Dual effect: High NADH levels contribute to efflux-mediated antibiotic resistance but drive ROS lethality
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ABSTRACT:
PROVIDER: PRJNA780411 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR16946466.fastq.gz | Fastqsanger.gz | |||
| SRR16946467.fastq.gz | Fastqsanger.gz | |||
| SRR16946468.fastq.gz | Fastqsanger.gz | |||
| SRR16946469.fastq.gz | Fastqsanger.gz | |||
| SRR16946470.fastq.gz | Fastqsanger.gz |
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Project description:In light of the antibiotic crisis, emerging strategies to sensitize bacteria to available antibiotics should be explored. Several studies on the mechanisms of killing suggest that bactericidal antibiotic activity is enforced through the generation of reactive oxygen species (ROS-lethality hypothesis). Here, we artificially manipulated the redox homeostasis of the model opportunistic pathogen Pseudomonas aeruginosa using specific enzymes that catalyze either the formation or oxidation of NADH. Increased NADH levels led to the activation of antibiotic efflux pumps and high levels of antibiotic resistance. However, higher NADH levels also resulted in increased intracellular ROS and amplified antibiotic killing. Our results demonstrate that growth inhibition and killing activity are mediated via different mechanisms. Furthermore, the profound changes in bioenergetics produced low-virulence phenotypes characterized by reduced interbacterial signaling controlled pathogenicity traits. Our results pave the way for a more effective infection resolution and add an antivirulence strategy to maximize chances to combat devastating P. aeruginosa infections while reducing the overall use of antibiotics. IMPORTANCE The emergence of antibiotic resistance has become one of the major threats to public health. A better understanding of antimicrobial killing mechanisms promises to uncover new ways to resensitize bacteria to commonly used antibiotics. In this context, there is increasing evidence that the metabolic status of the cell plays a fundamental role in reactive oxygen species (ROS)-mediated cell death. In this work, we artificially manipulated the redox balance in Pseudomonas aeruginosa by the expression of two orthologous enzymes. We found that the increase of intracellular NADH concentrations leads to higher antibiotic resistance but also generates a burst in the production of ROS that amplified antimicrobial killing. Our work suggests that the combination of bactericidal antibiotics with agents that disturb the cellular redox homeostasis could significantly enhance antibiotic killing via sensitization of pathogens to currently available antibiotics.
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Project description:Efflux pumps of the resistance-nodulation-division (RND) superfamily, particularly the AcrAB-TolC and MexAB-OprM, besides mediating intrinsic and acquired resistance, also intervene in bacterial pathogenicity. Inhibitors of such pumps could restore activities of antibiotics and curb bacterial virulence. Here, we identify pyrrole-based compounds that boost antibiotic activity in Escherichia coli and Pseudomonas aeruginosa by inhibiting their archetype RND transporters. The discovered efflux pump inhibitors (EPIs) inhibit the efflux of fluorescent probes, attenuate persister formation, and diminish resistant mutant development. Molecular docking and biophysical studies revealed that the EPIs bind to AcrB. EPIs also possess an anti-pathogenic potential and attenuate P. aeruginosa virulence in vivo. The excellent efficacy of the EPI-antibiotic combination was evidenced in animal lung infection and sepsis protection models. These findings indicate that EPIs discovered herein with no off-target effects and negligible toxicity are potential antibiotic adjuvants to address life-threatening bacterial infections.
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