Pre-treatment bacterial cell states shape antibiotic-induced transcriptional reprogramming and survival.

Bacteria can survive antibiotic treatment through phenotypic adaptation, a process that is often transient and involves heterogeneous transcriptional reprogramming. However, how this transcriptional heterogeneity is generated and how it influences antibiotic survival remains unclear. Here, we use bacterial single-cell RNA sequencing and functional assays in Klebsiella pneumoniae to characterize transcriptional heterogeneity and examine how pre-treatment cell states are associated with antibiotic-induced responses and survival outcomes. Using growth phase as a biologically meaningful axis of transcriptional variation, we reveal that even within an isogenic population, distinct transcriptional responses can be induced and co-contribute to survival. These responses are shaped by the cell's pre-treatment transcriptional state and the mechanism of antibiotic action. Genetic and environmental perturbations, such as rpoS deletion and nutrient supplementation, shift pre-treatment cell states and alter survival frequencies. Our findings establish the biological significance of transcriptional heterogeneity shaped by pre-treatment cell states, providing a systems-level framework for understanding bacterial antibiotic response and suggesting strategies to enhance antibiotic efficacy by modulating cell states.