College: College of Medicine
Department: Department of Molecular Genetics and Microbiology
Research interests: Burkholderia pseudomallei
Herbert Schweizer became part of the Emerging Pathogens Institute in the fall of 2014 as a preeminence hire. He is known for his international work in the biology and genetics of pathogens. He is currently conducting research on drug resistance in B. pseudomallei. His goal is to create an effective vaccine against the bacteria.
In his most recent research, Schweizer found that clinical bacterial isolates are often characterized by their resistance, either intrinsic or acquired, to established antibiotics. An ongoing challenge to microbiologists is identification of new drug targets and of mechanisms underlying drug resistance. Schweizer’s team is primarily studying two mechanisms: bacterial multidrug resistance and β-lactam resistance in Gram-negative bacteria.
Efflux pumps confer multidrug resistance and have traditionally been regarded as almost insurmountable challenges of antibacterial drug development. Recent research efforts, however, clearly demonstrate that an understanding of the structure, function and regulation of bacterial efflux systems can actually serve as an important asset for drug discovery. Biochemical and genetic studies are being employed to study the molecular architecture, function, regulation and clinical prevalence of efflux pumps of the resistance nodulation family in Burkholderia pseudomallei and, to a lesser extent, Pseudomonas aeruginosa.
Working with his team of graduate students and post-docs, he recently identified several novel aspects of β-lactam resistance in B. pseudomallei. PenA β-lactamase is the major β-lactam resistance determinant and unlike other such enzymes found in Gram-negative bacteria it is a TAT-secreted and membrane-anchored lipoprotein. They are trying to understand the significance of membrane localization. They also showed that deletion of a penicillin-binding protein 3 homolog is a novel mechanism of ceftazidime resistance in clinical isolates.
Large-scale chromosomal deletions or inversions do occur frequently in either drug-resistant or drug-susceptible clinical B. pseudomallei isolates, often with unintended consequences. One such mutant is fully virulent although it lacks a high-affinity siderophore whose homologs are required for virulence in other non-enteric bacteria. Evidence suggests that this mutant can utilize ferritin-iron and a new project in the lab is therefore geared towards identification of the molecular mechanisms of ferritin-iron acquisition.
To support these studies Schweizer is actively engaged in developing new genetic tools for pathogenic bacteria, especially those of contemporary interest because they are either emerging pathogens or of biodefense interest, for example B. pseudomallei.
B.S., M.S., Ph.D., University of Konstanz, Germany
• 2006, Fellow of the American Academy of Microbiology
• 1986, Feodor Lynen Postdoctoral Fellowship, Alexander von Humboldt Foundation
Emerging Pathogens Institute
University of Florida
P.O. Box 100009
Gainesville, Florida 32610-0009