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Dr Kimon-Andreas Karatzas (B.Sc., Ph.D.)
Marie Curie Experienced Researcher

Contact Information
Bacterial Stress Response Group
Department of Microbiology
National University of Ireland, Galway
University Road
Galway
Tel: 353 91 495091 (Ext 5091)
E-mail: kimon-andreas.karatzasnuigalway.ie

Research interests

• Investigation of the role of stress resistance mechanisms in virulence of L. monocytogenes, S. aureus and S. enterica. The roles of the two major stress gene regulators σ ^Β and CtsR in L. monocytogenes are of great interest due to their involvement in resistance to multiple stresses, virulence, motility and general phenotype.


• Investigation of the molecular basis of bacterial resistance to high hydrostatic pressure encountered during food pasteurization or deep sea environments. Involvement of heat shock proteins and investigation for new mechanisms of piezotolerance.


• Involvement of disinfectant use in the development of antibiotic resistance in enteric bacteria. Role of mechanisms of antimicrobial resistance in virulence.


• Culturing of cellulolytic and methanogenic bacteria with the use of anaerobic microbiological techniques.

Expertise

• 2D gel electrophoresis, transcriptomics, mutagenesis and cloning in gram and gram- bacteria, anaerobic microbiology, AFLP technology, tissue culture models for assessment of bacterial invasiveness, High Pressure technology.

Publications

• Karatzas K.A.G., Webber M.A., Jorgensen F., Woodward M.J., Piddock L.J.V.and T.J. Humphrey. 2007. Prolonged treatment of Salmonella enterica ser. Typhimurium with commercial disinfectants selects for multiple antibiotic resistance (MAR), increased efflux and reduced invasiveness. (in press, Journal of Antimicrobial Chemotherapy)


• Karatzas K.A.G., Zervos A., Tassou C., Mallidis C.G. and T.J. Humphrey. 2007. Piezotolerant small colony variants with increased thermotolerance, antibiotic susceptibility and low invasiveness in a clonal population of Staphylococcus aureus. Applied and Environmental Microbiology. 73(6): 1873-1881.


• Cysneiros D., Karatzas K.A.G., S. Heaven and C. Banks. 2007. Anaerobic Digestion of Maize for Energy Production in a Two-phase System. International Water Association. 11th World Congress, Anaerobic Digestion Bioenergy for our Future. Brisbane, Australia. 23-27/09/2007.


• Karatzas, K. A. G., Valdramidis V. and Bennik, M.H.J. 2005. Simple contingency locus in ctsR of Listeria monocytogenes ScottA: a strategy for inducing occurrence of abundant piezotolerant isolates within clonal populations. Applied and Environmental Microbiology 71(12) 8390-8396.


• Karatzas, K.A.G. 2004. High Hydrostatic Pressure treatment of Food. Journal of the Hellenic Veterinary Medical Society. 55(4): 324-330


• Karatzas, K.A.G., Wouters, J.A., Gahan, C.G.M., Hill, C., Abee, T. and Bennik, M.H.J. 2003. The CtsR regulator of Listeria monocytogenes contains a variant glycine repeat region that affects piezotolerance, stress resistance, motility and virulence. Molecular Microbiology, 49: 1227-1238.


• Wemekamp-Kamphuis, H.H., Karatzas, K.A.G., Wouters, J.A. and Abee, T. 2002. Enhanced levels of cold shock proteins in Listeria monocytogenes LO28 upon exposure to low temperature and high hydrostatic pressure. Applied and Environmental Microbiology, 68:456-463


• Karatzas, K.A.G. and Bennik, M.H.J. 2002. Characterisation of a Listeria monocytogenes Scott A isolate with high tolerance to high hydrostatic pressure. Applied and Environmental Microbiology. 68: 3183-3189.


• Karatzas, K.A.G., Kets, E.P.W., Smid, E.J. and Bennik, M.H.J. 2001. The combined action of carvacrol and high hydrostatic pressure on Listeria monocytogenes Scott A. Journal of Applied Microbiology. 90: 463-469.


• Karatzas, K.A.G., Bennik, M.H.J., Smid, E.J. and Kets E.P.W. 2000. Combined Action of S-Carvone and Mild Heat Treatment of Listeria monocytogenes Scott A. Journal of Applied Microbiology. 89: 296-301.

International Patent

• Karatzas, K.A.G., Bennik, M.H.J., Abee, T., De Vos, W.M. 2002. Stress-resistant, low virulence gram positive bacteria having an altered ctsR gene. Patent. International publication date, 18/9/2003. International publication number: WO 03/076463 A2.

Books

• Bennik, M.H.J., Karatzas, K.A.G., Moezelaar R. and T. Abee. 2006. Listeria monocytogenes UHP resistance and survival strategies. In Aertsen A. and C. Michiels (eds) High-Pressure Microbiology. ASM Press, Washington USA.

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