Antibiotic Susceptibility Test with Surface-Enhanced Raman Scattering in a Microfluidic System

Abstract

Antibiotic susceptibility test (AST) is essential in clinical diagnosis of serious bacterial infection, such as sepsis, while it typically takes 2−5 days for sample culture, antibiotic treatment, and reading result. Detecting metabolites secreted from bacteria with surface-enhanced Raman scattering (SERS) enables rapid determination of antibiotic susceptibility, reducing the AST time to 1−2 days. However, it still requires 1 day of culture time to obtain sufficient quantity of bacteria for sample washing, bacterial extraction, and antibiotic treatment. Additionally, the whole procedure, manually performed in open environment, often suffers from contamination and human error. To address the above problems, a microfluidic system integrating membrane filtration and the SERS-active substrate (MF-SERS) was developed to perform on-chip bacterial enrichment, metabolite collection, and in situ SERS measurements for antibiotic susceptibility test. Using Escherichia coli as the prototype bacterium, the lowest SERS detection limit of bacterial concentration of the MF-SERS system is 10 3 CFU/mL, which is 4 orders of magnitude lower than that using centrifugation−purification procedure, significantly shortening the bacterial culture time. The bacteria and secreted metabolites are enclosed during bacterial trapping, metabolite filtration, and SERS detection, thus minimizing possible contamination and human errors. Finally, the successful demonstration of AST on E. coli with a concentration of 10 3 CFU/mL is presented. Overall, the MF-SERS system with a miniature size and well-confined microenvironment allows the integration of multiple bacteria processes for bacterial enrichment, culture, and determination of AST.

Surface-enhanced Raman spectroscopy: benefits, trade-offs and future developments

“…Microuidic devices represent an alternative strategy for improving the SERS reproducibility of colloidal nanoparticles by: (1) enabling the precise control of the aggregation time using the strategy of replacing time with space; (2) reducing the mechanical and optical variations of the colloids; (3) making more efficient mixing with the analyte (automation); (4) decreasing the likely contamination (isolated systems). [75][76][77] 3.2.6 Shelf life. Another important aspect in the stability of SERS substrates lies in the shelf life, if their commercialization is desired.…”

Bacteria Detection: From Powerful SERS to Its Advanced Compatible Techniques

“…[135] The application of SERS for clinical bacterial detection and identification in human body fluids has gained much attention. [136,137] In recent years, there have been a series of reports about the clinical bacterial detection and identification of SERS. For example, Avci et al analyzed and identified the pathogenic bacteria of urinary tract infection that had been cultured for 1 h by combining SERS and PCA.…”

A WS2-gold nanoparticle heterostructure-based novel SERS platform for the rapid identification of antibiotic-resistant pathogens

“…26 As a result, there is a huge urgency in nding rapid and costeffective assays which will have the capability for rapid and accurate determination of the appropriate antibiotic for an infection in a timely manner. [31][32][33][34][35][36][37][38][39][40][41][42] Driven by this need, the current manuscript demonstrates that 0D-2D heterostructurebased SERS is capable of rapid identication of drug resistant bacteria by monitoring structural changes in the pathogen's cell wall during antibiotic treatment. Reported data show that the SERS can be used for the identication of multidrug resistant Salmonella DT104 and a normal strain Salmonella Typhi antimicrobial susceptibility test using Augmentin antibiotics, even at the concentration of 100 CFU mL À1 experimental data reported here indicates that heterostructure-based SERS has the capability of antimicrobial susceptibility testing in less than 2 hours, whereas the "gold standard" broth microdilution (BMD) test takes 16 to 20 h in clinics until the number of bacteria reaches above 10 5 CFU mL À1 .…”