Antimicrobial susceptibility testing for Gram positive cocci towards vancomycin using scanning electron microscopy

•SEM-based method can be applied for rapid phenotypic AST on Gram-positive cocci towards 2 vancomycin based on morphological changes 3.•The ratio of septa as a marker of bacterial division and size of grape-like clusters enabled the 4 profiling of E. faecalis, E. faecium and S. aureus after brief incubation with vancomycin 5.•SEM-AST strategy showed the feasibility of detecting antibiotic susceptibility or 6 resistance on Gram-positive cocci within one hour of exposition to vancomycin 7.