Recent Advances in Bacterial Separation and Enrichment from Blood for the Diagnosis of Bloodstream Infections

In this paper, recent advances (2016-2026) in bacterial separation and enrichment from blood for diagnosis of bloodstream infection (BSIs) through pathogen identification and antimicrobial susceptibility testing (AST) are reviewed. The review centers on sample processing as an indispensable front-end of biosensor and lab-on-chip platforms, since most sensors cannot operate directly in whole blood. Efficient separation and enrichment concentrate extremely low bacterial burdens, remove blood components that interfere with detection, and deliver bacteria in a sensor-compatible format; consequently, diagnostic sensitivity, specificity, turnaround time, and robustness are strongly determined by this step. We first summarize the clinical impact of BSIs and the value of rapid AST for guiding timely, targeted therapy, emphasizing that efficient bacterial isolation from blood is a prerequisite for accurate testing. We then discuss key challenges and recent progress in bacterial separation and enrichment from blood with major approaches, including filtration, centrifugation, functionalized magnetic beads, and microfluidic technologies. These strategies serve as core building blocks that interface with downstream identification and AST methods, supporting integrated biosensors and point-of-care devices. Finally, we outline future directions of bacterial separation and enrichment approaches to improve recovery, purity, integration, standardization, and overall diagnostic performance for BSI workflows.