Karen Maxwell, PhD

Assistant Professor
Department(s): Biochemistry
Location: MaRS West Tower
Email: karen.maxwell@utoronto.ca

The Maxwell lab studies the phages that infect and kill the human bacterial pathogens Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. Infections caused by these bacteria create a significant disease burden, and the increasing incidence of antibiotic resistant infections caused by these pathogens is one of our most serious health threats.

Phages play important roles in the infections caused by bacteria as they transmit genes that protect bacteria against both the human immune system and antibiotics, and in some cases, such as the E. coli O157:H7 strain that caused the Walkerton, Ontario outbreak, they carry toxins that cause the severe disease pathology. Conversely, since they attack and kill bacteria, genetically engineered phages may be useful as an alternative to antibiotics. Our lab investigates both the disease-causing properties and the potential diagnostic uses of phages and phage-derived molecules. 

Selected publications:

  1. Pawluk A, Shah M, Mejdani M, Calmettes C, Moraes TF, Davidson AR, Maxwell KL. Disabling a Type I-E CRISPR-Cas Nuclease with a Bacteriophage-Encoded Anti-CRISPR Protein. MBio. 2017 Dec 12;8(6). pii: e01751-17. doi: 10.1128/mBio.01751-17. PubMed PMID: 29233895; PubMed Central PMCID: PMC5727412.
  2. Harrington LB, Doxzen KW, Ma E, Liu JJ, Knott GJ, Edraki A, Garcia B, Amrani N, Chen JS, Cofsky JC, Kranzusch PJ, Sontheimer EJ, Davidson AR, Maxwell KL, Doudna JA. A Broad-Spectrum Inhibitor of CRISPR-Cas9. Cell. 2017 Sep 7;170(6):1224-1233.e15. doi: 10.1016/j.cell.2017.07.037. Epub 2017 Aug 24. PubMed PMID: 28844692; PubMed Central PMCID: PMC5875921.
  3. Pawluk A, Amrani N, Zhang Y, Garcia B, Hidalgo-Reyes Y, Lee J, Edraki A, Shah  M, Sontheimer EJ, Maxwell KL, Davidson AR. Naturally Occurring Off-Switches for CRISPR-Cas9. Cell. 2016 Dec 15;167(7):1829-1838.e9. doi: 10.1016/j.cell.2016.11.017. Epub 2016 Dec 8. PubMed PMID: 27984730; PubMed Central PMCID: PMC5757841.
  4. Bondy-Denomy J, Qian J, Westra ER, Buckling A, Guttman DS, Davidson AR, Maxwell KL. Prophages mediate defense against phage infection through diverse mechanisms. ISME J. 2016 Dec;10(12):2854-2866. doi: 10.1038/ismej.2016.79. Epub 2016 Jun 3. PubMed PMID: 27258950; PubMed Central PMCID: PMC5148200.
  5. Kala S, Cumby N, Sadowski PD, Hyder BZ, Kanelis V, Davidson AR, Maxwell KL. HNH proteins are a widespread component of phage DNA packaging machines. Proc Natl Acad Sci U S A. 2014 Apr 22;111(16):6022-7. doi: 10.1073/pnas.1320952111. Epub 2014 Apr 7. PubMed PMID: 24711378; PubMed Central PMCID: PMC4000778.
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