Modeling spatially structured environments with lyotropic liquid crystals for antimicrobial susceptibility testing

ABSTRACT

Antimicrobial resistance (AMR) is among the top 10 global public health threats. Antimicrobial overuse in part because of the overload of ICU departments in the context of the COVID-19 pandemic facilitates the phenomenon. Designing novel effective antimicrobial strategies necessitates the development of new methodologies of antimicrobial susceptibility testing (AST) instead of routinely used laboratory approaches that do not consider recent findings concerning the crucial impact of structural complexity inherent for macroorganism tissues, and physical characteristics of the environment on microbial population behavior and biological properties. Liquid crystal (LC) materials combining properties of both the liquid and the solid phase offer tremendous potential for the development of various spatially structured liquid model environments and solid surfaces for studying tripartite system bacterium-antibiotic-bacteriophage. Our pilot study was aimed to examine the behavior of the population of Proteus vulgaris ? the representative of the third most common etiological factor of nosocomial and catheter-associated urinary tract infections ? in different microcosms based on a lyotropic nematic liquid crystal. The study design included examining the bacterial growth, motility, and morphology under the transition of pre-grown population from different isotropic nutrient media to anisotropic microcosms based on LC. Growth kinetics, motility pattern as well as morphotype conversion from swimmers to swarmers changed significantly after the transition of the bacterial population to different microcosms based on LC as compared to those in isotropic conditions. The significance of swarming motility and swarming-specific induction of the virulence factors of Proteus for its pathogenicity and AMR has been debated widely yet remains unclear. Our findings indicate the attractiveness of artificial spatially structured microcosms based on LC for the study of these phenomena.