Novel dual-targeting biofilm inhibitors for potentiating antibiotic efficacy against multidrug-resistant Pseudomonas aeruginosa infections.

INTRODUCTION

With the increasing global challenge posed by multidrug-resistant Pseudomonas aeruginosa, which utilizes biofilm formation and virulence mechanisms to exacerbate infections, there is an urgent need for novel therapeutic strategies.

OBJECTIVES

This work presents a novel dual-targeting biofilm inhibitor that potentiates antibiotic efficacy, offering a potent and safe candidate to combat P. aeruginosa infections.

METHODS

To address this problem, we developed dual-targeting biofilm inhibitors that simultaneously disrupt the quorum sensing (QS) system and iron homeostasis system via computer-aided drug design. Through integrated in vitro screening and computational ADMET profiling, HK-34b, a 1-hydroxybenzimidazolone derivative, was identified.

RESULTS

HK-34b inhibited 89% biofilm formation (IC 50 = 0.15 μg/mL) and eradicated 93% mature biofilms. It also reduced virulence factor production in P. aeruginosa, thereby impairing swarming motility. Notably, HK-34b combined with tobramycin and ciprofloxacin achieved 99% bacterial clearance, enhancing antibiotic efficacy by 400-fold and 2000-fold in murine wound models, respectively. Furthermore, HK-34b exhibited low toxicity in vivo. Pharmacokinetic studies demonstrated that HK-34b possesses favorable bioavailability (36.86%) and a wide safety window. Mechanistic studies confirmed the dual targeting mechanism of HK-34b, which inhibits the pqs system of P. aeruginosa by binding to PqsR (KD PqsR = 3.23 μM), a key virulence regulator of the QS system, and disrupts bacterial iron homeostasis through interaction with FpvA (KD FpvA = 5.56 μM), the outer membrane receptor for siderophores. MD simulations revealed stable binding of HK-34b to both PqsR and FpvA.

CONCLUSIONS

This dual-targeting strategy demonstrates significant translational potential by employing a novel chemical scaffold, which not only avoids the cross-resistance risks associated with the shared molecular scaffolds of conventional siderophore-antibiotic conjugates, but also overcomes the drawbacks of insufficient biofilm efficacy seen with single-target inhibitors, thereby providing a sustainable approach for the treatment of multidrug-resistant P. aeruginosa infections.