rapid resolution of symptoms and negative C. difficile toxins were obtained in both patients with oral vancomycin. No relapse occurred during a four and eleven-month, respectively, follow up. These cases suggest that physicians should have a high index of suspicion for pseudomembranous colitis when evaluate patients with diarrhea following H. pylori eradication therapy.

Carbohydrate-based Clostridium difficile vaccines

Clostridium difficile is responsible for thousands of deaths each year and a vaccine would be welcomed, especially one that would disrupt bacterial maintenance, colonization and persistence in carriers and convalescent patients. Structural explorations at the University of Guelph (ON, Canada) discovered that C. difficile may express three phosphorylated polysaccharides, named PSI, PSII and PSIII; this review captures our recent efforts to create vaccines based on these glycans, especially PSII, the common antigen that has precipitated immediate attention. The authors describe the design and immunogenicity of vaccines composed of raw polysaccharides and conjugates thereof. So far, it has been observed that anti-PSII antibodies can be raised in farm animals, mice and hamster models; humans and horses carry anti-PSII IgA and IgG antibodies from natural exposure to C. difficile, respectively; phosphate is an indispensable immunogenic epitope and vaccine-induced PSII antibodies recognize PSII on C. difficile outer surface.

Is fidaxomicin worth the cost? An economic analysis

BACKGROUND

In May 2011, the Food and Drug Administration approved fidaxomicin for the treatment of Clostridium difficile infection (CDI). It has been found to be noninferior to vancomycin; however, its cost-effectiveness for the treatment of CDI remains undetermined.

METHODS

We developed a decision analytic simulation model to determine the economic value of fidaxomicin for CDI treatment from the third-party payer perspective. We looked at CDI treatment in these 3 cases: (1) no fidaxomicin, (2) only fidaxomicin, and (3) fidaxomicin based on strain typing results.

RESULTS

The incremental cost-effectiveness ratio for fidaxomicin based on screening given current conditions was >$43.7 million per quality-adjusted life-year and using only fidaxomicin was dominated (ie, more costly and less effective) by the other 2 treatment strategies explored. The fidaxomicin strategy tended to remain dominated, even at lower costs. With approximately 50% of CDI due to the NAP1/BI/027 strain, a course of fidaxomicin would need to cost ≤$150 to be cost-effective in the treatment of all CDI cases and between $160 and $400 to be cost-effective for those with a non-NAP1/BI/027 strain (ie, treatment based on strain typing).

CONCLUSIONS

Given the current cost and NAP1/BI/027 accounting for approximately 50% of isolates, using fidaxomicin as a first-line treatment for CDI is not cost-effective. However, typing and treatment with fidaxomicin based on strain may be more promising depending on the costs of fidaxomicin.

Rifaximin in the treatment of recurrent Clostridium difficile infection

BACKGROUND

Clostridium difficile can cause severe antibiotic-associated colitis. Conventional treatments with metronidazole and vancomycin improve symptoms, but after discontinuation of treatment, C. difficile infection (CDI) recurs in a number of patients. Rifaximin is a rifamycin-based non-systemic antibiotic that has effect against C. difficile.

AIM

To assess the effectiveness of rifaximin in recurrent C. difficile infection.

METHODS

We retrospectively evaluated the records of 32 patients who were treated with rifaximin for recurrent C. difficile infection. The symptoms were evaluated 12 weeks after the start of treatment and patient records were followed up until 1 year after treatment.

RESULTS

The mean age of the patients was 55 years (median 64, range: 19-84 years). Before the initiation of rifaximin therapy, the patients had undergone, on the average, 4.4 (range: 2-12) antimicrobial courses for C. difficile infection. C. difficile strain typing was performed in 27 patients. Eight (30%) patients had a strain with a DNA profile compatible with the BI/NAP1/027 ribotype. Antibiotic susceptibilities were determined of isolates from 22 patients. Most isolates (68%) had very low MIC-values for rifampin (<0.002 μg/mL) and the highest MIC value was 3.0 μg/mL. Isolates with a DNA profile compatible with the BI/NAP1/027 ribotype had, on the average, higher MICs of rifampin. After 12 weeks 17 (53%) patients had no relapse. The MIC value of rifampin seemed to predict the response to rifaximin treatment.

CONCLUSIONS

Rifaximin is a safe treatment for C. difficile infection. It has a reasonable effect in C. difficile infection and it can be considered as an optional treatment for recurrent C. difficile infection.

