Time to positivity in catheter-related bloodstream infections
Abstract:
Background: Time to positivity (TTP) of blood cultures is an inexpensive, laboratory-derived marker increasingly used in clinical practice. While shorter TTP has been linked to worse outcomes in bacterial bloodstream infections (BSIs), data on candidemia remains limited and inconsistent. Its prognostic role in catheter-related bloodstream infections (CRBSIs) is poorly defined, as most studies have focused on differential time to positivity (DTP) for diagnosis.
Methods: We conducted a retrospective, single-center study (July 2021-May 2025) including adult non-ICU patients with confirmed CRBSI. 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; cutoffs: 9 h for bacteria, 17 h for Candida spp.). Seventy-nine episodes were analysed (56 bacterial, 23 Candida spp.).
Results: In our exploratory analysis as for bacterial CRBSIs, the fast TTP subgroup showed numerically higher 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 numerically higher mortality (50.0% vs. 27.3%) and longer LOS (60 vs. 31 days), although these between-subgroup differences did not reach statistical significance. No significant differences emerged between TTP and disease severity markers.
Conclusions: In non-ICU CRBSIs, shorter bacterial TTP and longer Candida spp. TTP might be related with worse clinical outcomes and prolonged hospitalization, but these findings are to be considered exploratory and therefore further studies with larger samples are needed.
Reference:
Zizzo D, Conflitti C, Scaglione G, De Capitani G, Borgonovo F, Fattore R, Galli L, Schiavini M, Fassio F, Gidaro A, Calloni M, Casella F, Taino A, Bartoli A, Cogliati C, Busatto N, Antinori S, Gori A, Foschi A, Colaneri M. Time to positivity in bacterial and Candida spp. catheter-related bloodstream infections: a single-centre retrospective analysis. J Hosp Infect. 2026 Aug 7:S0195-6701(26)00313-0. doi: 10.1016/j.jhin.2026.07.027. Epub ahead of print. PMID: 42567322.