Assistant Professor John Chen

Research Interest

Staphylococcus aureus is a Gram-positive pathogen that causes a wide spectrum of diseases ranging from skin and soft tissue infections to fatal necrotising pneumonia and is a major threat to public health. It is an extremely versatile pathogen that carries a diverse array of immune system evasion factors that enables it to infect or colonise nearly every niche and tissue of a host. Its pathogenic versatility is further compounded by an extraordinary propensity for adaptation when faced with environmental challenges. Historically, S. aureus infections were treatable with antibiotics; but in recent decades, antibiotic-resistant strains have reached epidemic proportions. Methicillin resistant S. aureus (MRSA) strains that were once largely confined to the immune-compromised in healthcare settings are now expanding to the community and infecting healthy individuals.

Research in the Chen lab focuses on the bacteriophages and pathogenicity islands of the bacterial pathogen S. aureus. Recently, we have identified and characterized several novel and powerful mechanisms of gene transfer that are proposed to be the major means by which S. aureus evolves and acquires the antibiotic resistance and virulence factors that accelerate the emergence of new and progressively more pathogenic strains.

Recent Publications

1. Chen J*, Quiles-Puchalt N, Chiang YN, Bacigalupe R, Fillol-Salom A, Chee MSJ, Fitzgerald JR, Penadés JR*. Genome hypermobility by lateral transduction. Science, 12 Oct 2018: Vol. 362, Issue 6411, pp. 207-212 DOI: 10.1126/science.aat5867. *Co-corresponding.
2. Martínez-Rubio, Quiles-Puchalt, Martí M, Humphrey S, Ram G, Smyth D, Chen J, Novick RP, Penadés JR. Phage-inducible islands in the Gram-positive cocci. ISME J, 2016 Dec 13. doi: 10.1038/ismej.2016.163.
3. Chen J, Carpena N, Quiles-Puchalt N, Ram G, Novick RP, Penadés JR. Intra- and inter-generic transfer of pathogenicity island-encoded virulence genes by cos phages. ISME J, 2015 May;9(5):1260-3.
4. Chen J, Ram G, Penadés JR, Brown S, Novick RP. Pathogenicity Island-Directed Transfer of Unlinked Chromosomal Virulence Genes. Mol Cell, 2015 Jan 8;57(1):138-49.
5. Ram G, Chen J, Ross HF, Novick RP. Precisely modulated pathogenicity island interference with late phage gene transcription. Proc Natl Acad Sci U S A, 2014 Oct 7;111(40):14536-41.
6. Chen J, Novick RP. Phage-mediated intergeneric transfer of toxin genes. Science, 2009 Jan 2; 323(5910):139-41
7. Chen J, de Felipe KS, Clarke M, Lu H, Anderson OR, Segal G, Shuman HA. Legionella effectors that promote non-lytic release from protozoa. Science, 2004; 303(5662):1358-61