Background and aim In neonatal intensive care coagulase negative Staphylococcus species can be both blood culture contaminant and pathogen. False positive cultures can result in clinical uncertainty and unnecessary antibiotic use. Our aim was to assess the effect of a total sterile blood culture collection bundle on the incidence of false positive blood cultures in a regional surgical neonatal intensive care unit.
Method Clinical data of all infants who had blood cultures taken before and after the introduction of the collection bundle (sterile technique and 2% Chlorhexidine) were collected. The rates of false positive blood cultures, defined as the presence of a skin commensal and <3 predefined clinical signs (Modi et al. 2009), were compared.
Results In total 367 blood cultures from 294 babies were assessed, 197 pre-intervention (PRE) and 170 following bundle introduction (POST). The median birth weight and gestation were similar in both groups. The rate of false positive cultures in the total PRE group was 9/197 (4.6%) compared to 1/170 (0.6%) in the POST group (p < 0.05). In infants <28 weeks’ the rates reduced from 4/29 (13.8%) to 0/30 (0%) (p < 0.05). Unnecessary antibiotic exposure rate was 7.7% in the PRE group versus 0.0% in the POST group (p < 0.05).
Conclusion Implementation of this collection bundle reduced the number of false positive blood culture results. This has a potential benefit in reducing unnecessary antibiotic use and associated health care costs.