Related Experiment Video
Updated: Oct 16, 2026
Preparation of a Blood Culture Pellet for Rapid Bacterial Identification and Antibiotic Susceptibility Testing
Published on: October 15, 2014
Delayed Blood Culture Positivity in Fusobacterium nucleatum Bacteremia: A Retrospective Comparative Study
Ryutaro Tanizaki1, Yayoi Miyamatsu1, Shuhei Ichikawa2
1Center for Generalist Medicine Education and Research, Ise Municipal General Hospital, 3038 Kusube-cho, Ise, Mie 516-0014, Japan; Department of Internal Medicine and General Medicine, Ise Municipal General Hospital, 3038 Kusube-cho, Ise, Mie 516-0014, Japan.
Objectives:
Blood culture time to positivity (TTP) in Fusobacterium nucleatum bacteremia remains poorly characterized at the species level. We aimed to characterize TTP in F. nucleatum bacteremia and compare it with that of representative anaerobes and common bloodstream pathogens.
Methods:
We conducted a single-center retrospective study of all F. nucleatum bacteremia episodes detected between December 2020 and March 2026. Episodes of Bacteroides fragilis, Clostridium perfringens, Escherichia coli, and Staphylococcus aureus bacteremia served as comparators. Episode-level TTP was defined as the shortest TTP among blood culture bottles from which the index organism was recovered. Overall differences were assessed using the Kruskal-Wallis test, followed by pairwise Mann-Whitney U tests with Holm adjustment.
Results:
Nine F. nucleatum bacteremia episodes were identified, with TTP available for eight. The median TTP was 79.3 h, substantially longer than that of B. fragilis (32.1 h), C. perfringens (12.8 h), E. coli (11.7 h), and S. aureus (15.4 h). All pairwise comparisons remained significant after Holm adjustment (adjusted P < 0.001 for each). Six of eight episodes signaled positive after 48 h.
Conclusions:
F. nucleatum bacteremia was associated with substantially longer TTP than the comparator organisms. A negative blood culture at 48 h should be interpreted cautiously when F. nucleatum bacteremia remains clinically plausible.
