ダロバクチンBとコリスチンによる静的および動的環境下での抗バイオフィルム効果の検討

The increasing challenges of treating biofilm-associated infections highlight the importance to develop new options against biofilm-embedded bacteria. In this study, we evaluated darobactin B-a promising pre-clinical antibiotic candidate targeting the outer membrane protein BamA-against Pseudomonas aeruginosa biofilms. First, a static biofilm assay was used for primary screening and showed that darobactin B reduced the viable cells within a biofilm by six orders of magnitude compared to the untreated control. Subsequently, a microfluidic model was conducted to allow real-time monitoring of biofilm development, treatment, and potential regrowth under controlled hydrodynamic conditions. In this assay, the reference compound colistin exhibited strong activity after single-dose administration. Although less effective after single dosing, darobactin B showed notable anti-biofilm activity by killing 85%-97% of biofilm cells and suppressing biofilm recovery for at least 48 h when applied repeatedly once daily for 5 days. When administered repeatedly in the multi-dose regimen, darobactin B caused biofilm disruption and cell detachment, leading to ~40% surface coverage reduction. Our findings highlight the potential of darobactin B as an anti-biofilm agent.IMPORTANCEBacterial biofilms pose serious healthcare challenges, contributing to chronic and device-related infections. Biofilm-embedded bacteria are highly resistant to conventional antibiotics and lead to growing reliance on last-resort drugs, thus underscoring the need for new therapeutic approaches. This study shows that darobactin B consistently disrupts Pseudomonas aeruginosa biofilms and delays regrowth. The multi-dose microfluidic assay provides a flexible platform for real-time evaluation of biofilms, which may support the optimization of treatment regimens.