Using urine samples for early Staphylococcus aureus bacteremia diagnosis

• Applicant: Dr. Franziska Schuler
• Subject Area: Clinical Infectiology and Tropical Medicine ; Medical Microbiology and Mycology, Hygiene, Molecular Infection Biology
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 518834831

Staphylococcus aureus bacteremia (SAB) is common and has an incidence of 22-32/100,000/year. S. aureus is the causative agent of bacteremia in 6.8-8 % of cases at Münster University Hospital (n=90-104 per year), of which approximately 2 % are with methicillin-resistant S. aureus.Despite antibiotics, SAB has a high 90-day mortality (28-34 %). This decreases when adequate therapy with flucloxacillin or cefazolin for methicillin-sensitive S. aureus is initiated early. Many patients (7.8 %-39 %) have concomitant S. aureus bacteriuria (SABU) in addition to SAB, which is usually associated with a worse clinical outcome (including admission to an intensive care unit and death). Pathogen identification from blood cultures is comparatively slow (requiring 31-49 hours) and is particularly dependent on transport to the laboratory, incubation time, laboratory opening hours and associated processing of blood cultures. Therefore, we would like to investigate whether early detection of secondary SABU can be used for a more rapid SAB diagnosis in terms of Point of Care Testing. Thus, a presumptive SAB diagnosis could be made in the emergency room. the probability of SAB could already be estimated in the emergency room. With this information, the diagnostic workup could then be expedited advanced to search for the source of infection and secondary seeding of the SAB and adequate therapy could be initiated early, if necessary. For diagnostics of invasive Legionella and Pneumococcus infections, antigen-based rapid tests from urine have been available on the market for many years. To date, there is no established test that can measure S. aureus antigens from urine. Therefore, in a diagnostic study, we aim to compare the urinary proteome of individuals with SAB and non-S. aureus bacteremia with respect to S. aureus specific proteins. This should identify antigen candidates that could be used for the development of a rapid lateral flow test.

• DFG Programme: Research Grants