Blood culture contaminants

Abstract

Blood cultures are an essential diagnostic tool. However, contamination may impact on patients' care and lead to increased patient stay, additional tests, and inappropriate antibiotic use. The aim of this study was to review the literature for factors that influence the rate of blood culture contamination. A comprehensive literature search was performed using Medline and CINAHL on blood culture contamination. Hospitals/units should have in place a protocol for staff on how to take blood cultures, incorporating use of an aseptic technique. Studies have shown that several key factors in the process may lower contamination rates such as adherence to a protocol, sampling by peripheral venepuncture route rather than via an intravascular catheter, use of sterile gloves, cleaning tops of blood culture bottles with antiseptics and inoculating blood culture bottles before other blood tubes, samples being taken by a phlebotomy team, monitoring contamination rates, and providing individual feedback and retraining for those with contaminants. Although skin antisepsis is advocated there is still debate on which antiseptic is most effective, as there is no conclusive evidence, only that there is benefit from alcohol-containing preparations. In conclusion, hospitals should aim to minimize their blood culture contamination rates. They should monitor their rate regularly and aim for a rate of ≤3%.

Keywords: Blood cultures; Contamination; Cross-infection.