Diagnosis of bloodstream infections from positive blood cultures and directly from blood samples: recent developments in molecular approaches

Background: Bloodstream infections are a major cause of death with increasing incidence and severity. Blood cultures are still the reference standard for microbiological diagnosis, but are rather slow. Molecular methods can be used as add-on complementary assays. They can be useful to speed up microbial identification and to predict antimicrobial susceptibility, applied to direct blood samples or positive blood cultures. Aim: To review recent developments in molecular-based diagnostic platforms used for the identification of bloodstream infections, with a focus on assays performed directly on blood samples and positive blood cultures. Sources: Peer reviewed articles, conference abstracts, and manufacturers' websites. Content: We give an update on recent developments of molecular methods in diagnosing BSIs. We first describe the currently available molecular methods to be used for positive blood cultures including: a) in situ hybridization-based methods; b) DNA-microarray-based hybridization technology; c) nucleic acid amplification-based methods; and d) combined methods. Subsequently, molecular methods applied directly to whole blood samples are discussed, including the use of nucleic acid amplification-based methods, T2 magnetic resonance-based methods, and metagenomics for diagnosing BSIs. (C) 2018 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.