Clostridium difficile: development of a novel candidate vaccine

Clostridium difficile has become the most frequent hospital-acquired infection in North America and the EU. C. difficile infection (CDI) is present worldwide and disease awareness is increasing. In the US, EU, and Canada, in addition to hospital diagnosed disease, CDI has also been reported with increasing frequency in the community. Hypervirulent strains have increased the morbidity and mortality associated with CDI. Current treatment options are suboptimal. Of all patients treated for CDI, 20% relapse and 65% of those experiencing a second relapse become chronic cases. An association between increased serum levels of IgG antibody against toxin A and asymptomatic carriage of C. difficile provides a rationale for vaccine development. Sanofi Pasteur's C. difficile candidate vaccine is being developed for the prevention of primary disease. The target population is adults at risk of CDI, those with planned hospitalization, long-term care/nursing home residents, and adults with co-morbidities requiring frequent/prolonged antibiotic use.

Clostridium difficile: novel insights on an incessantly challenging disease

PURPOSE OF REVIEW

This review comprises recent insights on epidemiology, risk factors, diagnostic approaches, pathophysiologic mechanisms, novel treatment options and prevention strategies of Clostridium difficile infection (CDI).

RECENT FINDINGS

Incidence of Clostridium difficile continues to rise and hypervirulent subtypes such as polymerase chain reaction (PCR) ribotype 027 and 078 have emerged worldwide. Children and postpartum women are increasingly recognized as being at risk for development of CDI and community-associated infection is no longer rare. PCR technology may replace complicated two-step test algorithms in the future, because it is rapid, sensitive and specific. Pathophysiological studies have provided evidence that either one of the two exotoxins A and B is important in conferring virulence - the role of binary toxin requires further investigation. Proton pump inhibitors are now established as important risk factors for acquiring, complicating CDI, and developing recurrences. Fidaxomycin, monoclonal antibodies and intestinal microbiota transplantation are promising new treatment options, especially regarding prevention of recurrent disease. Future prevention strategies involve vaccination and novel insights on reservoirs for ongoing transmission, including the food chain.

SUMMARY

Important advances in research on CDI include novel diagnostic approaches, better understanding of the underlying pathophysiological mechanisms of disease and the development of new approaches to treatment.

Detecting and treating Clostridium difficile infections in patients with inflammatory bowel disease

The prevalence of CDI in patients with IBD has increased over the last decade. The excess morbidity and mortality associated with CDI appears to be greater in patients with IBD than in those without preexisting bowel disease. The risk factors for CDI in IBD and non-IBD populations appear similar; unique IBD-related risk factors are use of maintenance immunosuppression and extent and severity of prior colitis. Nevertheless, a significant proportion of CDI-IBD patients may have the disease without traditional risk factors (ie, antibiotic use, recent hospitalization). The absence of such risk factors must not preclude considering CDI in the differential diagnosis of IBD patients presenting with a disease flare. Vancomycin and metronidazole appear to have similar efficacy with vancomycin being the preferred agent for severe disease. Early surgical consultation is key for improving outcomes of patients with severe disease. Several gaps in research exist; prospective multicenter cohorts of CDI-IBD are essential to improve our understanding of the impact of CDI on IBD patients and define appropriate therapeutic regimens to improve patient outcomes.

Inappropriate Use of Gastric Acid Suppression Therapy in Hospitalized Patients with Clostridium difficile-Associated Diarrhea: A Ten-Year Retrospective Analysis

Purpose. The incidence of Clostridium difficile-associated diarrhea (CDAD) has steadily increased over the past decade. A multitude of factors for this rise in incidence of CDAD have been postulated, including the increased use of gastric acid suppression therapy (GAST). Despite the presence of practice guidelines for use of GAST, studies have demonstrated widespread inappropriate use of GAST in hospitalized patients. We performed a retrospective analysis of inpatients with CDAD, with special emphasis placed on determining the appropriateness of GAST. Methods. A retrospective analysis was conducted at a multidisciplinary teaching hospital on inpatients with CDAD over a 10-year period. We assessed the use of GAST in the cases of CDAD. Data collection focused on the appropriate administration of GAST as defined by standard practice guidelines. Results. An inappropriate indication for GAST was not apparent in a majority (69.4%) of patients with CDAD. The inappropriate use of GAST was more prevalent in medical (86.1%) than on surgical services (13.9%) (P < 0.001). There were more cases (67.6%) of inappropriate use of GAST in noncritical care than in critical care areas (37.4%) (P < 0.001). Conclusion. Our study found that an inappropriate use of inpatient GAST in patients with CDAD was nearly 70 percent. Reduction of inappropriate use of GAST may be an additional approach to reduce the risk of CDAD and significantly decrease patient morbidity and healthcare costs.

