Toward Rapid Detection of Viable Bacteria in Whole Blood for Early Sepsis Diagnostics and Susceptibility Testing

Sharath Narayana Iyengar, Jiri Dietvorst, Amparo Ferrer-Vilanova, Gonzalo Guirado, Xavier Muñoz-Berbel*, Aman Russom

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

4 Citations (Scopus)


Sepsis is a serious bloodstream infection where the immunity of the host body is compromised, leading to organ failure and death of the patient. In early sepsis, the concentration of bacteria is very low and the time of diagnosis is very critical since mortality increases exponentially with every hour after infection. Common culture-based methods fail in fast bacteria determination, while recent rapid diagnostic methods are expensive and prone to false positives. In this work, we present a sepsis kit for fast detection of bacteria in whole blood, here achieved by combining selective cell lysis and a sensitive colorimetric approach detecting as low as 103CFU/mL bacteria in less than 5 h. Homemade selective cell lysis buffer (combination of saponin and sodium cholate) allows fast processing of whole blood in 5 min while maintaining bacteria alive (100% viability). After filtration, retained bacteria on filter paper are incubated under constant illumination with the electrochromic precursors, i.e., ferricyanide and ferric ammonium citrate. Viable bacteria metabolically reduce iron(III) complexes, initiating a photocatalytic cascade toward Prussian blue formation. As a proof of concept, we combine this method with antibiotic susceptibility testing to determine the minimum inhibitory concentration (MIC) using two antibiotics (ampicillin and gentamicin). Although this kit is used to demonstrate its applicability to sepsis, this approach is expected to impact other key sectors such as hygiene evaluation, microbial contaminated food/beverage, or UTI, among others.

Original languageEnglish
Pages (from-to)3357-3366
Number of pages10
JournalACS Sensors
Issue number9
Publication statusPublished - 24 Sep 2021


  • E. coli
  • Prussian blue
  • bacteria
  • blood
  • colorimetric
  • selective cell lysis
  • sepsis


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