Researchers have developed a direct urine testing approach that bypasses traditional bacterial culture requirements.
Researchers at Technical University of Munich have developed two methods that enable direct antibiotic susceptibility testing of urine samples for urinary tract infections (UTI), reducing time to results by up to 24 hours compared to conventional laboratory testing, according ot research published in Microbiology Spectrum.
The new approach addresses a gap in UTI management, where approximately 152 million people worldwide are diagnosed annually. Current practice typically involves prescribing broad-spectrum antibiotics without determining the specific pathogen, while laboratory analysis for resistance testing takes two to three days and is reserved for high-risk patients.
“The sooner we know which antibiotic is effective, the more targeted our treatment can be,” says Oliver Hayden, Heinz Nixdorf professor of biomedical electronics at Technical University of Munich, in a release. “This means we won’t have to use broad-spectrum antibiotics as often, which should be used sparingly due to the development of resistance.”
Algorithm Adjusts for Bacterial Concentration
The method applies urine directly to agar plates containing antibiotic disks, then measures inhibition zones where bacterial growth is suppressed. The key innovation is an algorithm that accounts for actual bacterial concentration in urine and adjusts its influence on inhibition zone size, enabling reliable resistance profiles without prior standardization of bacterial suspensions required in conventional testing.
Initial validation data shows the direct testing method achieves approximately 94% correlation with standard laboratory methods. Researchers are using deviation analysis to optimize the test for cases involving very low bacterial concentrations or mixed infections.
The team is simultaneously developing a paper-based point-of-care device using similar principles to identify eight bacterial species through color changes and indicate antibiotic resistance patterns.
Point-of-Care and Home Testing Applications
“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,” says Henning Sabersky-Müssigbrodt, first author of the study and doctoral researcher in translational medicine at the Heinz-Nixdorf Chair of Biomedical Electronics, in a release.
The technology is designed for deployment in low-resource settings where rapid and reliable diagnostics are particularly critical, according to the researchers.
Current UTI diagnosis in medical practices relies on rapid urine tests detecting elevated nitrite and leukocyte levels as infection indicators. The resulting empirical antibiotic prescribing without pathogen identification can prolong treatment time, increase complication risks, and promote antibiotic resistance development.
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