Predictors of severe outcomes associated with Clostridium difficile infection in patients with inflammatory bowel disease

BACKGROUND

The increasing incidence of Clostridium difficile (C. difficile) infection (CDI) among patients with inflammatory bowel disease is well recognised. However, most studies have focused on demonstrating that CDI is associated with adverse outcomes in IBD patients. Few have attempted to identify predictors of severe outcomes associated with CDI among IBD patients.

AIM

To identify clinical and laboratory factors that predict severe outcomes associated with CDI in IBD patients.

METHODS

From a multi-institution EMR database, we identified all hospitalised patients with at least one diagnosis code for C. difficile from among those with a diagnosis of Crohn's disease or ulcerative colitis. Our primary outcome was time to total colectomy or death with follow-up censored at 180 days after CDI. Cox proportional hazards models were used to identify predictors of the primary outcome from among demographic, disease-related, laboratory and medication variables.

RESULTS

A total of 294 patients with CDI-IBD were included in our study. Of these, 58 patients (20%) met our primary outcome (45 deaths, 13 colectomy) at a median of 31 days. On multivariate analysis, serum albumin <3 g/dL (HR 5.75, 95% CI 1.34-24.56), haemoglobin below 9 g/dL (HR 5.29, 95% CI 1.58-17.69) and creatinine above 1.5 mg/dL (HR 1.98, 95% CI 1.04-3.79) were independent predictors of our primary outcome. Examining laboratory parameters as continuous variables or shortening our primary outcome to include events within 90 days yielded similar results.

CONCLUSION

Serum albumin below 3 g/dL, haemoglobin below 9 g/dL and serum creatinine above 1.5 mg/dL were independent predictors of severe outcomes in hospitalised IBD patients with Clostridium difficile infection.

Annual drug update: 2011 in review

Many new medications were approved throughout 2011. This article will cover a variety of drugs that will be useful in nurse practitioner practice.

Clostridium difficile infection: an update on epidemiology, risk factors, and therapeutic options

PURPOSE OF REVIEW

The incidence and severity of Clostridium difficile infection (CDI) around the world has increased over the past 20 years due to the emergence of hypervirulent strains, increased use and misuse of antibiotics, and the increase of susceptible at-risk populations. Treatments currently available for CDI are inadequate to impede the increasing spread and virulence of the infection, avoid recurrence in chronic patients or prevent infection in at-risk populations.

RECENT FINDINGS

New and promising evidence has been presented during the past year, focusing on two major points: preservation of gut microflora and optimization of immune response to CDI and toxins.

SUMMARY

The review aims to summarize the most recent evidence available on the epidemiology, risk factors and treatment of CDI. New antibiotics with selected action on C. difficile and limited effect on microflora (fidaxomicin) and donor fecal transplantation seem to have a relevant efficacy in treating CDI and reducing its recurrence. The use of selected monoclonal antibodies directed against C. difficile toxins in addition to standard therapy is a new, promising approach for the treatment of recurrent cases. Vaccination could be an additional weapon against CDI. New robust data are needed before recommendations can be made to abandon current treatment based on vancomycin and metronidazole and move toward new frontiers.

Extended multilocus variable-number tandem-repeat analysis of Clostridium difficile correlates exactly with ribotyping and enables identification of hospital transmission

PCR ribotyping is currently used in many countries for epidemiological investigation to track transmission and to identify emerging variants of Clostridium difficile. Although PCR ribotyping differentiates over 300 types, it is not always sufficiently discriminatory for epidemiological investigations particularly for common ribotypes, e.g., ribotypes 027, 106, and 017. Multilocus variable-number tandem-repeat analysis (MLVA) is a highly discriminatory molecular subtyping method that has been applied to a number of bacterial species for high-level subtyping. Two MLVA typing schemes for C. difficile have been previously published, each utilizing seven variable-number tandem-repeat (VNTR) loci on the genome with four loci common to both schemes. Although these schemes are good genotyping methods with the ability to discriminate between isolates, they do not identify the ribotype. We show here that increasing the number of VNTR loci to 15, creating the extended MLVA (eMLVA) scheme, we have successfully subtyped all clinically significant ribotypes while still clustering isolates in concordance with PCR ribotyping. The eMLVA scheme developed here provides insight into the genetic diversity of the C. difficile population at both global and cross-infection clusters in patient levels, with the possibility of replacing PCR ribotyping.