Genetics and dynamics of staphylococcal persister cells

• Applicant: Professor Dr. Friedrich Götz, since 1/2014
• Subject Area: Metabolism, Biochemistry and Genetics of Microorganisms
• Term: from 2012 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 218274938

This application aims at deciphering genetics and dynamics underlying the formation of staphylococcal persister cells. These constitute a phenotypic heterogeneous subpopulation encompassing very slow growing (‘dormant’) antibiotic tolerant cells within a common culture. We will analyze persister states in the (facultatively) pathogenic species S. aureus, S. epidermidis as well as in S. carnosus and S. equorum, relevant in biotechnology and food industry. Genome sequences are available for all of these species. Different strains and mutants of staphylococci will be analyzed. These will harbor single or multiple gene deletions regarding established and putative toxin-antitoxin (TA) systems, genes involved in stress-responses or those eliciting the small-colony-variant phenotype, which might be related to the persister state. Time and concentration dependent challenges with antimicrobial compounds will select for surviving cells of a culture to be separated by FACS for downstream analyses, particularly transcriptome studies. Time lapse microscopy will facilitate tracking persister formation on the single cell level. Cultivation of cells in microfluidic devices allows a repeated change between selective or non-selective media to also explore parameters of persister-resuscitation. Aided by gene expression profiling data and quantitative information on persister-protein abundance, biomathematical models will be established. These will reveal, which regulatory networks govern the persister state and whether it results from bistability or from a gradual physiologic downshift of cells within the culture. These models will probably serves as a valuable basis for the prediction of persister dynamics also in bacteria beyond staphylococci.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1617: Phenotypic Heterogeneity and Sociobiology of Bacterial Populations
• Ehemaliger Antragsteller: Privatdozent Dr. Ralph Alexander Bertram, until 1/2014