Australian Group on Antimicrobial Resistance (AGAR) Australian Gram-negative Sepsis Outcome Programme (GNSOP) Annual Report 2016

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 2016 survey was the fourth year to focus on blood stream infections, and included Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter species. Seven thousand five hundred and sixty-five species, comprising Enterobacteriaceae (6,750, 89.2%), P. aeruginosa (723, 9.6%) and Acinetobacter species (92, 1.2%), were tested using commercial automated methods (Vitek 2, BioMérieux; Phoenix, BD) and results were analysed using Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints (January 2017). Of the key resistances, non-susceptibility to the third-generation cephalosporin, ceftriaxone, was found in 11.8%/11.8% of Escherichia coli (CLSI/EUCAST criteria) and 7.7%/7.7% of Klebsiella pneumoniae, and 11.1%/11.1% K. oxytoca. Non-susceptibility rates to ciprofloxacin were 12.8%/16.3% for E.coli, 3.8%/10.0% for K. pneumoniae, 0.8%/2.1% for K. oxytoca, 1.8%/5.6% for Enterobacter cloacae complex, and 5.5%/9.4% for Pseudomonas aeruginosa. Resistance rates to piperacillin-tazobactam were 3.1%/6.5%, 3.6%/7.1%, 14.1%/14.9%, 19.9%/22.3%, and 5.2%/11.8% for the same 4 species respectively. Twenty-eight isolates were shown to harbour a carbapenemase gene, 14 blaIMP, five blaOXA-23, two blaOXA-48-like, two blaNDM, one blaKPC, one blaGES, three blaIMP+OXA-23.