Development of a portable SERS method for testing the antibiotic sensitivity of foodborne bacteria

A method for testing the antibiotic susceptibility of foodborne bacterial samples using a portable Raman spectrometer has been developed. Surface-enhanced Raman spectroscopy (SERS) was used to obtain the spectra from bacterial samples collected on a filter membrane after incubation with antibiotics. The SERS spectra revealed characteristic antibiotic response patterns, which can be used to assess the antibiotic sensitivity of the samples. Several species of bacteria, including Escherichia coli, Bacillus cereus, and Salmonella enterica, were used to test the procedure, as well as multiple classes of antibiotics. Characteristic bacterial SERS peaks could be identified in the spectra, as well as clear antibiotic response patterns that were consistent across the different species of bacteria and could be used to reliably determine the antibiotic sensitivity of the samples. The portable SERS method was then used to test bacteria isolated from ground beef, and the results show the procedure could be used to accurately test the antibiotic sensitivity of bacteria isolated from real food samples. Further optimization of this method to test the filtered liquid obtained from bacterial samples has demonstrated the capability of a simpler approach to identify antibiotic response patterns. The effectiveness and improved accessibility of the portable SERS method indicates that these procedures have great potential for future use in low-resource settings, which will facilitate the monitoring and control of antibiotic resistance.