Automated, Cost-Effective Optical System for Accelerated Antimicrobial Susceptibility Testing (AST) Using Deep Learning

Abstract

Antimicrobial susceptibility testing (AST) is a standard clinical procedure used to quantify antimicrobial resistance (AMR). Currently, the gold standard method requires incubation for 18-24 h and subsequent inspection for growth by a trained medical technologist. We demonstrate an automated, cost-effective optical system that delivers early AST results, minimizing incubation time and eliminating human errors, while remaining compatible with standard phenotypic assay workflow. The system is composed of cost-effective components and eliminates the need for optomechanical scanning. A neural network processes the captured optical intensity information from an array of fiber optic cables to determine whether bacterial growth has occurred in each well of a 96-well microplate. When the system was blindly tested on isolates from 33 patients with Staphylococcus aureus infections, 95.03% of all the wells containing growth were correctly identified using our neural network, with an average of 5.72 h of incubation time required to identify growth. 90% of all wells (growth and no-growth) were correctly classified after 7 h, and 95% after 10.5 h. Our deep learning-based optical system met the FDA-defined criteria for essential and categorical agreements for all 14 antibiotics tested after an average of 6.13 h and 6.98 h, respectively. Furthermore, our system met the FDA criteria for major and very major error rates for 11 of 12 possible drugs after an average of 4.02 h, and 9 of 13 possible drugs after an average of 9.39 h, respectively. This system could enable faster, inexpensive, automated AST, especially in resource limited settings, helping to mitigate the rise of global AMR.