National rates of resistance for many priority organisms have not changed substantially from those reported in AURA 2019. However, several changes in resistance are important to consider in the context of infection prevention and control, and antimicrobial prescribing.

• In Escherichia coli, resistances to common agents used for treatment continue to increase. Resistance to ciprofloxacin and other fluoroquinolones has continued to rise in isolates from community-onset infections, despite restriction of access to these agents on the Pharmaceutical Benefits Scheme. These changes in resistance may mean increasing treatment failures and greater
reliance on last-line treatments such as carbapenems. Meropenem resistance has remained low.
• In Enterobacterales, rates of resistance were somewhat lower in the community than in hospitals for most agents with available data. There were no major differences between rates in public versus private hospitals. Rates in aged care homes were often as high as, or higher than, rates in hospitals.
• Carbapenem resistance in Enterobacterales remains uncommon, but is found more often in the
Enterobacter cloacae complex than in E. coli or Klebsiella pneumoniae.
• In Enterococcus faecium, the overall rates of vancomycin resistance are declining nationally, but are still above 40%.
• In Salmonella, ciprofloxacin resistance in typhoidal species (Salmonella Typhi and Salmonella Paratyphi) exceeded 78% in 2019, confirming that ciprofloxacin should no longer be relied on for
empirical treatment.
In Staphylococcus aureus, patterns of methicillin resistance continue to evolve. Clones that were previously dominant are being replaced by other clones, and community-associated methicillin-resistant S. aureus has become prominent everywhere, but especially in remote and very remote regions. This demonstrates a need for a renewed focus on infection prevention and control in both community and acute settings.