Sending repeat cultures: is there a role in the management of bacteremic episodes? (SCRIBE study).
BMC Infect Dis. 2016 Jun 13;16(1):286.
Wiggers JB1, Xiong W2, Daneman N3,4,5,6.
1Department of Medicine, University of Toronto, Toronto, Canada.
2Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Canada.
3Department of Medicine, University of Toronto, Toronto, Canada. firstname.lastname@example.org
4Division of Infectious Diseases, Department of Medicine, Sunnybrook Health Sciences Centre, Toronto, Canada. email@example.com
5Institute for Clinical Evaluative Sciences, Toronto, Canada. firstname.lastname@example.org
6Division of Infectious Diseases & Clinical Epidemiology, Sunnybrook Health Sciences Centre, University of Toronto, Institute for Clinical Evaluative Sciences, 2075 Bayview Ave, G-wing Room 106, Toronto, M4N 3 M5, Canada. email@example.com
In the management of bacteremia, positive repeat blood cultures (persistent bacteremia) are associated with increased mortality. However, blood cultures are costly and it is likely unnecessary to repeat them for many patients. We assessed predictors of persistent bacteremia that should prompt repeat blood cultures.
We conducted a retrospective cohort study of bacteremias at an academic hospital from April 2010 to June 2014. We examined variables associated with patients undergoing repeat blood cultures, and with repeat cultures being positive. A nested case control analysis was performed on a subset of patients with repeat cultures.
Among 1801 index bacteremias, repeat cultures were drawn for 701 patients (38.9 %), and 118 persistent bacteremias (6.6 %) were detected. Endovascular source (adjusted odds ratio [aOR], 7.66; 95 % confidence interval [CI], 2.30-25.48), epidural source (aOR, 26.99; 95 % CI, 1.91-391.08), and Staphylococcus aureus bacteremia (aOR, 4.49; 95 % CI, 1.88-10.73) were independently associated with persistent bacteremia. Escherichia coli (5.1 %, P = 0.006), viridans group (1.7 %, P = 0.035) and β-hemolytic streptococci (0 %, P = 0.028) were associated with a lower likelihood of persistent bacteremia. Patients with persistent bacteremia were less likely to have achieved source control within 48 h of the index event (29.7 % vs 52.5 %, P < .001), but after variable reduction, source control was not retained in the final multivariable model.
Patients with S. aureus bacteremia or endovascular infection are at risk of persistent bacteremia. Achieving source control within 48 h of the index bacteremia may help clear the infection. Repeat cultures after 48 h are low yield for most Gram-negative and streptococcal bacteremias