Phenotypic antibiotic susceptibility testing at the ultimate limit of sensitivity

Time period:

1 December 2024 – 30 November 2027

Project leader:

Johan Elf

Funder:

Swedish Research Council

Type of award:

Project grant

Total funding:

3,600,000 SEK

We will explore the ultimate sensitivity limit for antibiotic susceptibility testing (AST) and species identification - one bacterial cell. Working at this limit is necessary to perform AST for blood stream infection without time-consuming preculturing. Building on our experience in single-cell biophysics and rapid AST, we will introduce a new concept to reach the sensitivity limit. The antibiotic growth response of individual cells is measured using the growth rate of the same cell at an earlier time as a reference. Our previous assay used untreated cells as the reference, which requires many cells to reach statistical significance. In addition, working with primary blood samples requires a modified cell growth analysis chip to filter out blood cell debris while still maintaining user-friendliness in operation and mass manufacturability In year one, we will construct a growth chip for capturing bacteria from sparse samples and monitoring the antibiotic response of single cells (WP1). This part is performed by a mechanical engineer and a senior researcher. In parallel, a postdoctoral researcher will measure the single-cell response to different antibiotics to characterize cell-to-cell heterogeneity and critical assay concentrations (WP2). Following the completion of WP1, we will start to evaluate the method for heteroresistance detection (WP3). The last part of the project, following WP1+2 or WP1+3, will be spent collecting and analyzing data to prepare for clinical trials.