Enhanced surveillance of Staphylococcus aureus bacteraemia to identify targets for infection prevention

Surveillance of Staphylococcus aureus bacteraemia (SAB) in Scotland is limited to the number of infections per 100,000 acute occupied bed-days and susceptibility to meticillin.

To demonstrate the value of enhanced SAB surveillance to identify targets for infection prevention.

Prospective cohort study of all patients identified with SAB over a five-year period in a single health board in Scotland. All patients were reviewed at the bedside by a clinical microbiologist.

In all, 556 SAB episodes were identified: 261 (46.6%) were hospital-acquired; 209 (37.9%) were healthcare-associated; 80 (14.4%) were community-acquired; and in six (1.1%) the origin of infection was not hospital-acquired, but could not be separated into healthcare-associated or community-acquired. These were classified as non-hospital-acquired. Meticillin-resistant S. aureus (MRSA) bacteraemia was associated with hospital-acquired and healthcare-associated infections. In addition, there was a significantly higher 30-day mortality associated with hospital-acquired (31.4%) and healthcare-associated (16.3%) infections compared to community-acquired SAB (8.7%). Vascular access devices were associated with hospital-acquired SAB and peripheral venous cannulas were the source for most of these (43.9%). Community-acquired infections were associated with intravenous drug misuse, respiratory tract infections and skeletal and joint infections. Skin and soft tissue infections were more widely seen in healthcare-associated infections.

The data indicate that enhanced surveillance of SAB by origin of infection and source of bacteraemia has implications for infection prevention, empirical antibiotic therapy, and health improvement interventions.