Persistence of detectable pathogens by culture independent systems (T2 Magnetic Resonance) in patients with bloodstream infection: prognostic role and possible clinical implications.

Persistent S. aureus bacteraemia is associated with metastatic infection and adverse outcomes while Gram-negative bacteraemia is normally transient and shorter course therapy is increasingly advocated for affected patients. Whether the prolonged detection of pathogen DNA in blood by culture-independent systems could have prognostic value and guide management decisions is unknown. We performed a multicentre prospective observational study on 102 patients with bloodstream infection, to compare time to bloodstream clearance according to T2 magnetic resonance and blood cultures over a 4-day follow-up. We also explored the association between duration of detectable pathogens according to T2 Magnetic resonance (Magnetic Resonance-DNAemia, MR-DNAemia) and clinical outcomes. Time to bloodstream clearance according to T2 Magnetic Resonance was significantly longer compared to blood culture clearance (HR 0.54, 95%CI 0.39-0.75) and did not differ according to the causative pathogen (p=0.5). Each additional day of MR-DNAemia increased the odds of persistent infection (defined as metastatic infection or delayed source control) both in the overall population (OR 1.98, 95%CI 1.45-2.70) and in S. aureus (OR 1.92, 95%CI 1.12-3.29) and Gram-negative bacteraemia (OR 2.21, 95%CI 1.35-3.60). MR-DNAemia duration was also associated with no improvement in Sequential Organ Failure Assessment score at day 7 from infection onset (OR 1.76, 95%CI 1.21-2.56). T2 Magnetic Resonance may help to diagnose bloodstream infection in patients on antimicrobials with negative blood cultures as well as to identify patients with metastatic infection, source control failure or adverse short-term outcome. Future studies may inform its usefulness within the setting of antimicrobial stewardship programs.

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© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America.