Epidemiology and clinical characteristics of paediatric bloodstream infections 1998-2018 in Stockholm

Abstract

Bloodstream infections (BSI) constitute a common, serious, and potentially preventable cause of morbidity and mortality in children. Good knowledge of epidemiology, aetiology and the occurrence of antimicrobial resistance is essential for early effective empiric antibiotic therapy. Also, to identify areas for improved antimicrobial therapy and possible preventive measurements for BSI in different risk groups. The general aims of this thesis were to describe the aetiology, risk factors, and occurrence of bacteria resistant to antimicrobial therapy in children aged 0–17 years, with BSI under 20 years.

In papers I, II and IV, we found a crude BSI incidence rate of 25.5/100,000 children, aged 0-17 years, over the study period, with differences between different ages and risk groups. From 15/100,000 in children, aged 3–17 years to 180/100,000 live births at neonatal wards (children 0–2 months), but 40/100,000 for 0–2 month-old children warded outside neonatal wards. Over the study period different strategies to prevent BSI attributed to a decreased risk for BSI. Introduction of vaccine against Streptococcus pneumoniae declined the incidence of BSI with 30% in children aged between 3 months and 2 years. Implementation of a a risk-based intrapartal antibiotic prophylax program against early onset Streptococcus agalactiae BSI had most impact to reduce the incidende in new-borns. BSI in children without underlying co-morbidities has become rare and are caused by a limited numer of pathogens. In children with cancer, underlying co-morbidities and neonates warded at the neonatal wards the aetioloogy is much more diversed. S. aureus was the most prevalent pathogen. In paper III, we studied the antibiotic prescription, and concluded a changing pattern in the prescription of antimicrobial therapy, with a proportional decrease in the treatment of community-acquired infections and an increase in prophylactic therapy to specific risk groups of patients. In paper V, we found acquired antimicrobial resistance (AMR) in 9.2% of all invasive isolates. The trend for AMR increase for both Gram-positives and Gram-negative bacteria. The proportion of Enterobacterales producing extended-spectrum beta-lactamases (ESBL) increased from 1.6% to 14.1%. A high proportion (64.7%) of ESBL-producing strains was multidrug-resistant. During the last period, 6% of S. aureus were MRSA (methicillin-resistant Staphylococcus aureus). The oncology patient group had the highest proportion of ESBL-producing Enterobacterales. A history of travel in the past six months to a non-Nordic country by the child or a household member was identified as a risk factor.

In conclusion, the thesis adds knowledge about the aetiology and epidemiology of BSI in children from a Swedish perspective. The findings are highly important for designing empiric antibiotic therapy regimes and for planning targeted measurements to improve therapy and prevent BSI.