P Taylor^1,2, R Pratama¹, R Stevens^1,2,, D Rafferty¹.

¹NSW Health Pathology, Microbiology at St George Hospital; 2School of Biomedical Sciences, UNSW

We report 25 years of AST data for Staphylococcus aureus non-duplicate² isolates extracted from >1,000,000 episodes with reported AST. 

 

Prevalence of staphylococcal bacteraemia and focal infections were calculated from laboratory data, excluding duplicates. Filters were applied for antibiotic resistance and location of collection.  

 

Between 2000 and 2024, 1.39 million  blood culture episodes were received from 820,000 patients  and 4.2 million swabs, fluids and soft tissue samples (non-bacteraemic) from 2.98 million patients, categorised by location of collection as ED or non-ED. Blood culture workload increased by 120% and non-bacteraemia samples by 40% over 25 years.

 

Staphylococcal bacteraemia became less prevalent over the period, however as MRSa infection decreased, MSSa increased. Prevalence of MRSa as a cause of nosocomial bacteraemia has fallen 8-fold and non-bacteraemic infection 2-fold. MRSa is now more commonly isolated from blood cultures collected in ED than other locations. Prevalence of nosocomial MSSa bacteraemia has fallen 3-fold. Prevalence of staphylococcal infection presenting at ED has increased due to both MRSa and MSSa. Multidrug-resistant  MRSa has become less prevalent, however macrolide and quinolone resistance has increased among  MSSa isolates from all locations.

 

Antimicrobial Stewardship, Infection Control and hand hygiene became more prominent influences on these improved nosocomial outcomes.

 

References

1.        Bell SM, Pham JN, Rafferty DL, Allerton JK, James PM. Antibiotic Susceptibility Testing by the CDS Method. A Manual for Medical and Veterinary Laboratories 2018. Ninth edition (Available from: http://cdstest.net/manual/)

2.        Australian Commission on Safety and Quality in Health Care. ACSQHC Data Governance Framework 2023. Sydney:ACSQHC, 2023.

All authors have contributed to data collection. Abstract was prepared by  P Taylor, R Pratama and R Stevens.