Sheng Chengju, Zhou Chao, Guo Mingming, McGiffin David C, Kaye David M, Truong Vinh X, Qian Changrui, Kostoulias Xenia, Peleg Anton Y, Forsythe John S, Scott Timothy F, Qu Yue
Department of Materials Science and Engineering, Monash University, Melbourne 3800, Victoria, Australia.
Monash Institute of Medical Engineering, Monash University, Clayton 3800, Victoria, Australia.
ACS Omega. 2025 Aug 27;10(35):40271-40281. doi: 10.1021/acsomega.5c05384. eCollection 2025 Sep 9.
We recently fabricated a double-shelled microparticle (DSMP) incorporating a quaternary ammonium compound (QAC) and quinine, which demonstrated promising anti-infective properties. In this study, we aimed to elucidate biological merits and antibiofilm mechanisms of action of the specifically designed DSMP. Antimicrobial activities of the DSMP against 32 Gram-positive clinical isolates and laboratory strains were assessed by determining the minimum inhibitory concentrations (MICs). Antibiofilm efficacies of the DSMP were evaluated by using a tetrazolium salt reduction assay and confocal laser scanning microscopy. The fractional inhibitory concentration index was determined to clarify drug-drug interactions between QAC and quinine. Evolution of DSMP resistance was experimentally assessed by using an adaptive laboratory evolutionary assay. Molecular mechanisms underlying DSMP resistance was investigated by whole genome sequencing. The DSMP demonstrated strong activity against antibiotic-susceptible clinical isolates of species, and , with MICs of 4-8 μg/mL, and notable antibiofilm capacities. Weakly positively charged DSMP readily penetrated through the negatively charged biofilm matrix in 3 h and accumulated in biofilm water pores by 24 h, thereby killing biofilm-embedded cells. The copresence of the QAC and quinine demonstrated synergistic effects against Gram-positive bacteria while simultaneously mitigating the development of resistance. Whole-genome sequences revealed genetic mutations in efflux pumps that are associated with cross-resistance to antibiotics and the DSMP components. Co-presence of the QAC and quinine in the DSMP lays the foundation for its antimicrobial and antibiofilm properties against Gram-positive bacteria, allowing the DSMP to maintain efficacy while limiting the development of resistance.
我们最近制备了一种包含季铵化合物（QAC）和奎宁的双壳微粒（DSMP），其展现出了有前景的抗感染特性。在本研究中，我们旨在阐明这种特别设计的DSMP的生物学优点和抗生物膜作用机制。通过测定最低抑菌浓度（MIC）来评估DSMP对32株革兰氏阳性临床分离株和实验室菌株的抗菌活性。使用四氮唑盐还原试验和共聚焦激光扫描显微镜评估DSMP的抗生物膜效果。测定分数抑菌浓度指数以阐明QAC和奎宁之间的药物相互作用。通过适应性实验室进化试验对DSMP耐药性的演变进行实验评估。通过全基因组测序研究DSMP耐药性的分子机制。DSMP对、和物种的抗生素敏感临床分离株表现出强大活性，MIC为4 - 8μg/mL，并且具有显著的抗生物膜能力。带弱正电荷的DSMP在3小时内易于穿透带负电荷的生物膜基质，并在24小时内积聚在生物膜水孔中，从而杀死嵌入生物膜的细胞。QAC和奎宁同时存在对革兰氏阳性菌表现出协同作用，同时减轻耐药性的产生。全基因组序列揭示了与抗生素和DSMP成分交叉耐药相关的外排泵中的基因突变。DSMP中QAC和奎宁的同时存在为其针对革兰氏阳性菌的抗菌和抗生物膜特性奠定了基础，使DSMP在限制耐药性产生的同时保持疗效。
