Abstract:

Bloodstream infections refer to disseminated infections caused by pathogenic microorganisms invading bloodstream,including bacteremia and septicemia,which can lead to serious clinical consequence and high fatality rates. As the gold standard for the diagnosis of bloodstream infection,blood culture has high specificity,but an unsatisfactory positive rate and considerable patients with bloodstream infection have negative blood culture results. On one hand,the using of antibiotics before blood collection,insufficient blood volume,extended pre-analysis time and other factors should be accountable. On the other hand,there are some fastidious microorganisms needing prolonged incubation. The diagnostic efficiency of bloodstream infection can be improved by the enrichment of pathogens after reporting positive in culture flasks and rapid identification with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry（MALDI-TOF MS） and fluorescence in situ hybridization（FISH）. Serological test and molecular biotechnology,such as serum antibody determination,bacterium 16S rRNA,real-time fluorescence polymerase chain reaction（PCR）,multiplex PCR and next-generation sequencing（NGS）,can improve the detection rate of pathogens in bloodstream. This review focuses on the influence factors of negative blood culture and the progress of laboratory determination of bloodstream infection.

Key words: Bloodstream infection, Blood culture, Negative, Pathogen, Enrichment culture, Polymerase chain reaction