New Delhi Metallo-Beta-Lactamase (NDM) plasmid predictions
The complete detection and genome sequencing of resistance plasmids is required to understand the co-occurrence of resistance genes on plasmids and their transmission, which is necessary to mitigate the spread of drug resistant bacterial infections. One group of multi-drug resistance plasmids of interest are the New Delhi Metallo-beta-lactamase (NDM) associ-ated plasmids. Bacteria pathogens with NDM genes are resistant to a broad range of beta-lactam antibiotics, including carbapenems, a mainstay for treating bacterial infections. We sequenced clinical isolates collected from patients that failed to respond to antibiotic treatments in the Hamilton-Niagara community using Next Generation Sequencing (NGS) technology, which is the standard technique for sequencing bacterial genomes. I analyzed their assembled genomes via the development of a new resistance plasmid prediction bioinformatics pipeline: RGI:Mobilome. RGI:Mobilome predicted NDM bearing plasmids in 15 isolates, along with other resistance genes on plasmids. However, the NDM plasmid predictions of all 15 isolates were fragmented due to incomplete genome assemblies, caused by repetitive sequences within bacterial genomes and use of short-read NGS technology. However, plasmid predictions greatly improved when we leveraged the high nucleotide accuracy of NGS reads and the structural resolving power of long reads generated with the Oxford Nanopore Technology (ONT) to produce ‘hybrid’ genome assemblies. From the 15 putative hybrid assembly NDM plasmids, one plasmid was a complete match to a known pKP-NDM1 plasmid, seven plasmids were “variants” of known and well characterized plasmids, and the remaining seven plasmids were “distant homologs” of known and well characterized plasmids, suggesting previously undescribed NDM-associated plasmids in our community. This thesis project reveals the diversity of NDM plasmid types within the Hamilton-Niagara community, which is valuable to epidemiologists and public health practitioners to devise actionable plans required to mitigate the spread of multi-drug resistance NDM plasmids and for clinicians to treat infections caused by NDM positive strains.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) recently emerged to cause widespread infections in humans. SARS-CoV-2 infections have been reported in the Kingdom of Saudi Arabia, where Middle East respiratory syndrome coronavirus (MERS-CoV) causes seasonal outbreaks with a case fatality rate of ~37 %. Here we show that there exists a theoretical possibility of future recombination events between SARS-CoV-2 and MERS-CoV RNA. Through computational analyses, we have identified homologous genomic regions within the ORF1ab and S genes that could facilitate recombination, and have analysed co-expression patterns of the cellular receptors for SARS-CoV-2 and MERS-CoV, ACE2 and DPP4, respectively, to identify human anatomical sites that could facilitate co-infection. Furthermore, we have investigated the likely susceptibility of various animal species to MERS-CoV and SARS-CoV-2 infection by comparing known virus spike protein-receptor interacting residues. In conclusion, we suggest that a recombination between SARS-CoV-2 and MERS-CoV RNA is possible and urge public health laboratories in high-risk areas to develop diagnostic capability for the detection of recombined coronaviruses in patient samples.
The growing challenge of microbial resistance emphasizes the importance of new antibiotics or reviving strategies for the use of old ones. Macrolide antibiotics are potent bacterial protein synthesis inhibitors with a formidable capacity to treat life-threatening bacterial infections, however, acquired and intrinsic resistance limits their clinical application. In the work presented here, we reveal that bicarbonate is a potent enhancer of the activity of macrolide antibiotics that overcomes both acquired and intrinsic resistance mechanisms. With a focus on azithromycin, a highly prescribed macrolide antibiotic, and using clinically relevant pathogens, we show that physiological concentrations of bicarbonate overcome drug resistance by increasing the intracellular concentration of azithromycin. We demonstrate the potential of bicarbonate as a formulation additive for topical use of azithromycin in treating a murine wound infection caused by Pseudomonas aeruginosa. Further, using a systemic murine model of methicillin-resistant Staphylococcus aureus infection, we demonstrate the potential role of physiological bicarbonate, naturally abundant in the host, to enhance the activity of azithromycin against macrolide-resistant MRSA. In all, our findings suggest that macrolide resistance, observed in the clinical microbiology laboratory using standard culturing techniques, is a poor predictor of efficacy in the clinic and that observed resistance should not necessarily hamper the use of macrolides. Whether as a formulation additive for topical use or as a natural component of host tissues, bicarbonate is a powerful potentiator of macrolides with the capacity to overcome drug resistance in life-threatening bacterial infections.
