Blood Cultures: Clinical Aspects And Controversies
Bloodstream infections continue to be a major cause of morbidity and mortality despite advances in antimicrobial therapy and supportive care. Early diagnosis and appropriate treatment of bloodstream infections are important clinical concerns.
Culturing of blood is the only method to detect bloodstream infection. During the last two decades, there have been major advances in blood culture technology. These advances (e.g. automated systems that monitor blood culture bottles every ten to fifteen minutes) have decreased the time me to detection and identification of organisms causing bloodstream infection. However, there are many facets of the blood culture as a diagnostic test that are not affected by new culture methods, but continue to cause problems with interpretation of test results.
Types of Bloodstream Infection
In general, bloodstream infections have been classified as transient, intermittent, and continuous. Transient bloodstream infection usually follows mechanical or surgical manipulation of infected tissue. It might also occur during routine daily activities, such as toothbrushing or bowel movements. Intermittent bacteraemia is typically seen with undrained abscesses or in association with localised infections such as pneumonia, urinary tract infections and central nervous system infections. Continuous bacteraemia is observed with intravascular infections such as infective endocarditis, septic thrombophlebitis, or a mycotic aneurysm.