Abstract

Purpose: To examine whether the epidemiology of bacteraemia caused by MSSA and MRSA differed in children aged <1 year and in comparison to older age groups. Methodology: English mandatory MRSA and MSSA surveillance data from 2006 and 2011, respectively, were collected. Epidemiological information was descriptively analysed in relation to methicillin susceptibility and patient age. Ninety-five percent confidence intervals (CIs) are reported. Results/key findings: The average incidence rate of MSSA and MRSA bacteraemia in <1 year olds was 60.2 and 4.8 episodes per 100,000 population per year, respectively. Of the cases of MSSA bacteraemia in children aged <1 year, 47.5% (95% CI: 45.1-50.0; n=760/1,599) were in neonates. With increasing age up to one year, more MSSA bacteraemias were detected ≥ seven days after admission, ranging from 0% (95% CI: 0-2.5%) in 0-2 day olds to 68.4% (95% CI: 64.0-72.5%; 333/487) in 8-28 day olds and 50.5% (95% CI: 47.1-54.0%; 423/837) in 29 day-1 year olds, a higher proportion than in older children but similar to MRSA bacteraemia. Amongst <1 year olds with MSSA bacteraemia, the underlying source was most commonly recorded as intravascular devices (34.4% [95% CI: 30.5-38.6%]; n=190/552) whilst in older age groups this declined. A similar trend was observed for MRSA bacteraemia. Conclusions: Our analysis indicates that S. aureus bacteraemia in <1 year olds is primarily healthcare-associated, unlike MSSA bacteraemia in older age groups. Paediatric-specific interventions targeted at the healthcare setting, such as neonatal unit-specific care bundles and paediatric device-specific strategies, are required.