L-Tryptophan represses persister formation via inhibiting bacterial motility and promoting antibiotics absorption.

Aim: The bacterial persisters have emerged as a huge threat to human health. Here, we investigated the role of L-tryptophan in bacterial persister killing by aminoglycoside antibiotics (AGs). Materials & methods: The relevance to the antibiotic susceptibility of Escherichia coli including transcriptional sequencing, gene expression, intracellular ATP, Nicotinamide adenine dinucleotide (NAD/NADH), reactive oxygen species and membrane depolarization were determined. Results & conclusion: We found that exogenous L-tryptophan efficiently inhibited AGs-enabled persisters. The flagellar genes were almost significantly downregulated. Besides, the AGs uptake was obviously increased as the result of elevation in proton motive force (PMF) in response to L-tryptophan-mediated NADH production. Taken together, these data supported a novel role of L-tryptophan in eradicating AGs persisters against E. coli.