We are very excited to have Arman Edalatmand join us as a new MSc student in the Biochemistry & Biomedical Sciences graduate program! Arman has been a great lab member these last two years, with an emphasis upon machine learning and natural language processing for molecular epidemiological analyses, which he will expand upon in his thesis. Welcome aboard, Arman!
The McArthur Lab welcomes our 2020-2021 4th year thesis students from both the Biochemistry & Biomedical Sciences (BBS) and Biomedical Discovery & Commercialization (BDC) programs! Welcome Keyu (Corie) Niu, Romeo Chalil, Megan Kwong, Prabakar Shan, Komal Kaur, Xingjian (Jim) Jiang, Jasmine Yang, Bahar Golbon!
Jalees A. Nasir, Robert A. Kozak, Patryk Aftanas, Amogelang R. Raphenya, Kendrick M. Smith, Finlay Maguire, Hassaan Maan, Muhannad Alruwaili, Arinjay Banerjee, Hamza Mbareche, Brian P. Alcock, Natalie C. Knox, Karen Mossman, Bo Wang, Julian A. Hiscox, Andrew G. McArthur, & Samira Mubareka
Genome sequencing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is increasingly important to monitor the transmission and adaptive evolution of the virus. The accessibility of high-throughput methods and polymerase chain reaction (PCR) has facilitated a growing ecosystem of protocols. Two differing protocols are tiling multiplex PCR and bait capture enrichment. Each method has advantages and disadvantages but a direct comparison with different viral RNA concentrations has not been performed to assess the performance of these approaches. Here we compare Liverpool amplification, ARTIC amplification, and bait capture using clinical diagnostics samples. All libraries were sequenced using an Illumina MiniSeq with data analyzed using a standardized bioinformatics workflow (SARS-CoV-2 Illumina GeNome Assembly Line; SIGNAL). One sample showed poor SARS-CoV-2 genome coverage and consensus, reflective of low viral RNA concentration. In contrast, the second sample had a higher viral RNA concentration, which yielded good genome coverage and consensus. ARTIC amplification showed the highest depth of coverage results for both samples, suggesting this protocol is effective for low concentrations. Liverpool amplification provided a more even read coverage of the SARS-CoV-2 genome, but at a lower depth of coverage. Bait capture enrichment of SARS-CoV-2 cDNA provided results on par with amplification. While only two clinical samples were examined in this comparative analysis, both the Liverpool and ARTIC amplification methods showed differing efficacy for high and low concentration samples. In addition, amplification-free bait capture enriched sequencing of cDNA is a viable method for generating a SARS-CoV-2 genome sequence and for identification of amplification artifacts.
