Multiplexed, rapid phenotypic antibiotic susceptibility testing based on angle-resolved light scattering imaging of microfluidic droplets

Introduction

There is an urgent need for rapid, high-throughput phenotypic antimicrobial susceptibility testing (AST) capable of assessing a microbial sample’s susceptibility to multiple antibiotics.

Objectives

In this study, we have established a multiplexed rapid AST platform that employs droplet microfluidics for high-throughput single-cell based analysis, 2D angle-resolved light scattering for growth detection, and fluorescence detection via optical fibers to identify the antibiotic condition within each droplet.

Methods

For this, multiple antibiotic conditions are coded with fluorescence dyes and encapsulated with single cells to enable the testing of multiple antibiotics in a single experiment. We utilize convolutional neural networks (CNNs) and statistical models to assess the growth of various Staphylococcus aureus strains and determine the probability of susceptibility to different antibiotics.

Results

Our platform achieved a 95 % categorical agreement with the disc diffusion reference method after just three hours of incubation, demonstrating the same level of accuracy as the established VITEK 2 system for the tested strains and antibiotics. Notably, our platform reduced the incubation time by 5–11 h compared to VITEK 2 and by 13–17 h compared to the gold standard disc diffusion method.

Conclusions

With the presented innovations, our technology takes a big step towards realizing true phenotypic determination of antibiotic resistance profiles for timely antimicrobial treatment decisions.