Mortality outcomes and economic burden of antimicrobial-resistant bacterial bloodstream infections in a Nigerian tertiary hospital

Antimicrobial resistance (AMR) poses a global public health and economic challenge, significantly contributing to poor outcomes of bacteria bloodstream infections (BSI). There is a paucity of local data on outcomes of AMR BSIs in Nigeria. This prospective cohort study determined outcomes and healthcare costs of BSIs stratified by resistance status. Data were prospectively collected from enrolled participants (neonates, children and adults) with susceptible (cohort 1) and resistant (cohort 2) BSIs caused by Enterobacterales , Pseudomonas spp, Acinetobacter spp., Staphylococcus aureus , and Enterococcus spp, and a control group without BSI (cohort 3), at the University of Port Harcourt Teaching Hospital between April and November 2025. Outcomes (in-hospital mortality and extra length of hospital stay, LOS) were compared between the three cohorts using time-dependent and multi-state regression models that adjusted for patients’ characteristics, time-varying cofounders and competing risks, while healthcare costs were compared using Students’ t’ test and analysis of variance. A total of 952 patients were recruited, with 330 neonates, 271 children and 351 adults. The overall prevalence of bacteria-confirmed BSI was 18.1%, with neonatal BSI of 27.3%, childhood BSI of 12.5% and adult BSI of 13.7% ( p < 0.0001). In-hospital mortality was higher for healthcare onset (HO) compared to community onset (CO) BSI ( sd HR:1.7 (0.65–4.5)], MRSA compared to MSSA BSI [ sd HR: 4.1 (0.49–33.5)], and clindamycin-resistant compared to clindamycin-susceptible S. aureus BSI ( sd HR: 6.8 (0.36–129.4)]. Multistate modelling showed that HO-BSI caused extra LOS of 2.28 days compared to CO-BSI, resistant BSI caused extra LOS of 1.72 days compared to susceptible BSI, MRSA-BSI caused extra LOS of 2.83 days compared to MSSA-BSI, and ESBL-BSI caused extra LOS of 4.28 days compared to non-ESBL-BSIs. Healthcare costs, catastrophic expenditures and impoverishment from out-of-pocket spending were high for all groups but generally higher for patients with HO and resistant BSIs. Compared to susceptible bacterial BSIs, resistant bacterial BSIs are associated with higher mortality, extra length of hospital stays and excess healthcare costs. Policies to reduce the burden of resistant BSIs should focus on improving infection prevention and control and antimicrobial stewardship practices in both hospital settings and the community.