Culture-free Rapid Isolation and Detection of Bacteria from Whole Blood at Clinically Relevant Concentrations

Abstract

Rapid detection and antibiotic susceptibility profiling of bacterial agents in the blood of sepsis patients are crucial for determining appropriate treatment. The low bacteria concentrations and high abundance of blood cells currently necessitate culture-based diagnostic methods, which can take several days. Here, we introduce a method to isolate bacteria from whole blood with high separation power by smart centrifugation, followed by detection through microscopy in microfluidic traps within 2 h without the need for blood culture. We detected E. coli, K. pneumonia, or E. faecalis from spiked samples of healthy human donor blood at clinically relevant concentrations as low as 9, 7 and 32 colony-forming units per ml of blood, respectively. This rapid isolation of living bacteria from blood at clinically relevant concentrations opens possibilities for rapid phenotypic antibiotic susceptibility testing for bloodstream infections without blood culture.