TUM method speeds up antibiotic resistance testing for UTIs

Urinary tract infections (UTIs) affect around 152 million people worldwide each year, making them one of the most common bacterial infections. In many medical practices, UTIs are initially assessed using rapid urine tests that measure nitrite and leukocyte levels. Treatment often begins with a broad-spectrum antibiotic without identifying the exact pathogen or its resistance profile.

Laboratory-based antibiotic susceptibility testing is typically reserved for high-risk patients and takes two to three days. Incorrect or unnecessary antibiotic prescriptions can prolong treatment, increase the risk of complications, and contribute to rising antibiotic resistance.

Researchers at TUM have developed two methods that allow urine samples to be tested directly for antibiotic susceptibility. Because the procedures do not require standardized bacterial suspensions used in routine laboratory diagnostics, time to result is reduced by up to 24 hours compared with conventional testing.

Key steps in the workflow include:

• Applying urine directly to an agar plate
• Placing antibiotic disks on the plate
• Measuring the inhibition zones, i.e., areas where bacterial growth is suppressed
• Using an algorithm that accounts for bacterial concentration in urine and adjusts its impact on inhibition zone size

This makes it possible to determine resistance profiles reliably, even when samples are tested without prior standardization. The method is intended to support faster clinical decision-making in UTI treatment.

In parallel, the team is developing a paper-based point-of-care device that uses similar principles. It aims to identify eight bacterial species via color changes and indicate antibiotic resistance. According to the researchers, this work provides the foundation for a home-use rapid test with smartphone-based result display, which could also be useful in low-resource settings.

“The sooner we know which antibiotic is effective, the more targeted our treatment can be,” says Oliver Hayden, Heinz Nixdorf Professor of Biomedical Electronics. "This means we won't have to use broad-spectrum antibiotics as often, which should be used sparingly due to the development of resistance."

Initial data show that the accelerated method performs well compared with established approaches. In directly tested urine samples, it achieves a correlation of approximately 94 percent with the standard method. Deviations are being used to optimize the test further, including for very low bacterial concentrations and mixed infections.

“Our goal is a small, easy-to-use test that can be deployed in any medical practice with minimal effort and, in the future, also allows patients to test themselves at home using a paper-based device with results displayed on their smartphone. The technology is designed so that it can also be applied in low-resource settings, where rapid and reliable diagnostics are particularly critical.” says Henning Sabersky-Müssigbrodt, first author of the study and doctoral researcher in Translational Medicine at the Heinz-Nixdorf Chair of Biomedical Electronics.

MEDICA-tradefair.com; Source: Technical University of Munich