Safety & quality
Healthcare-associated Staphylococcus aureus bloodstream infections
This page explains the Staphylococcus aureus (S. aureus) measure used on this website and describes how the measure is calculated.
S. aureus (‘Golden staph’) is a type of bacterium that can cause an infection of the bloodstream and can be acquired after a patient receives medical care or treatment in hospital. Contracting an S. aureus bloodstream infection while in hospital can be life threatening. Hospitals aim to have as few cases as possible.
For this measure, data for public hospitals are provided by state and territory health authorities. Data for private hospitals are provided by individual private hospitals and private sector hospital groups.
The nationally agreed benchmark set under the National Healthcare Agreement (NHA) is no more than 2.0 cases of healthcare-associated S. aureus bloodstream infection per 10,000 days of patient care for public hospitals in each state and territory.
Hospital peer groups
The hospital peer groups for this measure are based on the standard Australian hospital peer groups published by the Australian Institute of Health and Welfare (AIHW 2015), see 2015 Australian hospital peer groups (AIHW, 2015).
The following peer groups have been used:
||AIHW 2015 hospital peer groupings
||Public acute group A
||Public acute group B
||Public Children's hospitals and public Combined women's and children's hospitals
|Hospitals that are not included in the above categories are considered ‘Unpeered’ in MyHospitals reports. ‘Unpeered’ hospitals are a diverse group of specialised hospitals, sub and non-acute hospitals, small hospitals and clinics. Their results may not be comparable.
Rate of healthcare-associated S. aureus bloodstream infection
Cases of healthcare-associated S. aureus bloodstream infection per 10,000 bed days under surveillance.
National Staphylococcus aureus Bacteraemia Data Collection (NSABDC).
About the measure
This measure is the rate of S. aureus bloodstream infection associated with care provided at this hospital. Data are presented for total cases, and from 2016–17 cases are disaggregated by methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA).
A case of S. aureus bloodstream infection is defined as a positive blood culture for S. 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 case is recorded.
A case (patient episode) of S. aureus is considered to be healthcare-associated if the first positive blood culture is collected more than 48 hours after hospital admission or less than 48 hours after discharge, or if the first positive blood culture is collected 48 hours or less after admission and one or more of the following clinical criteria was met for the case of S. aureus:
- S. aureus is a complication of the presence of an indwelling medical device (for example, intravascular line, haemodialysis vascular access, cerebrospinal fluid shunt, urinary catheter)
- S. aureus occurs within 30 days of a surgical procedure where the S. aureus is related to the surgical site
- S. aureus was diagnosed within 48 hours of a related invasive instrumentation or incision
- S. aureus 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 three calendar days before and three calendar days after.
The definition of healthcare-associated S. aureus was developed by the Australian Commission on Safety and Quality in Health Care (the Commission). The Commission changed the definition in 2016, with clarification of the neutropenia criterion above. This definition of a healthcare-associated case of S.aureus was used by all states and territories for the 2015–16 and 2016–17 reporting years.
Data for 2010–11 to 2014–15 are provided according to the previous neutropenia criterion:
- S. aureus is associated with neutropenia (<1 x 109/L) contributed to by cytotoxic therapy.
The definition used for healthcare-associated S. aureus cases occurring prior to the 2015–16 reporting period is available at: http://meteor.aihw.gov.au/content/index.phtml/itemId/598734.
This change in definition does not impact the comparability of counts of S. aureus bloodstream infection from previous years.
- The bed days under surveillance is the total number of days of admitted patient care under surveillance by infection control surveillance systems within the hospital.
Calculating the measure
The rate is calculated as the number of healthcare-associated cases of S. aureus divided by the total number of bed days under surveillance (x 10,000).
Rates based on less than 5,000 bed days under surveillance are denoted as NP.
If the surveillance rate (bed days under surveillance/total number of bed days) is less than 95%, the rate is reported as interpret with caution (using the symbol *), as the sample under surveillance may not be representative of the hospital.
The Performance and Accountability Framework (PAF) indicator has the same definition as the NHA indicator, but the PAF indicator reports at establishment level. Further details of the data specification for this indicator are available on Australia's metadata online registry, METeOR.