Research Staff - Dr Stephen Kwong

Stephen Kwong Photo
Position: Research Associate
Phone: +61 2 9351 5998
Fax: +61 2 9351 4771
Mobile Phone: N/A
Location: Room 216
Address: A12 - Macleay, The University of Sydney, NSW 2006 Australia 
Links: N/A

Areas of Interest

Plasmids are extrachromosomal DNA elements that are an important genetic component in many bacteria. Plasmids promote the spread of genes between bacterial cells leading to remarkable diversity and adaptability. In hospital environments, plasmids have played a central role in the evolution of antibiotic resistant “superbugs” such as multi-drug resistant Staphylococcus aureus.

I am interested in the molecular biology of plasmid replication and maintenance systems. These genetic systems define the ability of plasmids to establish and persist in new bacterial hosts. The multiresistance staphylococcal plasmids pSK41 and pSK1 serve as prototypes in our laboratory for the study of replication. Areas that are actively being studied include:

  • Molecular characterisation of antisense RNA-mediated replication control systems
  • Molecular interactions between replication initiation proteins and origins of replication
  • Identification of host-factors required for efficient plasmid replication
  • Novel strategies for the elimination of plasmids

Research Output

Journal Publications

  • Kwong, S.M., Jensen, S.O., Firth, N. (2010) Prevalence of Fst-like toxin antitoxin systems. Microbiology 156:975-7.
  • Perez-Roth, E., Kwong, S.M., Alcoba-Florez, J., Firth, N., Mendez-Alvarez, S. (2010) Complete nucleotide sequence and comparative analysis of pPR9, a 41.7-kilobase conjugative staphylococcal multiresistance plasmid conferring high-level mupirocin resistance. Antimicrobial Agents & Chemotherapy 54:2252-7.
  • Jensen, S.O., Apisiridej, S., Kwong, S.M., Yang, Y.H., Skurray, R.A., Firth, N. (2010) Analysis of the prototypical Staphylococcus aureus multiresistance plasmid pSK1. Plasmid 64:135-42.
  • Ni, L., Jensen, S.O., Ky Tonthat, N., Berg, T., Kwong, S.M., Guan, F.H., Brown, M.H., Skurray, R.A., Firth, N., Schumacher, M.A. (2009) The Staphylococcus aureus pSK41 plasmid-encoded ArtA protein is a master regulator of plasmid transmission genes and contains a RHH motif used in alternate DNA-binding modes. Nucleic Acids Research 37:6970-83.
  • Weaver, K.E., S.M. Kwong, N. Firth, and M.V. Francia (2009) The RepA_N replicons of Gram-positive bacteria: A family of broadly distributed but narrow host range plasmids. Plasmid 61:94-109.
  • Jensen, S.O., S.M. Kwong, B.R. Lyon, and N. Firth (2008) Evolution of multiple drug resistance in staphylococci. Microbiology Australia 29:120-4.
  • Kwong, S.M., R. Lim, R.J. LeBard, R.A. Skurray, and N. Firth (2008) Analysis of the pSK1 replicon, a prototype from the staphylococcal multiresistance plasmid family. Microbiology 154:3084-94.
  • Kwong, S.M. and N. Firth (2006) Regulatory RNA molecules. Microbiology Australia 27(3):124-7.
  • Kwong, S.M., R.A. Skurray, and N. Firth (2006) Replication control of staphylococcal multiresistance plasmid pSK41: an antisense RNA mediates dual-level regulation of Rep expression. Journal of Bacteriology 188:4404-12
  • Kwong, S.M., R.A. Skurray, and N. Firth (2004) Staphylococcus aureus multiresistance plasmid pSK41: Analysis of the replication region, initiator binding and antisense RNA control. Molecular Microbiology 51: 497-509.
  • Kwong, S.M., C.C. Yeo, and C.L. Poh (2001) Molecular analysis of the pRA2 partitioning region: ParB autoregulates parAB transcription and forms a nucleoprotein complex with the plasmid partitioning site, parS. Molecular Microbiology 40: 621-33.
  • Kwong, S.M., C.C. Yeo, A. Suwanto and C.L. Poh (2000) Characterization of the endogenous plasmid from Pseudomonas alcaligenes NCIB 9867: DNA sequence and mechanism of transfer. Journal of Bacteriology 182:81-90.
  • Kwong, S.M., C.C. Yeo, D. Chuah and C.L. Poh (1998) Sequence analysis of plasmid pRA2 from Pseudomonas alcaligenes NCIB 9867 reveals a novel replication region. FEMS Microbiology Letters 158:159-65.
  • Yeo, C.C., J.M. Tham, S.M. Kwong and C.L. Poh (1998) Characterization of the pac25I restriction-modification genes isolated from the endogenous pRA2 plasmid from Pseudomonas alcaligenes NCIB 9867. Plasmid 40:203-13.
  • Yeo, C.C., J.M. Tham, S.M. Kwong, S. Yiin and C.L. Poh (1998) Tn5563, a transposon encoding putative mercuric ion transport proteins located on plasmid pRA2 of Pseudomonas alcaligenes. FEMS Microbiology Letters 165:253-60.