Low-concentration Bacteria Separation from Whole Blood through a Slanted Filter in a Centrifuge Tube

Sammanfattning: Sepsis characterized by severe bloodstream bacterial infection that results in high mortality rates and medical expenses has become a global healthcare challenge. The current clinical sepsis diagnosis is based on blood culture and requires a long waiting time, delaying effective treatments. The emerging sepsis diagnosis shortens the turn-around of time but requires an efficient bacteria separation from the blood beforehand. In this master’s degree project, a new filter-based method of separating bacteria from the blood is investigated to meet the clinical need for future sepsis diagnosis. The separation device is controlled within the size of a centrifuge falcon tube and integrated with a slanted filter inside. Through a centrifuge, blood cells and bacteria are maneuvered toward the filter and separated by it. Using the optimal design, at concentrations as low as 100 CFU/mL, the device can recover around 30% of bacteria of E. coli, K. pneumoniae, and S. aureus from 1 mL of whole blood within 60 minutes, and reject 99.4% RBCs from going through the filter. Bacteria recovery at 10 CFU/mL concentration demonstrated all-positive results, making this new separation method a promising candidate for future clinic needs in sepsis diagnosis.