Helmut Hirt

 

346 Ackert Hall
(785) 532-2816
hhirt@ksu.edu

Research Focus

My lab is interested in the biology and genetics of a major surface molecule of Gram-positive bacteria called lipoteichoic acid (LTA).  The model organism is the human commensal and important nosocomial pathogen Enterococcus faecalis.  LTA plays an essential role for Gram-positive bacteria, however the exact function of the molecule for the cell is not very well understood.  Revealing the function of LTA can have implications for understanding the pathogenicity of the organism and the potential to point to new targets for antibiotic treatment. 

In E. faecalis LTA also serves as a receptor to allow the cells the spread of extrachromosomal elements that often carry antibiotic resistance within the population and contribute to virulence and the increasing challenge to treat these infections.

Selected Research Publications

Hirt, H., P.M. Schlievert, and G.M. Dunny.  2002.  In vivo induction of virulence and antibiotic resistance transfer in Enterococcus faecalis mediated by the sex pheromone sensing system of pCF10. Infect. Immun. 70: 716-723.  

McCormick, J.K., H. Hirt, C.M. Waters, T.J. Tripp, G.M. Dunny, and P.M. Schlievert.  2001.  Antibodies to a surface-exposed, N-terminal domain of aggregation substance are not protective in the rabbit model of Enterococcus faecalis infective endocarditis. Infect. Immun. 69: 3305-3314.  

Wells, C.L., W.M. Tam, E.A. Moore, J.A. Hoag, H. Hirt, G.M. Dunny, and S.L. Erlandsen.  2000.  Inducible expression of Enterococcus faecalis pCF10 aggregation substance surface protein facilitates internalization by cultured enterocytes. Infect. Immun. 68: 190-7194.  

 Hirt, H., S.L. Erlandsen, and G.M. Dunny.  2000.  Heterologous inducible expression of Enterococcus faecalis pCF10 aggregation substance Asc10 demonstrates contribution to mating pair formation, cell hydrophobicity and adhesion to fibrin. Journal of Bacteriol. 182: 2299-2306.  

Schlievert, P.M., P.J. Gahr, A.P. Assimacopoulos, M.M. Dinges, J.A. Stoehr, J.W. Harmala, H. Hirt, and G.M. Dunny. 1998.  Aggregation and binding substances enhance pathogenicity in rabbit models of Enterococcus faecalis endocarditis. Infect. Immun. 66: 218-223.