A new filtration-based diagnostic platform can detect low concentrations of bacteria and assess their response to antibiotics within hours, potentially accelerating the diagnosis and treatment of life-threatening infections, including sepsis.
Researchers at the Korea Institute of Materials Science and Hanyang University developed the system using surface-enhanced Raman scattering (SERS), an optical technique that identifies molecular signatures using laser light.
Published in Small Methods, the study addresses a persistent challenge in clinical microbiology: detecting small numbers of bacteria in complex samples, such as blood and urine, while obtaining timely information about antibiotic susceptibility.
The platform uses a glass microfiber filter coated with gold nanostructures to capture and concentrate bacteria from liquid samples. Additional gold particles are then grown directly around the trapped bacterial cells, amplifying their molecular signals while minimizing interference from other sample components.
Using Escherichia coli as a model organism, the researchers demonstrated bacterial capture efficiency exceeding 99.9 percent at the concentrations tested. The system initially detected concentrations as low as 1,000 colony-forming units (CFU)/mL. Introducing a 1-hour culture step improved sensitivity to 10 CFU/mL.
This sensitivity could be particularly valuable in suspected sepsis, where bacterial concentrations in the bloodstream may be extremely low. Earlier detection of bloodstream infections could help clinicians identify an infectious cause of sepsis and initiate targeted treatment sooner.
The researchers also demonstrated that the platform could distinguish E. coli, Staphylococcus aureus, and Klebsiella pneumoniae using their molecular fingerprints.
Importantly, the technique provided functional information about antibiotic susceptibility. When E. coli was exposed to amikacin, bacterial signals declined, indicating susceptibility. In contrast, signals continued increasing following ampicillin exposure, indicating reduced susceptibility. The responses could be distinguished within 2 hours.
Combining bacterial detection with rapid susceptibility assessment could help clinical laboratories shorten the time to actionable results, particularly for patients with suspected sepsis who require urgent antimicrobial treatment.
Further validation using patient blood samples and a broader range of pathogens will be essential. Nevertheless, the platform offers a potential route toward faster diagnosis and more informed antimicrobial decisions in critical care.
Newsletters
Receive the latest pathologist news, personalities, education, and career development – weekly to your inbox.
