Australian Group on Antimicrobial Resistance (AGAR) Australian Gram-negative Surveillance Outcome Program (GnSOP) Bloodstream Infection Annual Report 2023

The Australian Group on Antimicrobial Resistance (AGAR) performs regular period-prevalence studies to monitor changes in antimicrobial resistance in selected enteric gram-negative pathogens. From 1 January 2023 to 31 December 2023, a total of 57 hospitals across Australia participated in the Australian Gram-negative Surveillance Outcome Program (GnSOP). The 2023 survey tested 10,453 isolates, comprising (9,503; 90.9%), (806; 7.7%) and species (144; 1.4%), using commercial automated methods. The results were analysed using European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints (January 2024). Key resistances reported are to the third-generation cephalosporin ceftriaxone in 12.9% of and in 6.9% of complex isolates. Resistance rates to ciprofloxacin were 14.5% for ; 7.8% for the complex; 3.2% for the complex; and 7.6% for . Resistance rates to piperacillin-tazobactam were 6.0%; 9.4%; 23.3%; and 13.7% for the same four species/complexes, respectively. Thirty isolates from 30 patients were shown to harbour a carbapenemase gene: ten with a gene ( [4], [4], [2]); nine with a -like gene ( [4], [2], [1], [1], [1]); eight with ; two with + a -like gene; and one with + + . Transmissible carbapenemase genes were also detected in two complex isolates (; + + ) and one ().