Speicher, D.J., K. Luinstra, J. Maciejewski, K.K. Tsang, A.G. McArthur, & M. Smieja. 2019. Clostridioides difficile strain divergence over time. Oral presentation at the Association of Medical Microbiology and Infectious Disease Canada (AMMI Canada) & Canadian Association for Clinical Microbiology and Infectious Diseases (CACMID) Joint Annual Conference, Ottawa, Ontario.

Background: Clostridioides difficileinfection (CDI) is a serious hospital-associated infection with severe outbreaks caused by the hypervirulent NAP1/MLST-1 strain.  Whole genome sequencing has shown that most outbreak strains are clonal whereas non-outbreaks display a wide diversity of strains.  To examine strain diversity in clinical settings, a subset of C. difficileisolates from symptomatic CDI from an acute care hospital were compared to isolates from C. difficilecolonized (CDC) asymptomatic subjects from the same hospital.

Methods: A subset of PCR-positive stool samples from clinically confirmed CDI isolates from 2016 (13/110), 2017 (8/111), and 2018 (13/65), and CDC from 2017 (17/185) were cultured 3-times consecutively on CHROMagar™ C. difficile, sub-cultured on Columbia colistin-nalidixic acid (CNA) media, had DNA isolated, shotgun sequenced, and genome assembled for both MLST typing and genome-wide SNP phylogenetic analysis.

Results: Based on MLST profiles, the C. difficiletypes detected were diverse. Of the presumed binary toxin positive/NAP1 strains (i.e. PCR tcdA/tcdBpositive) 7/12 (58%) were NAP1/MLST-1 and 3/12 (25%) were NAP7/MLST-11.  NAP1/MLST-1 was not detected in any CDC isolate.  NAP4/MLST-2,14 were detected in 2016 (n=4), 2017 (n=2), 2018 (n=1), and in CDC isolates (n=3).  MLST-42 was dominant in CDC isolates (5/17; 29%) and decreased in prevalence in CDI isolates over time (2016=4; 2017=0; 2018=1).

Conclusion:  C. difficilestrains amongst both CDI and CDC individuals are highly divergent. Whilst molecular assays are misclassifying 25% of “NAP1” strains, both NAP1 and NAP7 are hypervirulent.  The number of MLST-42 CDC isolates is concerning as it has been reported to be the most common strain causing CDI among U.S. adults.  This highlights the need for continued genomic surveillance of both CDI and CDC individuals. Genome-wide SNP phylogenetic analysis is currently being performed.

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Congratulations to Rachel Tran on winning a 2019 DBCAD Summer Fellowship! These competitive awards are designed to support students working in the labs of members from both the David Braley Centre for Antibiotic Discovery and Michael G. DeGroote Institute for Infectious Disease Research during their summer practicum. A full list of awardees can be found here. Learn more about Rachel’s work at Ontario Biology Day 2019:

Tran, H.K.R., S. Ahmad, J.C. Whitney, & A.G. McArthur. 2019. Expanding the Virulence Ontology (VIRO) to determine the evolution of a secretion system effector. Presentation at Ontario Biology Day, London, Ontario, Canada.

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The Comprehensive Antibiotic Resistance Database has been updated, http://card.mcmaster.ca

CARD Curation: Expanded MCR, OXA & IMP beta-lactamase, and macrolide phosphotransferase (MPH) sequence curation. Updated nomenclature for MPHs and drug resistant dihydrofolate reductases (dfr). Updated classification of ADC beta-lactamases.

Ontologies: Addition of 518 draft virulence ontology (VIRO) terms.

Prevalence, Resistomes, & Variants: Expansion to 82 pathogens (more Brucella species), 81,000+ resistomes, and 173,000+ AMR allele sequences based on sequence data acquired from NCBI on 28-Feb-2019, analyzed using RGI 4.2.2 (DIAMOND homolog detection) and CARD 3.0.1.

