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