Tag Archives: C difficile research and development

Clostridium difficile Research and Development Community August 2014

laboratorytests

Here’s the latest from the

Clostridium difficile Research Community:

 

 
Scientists at the University of Leicester have identified a rapid method of identifying C.difficile based on volatile organic compounds (VOCs) emitted by different C.difficile strains using Proton transfer reaction–time of flight–mass spectrometry (PTR–ToF–MS). Current methods of detecting and diagnosing CDI take anywhere between 2-5 days, leading to a delay in treatment that could have potential life threatening implications in some patients. PTR–ToF–MS analysis is capable of detecting VOCs of C.difficile metabolites in cultures within minutes and could potentially be used to detect VOCs in fecal samples from CDI patients.
http://download.springer.com/static/pdf/426/art%253A10.1007%252Fs11306-014-0692-4.pdf?auth66=1409931636_01f1fc8253ca189e0b0aba9b0e213055&ext=.pdf

 
CRISPR/Cas system is a form of bacterial adaptive immunity that helps control phage infections. Multiple CRISPR/Cas arrays have been identified in C.difficile. In this artciel by Hargreaves et al. the distribution and diversity of the CRISPRs have been studied and how these affect phage predation, evolution and pathogenecity.
http://www.ncbi.nlm.nih.gov/pubmed/25161187

 
C. difficile express flagella as a mechanism for motility, although the role of flagella in the pathogenecity of CDI is not clearly understood. Faulds-Pain et al have studied the post-translational modification of flagellin in C. difficile 630 using NMR and have identified 4 gene modification locus. Mutants strains had some impact on motility, colonization, and recurrence in a murine model of CDI showing that alterations in the flagellar structure can play a significant role in disease.
http://onlinelibrary.wiley.com/doi/10.1111/mmi.12755/pdf

 
A history of C.difficile from the beginning to where we are today.
http://cid.oxfordjournals.org/content/59/suppl_2/S66.long

 

Chandrabali Ghose-Paul,MS,PhD, Chairperson of Research and Development

C Diff Foundation Welcomes Dr. Rosie D. Lyles, MD, MHA

welcome-sign

We are pleased to welcome                                  Dr. Rosie D. Lyles, MD, MHA to the C Diff Foundation’s Research and Development Committee and Research Community.

Dr. Lyles extensive educational background includes the Texas Woman’s University, Denton, Texas BS, Biology, St. Matthew’s School of Medicine, Grand Cayman MD 05/04 Medicine – St. Joseph’s College, Standish, Maine MHA 05/06 Health Services Administration – University of Illinois at Chicago MSc 2014 Clinical and Translational Science.

Dr. Lyles currently serves as the primary liaison for Client’s Healthcare division, in a major healthcare corporation, as a department head to relevant professional, research and academic institutions, public health agencies, and forums. Her role provides strategic guidance and assists with the development and implementation of a plan for clinical/scientific support of marketing initiatives. This includes overall responsibility for public health message development, publication planning, key opinion leader development and provides relevant input into the clinical and product intervention design and development.

C Diff Foundation Welcomes Dr. Martha R. J. Clokie, MS, PhD

Welcome cloudWe are pleased to welcome                              Dr. Martha R. Clokie, from the Department of Microbiology and Immunology at the University of Leicester, UK to the C Diff Foundation’s Research and Development Committee and Research Community.

Dr. Clokie obtained a BSc in Biology (1st class hons) from the University of Dundee in 1996. An interest in ecology and molecular biology led her to an MSc at Edinburgh (1997) and a PhD at Leicester (2001) where she focused on designing molecular tools in order to establish the basis of plant biogeography.   ” I then wanted to study a system which evolved more rapidly than plants, so in Jan 2001 I started to work on cyanobacteria and viruses with Prof Nick Mann at the University of Warwick. I stayed in this field for 6 years during which time I became fascinated at the extent to which phages impacted the evolution and ecology of their cyanobacterial hosts.”

