Australian Group on Antimicrobial Resistance (AGAR) Australian Gram-negative Sepsis Outcome Programme (GNSOP) Annual Report 2018

Abstract

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 three hundred and fifty isolates, comprising Enterobacterales (7,512, 90.0%), P. aeruginosa (743, 8.9%) and Acinetobacter species (95, 1.1%), 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 2019). Of the key resistances, resistance to the third-generation cephalosporin, ceftriaxone, was found in 13.4%/13.4% of Escherichia coli (CLSI/EUCAST criteria), and 9.4%/9.4% of Klebsiella pneumoniae. Resistance rates to ciprofloxacin were 15.2%/15.2% for E. coli, 11.3%/11.3% for K. pneumoniae, 7.4%/7.4% for Enterobacter cloacae complex, and 3.6%/7.7% for P. aeruginosa. Resistance rates to piperacillin-tazobactam were 3.0%/6.0%, 4.3%/7.9%, 18.2%/22.0%, and 5.1%/11.1% for the same four species respectively. Thirty-one isolates from 27 patients were shown to harbour a carbapenemase gene: 14 blaIMP-4 (11 patients), including one with blaIMP-4+blaOXA-23, four blaKPC (three patients), three blaOXA-48, three blaNDM, three blaGES, two blaOXA-181, and two blaOXA-23.