Time to positivity in bacterial and Candida spp. catheter-related bloodstream infections: a single-centre retrospective analysis

Background: Time to positivity (TTP) of blood cultures is an inexpensive, laboratory-derived marker used increasingly in clinical practice. While shorter TTP has been linked to worse outcomes in bacterial bloodstream infections (BSIs), data on candidaemia remain limited and inconsistent. Its prognostic role in catheter-related bloodstream infections (CRBSIs) is poorly defined, as most studies have focused on differential TTP for diagnosis. Methods: A retrospective, single-centre study (July 2021–May 2025) including adult non-intensive-care-unit (ICU) patients with confirmed CRBSI was conducted. Demographic, clinical and microbiological data were collected, and outcomes included in-hospital mortality, infection-related mortality, length of stay (LOS) and post-CRBSI LOS. Disease severity was assessed using 11 clinical and laboratory markers. Episodes were stratified by pathogen (bacteria vs Candida spp.) and TTP (fast vs slow; cut-offs: 9 h for bacteria, 17 h for Candida spp.). Seventy-nine episodes were analysed (56 bacterial, 23 Candida spp.). Results: In this exploratory analysis, for bacterial CRBSIs, the fast TTP subgroup showed more cases of in-hospital mortality (25.8% vs 12.0%) and infection-related mortality (12.9% vs 4.0%). In Candida spp. CRBSIs, the slow TTP subgroup showed more cases of in-hospital mortality (50.0% vs 27.3%) and longer LOS (60 vs 31 days), although these between-subgroup differences did not reach significance. No significant differences emerged between TTP and disease severity markers. Conclusions: In non-ICU CRBSIs, shorter bacterial TTP and longer Candida spp. TTP may be associated with worse clinical outcomes and prolonged hospitalization, but these findings should be considered exploratory; further studies with larger samples are needed.