The Changing Burden of Pediatric Bloodstream Infections in Calgary, Canada, 2000-2006

Background: The epidemiology of pediatric bloodstream infection has not been well defined in general populations. The primary objective of this study was to describe the burden of illness of pediatric bloodstream infections in a large Canadian region and secondarily to assess the effect of implementation of universal infant immunization with 7-valent pneumococcal conjugate vaccine (PCV7) in 2002. Methods: Surveillance for all bloodstream infections was conducted among pediatric (< 18 years) residents of the Calgary Health Region during 2000-2006. Results: Nine hundred ninety-five episodes of bloodstream infection occurred for an overall annual incidence of 53.7 per 100,000. Forty-eight percent were community-acquired, 27% were nosocomial-acquired, and 26% were healthcare-associated community onset. The risk for bloodstream infection was highest in neonates. The annual incidence of bloodstream infection changed significantly (P < 0.001) and was attributed to a decreasing incidence of community (P = 0.001) acquired disease. The most common species isolated were Streptococcus pneumoniae, Staphylococcus aureus, and Escherichia coli. Overall rates of pneumococcal infection decreased significantly in the post-PCV7 era (2004-2006) as compared with pre-PCV7 era (2000-2001) (4.6 vs. 13.6 per 100,000; P < 0.0001). This was even more pronounced in the subset with community-acquired disease (3.0 vs. 11.3 per 100,000; P < 0.0001) especially in the age group between 1 and 23 months of age (7.3 vs. 58.9 per 100,000; P < 0.0001). The overall mortality rate was 2 per 100,000/yr. Conclusions: Bloodstream infections are an important cause of disease in children. Implementation of PCV7 has been associated with a significant reduction in the overall burden of disease.