When a urine sample arrives at a microbiology lab today, the standard path is a two-to-three-day wait while bacteria grow in culture. By the time results come back, the patient is often already home — sometimes already finished a course of the wrong antibiotic. A new test, published March 31 in the Journal of Antimicrobial Chemotherapy, cuts that window to under six hours and could, its developers say, change which drug a patient leaves the hospital with.
The system, called rapid microbe detection antibiotic susceptibility testing (RMD AST), was developed by researchers at the University of Reading and the University of Southampton. It works by dipping thin tubes loaded with different antibiotics directly into urine samples. Optical imaging tracks whether bacterial growth continues or stops in each tube, revealing which drugs the infection will respond to. Across 352 urine samples, the test matched standard laboratory methods in 96.95 percent of cases, with a mean time to result of 5.85 hours, according to the study in JAC-Antimicrobial Resistance.
The headline number is strong. But researchers are more excited by what it enables than by the precision itself. "We are essentially providing susceptibility results at a time that is clinically actionable," said Dr. Oliver Hancox, a pharmacist at the University of Reading and CEO of Astratus Limited, the spinout company formed from this research. The standard culture test "returns results after the patient has left hospital, often after the first dose of antibiotic has already been prescribed."
The numbers behind that problem are large. More than 800,000 people were admitted to UK hospitals because of a UTI from 2018 to 2023, according to CIDRAP, which first reported the data. Approximately one in three UTIs globally is now resistant to first-line antibiotics, per the WHO's GLASS 2025 report. And roughly 25 percent of urine samples analyzed in NHS laboratories already contain bacteria resistant to at least one common antibiotic, CLP Magazine reported.
The test was funded by the National Institute for Health and Care Research (NIHR) and co-authored by Dr. Matthew Inada-Kim, an acute physician and antimicrobial resistance lead at Hampshire Hospitals NHS Foundation Trust. In a university press release, Prof. Mike Lewis, NIHR's scientific director for innovation, called faster diagnostics "a critical component" of addressing resistance. The nuance in his comment was audible: a faster test does not automatically fix the incentive problems that make AMR worse.
The technical challenge solved here is not novel in principle. Microbial growth curves have been readable by optical instruments for years. What the Reading-Southampton team built is a workflow fast enough to return a susceptibility result during a hospital stay, using a device that fits into existing lab infrastructure. The spinout, Astratus Limited, was founded in November 2024 — which means it is roughly two months old as of this publication. Its ability to scale manufacturing, negotiate NHS procurement, and get the optical hardware into labs that do not currently have it is the unglamorous work that follows the peer-reviewed result.
There is a version of this story where the test changes practice. UTI admissions are common, resistance is rising, and a clinician who knows by noon which antibiotic will work can adjust the prescription before discharge rather than waiting days for a call that arrives too late. That is the clinical window this test is designed to close.
The harder question is whether the infrastructure will follow. NHS labs are stretched, the device requires specialized optical equipment that most labs do not currently own, and the company has not disclosed pricing. Astratus is early-stage by any measure. None of that is a reason to dismiss the result — but it is a reason not to confuse a validated study with a deployed solution.
UTI complications are a leading driver of sepsis admissions. The National Institute for Health and Care Excellence (NICE) has flagged diagnostic delay as a contributor to preventable deterioration. For the patients caught in that gap — sent home with an antibiotic that cannot touch their infection — a six-hour result rather than a three-day one is not an incremental improvement. It is a different clinical scenario entirely.
Astratus will now need to move from a published study to a product that NHS labs can actually run. The science is done. The harder test — whether the timing gap the test solves is also a gap the system is ready to close — is still ahead.
