Clostridium difficile

Microencapsulation of Enteric Bacteriophages in a pH-Responsive Solid Oral Dosage Formulation Using a Scalable Membrane Emulsification Process

A scalable low-shear membrane emulsification process was used to produce microencapsulated Escherichia coli-phages in a solid oral dosage form. Uniform pH-responsive composite microparticles (mean size ~100 µm) composed of Eudragit® S100 and alginate were produced. The internal microstructure of the gelled microcapsules was studied using ion-milling and imaging, which showed that the microparticles had a solid internal core. The microencapsulation process significantly protected phages upon prolonged exposure to a simulated gastric acidic environment. Encapsulated phages that had been pre-exposed to simulated gastric acid were added to actively growing bacterial cells using in vitro cell cultures and were found to be effective in killing E. coli. Encapsulated phages were also shown to be effective in killing actively growing E. coli in the presence of human epithelial cells. Confocal microscopy images showed that the morphology of encapsulated phage-treated epithelial cells was considerably better than controls without phage treatment. The encapsulated phages were stable during refrigerated storage over a four-week period. The process of membrane emulsification is highly scalable and is a promising route to produce industrial quantities of pH-responsive oral solid dosage forms suitable for delivering high titres of viable phages to the gastrointestinal tract.

Isolation of toxigenic Clostridium difficile from ready-to-eat salads by multiplex polymerase chain reaction in Isfahan, Iran

Background:

Since 2003, the incidence of community associated Clostridium difficile infection (CA-CDI) has increased; different types of food have been supposed to be the vectors of C. difficile strains. The purpose of this study is to investigate the occurrence of C. difficile strains in ready-to-eat salads distributed in food services.

Materials and Methods:

A total of 106 ready-made salad specimens were sampled from different restaurants and food services located in Isfahan, in the center of Iran. Positive isolates of C. difficile were identified and confirmed for the existence of three genes including tpi, tcdA and tcdB by multiplex PCR.

Results:

A total of six (5.66%) samples were positive for C. difficile strains. Of which, one strain (16.6%) was positive for A and B toxins.

Conclusion:

The existence of toxigenic C. difficile in ready-made salads could be a caution for public health. Further investigation is required to assess the relationship between the isolated strains in our study and those from diarrheic patients through molecular typing.

Interactions Between the Gastrointestinal Microbiome and Clostridium difficile

Antibiotics have significant and long-lasting effects on the intestinal microbiota and consequently reduce colonization resistance against pathogens, including Clostridium difficile. By altering the community structure of the gut microbiome, antibiotics alter the intestinal metabolome, which includes both host- and microbe-derived metabolites. The mechanisms by which antibiotics reduce colonization resistance against C. difficile are unknown yet important for development of preventative and therapeutic approaches against this pathogen. This review focuses on how antibiotics alter the structure of the gut microbiota and how this alters microbial metabolism in the intestine. Interactions between gut microbial products and C. difficile spore germination, growth, and toxin production are discussed. New bacterial therapies to restore changes in bacteria-driven intestinal metabolism following antibiotics will have important applications for treatment and prevention of C. difficile infection.

The roles of host and pathogen factors and the innate immune response in the pathogenesis of Clostridium difficile infection

Clostridium difficile (C. difficile) is the most common cause of nosocomial antibiotic-associated diarrhea and the etiologic agent of pseudomembranous colitis. The clinical manifestation of C. difficile infection (CDI) is highly variable, from asymptomatic carriage, to mild self-limiting diarrhea, to the more severe pseudomembranous colitis. Furthermore, in extreme cases, colonic inflammation and tissue damage can lead to toxic megacolon, a condition requiring surgical intervention. C. difficile expresses two key virulence factors; the exotoxins, toxin A (TcdA) and toxin B (TcdB), which are glucosyltransferases that target host-cell monomeric GTPases. In addition, some hypervirulent strains produce a third toxin, binary toxin or C. difficile transferase (CDT), which may contribute to the pathogenesis of CDI. More recently, other factors such as surface layer proteins (SLPs) and flagellin have also been linked to the inflammatory responses observed in CDI. Although the adaptive immune response can influence the severity of CDI, the innate immune responses to C. difficile and its toxins play crucial roles in CDI onset, progression, and overall prognosis. Despite this, the innate immune responses in CDI have drawn relatively little attention from clinical researchers. Targeting these responses may prove useful clinically as adjuvant therapies, especially in refractory and/or recurrent CDI. This review will focus on recent advances in our understanding of how C. difficile and its toxins modulate innate immune responses that contribute to CDI pathogenesis.

