Structural Infection Biology
Within this topic we investigate in collaborations with partner Institutions, particular UKE, Institute of Microbiology, the molecular, structural and dynamic mechanism of resistance, an essential prerequisite for development of sophisticated and future (e.g. anti-resistance, anti-virulence) strategies to combat multi-resistant bacteria. Selected examples are summarized below.
One project is focusing to understand the emergence of ceftazidime/avibactam resistance in clinical, multiresistant, CTX-M-14-producing Klebsiella pneumoniae isolate during ceftazidime/avibactam treatment (Both et al., 2017). We have recently identified a mutated CTX-M-14P167S isoform that inactivates also a last resort combination drug containing a 3rd generation antibiotic (ceftazidime) and a novel β-lactamase inhibitor avibactam. Structural investigations are aiming to apply also XFEL radiation for time resolved experiments. First successful XFEL data collection were performed already beginning of 2018 A second example is the analysis of molecular Mechanisms involved in staphylococcal biofilm formation. We are interested in the three-dimensional structures of the key proteins in bacterial biofilm formation. Biofilm formation is a twostep process including adherence of the bacteria to the surface to be colonized and subsequent assembly of a multi layered biofilm architecture. The latter phase depends on the expression of intercellular adhesins, stabilizing the biofilm consortium. Different proteins are involved in this process. Presently we target the accumulation associated protein Aap, the small basic protein Sbp and the extracellular matrix binding protein Embp. In terms of pro-drug design investigations we target particular the methicillin resistant Staphylococcus aureus, known also as MRSA. S. aureus is a commensal gram-positive bacterium that colonises mostly the nasal mucosa of 20% of the healthy population permanently and up to 60% transiently. In conjunction with hospitalised patients, colonisation sites like the skin, vascular catheters, and wound sites, as well as the nasophary have been reported. Colonisation from the nose can pass to the skin and can infect wounds or enter the body of patients with intravascular catheters. Once S. aureus becomes virulent, it causes symptoms which range from wound infections to serious conditions like pneumonia, endocarditis or meningitis. Infections of extremities often require long term treatment or even amputation. This bacterium has developed resistance against various antibiotics, such as vancomycin and methicillin, which makes treatment of S. aureus infections difficult, especially for immune-deficient patients. Therefore, structural research activities are aiming to identify and score novel S. aureus drug targets. In collaboration with partners at USP São Paulo we focus on pathogen-specific enzymes involved in the vitamin B1 biosynthesis, which represents an ideal drug target, because this pathway is not present in humans, thus avoiding cross-reactions with the host. The novelty of the selected target enzymes guarantees also no latent drug resistance. We could analyse already key-structures and complexes.
One project is focusing to understand the emergence of ceftazidime/avibactam resistance in clinical, multiresistant, CTX-M-14-producing Klebsiella pneumoniae isolate during ceftazidime/avibactam treatment (Both et al., 2017). We have recently identified a mutated CTX-M-14P167S isoform that inactivates also a last resort combination drug containing a 3rd generation antibiotic (ceftazidime) and a novel β-lactamase inhibitor avibactam. Structural investigations are aiming to apply also XFEL radiation for time resolved experiments. First successful XFEL data collection were performed already beginning of 2018 A second example is the analysis of molecular Mechanisms involved in staphylococcal biofilm formation. We are interested in the three-dimensional structures of the key proteins in bacterial biofilm formation. Biofilm formation is a twostep process including adherence of the bacteria to the surface to be colonized and subsequent assembly of a multi layered biofilm architecture. The latter phase depends on the expression of intercellular adhesins, stabilizing the biofilm consortium. Different proteins are involved in this process. Presently we target the accumulation associated protein Aap, the small basic protein Sbp and the extracellular matrix binding protein Embp. In terms of pro-drug design investigations we target particular the methicillin resistant Staphylococcus aureus, known also as MRSA. S. aureus is a commensal gram-positive bacterium that colonises mostly the nasal mucosa of 20% of the healthy population permanently and up to 60% transiently. In conjunction with hospitalised patients, colonisation sites like the skin, vascular catheters, and wound sites, as well as the nasophary have been reported. Colonisation from the nose can pass to the skin and can infect wounds or enter the body of patients with intravascular catheters. Once S. aureus becomes virulent, it causes symptoms which range from wound infections to serious conditions like pneumonia, endocarditis or meningitis. Infections of extremities often require long term treatment or even amputation. This bacterium has developed resistance against various antibiotics, such as vancomycin and methicillin, which makes treatment of S. aureus infections difficult, especially for immune-deficient patients. Therefore, structural research activities are aiming to identify and score novel S. aureus drug targets. In collaboration with partners at USP São Paulo we focus on pathogen-specific enzymes involved in the vitamin B1 biosynthesis, which represents an ideal drug target, because this pathway is not present in humans, thus avoiding cross-reactions with the host. The novelty of the selected target enzymes guarantees also no latent drug resistance. We could analyse already key-structures and complexes.
Selected References
- A. Both, H. Büttner, J. Huang, M. Perbandt, C. Belmar Campos, M. Christner, F.P. Maurer, S. Kluge, C. König, M. Aepfelbacher, D. Wichmann, H. Rohde: Emergence of ceftazidime/avibactam non-susceptibility in an MDR Klebsiella pneumoniae isolate. J Antimicrob Chemother 72 (9), 2483-2488 (2017).
- J. Drebes, M. Künz, B. Windshügel, A. G. Kikhney, I. B. Müller, R. J. Eberle, D. Oberthür, H. Cang, D. I. Svergun, M. Perbandt, C. Betzel, C. Wrenger: Structure of ThiM from Vitamin B1 biosynthetic pathway of Staphylococcus aureus - Insights into a novel pro-drug approach addressing MRSA infections. Scientific Reports 6, 22871 (2016).
- J. Drebes, M. Künz, C. A. Pereira, C. Betzel, C. Wrenger: MRSA Infections: From Classical Treatment to Suicide Drugs. Current Medicinal Chemistry 21, 1809-1819 (2014).
- A. Begum, J. Drebes, A. Kikhney, I. B. Müller, M. Perbandt, D. I. Svergun, C. Wrenger, Ch. Betzel: “Staphylococcus aureus thiaminase II: oligomerization warrants proteolytic protection against serine proteases”.Acta Crystallographica, Section D: Biological Crystallography D69, 2320-2329 (2013).