A patient episode of Staphylococcus aureus bacteraemia (SAB) is a positive blood culture for Staphylococcus aureus.

For surveillance purposes, only the first isolate per patient is counted, unless at least 14 days has passed without a positive blood culture, after which an additional episode is recorded.

A SAB will be considered to be a healthcare-associated event if either:

CRITERION A: The patient’s first positive Staphylococcus aureus blood culture is collected more than 48 hours after hospital admission or less than 48 hours after discharge.

OR

CRITERION B: The patient’s first Staphylococcus aureus positive blood culture is collected less than or equal to 48 hours after admission to hospital and the patient-episode of SAB meets at least one of the following criteria:

1. SAB is a complication of the presence of an indwelling medical device (e.g. intravascular line, haemodialysis vascular access, cerebrospinal fluid (CSF) shunt, urinary catheter)
2. SAB occurs within 30 days of a surgical procedure where the SAB is related to the surgical site
3. SAB was diagnosed within 48 hours of a related invasive instrumentation or incision
4. SAB is associated with neutropenia contributed to by cytotoxic therapy. Neutropenia is defined as at least two separate calendar days with values of absolute neutrophil count (ANC) or total white blood cell count (WBC) <500 cells/mm³ (0.5 × 10⁹ / L) on or within a seven-day time period which includes the date the positive blood specimen was collected (Day 1), the 3 calendar days before and the 3 calendar days after.

If none of these criteria are met, then the episode of SAB is considered to be community-acquired for the purposes of surveillance.