ABSTRACTBiofilm formation and host-pathogen interactions are frequently studied using multiwell plates; however, these closed systems lack shear force, which is present at several sites in the host, such as the intestinal and urinary tracts. Recently, microfluidic systems that incorporate shear force and very small volumes have been developed to provide cell biology models that resemblein vivoconditions. Therefore, the objective of this study was to determine if the BioFlux 200 microfluidic system could be used to study host-pathogen interactions and biofilm formation by pathogenicEscherichia coli. Strains of various pathotypes were selected to establish the growth conditions for the formation of biofilms in the BioFlux 200 system on abiotic (glass) or biotic (eukaryotic-cell) surfaces. Biofilm formation on glass was observed for the majority of strains when they were grown in M9 medium at 30°C but not in RPMI medium at 37°C. In contrast, HRT-18 cell monolayers enhanced binding and, in most cases, biofilm formation by pathogenicE. coliin RPMI medium at 37°C. As a proof of principle, the biofilm-forming ability of a diffusely adherentE. colimutant strain lacking AIDA-I, a known mediator of attachment, was assessed in our models. In contrast to the parental strain, which formed a strong biofilm, the mutant formed a thin biofilm on glass or isolated clusters on HRT-18 monolayers. In conclusion, we describe a microfluidic method for high-throughput screening that could be used to identify novel factors involved inE. colibiofilm formation and host-pathogen interactions under shear force.
Future perspective on host–pathogen interactions during bacterial biofilm formation within the nasopharynx
