Impact of hand washing: COVID-19 and SABSI
In the absence of focused clinical studies, the relationship between Staphylococcus aureus bloodstream infections and COVID-19 is unclear. However, the impact of hand washing as means of combatting rates of infection transmission is significant. Between 2009 and 2017, among Australia's 132 major public hospitals, improved hand hygiene compliance was associated with declines in the incidence of healthcare-associated SABSI (incidence rate ratio 0.85; 95% CI 0.79–0.93; p≤0.0001) (Grayson et al., 2018). For every 10% increase in hand hygiene compliance, the incidence of healthcare-associated SABSI decreased by 15%.
NSABDC Data Quality Statement
National Healthcare Agreement: PI 22-Healthcare associated infections: Staphylococcus aureus bacteraemia
Appendixes and caveat information is available on the About the data page.
Definitions of the terms used in this section are available in the Glossary.
Data for public hospitals are provided by state and territory health authorities. Data for private hospitals are voluntarily 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 SABSI per 10,000 days of patient care for public hospitals in each state and territory.
Rate calculation
The SABSI rate is calculated as the number of healthcare-associated cases of S. aureus divided by the total number of patient days under surveillance (x 10,000).
Rates based on less than 5,000 patient days under surveillance are denoted as NP.
If the surveillance rate (patient days under surveillance/total number of patient 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.
Case (patient-episode) of SABSI
A case (patient-episode) of SABSI 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 episode is recorded.
Healthcare-associated SABSI
A case of SABSI 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, 2016–17, 2017–18, 2018–19 and 2019–20 reporting years.
Patient days under surveillance
Patient days under surveillance is the total number of days of admitted patient care under surveillance by infection control surveillance systems within the hospital.
Staphylococcus aureus resistance to antimicrobials
Antimicrobial resistance occurs when some of the bacteria that cause infections resist the effects of the medicines used to treat them. This may lead to ‘treatment failure’, or the inability to treat the cause of the infection (Department of Health, 2020). Methicillin is an antimicrobial used to treat SABSI.
A case of SABSI that is identified by a laboratory as being caused by a methicillin-resistant strain of S. aureus is referred to as MRSA. A SABSI case that is identified by a laboratory as being caused by a S. aureus strain that is sensitive to commonly used antimicrobials (methicillin-sensitive) is referred to as MSSA.
SABSI caused by MRSA may cause more harm to patients and is associated with poorer patient outcomes as there are fewer antimicrobials available to treat the infection.
More information on antimicrobial resistance is available from the Department of Health website.
References
Grayson ML, Stewardson AJ, Russo PL, Ryan KE, Olsen KL, Havers SM et al. 2018. Effects of the Australian National Hand Hygiene Initiative after 8 years on infection control practices, health-care worker education, and clinical outcomes. The Lancet. 18 (11), 1269-1277.