Bettina Buttaro, PhD
Associate Professor, Microbiology and Immunology
Department of Microbiology and Immunology
The research in Dr. Buttaro's laboratory focuses on streptococcal physiology. The first project examines plasmid maintenance in Enterococcus faecalis. E. faecalis is a member of the intestinal tract normal flora and is also an opportunistic pathogen that can be resistant to all known antibiotics. This antibiotic resistance is mediated by plasmids and transposons which are highly stable in the absence of antibiotic selection. Thus, Enterococci represent a significant reservoir of antibiotic resistance genes. We have discovered that some of the plasmids encoding resistance may be maintained by a peptide signal related to peptide signaling used for the induction of plasmid transfer by conjugation. This is the first description of a peptide signaling system needed for plasmid maintenance, hence representing a unique system in plasmid biology. Further definition of this peptide maintenance system may lead to an understanding of why Enterococcal plasmids are so stably maintained in the intestinal tract.
Our second project focuses on the persistence of Streptococcus pyogenes in the human host. Humans are the only known host for S. pyogenes and there is evidence that some patients can be asymptomatically colonized. Using an in vitro model, we described the formation of alternate phenotypes of S. pyogenes during persistence in batch cultures. A further characterization of the physiology of these phenotypes and a screening for their presence in eukaryotic cell co-cultures and patient samples will lead to a better understanding of the persistence of S. pyogenes in the human host. These studies may have implications in the development of vaccine targets and the treatment of post-streptococcal sequelae such as rheumatic fever and glumeronephritis. Dr. Buttaro also has collaborative studies with Dr. Patrick Piggot (survival of S. mutans in biofilms), Dr. Glenn Isaacson (post-operative Otorrhea), and Dr. Douglas Markham (SAM synthetase in S. pyogenes).
Podbielski, A., Leonard, B.A.B. The group A streptococcal dipeptide permease (Dpp) is involved in uptake of essential amino acids and affects expression of cysteine protease. Mol. Microbiol. 23:1323-1334, 1998.
Leonard, B.A.B., Woischnik, M., Podbielski, A. The production of stabilized virulence factor negative variants by Group A Streptococci during stationary phase. Infect. Immun. 66:3841-3847, 1998.
Leonard, B.A.B., Podbielski, A. Emerging density dependent control systems in Gram-positive cocci. In Cell-Cell Communication in Bacteria. Dunny, G.M., Winans, S., eds. ASM Press, Washington, DC, pp. 315-329, 1999.
Podbielski, A., Woischnik, M., Leonard, B.A.B., Schmidt, K.-H. Characterization of nra, a global negative regulator gene in group A streptococci. Mol. Microbiol. 31:1051-1064, 1999.
Podbielski, A., Woischnik, M., Bettenbrock, K., (Leonard) Buttaro, B.A. Cysteine protease SpeB expression in group A streptococci is influenced by the nutritional environment but SpeB does not contribute to obtaining essential nutrients. Med. Microbiol. Immunol. (Berl.) 188:99-109, 1999.
Woischnik, M., Buttaro, B.A. (Leonard), Podbielski, A. Inactivation of the cysteine protease SpeB affects hyaluronic acid capsule expression in group A streptococci. Microb. Pathog. 28:221-226, 2000.
Buttaro, B.A. (Leonard), Dunny, G.M., Antiporta, M. Cell-associated pheromone peptide (cCF10) production and pheromone inhibition in Enterococcus faecalis. J. Bacteriol. 182:4926, 2000.
Kreikemeyer, B., Boyle, M.D.P., Buttaro, B.A. (Leonard), Heinemann, M., Podbielski, A. Molecular characterization of the group A streptococcal fas regulon exhibiting functional similarities to the Staphylococcus aureus agr operon. Mol. Microbiol. 39:392-406, 2001.
Elsner, A., Kreikemeyer, B., Braun-Kiewnick, A., Spellerberg, B., Buttaro, B.A., Podbielski, A. Involvement of Lsp, a member of the LraI-lipoprotein family in Streptococcus pyogenes, in eukaryotic cell adhesion and internalization. Infect. Immun. 70:4859-4869, 2002.
Renye, J., Daneo-Moore, L, Piggot, P., Buttaro, B. A. Starvation survival of Streptococcus mutans in batch culture and biofilms. Appl. Environ. Microbiol. 70:6181-6187, 2004.
Wood, D. , Chaussee, M. A., Chaussee, M. S., Buttaro, B. A.. Persistence of Streptococcus pyogenes in stationary phase cultures. J. Bacteriol. 187:3319-28, 2005.
Isaacson, G. C., Buttaro, B. A., Mazeffa, V., Geming, L., Frenz, D. Oxymetazoline solutions inhibit middle ear pathogens and are not ototoxic. Ann. Otol. Rhinol. Laryngol. 114:645-651, 2005.
Certain Recent Graduates:
Current or Recent Grant Support of Active Projects:
Bettina A. Buttaro, PhD as Principal Investigator:
Bettina A. Buttaro, PhD as Co-Investigator: