The challenge of molecular diagnosis of bloodstream infections

Early detection and identification of pathogens in bloodstream infections (BSI) is important to initiate or adjust antibiotic therapy as soon as possible. The current gold standard for diagnostic of BSI infection is the blood culture, that has a turnaround time of one to few days. Molecular tests performed directly in blood samples have promised faster diagnostics, with response times of a few hours, but their implementation into the clinical routine has been hampered by critical technical and procedural problems. Assay integration into laboratory workflows with random-access loading mode and minimal hands-on time is essential to meet rapid response times. Decreasing assay costs will favor fair clinical evaluations and might increase the applicability of the assays. Control of background contamination with bacterial DNA is one of the most difficult problems and might be avoided with pathogen-specific real-time PCR designs oriented to particular patient groups, or perhaps by quantitative, next-generation sequencing approaches.