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.
Staphylococcus saccharolyticus is a slow-growing anaerobic coagulase-negative staphylococcus and a rare cause of bloodstream infections. We report the case of a previously healthy 35-year-old woman who presented with fever and headache. One anaerobic bottle from each of two separately collected blood culture sets became positive after 53 h, and S. saccharolyticus was identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; both aerobic bottles remained negative. No focus of infection was detected. Repeat cultures drawn on day 3, before vancomycin treatment was started, were already negative. The patient received ceftriaxone for 3 days, vancomycin for 4 days, and oral clindamycin for 8 days, and recovered without relapse. The minimum inhibitory concentrations were obtained using a panel developed for aerobically growing gram-positive cocci and were reported without categorical interpretation, as no breakpoints have been validated for this species. Detection in two separately collected sets may represent true bacteremia even in the absence of an implanted device or comorbidity.
Objective Co-fermentation of lignocellulosic biomass and food waste (FW) can enhance the production of volatile fatty acids (VFAs) during anaerobic fermentation. However, the effect and mechanism of co-fermentation of Auricularia auricula waste (AW) with FW remains unclear. This study aimed to investigate the effect and mechanism of co-fermentation of Auricularia auricula waste (AW) with food waste (FW) on volatile fatty acid (VFA) production. Methods Anaerobic fermentation experiments were conducted at different AW/FW ratios (1:0, 1:1, 2:1, 3:1, 4:1, 0:1) based on volatile solids (VS). VS removal and VFA concentration were measured, and metagenomic sequencing was performed to elucidate the underlying enhancement mechanism. Results Co-fermentation significantly improved VS removal and VFA production, with both parameters increasing as the proportion of FW increased. The highest VS removal (48.9%) and VFA concentration (7929 mg/L) were achieved at an AW/FW ratio of 1:1, which were approximately double those of AW alone (22.4% and 3659 mg/L, respectively). Metagenomic analysis revealed that co-fermentation enriched bacterial genera such as Rummeliibacillus (25.4%) and Leuconostoc (9.2%), while Fungal genera Piromyces and Neocallimastix became dominant. Moreover, co-fermentation increased the relative abundance of carbohydrate-active enzymes and activated key functional genes in the VFA production pathway (e.g., ackA, PTA, MDH, HBD). Conclusion Co-fermentation of AW and FW significantly enhanced the hydrolysis and VFA production. The enhancement mechanism of VFA production during co-fermentation primarily involved the synergistic interaction between substrate nutrient complementation and efficient microbial community. This study provides a feasible strategy for efficient VFA production from spent mushroom waste.