After a fellowship at the Scripps Research Institute, La Jolla, San Diego, Dr. Clokie started her own research group at the University of Leicester in 2006.  “I have focused on the gut pathogen Clostridium difficile where I have isolated and sequenced novel phages in order to determine how they are shaping populations in natural settings and to establish how we might be able to better understand these phages in order to develop them for therapeutic and diagnostic purposes.”

Her work has focused on Clostridium difficile as is the major cause of bacterial infectious diahorrea in the western world. The pathogen is difficult to diagnose and to treat as there are complications associated with the only 3 antibiotics that are effective against it.

Sera Care Life Sciences introduces Accurun 501C. difficile control

* In The News *

SeraCare Life Sciences, a provider of high-quality biological materials that help optimize diagnostic performance, reliability and repeatability across the IVD lifecycle, today announced the launch of its new ACCURUN® 501 C. difficile Control – the company’s first molecular control product targeting hospital acquired infections.

ACCURUN 501 C. difficile Control

ACCURUN 501 C. difficile Control is formulated for use with in vitro diagnostic tests that detect C. difficile DNA in human stool samples. Manufactured from cultured Clostridium bacteria of four different strains or species delivered in a set of four vials, the bacteria are inactivated and in a human synthetic stool matrix. The control is ready-to-use in assays that detect C. difficile DNA with any transport system.

“Hospital acquired infection assays present unique sample challenges which require dependable, whole cell controls. Our new ACCURUN® 501 product is a full process control that is intended to not only estimate laboratory testing performance but also immediately detect analytical errors and monitor the entire testing process. As a result, our customers have greater confidence in fulfilling their QC requirements,” says Christopher Long, Product Manager at SeraCare.

SeraCare’s new ACCURUN® 501 product is available immediately in the U.S. and internationally. For more information, contact SeraCare Customer Service at 1-800-676-1881 or visit www.seracare.com.

About SeraCare Life Sciences, Inc.
SeraCare works with diagnostics researchers, IVD manufacturers, and clinical laboratories to shape the future of medical diagnostics. Our innovative portfolio includes ACCURUN® quality controls, research panels, KPL™ antibodies and immunoassay reagents, SeraCon™ processed plasma, specialty human blood products, and Complete BioCollections™ materials. SeraCare helps bridge the gap between today’s diagnostic solutions and tomorrow’s emerging technologies for molecular diagnostics, next generation sequencing and companion diagnostics.

Company Contact:

Agency Contact:

Marsha Ann Marsh

Shannon Meirzon

SeraCare Life Sciences, Inc.

Pyxis Communications

508.244.6400 ext. 6106

203.550.5978

mmarsh@seracare.com  

shannon@pyxiscommunications.com  

www.seracare.com

www.pyxiscommunications.com  

Clostridium difficile Research and Development Community June – July 2014

laboratorybeakers

Here’s the latest from the Clostridium difficile research community:

Two of the leading symptoms associated with Clostridium difficile infection in the intestine are colitis and pseudomembranous colitis. In this paper, the authors study the role of GM-CSF, an inflammatory cytokine, using a neutralizing monoclonal antibody. It was found that treating mice with an anti-GM-CSF mAb did not affect C. difficile colonization levels but did reduce the expression of the neutrophil chemokines CXCL1 and CXCL2. In addition, there were reduced numbers of neutrophils in histology sections and reduced expression of SLPIs, secretory leukocyte protease inhibitors. The authors conclude that GM-CSF is involved in the signaling network associated with neutrophil recruitment but does not have an effect on the elimination of infection.

https://www.landesbioscience.com/journals/gutmicrobes/article/29964/?nocache=794108227

