An in vitro microfluidic gradient generator platform for antimicrobial testing

Methicillin Resistant Staphylococcus pseudintermedius (MRSP) biofilm-related infections are currently a leading concern for veterinary hospitals, as these types of infections are highly resistant to assaults by both the immune system and antimicrobial therapies, impeding their clearance. Research suggests that fosfomycin, a low molecular weight bactericidal antibiotic, has the potential to effectively penetrate and subsequently disrupt/destroy biofilm layers. Our study utilized a fabricated microfluidic gradient generator platform as an assay to perform a quantitative assessment of varying concentrations of a selected antimicrobial agent against MRSP biofilm formed under physiologically relevant conditions. Our results verified the feasibility of using a microfluidic device for rapid antimicrobial testing against biofilms, which was successful in demonstrating that fosfomycin is an effective agent that can disrupt established MRSP biofilms. Additionally, Atomic Force Microscopy (AFM) analysis revealed that the cell walls of MRSP cells within the biofilms were disrupted by fosfomycin treatment, which speaks to the mechanism of action and the antimicrobial efficacy of this agent. This study provides compelling evident that microfluidic device and nanoscale AFM imaging-based investigations of biofilms can aid in the study of biofilm-related infectious diseases.