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Srinivasan, K.A., S.K. Virdee, & A.G. McArthur. 2019. Strandedness during cDNA synthesis, the stranded parameter in htseq-count, and analysis of RNA-Seq data. Preprints 2019, 2019030124. [Preprint]

Matthews, T., F. Bristow, E. Griffiths, A. Petkau, J. Adam, D. Dooley, P. Kruczkiewicz, J. Curatcha, J. Cabral, D. Fornika, G. Winsor, M. Courtot, C. Bertelli, A. Roudgar, P. Fejaio, P. Mabon, E. Enns, J. Thiessen, A.W.S. Keddy, J. Isaac-Renton, J. Gardy, P. Tang, The IRIDA consortium, J. Carriço, L. Chindelevitch, C. Chauve, M. Graham, A.G. McArthur, E. Taboada, R. Beiko, F.S.L. Brinkman, W.W.L. Hsiao, & G. Van Domselaar. 2018. The Integrated Rapid Infectious Disease Analysis (IRIDA) Platform. BioRxiv 381830 [Preprint].

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A week of lectures, demos, and training for the Comprehensive Antibiotic Resistance Database

During McMaster Spring Mid-Term Recess (February 18-24), the McArthur lab is pleased to present a series of lectures, demonstrations, and training sessions for the Comprehensive Antibiotic Resistance Database (card.mcmaster.ca) and its associated Resistance Gene Identifier (RGI) software, sponsored by the Michael G. DeGroote Institute for Infectious Disease Research (IIDR).

Questions? Email card@mcmaster.ca

  


Workshop & Lecture material will be available herehttps://github.com/arpcard/state-of-the-card-2019


 

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A busy year for Dr. McArthur outside of academia…

  • Integrated Health Biosystems Chair – Combatting Antimicrobial Resistance in the Age of Molecular Epidemiology. Invited presentation at the Cisco Research Chairs Summit, Toronto.
  • The Comprehensive Antibiotic Resistance Database (CARD) and the Resistance Gene Identifier – prediction of antimicrobial resistance genes for genomic and metagenomic sequencing data. Invited presentation at the Integrated Rapid Infectious Disease Analysis (IRIDA) Annual General Meeting, Winnipeg, Manitoba.
  • The Comprehensive Antibiotic Resistance Database. Invited presentation at the Agriculture & Agri-Food Canada and Canadian Food Inspection Agency Genomics Research and Development Initiative: GRDI-AMR Annual General Meeting.
  • Facilitator & Speaker, Artificial Intelligence: The Art of the Possible, Niagara Health Board of Directors Retreat (Niagara-on-the-Lake, Ontario).
  • Represented McMaster University at McMaster – Queen’s Park Government Reception, Gardiner Museum, Toronto.
  • Represented McMaster University at Research Canada’s Health Research Caucus – Reshaping Health Research and Innovation: Artificial Intelligence and Machine Learning (Parliament Hill, Ottawa, Ontario).
  • Panellist – Artificial Intelligence in Healthcare, Norwegian Health Ministry & Government of Canada Round Table hosted by Hamilton Health Sciences (Hamilton, Ontario).
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Dr. David Speicher has joined the McArthur Lab as our new Molecular Epidemiology Postdoctoral Fellow! David joins us via clinical epidemiology research in infectious disease at St. Joseph’s Healthcare Hamilton plus extensive training and experience in Cambodia, India, Sri Lanka, Kenya, and Australia. David has a depth of experience in infectious disease, virology, molecular biology, epidemiology and biostatistics, microbiology, and diagnostic techniques and will be leading infectious disease molecular epidemiology collaborations with McMaster Children’s Hospital, St. Joseph’s Healthcare Hamilton, and Hamilton Health Sciences with an emphasis on antimicrobial resistance, C. difficile, H. pylori, ShigellaChlamydia trachomatis, and Mycoplasma genitalium. Hear Dr. Speicher talk about his research program on CFMU radio.

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Antimicrobial Resistance: Emergence, Transmission, and Ecology (ARETE). R. Beiko (PI; Dalhousie University), F. Brinkman (co-PI, Simon Fraser University), A.G. McArthur (co-Applicant) + 4 additional co-Applicants. Genome Canada Bioinformatics and Computational Biology Competition.

 

Bioinformatics Tools to Improve Data Sharing and Re-use in Public Health – applications in antimicrobial resistance profiling and source tracking. W. Hsiao (PI; University of British Columbia), A.G. McArthur (co-Applicant) + 8 additional co-Applicants. CIHR Project Grant.

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