Dr Guoqing Xia Ph.D.

Senior Lecturer in Molecular and Medical Microbiology

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Research interests

1. Tackling Antibiotic Resistance: Novel Mechanisms and agents

     Antibiotic resistance has become a global problem, and methicillin-resistant Staphylococcus aureus (MRSA) in particular poses a serious threat to our healthcare system. Our research focuses on  β-lactam resistance mechanisms in MRSA and new agents  to treat MRSA infections.

            Fig 1:   Scanning electron micrograph of Staphylococcus aureus(by courtesy of CDC/ Matthew J. Arduino, DRPH )


  • Mikkelsen K, Sirisarn W, et al (2021 ). The novel membrane-associated auxiliary factors AuxA and AuxB modulate β-lactam resistance in MRSA by stabilizing lipoteichoic acids. Int J Antimicrob Agents. 2021 Mar;57(3):106283.

  • Gerlach D, Guo Y, et al (2018) Methicillin-resistant Staphylococcus aureus alters cell wall glycosylation to evade immunityNature. 563, 705-709. 

  • Waters EM, Rudkin JK, et al  (2017) Redeploying β-lactam antibiotics as a novel anti-virulence strategy for the treatment of severe MRSA infections, J Infect Dis, 215, 80-87.

  • Brown S, Xia G, et al (2012) Methicillin resistance in Staphylococcus aureus requires glycosylated wall teichoic acids. Proc. Natl. Acad. Sci. USA,109: 18909-14

2. Bacteriophage-Host Interactions: Biology and Biomedical Application

    Increasing antibiotic resistance has prompted a renewed interest in phage research. Our research focuses on S. aureus phages and aims to investigate phage-host interactions, such as phage adsorption, replication, and host immunity to phage infections. We believe that this study will provide new insights and tools for the development of new diagnostics and therapeutics for drug-resistant bacterial infections.




Figure 2: Bacteriophage–host interaction at the cell envelope of S. aureusA:) Wall teichoic acids (WTA) but not lipoteichoic acids(LTA) serve as the receptors for S aureus phage.B:) Identification of Gp45 as the Receptor binding protein(RBP) of phage Φ11. Gp45 forms trimer (right) and there are six trimers of Gp45 in the baseplate (middle).  Dit (distal end protein)



  • Xia G, Corrigan RM, et al (2011).Wall teichoic acid-dependent adsorption of staphylococcal siphovirus and myovirus. J. Bacteriol.,193, 4006-09.

  • Winstel V, Liang C, et al (2013) Wall teichoic acid structure governs horizontal gene transfer between major bacterial pathogens. Nat. Commun, 4: Article number 2345.

  • Xia G, Wolz C.(2014) Phages of Staphylococcus aureus and their impact on host evolution. Infect. Genet. Evol. 21:593-601.

  • Idelevich E, Walther T, et al (2014).Bacteriophage-based latex agglutination test for rapid identification of Staphylococcus aureusJ. Clin. Microbiol. 52(9), 3394-3398

  • Li, X, Gerlach D, et al  (2015). An accessory wall teichoic acid glycosyltransferase protects Staphylococcus aureus from the lytic activity of Podoviridae. Sci Rep, 5, 17219.

  • Koc C, Xia G,  et al. (2016). Structure of the host-recognition device of Staphylococcus aureus phage Φ11.  Sci Rep, 6, 27581.

  • Li X, Koc C,  et al (2016). An essential role for the baseplate protein Gp45 in phage adsorption to Staphylococcus aureus. Sci Rep, 6, 26455.

  • Whittard E, Redfern J, et al ( 2021 ) Phenotypic and genotypic characterization of novel polyvalent bacteriophages with potent in vitro activity against an international collection of genetically giverse Staphylococcus aureus. Front. Cell. Infect. Microbiol., 11, 698909.

3.  Structures and Functions of Surface Glycopolymers in Gram-positive Bacteria

         The cell surfaces of gram-positive bacteria are decorated with various glycopolymers such as wall teichoic acids and capsules. We aim to study the diversity, structure, and regulation of these molecules and their functions in bacterial physiology, antibiotic resistance, and host-pathogen interactions. 

 Figure 3:    Critical interactions and processes mediated by wall teichoic acids (in green), the most abundant surface glycopolymers in S. aureus.  








Research and projects

No current projects are available for public display