Bloodstream infections among people who inject drugs in Finland, 2019-2023

Abstract Background In the last decade, Finland has seen growth in bloodstream infections (BSI) as well as in injecting drug use, a practice which increases the risk of infections, including BSI. Our aim was to describe BSIs and causative microbes among persons who inject drugs (PWID) in Finland during 2019-2023 in order to identify targets for public health interventions. Methods We conducted a register-based study, using data from national registries linked by personal identifiers. We identified BSI episodes from the infectious diseases register, PWIDs from the hospital discharge and outpatient care registers, and date of death from the population register. PWID were retrieved by ICD-10 code “F11 - Opioid related disorders”, predating the BSI episode for up to 2 years. We analysed demographics, and case fatality (CF) within 30 days of positive blood culture. Results In total we identified 95835 BSIs of which 1532 (1.6%) were among 1162 PWID. Of these, 1009 (66%) were among males, 75 (5%) in foreign-born and median age was 35 years (interquartile-range 28, 42 years). Of the PWID, 20% had ≥2 BSI episodes. Of the BSIs, 173 (11%) were polymicrobial. The most common microbes were Staphylococcus aureus (36%), Bacillus cereus (9%) and Streptococcus pyogenes (8%). Of all S. aureus BSIs, 61 (9%) were caused by methicillin resistant S. aureus (MRSA). 30-day CF was 2.7%; 21/42 were aged <40 years. During 2019-2023 the annual number and proportion of all BSIs increased from 214 (1.1%) to 403 (2%) and 30-day CF from 1.4% to 3.7%. Conclusions The two-fold increase in BSIs and three-fold increase in CF among PWID and young age of this population represent a public health concern that requires infection control interventions and appropriate clinical management. Supervised injection rooms should be considered in Finland. Microbiological findings can be used when updating treatment guidelines for PWID. Key messages • BSIs and 30 days-case fatality in PWID are seen in younger age groups when compared to population in Finland. • The two-fold increase in BSIs and three-fold increase in CF among PWID represents a public health concern that requires both effective prevention strategies and appropriate clinical management.