  Rapid antimicrobial susceptibility testing (AST) is urgently needed for
treating infections with correct antibiotics and slowing down the emergence of
antibiotic-resistant bacteria. Here, we report a phenotypic platform that
rapidly produces AST results by femtosecond stimulated Raman scattering imaging
of deuterium oxide (D2O) metabolism. Metabolic incorporation of D2O into
biomass in a single bacterium is probed in as short as 10 minutes after culture
in 70% D2O medium, the fastest among current technologies. Single-cell
metabolism inactivation concentration (SC-MIC) is obtained in less than 2.5
hours from colony to results. The SC-MIC results of 37 sets of samples, which
include 8 major bacterial species and 14 different antibiotics often
encountered in clinic, are validated by standard minimal inhibitory
concentration blindly measured via broth microdilution. Towards clinical
translation, SRS imaging of D2O metabolic incorporation and SC-MIC
determination after 1-h antibiotics treatment and 30-minutes mixture of D2O and
antibiotics incubation of bacteria in urine or whole blood is demonstrated.
