# SERS-Based Universal AST: Rapid Treatment Guidance for Blood-Culture Bacteria before Species Identification

## TL;DR

This paper introduces a new rapid method to test bacteria's response to antibiotics without needing to identify the bacteria's species first.

## Contribution

The novel contribution is a species-independent antimicrobial susceptibility testing platform using SERS that works across diverse bacteria.

## Key findings

- SERS-Uni-AST achieved 92% agreement with standard testing on 191 clinical isolates in 5 hours.
- The method works effectively for both Gram-positive and Gram-negative bacteria, including ESKAPE pathogens.
- It eliminates the need for prior species identification, enabling faster treatment decisions.

## Abstract

Rapid antimicrobial susceptibility testing (AST) is essential
for
managing bloodstream infections with high mortality, yet most current
methods require prior identification of bacterial species, limiting
their speed and applicability. To address these limitations, we developed
SERS-Uni-AST, a species-independent platform based on surface-enhanced
Raman scattering (SERS) that monitors the metabolic responses of bacteria
to antibiotics through label-free detection. This approach eliminates
the need for species identification, simplifying the testing workflow,
and expands applicability to rare or previously unknown bacterial
species while significantly reducing turnaround time. Validated on
191 clinical blood-culture isolates encompassing 43 bacterial species
and 7 clinically relevant antibiotics, SERS-Uni-AST achieved 92% categorical
agreement with standard testing within 5 h. The method demonstrated
robust performance across Gram-positive and Gram-negative bacteria,
including ESKAPE pathogens, using a predefined, species-independent
decision threshold. By enabling timely, susceptibility-guided antimicrobial
therapy, SERS-Uni-AST supports early treatment optimization and aligns
with the goals of the Surviving Sepsis Campaign and WHO antimicrobial
stewardship initiatives.