RESUMO
The Australian Group on Antimicrobial Resistance (AGAR) performs regular period-prevalence studies to monitor changes in antimicrobial resistance in selected enteric gram-negative pathogens. The 2018 survey was the sixth year to focus on bloodstream infections, and included Enterobacterales, Pseudomonas aeruginosa and Acinetobacter species. Eight thousand eight hundred and fifty-seven isolates, comprising Enterobacterales (7,983; 90.1%), P. aeruginosa (764; 8.6%) and Acinetobacter species (110; 1.2%), were tested using commercial automated methods. The results were analysed using Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints (January 2020). Of the key resistances, resistance to the third-generation cephalosporin ceftriaxone was found in 13.3%/13.3% (CLSI/EUCAST criteria) of Escherichia coli and 8.4%/8.4% of Klebsiella pneumoniae. Resistance rates to ciprofloxacin were 16.0%/16.0% for E. coli, 10.2%/10.2% for K. pneumoniae complex, 5.9%/5.9% for Enterobacter cloacae complex, and 4.1%/9.3% for P. aeruginosa. Resistance rates to piperacillin-tazobactam were 3.2%/5.7%, 4.7%/8.5%, 14.8%/21.4%, and 6.9%/12.5% for the same four species/complex respectively. Twenty-nine isolates from 29 patients were shown to harbour a carbapenemase gene: 15 blaIMP-4, five blaOXA-181, four blaOXA-23 (one with blaOXA-58 also), three blaNDM-4/5, one blaGES-5, and one blaIMP-1.