In this paper, the serum levels of antibodies of patients with a single episode of CDI are compared to the levels of patients who have had a recurrence of CDI to determine if lower serum concentrations of anti-TcdA and anti-TcdB antibodies correlate with a higher risk of recurrence. The authors examined the IgA and IgG antibody levels against the two major toxins and against non-toxin cell surface antigens in serum. They found that advanced age and low serum concentrations of anti-toxin antibodies are associated with recurrence but anti-cell surface antigen antibodies were not. The authors also note that serum TcdB neutralizing capacity was not significantly associated with recurrence of Clostridium difficile infection.

http://onlinelibrary.wiley.com/doi/10.1111/1469-0691.12769/abstract;jsessionid=D532390E50ED61A88A1E011B8EE768A6.f04t02

Disturbance of a host’s natural intestinal microbiota by means of antibiotic intake, most commonly after hospitalization, makes a patient susceptible to colonization of Clostridium difficile and prone to CDI. In this paper, the authors use the lethal enterocolitis model in Syrain golden hamsters to evaluate changes in intestinal microbiota following a dose of Clindamycin. Using 16S ribosomal RNA analysis and sequencing, it was found that there were drastic changes in fecal microbiota, particularly involving the phyla of Bacteriodetes and Proteobacteria. The authors mention that the host’s gut microbiota produces certain soluble factors that may be involved in the interruption of the growth of C. difficile.

http://www.nature.com/ismej/journal/vaop/ncurrent/full/ismej2014127a.html

Although toxin-neutralizing epitopes have been found on the receptor-binding domains (RBD) of Toxin A and Toxin B, which have gained attention since they are viable vaccine targets, the authors of this paper evaluate the potential of DNA vaccination against CDI. Highly optimized plasmids that encode this receptor-binding domain were created and introduced to mice and non-human primates intramuscularly. It was found that this immunization significantly increased the levels of both anti-RBD antibodies and RBD antibody secreting cells. In addition, the immunized mice were protected from a lethal challenge of purified toxins and from a challenge with C. difficile spores from UK1 and VPI 10463 strains.

http://iai.asm.org/content/early/2014/07/08/IAI.01950-14.long

Cwp84, a surface-located cysteine protease, is responsible for the post-translational cleavage of SlpA, a surface protein, into subunits during S-layer biogenesis. In this paper, the first crystal structure of Cwp84 is illustrated at a 1.4 Å resolution. The authors identify the important structural components of the enzyme and give insight to the role of Cwp84 in C. difficile S-layer maturation.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4089489/

Alanine racemase (Alr) is a PLP-dependent enzyme that catalyzes the reversible racemization of L- and D-alanine, an important part of the peptidoglycan cell wall of bacteria. Being that there are no known alanine racemase homologue in humans, the authors of this paper decided to test it as an antibiotic target. In this paper, the catalytic properties and crystal structures of alanine racemase from Clostridium difficile 630 are evaluated, the first steps towards Alr structure-based therapeutics for CDI.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4089486/

 

Chandrabali Ghose-Paul,MS,PhD, Chairperson of Research and Development

 

Clostridium difficile Research and Development May/June 2014

laboratorybeakers3

 

