Enrichment of Persister Cells Through Β-Lactam-Induced Filamentation and Size Separation

Analyzing persisters at the single-cell level is crucial to properly define their phenotypic traits. However, single-cell analyses are challenging due to the rare and temporary nature of persister cells, thus requiring their rapid and efficient enrichment in a culture. Existing methods to isolate persisters from a bacterial population show important shortcomings, including contamination with susceptible cells and/or cell debris, which complicate subsequent microscopic analyses. We here describe a protocol to enrich persisters in a culture using β-lactam-induced filamentation followed by size separation. This protocol minimizes the amount of cell debris in the final sample, facilitating single-cell studies of persister cells.