NEW DELHI: Indian researchers have developed a low-cost chip-based device for rapid antibiotic susceptibility testing (AST) that can rapidly determine whether bacteria are resistant or susceptible to antibiotics.
The low-cost device offers a faster, simpler and more accessible alternative to conventional antimicrobial susceptibility testing, which usually takes 48–72 hours
The low-cost device, developed by the Indian Institute of Technology Madras (IIT Madras) uses electrochemical signals to detect bacterial resistance to antibiotics within just three hours.
The research, which was published in the prestigious Nature Scientific Reports, said, "With its low-cost, sensitive, and easy-to-use features, the proposed device could enable widespread susceptibility testing to combat antimicrobial resistance, particularly in rural settings."
Designed for speed, sensitivity, and ease of use, it holds strong potential for early diagnosis and better treatment of bacterial infections, particularly in regions with limited access to advanced laboratory infrastructure, it added.
Antimicrobial resistance (AMR) is one of the most pressing challenges facing global healthcare systems today.
The World Health Organisation (WHO) has identified AMR as one of the top ten threats to global health, and estimates suggest that nearly 4.95 million deaths worldwide in 2019 were associated with bacterial AMR.
The ε-µD device can deliver results within three hours and is based on ‘Electrochemical Impedance Spectroscopy,’ the institute said.
According to Prof. S Pushpavanam, Y B G Varma Institute Chair Professor, Department of Chemical Engineering, IIT Madras, said, “An important aspect of our device is the use of a specially prepared nutrient solution that serves a dual purpose.”
“It not only supports bacterial growth, which is essential for testing, but also enhances the sensitivity of the electrical signals we use for detection. As the bacteria grow, they cause measurable changes in the electrical properties of the solution, which our system can accurately track.”
Prof. S Pushpavanam added, “This approach will make a real impact on patients in Intensive Care Units, who may be suffering from complications due to bacterial infections. This will help the doctors prescribe the right treatment and can be life-saving."
Currently, the researchers are conducting clinical validation in collaboration with the IITM Institute hospital. After rigorous clinical validation, they are planning to commercialise this through a startup, Kaappon Analytics India Private Limited, the institute added.
Dr Richa Karmakar, Assistant Professor, Department of Biotechnology, IIT Madras, added, “The device monitors how the electrical signal changes over time to determine whether bacteria are continuing to grow in the presence of an antibiotic.”
“If the bacteria are resistant, they multiply despite the drug, and this activity causes a distinct change in the electrical signal. In contrast, if the bacteria are killed by the antibiotic, their growth is inhibited, and the signal remains relatively unchanged. A metric called ‘Normalized Impedance Signal’ (NIS) developed by the researchers allows clear differentiation between resistant and non-resistant bacterial strains in a matter of hours.”
The researchers tested the device on two types of bacteria - gram-negative E. coli and gram-positive B. subtilis. They used two antibiotics with different modes of action — ampicillin, which kills bacteria and tetracycline, which prevents them from growing — to confirm the device’s ability to detect both kinds of responses. The ε-µD was able to detect susceptibility profiles within three hours.
In an important demonstration of real-world applicability, the team also tested the device on urine samples spiked with E. coli and successfully identified resistance to tetracycline, showing the potential of this device in clinical diagnostics, according to the institute.