Faecal microbiota transplantation for the treatment of recurrent Clostridium difficile infection: current promise and future needs

PURPOSE OF REVIEW

The use of faecal microbiota transplantation (FMT) as treatment for recurrent Clostridium difficile infection (CDI) has increased rapidly over the past few years. In this review, we highlight clinical studies of FMT for treatment of recurrent CDI and discuss the safety, standardization and future of this treatment option. The major risk factor for CDI is prior antibiotic use, which results in an altered state of the gut microbiota characterized by decreased microbial diversity. This altered gut microbiota increases the patient's susceptibility to CDI. In patients with recurrent CDI, the microbiota remains in a state with decreased diversity, and FMT from a healthy individual restores the gut microbiota and subsequently colonization resistance against the pathogen.

RECENT FINDINGS

Recent studies have shown the success rate for FMT as treatment for recurrent CDI being greater than 90%. Standardized, frozen preparations of faeces can be used, which increases the availability of faeces for FMT and decreases the cost of screening individual donors. In addition, there have been recent advances in identifying a defined microbial community isolated from faeces that can restore colonization resistance against C. difficile.

SUMMARY

The use of FMT is a successful treatment for recurrent CDI when primary treatment options have failed. However, more work needs to define potential long-term consequences of this treatment and understand how specific members of the gut microbiota can restore colonization resistance against C. difficile.

Protective efficacy induced by recombinant Clostridium difficile toxin fragments

Clostridium difficile is a spore-forming bacterium that can reside in animals and humans. C. difficile infection causes a variety of clinical symptoms, ranging from diarrhea to fulminant colitis. Disease is mediated by TcdA and TcdB, two large enterotoxins released by C. difficile during colonization of the gut. In this study, we evaluated the ability of recombinant toxin fragments to induce neutralizing antibodies in mice. The protective efficacies of the most promising candidates were then evaluated in a hamster model of disease. While limited protection was observed with some combinations, coadministration of a cell binding domain fragment of TcdA (TcdA-B1) and the glucosyltransferase moiety of TcdB (TcdB-GT) induced systemic IgGs which neutralized both toxins and protected vaccinated animals from death following challenge with two strains of C. difficile. Further characterization revealed that despite high concentrations of toxin in the gut lumens of vaccinated animals during the acute phase of the disease, pathological damage was minimized. Assessment of gut contents revealed the presence of TcdA and TcdB antibodies, suggesting that systemic vaccination with this pair of recombinant polypeptides can limit the disease caused by toxin production during C. difficile infection.

Recent changes in Clostridium difficile infection

Clostridium difficile is the main cause of nosocomial diarrhea. Diarrhea associated with C. difficile has increased incidence, morbidity, and mortality in the last few years. The major related risk factors include use of antibiotics, elderly patients and prolonged hospital stay. Many patients receive combinations of antibiotics or multiple antibiotics, which represents the main risk to develop diarrhea associated to C. difficile or its recurrence. Therefore, interventions to improve antibiotic prescribing, as well as compliance with infection control measures can reduce hospital-acquired C. difficile infections. This review addresses the epidemiological changes in C. difficile disease and its treatment.

Clostridium difficile infection and proton pump inhibitors

PURPOSE OF REVIEW

Clostridium difficile is an intestinal infection associated with antibiotic use, commonly seen in patients with chronic medical issues. The purpose of this review is to discuss the association of C. difficile-associated diarrhea with use of proton pump inhibitors.

