Identification of microorganisms grown in blood culture flasks using liquid chromatography-tandem mass spectrometry.

Aim: Bloodstream infections are a common cause of disease and a fast and accurate identification of the causative agent or agents of bloodstream infections would aid the start of adequate treatment.

Materials & Methods: A liquid chromatography-tandem mass spectrometry (LC-MS/MS) shotgun proteomics method was developed for the identification of bacterial species directly from blood cultures that were simulated by inoculating blood culture bottles with single or multiple clinically relevant microorganisms.

Results: Using LC-MS/MS, the single species were correctly identified in 100% of the blood cultures, whereas for polymicrobial infections, 78% of both species were correctly identified in blood cultures.

Conclusion: The LC-MS/MS method allows for the identification of the causative agent of positive blood cultures.