Here’s the latest from the

Clostridium difficile research community:
Formaldehyde, a chemical commonly used to inactivate bacterial products, plays an important role in the formulation of a toxoid vaccine against C. difficile infection. In this paper, B. Wang describes how the toxicity of Toxin B (TcdB) can be removed by a treatment with formaldehyde solution but states that the storage of the formaldehyde-treated toxin can result in a reversion of the detoxification treatment, reestablishing toxicity. The authors highlight the importance of maintaining a minute amount of formaldehyde in liquid formulations, which prevents the reversion to toxicity.
http://www.ncbi.nlm.nih.gov/pubmed/24951860
One of the most successful treatments for Clostridium difficile infection is a fecal microbiota transplant (FMT), in which a patient’s intestinal microbiome is reestablished using the stool from another individual. Here, the authors evaluate the changes in fecal microbiota structure post-fecal transplantation using metagenomic sequencing of the 16S rRNA. It was found that a patient’s intestinal microbiota was more diverse, with a lower number of Proteobacteria but a higher number of Bacteriodetes, along with functional changes in the overall microbial structure as compared to pre-FMT.
http://www.ncbi.nlm.nih.gov/pubmed/24939885
A patient’s risk to Clostridium difficile infection can be determined by analyzing antibody levels to Toxin A (TcdA). In contrast to the accepted belief that TcdA is the key virulence factor in CDI, J. Islam evaluated the role of TcdA and TcdB antibodies in patients to determine their susceptibility to infection and found that mucosal immunity to TcdB can be a significant factor in determining early stages of infection, a target for preventing its advancement.
http://www.ncbi.nlm.nih.gov/pubmed/24708941
Clostridium difficile spores are the leading culprits in the spread of CDI because they can survive in the environment for long periods of time and are resistant to most cleaning products. Here, an outbreak of Clostridium difficile infection is reported in a hospital and is linked to the contamination of mop pads after a laundry machine mishap.
http://www.ncbi.nlm.nih.gov/pubmed/24837118

 

Chandrabali Ghose-Paul,MS,PhD, Chairperson of Research and Development

Clostridium difficile; Research and Development April 2014

Here’s the latest from the Clostridium difficile research community:
The importance of biofilm formation in chronic and recurrent infections across a cross-section of pathogens, including C. difficile has been studied in great detail. Whether biofilm formation in CDI is an important marker for recurrence is not clearly understood. Crowther et al compared germination, proliferation and toxin production between planktonic and sessile communities of C.difficile in a triple-stage chemostat gut model and here have reported that planktonic populations of C.difficile may be a reservoir for spore persistence and recurrence.
http://jac.oxfordjournals.org/content/early/2014/04/30/jac.dku116.long
Ransom et al have identified a gene cluster that is found exclusively in C.difficile and some closely-related species of bacteria that encode three cell division proteins: MldA, MldB and MldC. Mutant strains that lack the Mld proteins are severely attenuated for pathogenesis in a hamster model of CDI and thus are potential targets for therapeutics that can disrupt the spread of CDI.
http://jb.asm.org/content/early/2014/04/08/JB.00038-14.long
C.difficile are spores formers and the infectious unit for CDI is the spore. The proteins present on the outerlayer of the spores can be used as potential vaccine targets. Spore proteins present on the outer layer of spores, the exosporium, may be essential for the initiation and persistence of CDI. Three C.difficile collagen-like exosporium proteins (BclA) are expressed on the exosporium of the spore. Mutants of BclA proteins were reported to have aberrant structure and faster germination rates than wild type strains. Infection experiments done in mice suggest that BclA1 plays a role in the early stages of infection.
http://onlinelibrary.wiley.com/doi/10.1111/mmi.12611/abstract
C.difficile strains express three highly complex cell-surface polysaccharides (PSI, PSII and PSIII). PSII is the more abundantly expressed by most strains and is a potential target for vaccine development. The efficacy of PSII glycoconjugate-based vaccine using recombinant fragments of toxin A and toxin B were studied in mice. This vaccine was immunogenic and able to illicit toxin neutralizing antibody, one of the correlates of protection against CDI.
http://www.mdpi.com/2072-6651/6/4/1385
The last decade has seen a rapid change in the epidemiology of CDI due to the emergence of so called ”hypervirulent”strains of C. difficile BI/NAP1/027 . Although it is still unclear what exactly contributes to this rapid spread of this strain, Robinson et al hypothesize that the rapid spread of these hypervirulent ribotype 027strains is due to increased fitness over the historic strains such as ribotypes (001, 002, 014, and 053). Looking at in vitro as well as an in vivo model of competition in mice, data suggests that these hypervirulent strains may be able to outcompete historic strains in a mixed infection/complex microbiota environment.
http://iai.asm.org/content/early/2014/04/08/IAI.01524-14.long

Chandrabali Ghose-Paul,MS,PhD, Chairperson of Research and Development