Emma J. Griffiths, Ruth E. Timme, Andrew J. Page, Nabil-Fareed Alikhan, Dan Fornika, Finlay Maguire, Catarina Inês Mendes, Simon H. Tausch, Allison Black, Thomas R. Connor, Gregory H. Tyson, David M. Aanensen, Brian Alcock, Josefina Campos, Alan Christoffels, Anders Gonçalves da Silva, Emma Hodcroft, William W.L. Hsiao, Lee S. Katz, Samuel M. Nicholls, Paul E. Oluniyi, Idowu B. Olawoye, Amogelang R. Raphenya, Ana Tereza R. Vasconcelos, Adam A. Witney, & Duncan R. MacCannell
The Public Health Alliance for Genomic Epidemiology (PHA4GE) (https://pha4ge.org) is a global coalition that is actively working to establish consensus standards, document and share best practices, improve the availability of critical bioinformatic tools and resources, and advocate for greater openness, interoperability, accessibility and reproducibility in public health microbial bioinformatics. In the face of the current pandemic, PHA4GE has identified a clear and present need for a fit-for-purpose, open source SARS-CoV-2 contextual data standard. As such, we have developed an extension to the INSDC pathogen package, providing a SARS-CoV-2 contextual data specification based on harmonisable, publicly available, community standards. The specification is implementable via a collection template, as well as an array of protocols and tools to support the harmonisation and submission of sequence data and contextual information to public repositories. Well-structured, rich contextual data adds value, promotes reuse, and enables aggregation and integration of disparate data sets. Adoption of the proposed standard and practices will better enable interoperability between datasets and systems, improve the consistency and utility of generated data, and ultimately facilitate novel insights and discoveries in SARS-CoV-2 and COVID-19.
Ana T Duggan, Jennifer Klunk, Ashleigh F Porter, Anna N Dhody, Robert Hicks, Geoffrey L Smith, Margaret Humphreys, Andrea M McCollum, Whitni B Davidson, Kimberly Wilkins, Yu Li, Amanda Burke, Hanna Polasky, Lowell Flanders, Debi Poinar, Amogelang R Raphenya, Tammy T Y Lau, Brian Alcock, Andrew G McArthur, G Brian Golding, Edward C Holmes, Hendrik N Poinar
Vaccination has transformed public health, most notably including the eradication of smallpox. Despite its profound historical importance, little is known of the origins and diversity of the viruses used in smallpox vaccination. Prior to the twentieth century, the method, source and origin of smallpox vaccinations remained unstandardised and opaque. We reconstruct and analyse viral vaccine genomes associated with smallpox vaccination from historical artefacts. Significantly, we recover viral molecules through non-destructive sampling of historical materials lacking signs of biological residues. We use the authenticated ancient genomes to reveal the evolutionary relationships of smallpox vaccination viruses within the poxviruses as a whole.
Image: CDC/Dr. Fred Murphy; Sylvia Whitfield, CC BY
Arinjay Banerjee, Patrick Budylowski, Daniel Richard, Hassaan Maan, Jennifer A. Aguiar, Nader El-Sayes, Michael R. D’Agostino, Benjamin J.-M. Tremblay, Sam Afkhami, Mehran Karimzadeh, Lily Yip, Mario Ostrowski, Jeremy A. Hirota, Robert Kozak, Terence D. Capellini, Matthew S. Miller, Andrew G. McArthur, Bo Wang, Andrew C. Doxey, Samira Mubareka, & Karen Mossman
Two highly pathogenic human coronaviruses that cause severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) have evolved proteins that can inhibit host antiviral responses, likely contributing to disease progression and high case-fatality rates. SARS-CoV-2 emerged in December 2019 resulting in a global pandemic. Recent studies have shown that SARS-CoV-2 is unable to induce a robust type I interferon (IFN) response in human cells, leading to speculation about the ability of SARS-CoV-2 to inhibit innate antiviral responses. However, innate antiviral responses are dynamic in nature and gene expression levels rapidly change within minutes to hours. In this study, we have performed a time series RNA-seq and selective immunoblot analysis of SARS-CoV-2 infected lung (Calu-3) cells to characterize early virus-host processes. SARS-CoV-2 infection upregulated transcripts for type I IFNs and interferon stimulated genes (ISGs) after 12 hours. Furthermore, we analyzed the ability of SARS-CoV-2 to inhibit type I IFN production and downstream antiviral signaling in human cells. Using exogenous stimuli, we discovered that SARS-CoV-2 is unable to modulate IFNβ production and downstream expression of ISGs, such as IRF7 and IFIT1. Thus, data from our study indicate that SARS-CoV-2 may have evolved additional mechanisms, such as masking of viral nucleic acid sensing by host cells to mount a dampened innate antiviral response. Further studies are required to fully identify the range of immune-modulatory strategies of SARS-CoV-2.