Decreasing contamination rates in blood cultures: A plan-do-study-act approach

Background The gold standard investigation to confirm a diagnosis of sepsis is blood culture. Contamination of blood culture with skin commensals contributes to increased health-care costs, unnecessary antibiotic treatment, and prolonged hospital stay. We did a study to identify the causes of contamination of blood culture samples and methods to decrease blood culture contamination rates. Methods This clinical audit study was a before-and-after, interventional study. Fish bone analysis was done to identify the possible issues responsible for blood culture contamination, following which intervention strategies were implemented by the plan-do-study-act model. The intervention consisted of a training session on the standard operating procedure for aseptic collection of blood culture. Thereafter, the collection of each blood culture sample was supervised by the infection control team. Regular feedback was provided to the staff if there was growth of skin contaminants in the samples collected by them, to reinforce strict adherence to all aseptic precautions. Results A total of 7329 blood culture specimens collected over a period of 17 months were included in this study, of which 5700 were collected in the post-intervention period. As compared to the pre-intervention period, there was a significant decrease in the proportion of blood culture samples growing contaminants in the post-intervention period from 10.7% to 3.4% (p<0.0001). Conclusion A detailed analysis of the problem, repeated training sessions, continuous surveillance, and regular feedback need to be adopted for reinforcing proper aseptic collection and processing of blood culture specimens to ensure optimal resource utilisation.