Innovative microparticle strategies: harnessing essential oil-loaded lecithin/chitosan systems against <i>Burkholderia pseudomallei</i>

<i>Burkholderia pseudomallei</i>, the causative agent of melioidosis, presents high antimicrobial resistance, largely due to its biofilm-forming ability. Here, innovative lecithin/chitosan microparticles loaded with lemongrass (LEO) and geranium (GEO) essential oils (LEOLCN and GEOLCN) were developed and characterized as a novel strategy to combat <i>B. pseudomallei</i>. Microparticles were characterized and evaluated for their effects on planktonic growth and biofilm inhibition, as well as for potential synergistic interactions with antibiotics. Microparticles exhibited a spherical morphology, high encapsulation efficiency, and sustained release profiles, with up to 45% of EO released at pH 2.0 and 32% at pH 7.4 after 50 h. LEOLCN demonstrated MICs ranging from 64 to 128 µgml^-1 for most strains, although some resistant isolates exhibited MICs of up to 2,048 µgml^-1. At a concentration of 512 µgml^-1, both LEOLCN and GEOLCN reduced biofilm biomass and metabolic activity by more than 50%. LEOLCN exhibited synergistic effects with conventional antibiotics, reducing ceftazidime MICs by 2- to 9-fold, suggesting its potential to enhance antibiotic therapy against resistant strains. Scanning electron microscopy confirmed biofilm disruption. Overall, the dual antimicrobial and antibiofilm action of these compounds introduces a promising and innovative <i>in vitro</i> platform to address the persistent challenge of <i>B. pseudomallei</i> infections and biofilm-associated resistance.