Thermal shifts can override the effects of Transcription-targeting Antibiotics

Bacteria traverse diverse stresses but rarely experience them in isolation. Thermal fluctuations and antibiotic exposure often coincide. Yet, how cells transduce these concurrent cues into gene regulatory programs remains unresolved. Here, we show that in Escherichia coli, cold and heat shocks exert dominance over antibiotic stresses across multiple levels of bacterial physiology. First, combined exposure to antibiotics and thermal shifts produced transcriptomes that consistently converged to temperature-defined transcriptomic states. This dominance emerges through the effects of thermal shifts on metabolism, nucleoid organization, engagement of antibiotic targets with DNA, over-expression of global transcription regulators, drug-target conformational plasticity, and regulatory induction of efflux pathways during combined exposure. Finally, cross-species simulations and phylogenetic analysis revealed that thermal disruption of antibiotic efficiency is conserved across evolutionary distant bacterial species. Together, these results identify temperature as a critical determinant of antibiotic efficacy.