Tannic acid attenuates Pseudomonas aeruginosa virulence and promotes healing of infected cutaneous wounds: phenotypic and transcriptomic analyses.

BACKGROUND: Pseudomonas aeruginosa (P. aeruginosa) is a common opportunistic pathogen responsible for skin infections. Tannic acid, a representative hydrolysable tannin, has broad-spectrum antibacterial properties and potential applications in wound healing.

OBJECTIVE: To characterize the concentration-dependent antibacterial and anti-virulence effects of TA against P. aeruginosa, identify associated transcriptional responses, and evaluate its therapeutic potential in an infected wound model.

RESULTS: High concentrations of tannic acid disrupted the integrity of the P. aeruginosa cell membrane, leading to leakage of intracellular components, and were associated with marked alterations in bacterial protein profiles. At sub-inhibitory concentrations (sub-MICs), tannic acid significantly attenuated bacterial virulence by suppressing pyocyanin and rhamnolipid biosynthesis, biofilm formation, proteinase activity, and bacterial motility. TA treatment at 64 μg/mL was associated with transcriptional changes in genes involved in biofilm formation and efflux functions. In a rat wound model infected with P. aeruginosa, tannic acid treatment significantly decreased bacterial burden, attenuated histopathological injury, contained infection progression, and expedited wound closure.

CONCLUSION: This study evaluated the antibacterial and anti-virulence effects of tannic acid against P. aeruginosa, characterized associated transcriptional responses using RNA sequencing, and assessed its therapeutic potential in an infected wound model.