Incidence, aetiology and temporal trend of bloodstream infections in southern Sweden from 2006 to 2019 : a population-based study

BackgroundBloodstream infections (BSI) are a public health concern, and infections caused by resistant bacteria further increase the overall BSI burden on healthcare.AimTo provide a population-based estimate of BSI incidence and relate this to the forthcoming demographic ageing western population change.MethodsWe retrieved positive blood cultures taken from patients in the Skåne region, southern Sweden, 2006-2019 from the Clinical Microbiology Department database and estimated incidence rates (IR), stratified by age (0-49, 50-64, 65-79, ≥ 80 years), sex, year, and species and described antimicrobial susceptibility for Enterobacterales.ResultsWe identified 944,375 blood culture sets, and 129,274 (13.7%) were positive. After deduplication and removal of contaminants, 54,498 separate BSI episodes remained. In total, 30,003 BSI episodes (55%) occurred in men. The overall IR of BSI was 307/100,000 person-years, with an average annual increase of 3.0%. Persons ≥ 80 years had the highest IR, 1781/100,000 person-years, as well as the largest increase. Escherichia coli (27%) and Staphylococcus aureus (13%) were the most frequent findings. The proportion of Enterobacterales isolates resistant to fluoroquinolones and third generation cephalosporins increased from 8.4% to 13.6%, and 4.9% to 7.3%, (p for trend < 0.001), with the largest increase in the oldest age group.ConclusionWe report among the highest BSI IRs to date worldwide, with a higher proportion among elderly persons and males, including resistant isolates. Given expected demographic changes, these results indicate a possible substantial future BSI burden, for which preventive measures are needed.