A Simple, Low-Cost, and Efficient Protocol for Rapid Isolation of Pathogenic Bacteria from Human Blood.

Bacteremia is a serious clinical condition in which pathogenic bacteria enter the bloodstream, putting patients at risk of septic shock and necessitating antibiotic treatment. Choosing the most effective antibiotic is crucial not only for resolving the infection but also for minimizing side effects, such as dysbiosis in the healthy microbiome and reducing the selection pressure for antibiotic resistance. This requires prompt identification of the pathogen and antibiotic susceptibility testing, yet these processes are inherently slow in standard clinical microbiology labs due to reliance on growth-based assays. Although alternative methods exist, they are rarely adopted in clinical settings because they involve complex protocols and high costs for training and infrastructure. Here, we present an optimized, simple protocol for rapidly and efficiently isolating bacterial pathogens from blood without altering typical laboratory workflows. Our method is cost-effective and compatible with commonly available laboratory instruments, offering the advantage of isolating bacterial cells directly, which bypasses the delays associated with traditional blood culture methods and enables faster diagnostic results. The protocol achieved over 70% efficiency within 30 minutes, remained effective at low bacterial concentrations (1-10 bacteria/0.3 mL blood), and preserved bacterial viability with no notable change in growth lag times. We validated the protocol on several clinically relevant bacterial strains, including