ABSTRACT
AIM: Staphylococcus aureus (SA) causes serious invasive disease in children. Large studies have measured the incidence of SA bacteraemia, but there is less information on the total burden of community-acquired invasive SA (iSA) in children. METHODS: A retrospective, cross-sectional analysis of Auckland resident children aged 0-14 years who were hospitalised with iSA between 2011 and 2015 was performed. Laboratory databases and SA-related international classification of diseases 10 discharge codes were searched to identify community-onset cases with SA isolated from a normally sterile site. Clinical records and coroner's reports were reviewed to determine clinical syndromes and exclude nosocomial infections. RESULTS: A total of 295 children with iSA were identified. The average annual incidence of iSA was 18.6 per 100 000 - for Pacific populations 44.3 per 100 000, Maori 24.3 per 100 000 and New Zealand European and other 8.8 per 100 000; 68% had bacteraemia. The incidence of iSA for Pacific infants was 10 times greater than non-Maori/non-Pacific (113.4/100 000 population vs. 11.8/100 000). Multivariate analysis found a higher risk of admission in Pacific children, males and those living in areas of high deprivation. Thirty-two patients (10.8%) were admitted to the intensive care unit; risk was higher in infants, Pacific children and those with respiratory infection (Relative Risk (RR) 12.2, 95% confidence interval (CI) 5.7-26.4) and multifocal (RR 6.9, 95% CI 3.4-13.8) and endovascular disease (RR 8.9, 95% CI 3.9-20.6). All deaths (n = 7) had respiratory infections, and four were patients <1 year of age. CONCLUSIONS: Studies investigating SA bacteraemia alone significantly underestimate the total burden of iSA disease. There are marked ethnic and socio-economic disparities in iSA disease among Auckland children. Pacific infants are at the highest risk.
