J Infect Dis. 2025 Nov 26:jiaf594. doi: 10.1093/infdis/jiaf594. Online ahead of print.
ABSTRACT
OBJECTIVES: Vascular graft or endograft infections (VGEI) pose a detrimental complication when using vascular grafts and are challenging to diagnose and treat. This study examined the progression of infection and the antimicrobial response in VGEI using [18F]Fluorodeoxyglucose (FDG) Positron Emission Tomography (PET), ex vivo bacterial quantification, and histology in a VGEI rat model.
METHODS: In this experimental study, 97 male Sprague-Dawley rats had a polytetrafluorethylene graft surgically implanted in the carotid artery. The graft was either pre-inoculated with Staphylococcus aureus, Staphylococcus epidermidis, or saline. Up to 31 days after surgery, rats were FDG-PET-scanned. Subsequently, they were euthanised, and the implants were retrieved for analysis. A subgroup of infected rats received daptomycin and rifampicin from days 20 to 29.
RESULTS: Tracer uptake around the implant, measured by maximum standardised uptake value (SUVmax), declined over time in all groups. Between groups, SUVmax was highest in untreated S. aureus-infected rats. When comparing antibiotic-treated and uninfected rats by day 31, there was no difference in SUVmax, although the treated rats were still infected.Histology revealed widespread inflammation by day 10 in S. aureus-infected rats, which decreased by days 20 and 31 with encapsulation of the infection, alongside increased plasma interleukin-10.
CONCLUSIONS: FDG-PET differentiated untreated S. aureus-infected rats from uninfected ones but failed to monitor infection progression, as SUVmax declined over time despite a constant bacterial load.FDG-PET could not distinguish between uninfected rats and those with suppressed infection, likely due to reduced inflammation and encapsulation of the infection.
PMID:41296646 | DOI:10.1093/infdis/jiaf594