RECENT FINDINGS

Multiple medical factors predispose patients to C. difficile-associated diarrhea. Proton pump inhibitors, commonly used for gastric acid suppression, have been shown to have an association with C. difficile-associated diarrhea in both the outpatient and hospital setting. C. difficile-associated diarrhea also has been reported in the pediatric age range linked with proton pump inhibitor use.

SUMMARY

An association exists between C. difficile infection and proton pump inhibitor use. Treatment options exist for C. difficile-associated diarrhea, although judicious use of proton pump inhibitors and antibiotics, emphasis on hand washing, and appropriate use of patient isolation should be implemented as well.

[Intrahospital mortality in patients with Clostridium difficile-associated diarrhea infection]

BACKGROUND

Clostridium difficile (C. difficile) is a gram-positive anaerobic bacillus capable of producing diarrhea or colitis in the hospitalized patient, particularly in those exposed to the use of antibiotics, and 6% to 38% mortality in patients with C. difficile-associated diarrhea (CDAD) has been described.

AIMS

To determine the hospital death rate in patients presenting with CDAD. As a secondary aim, hospital stay and risk factors for unfavorable outcome were recorded.

METHODS

A retrospective cohort study was carried out. The case records of hospitalized patients presenting with diarrhea and that tested positive for C. difficile through toxin A and B assays were reviewed. The number of non-surviving patients that presented with CDAD during hospitalization was recorded along with the principal factors associated with the worst outcome.

RESULTS

Of the 66 patients enrolled in the study, 6 (9,1%) died during their hospitalization. The median age was lower in the group of surviving patients than in the group of non-surviving patients, with 51,5 years (range 36 to 66,75) and 81,5 years (range 69,5 to 83,25), respectively (p=0,002). Hospital stay was 32,50 days (range 8,25 to 64,25) in the group of non-surviving patients and was 6,5 days (range 4 to 15,75) (p=0,045) in the group with no deaths.

CONCLUSIONS

The elevated mortality found in the hospitalized CDAD patients in the Intensive Care Unit makes the maintenance of strict surveillance in this population imperative so there can be opportune detection and treatment.

Systematic review: faecal transplantation for the treatment of Clostridium difficile-associated disease

BACKGROUND

Management of recurrent Clostridium difficile-associated disease (CDAD), particularly in elderly patients, remains clinically challenging. Faecal transplantation (FT) may restore normal microbiota and break the cycle of recurrent CDAD.

AIM

To critically appraise the clinical research evidence on the safety and effectiveness of FT compared with standard care in the treatment of patients with CDAD.

METHODS

A comprehensive literature search was conducted by a research librarian to identify relevant studies published between 2000 and 2011. The Cochrane Library, PubMed, EMBASE, CINAHL, Biological Abstracts, BIOSIS Previews and Web of Science were searched using the following Medical Subject Headings (MeSH) terms and keywords, alone or in combination: Clostridium infections/Clostridium difficile/pseudomembranous/colitis/faeces/rectal/colon flora/gastrointestinal/nasogastric tube/enema/donor/transplant/infusion/bacteriotherapy/human probiotic infusion. Methodological quality of the included case series studies was assessed in terms of patient selection criteria, consecutive recruitment, prospective data collection, reporting of lost to follow-up, and follow-up rates.

RESULTS

No controlled studies were found. Based on the weak evidence from seven full-text case series studies of 124 patients with recurrent/refractory CDAD, FT appears to be a safe and effective procedure. In most cases (83%) symptoms improved immediately after the first FT procedure, and some patients stayed diarrhoea free for several months or years.

CONCLUSIONS

Although these results appear to be promising, the treatment effects of faecal transplantation cannot be determined definitively in the absence of a control group. Results from randomised controlled trials that compare faecal transplantation to oral vancomycin without or with a taper regimen will help to better define the role of faecal transplantation in the management of recurrent CDAD.

Quantification of Clostridium difficile in antibiotic-associated-diarrhea patients

Comparing culture- and non-culture-based methods for quantifying Clostridium difficile in antibiotic-associated-diarrhea patients, we found that the real-time PCR method correlated well with quantitative culture and was more sensitive. A positive association between the population levels of C. difficile and the presence of its toxins was found.