Surface-enhanced Raman spectroscopy on the membranes for antimicrobial resistance testing

Antimicrobial resistance is one of the top global health threats; it is associated with millions of deaths per year. Traditional and most commonly used antibiotic susceptibility tests are based on detection of bacterial growth and its inhibition in the presence of an antimicrobial. These tests typically take over 1-2 days to perform, so empirical therapy schemes are often administered before the proper testing. Rapid tests for antimicrobial resistance are necessary to optimize the treatment of bacterial infection. A combination of MTT test with Raman spectroscopy to provide 1.5-hour long test antimicrobial susceptibility determination requiring 10^6-10^8 CFU/mL of bacteria. Here the first rapid antibiotic susceptibility test for trace amounts of bacteria is described. The bacterial titer can be decreased down to 10^2 CFU/mL using surface-enhanced Raman spectroscopy (SERS) of the MTT-treated bacteria caught with the silver coated track-etched membranes allowing the antimicrobial testing of low-titer bacterial samples within 1.5 hour.