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Emerging resistance to antimicrobials is a global crisis driven by the overuse of antibiotics and diagnostic uncertainty, therefore reliable assays for rapid identification of bacteria and antimicrobial susceptibility testing are important. 

In this study, five antimicrobial peptides (AMPs) received from the Pharmacognosy research group were tested in rapid antimicrobial susceptibility testing, ASTar®. The aim was to study the stability of these peptides and develop a formulation intended for AST Disc to be used in ASTar. The stability of the peptides were investigated using high- performance liquid chromatography at different temperatures over time. Antibacterial assays with various approaches were performed to evaluate the antibacterial activity and use as a reference for ASTar. This was followed by AST Disc manufacturing loaded with AMPs in various concentrations. 

Antimicrobial susceptibility testing by ASTar resulted in a minimum inhibitory concentration (MIC) of 40 μM of LRS-21 against E. coli using the algorithm. However, the algorithm was not applicable to all AMPs and once the normalization formula was applied it resulted in MIC of 20 μM of LL-37 against E. coli and 80 μM against S. aureus. No antibacterial activity was exhibited in ASTar for the three remaining peptides (MIC>160 μM) against E. coli and S. aureus. 

These findings show that antimicrobial peptides can be tested using ASTar however the current algorithm is not applicable to all AMPs. The results of the thesis could be used for time-effective research of other AMPs, to understand their effectiveness against different bacterial strains, as they are of pharmaceutical interest, especially since the emergence of antibiotic resistance.