Australian Group on Antimicrobial Resistance (AGAR) Australian Gram-negative Sepsis Outcome Programme (GNSOP) Annual Report 2017

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 2017 survey was the fifth year to focus on blood stream infections, and included Enterobacterales, Pseudomonas aeruginosa and Acinetobacter species. Seven thousand nine hundred and ten isolates, comprising Enterobacterales (7,100, 89.8%), P. aeruginosa (697, 8.8%) and Acinetobacter species (113, 1.4%), 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 2018). Of the key resistances, non-susceptibility to the third-generation cephalosporin, ceftriaxone, was found in 11.3%/11.3% of Escherichia coli (CLSI/EUCAST criteria), 8.8%/8.8% of Klebsiella pneumoniae, and 5.7%/5.7% of K. oxytoca. Non-susceptibility rates to ciprofloxacin were 12.1%/18.0% for E. coli, 4.4%/11.2% for K. pneumoniae, 1.3%/3.5% for K. oxytoca, 3.0%/8.5% for Enterobacter cloacae complex, and 5.1%/9.8% for P. aeruginosa. Resistance rates to piperacillin-tazobactam were 2.8%/5.9%, 3.7%/7.3%, 9.6%/11.0%, 22.5%/27.6%, and 6.4%/13.2% for the same five species respectively. Twenty-seven isolates from 25 patients were shown to harbour a carbapenemase gene: 12 bla_IMP (11 patients), five bla_OXA-181 (four patients), three bla_OXA-23, two bla_NDM, two bla_KPC, two bla_VIM, and one bla_GES.

Keywords: Australian Group on Antimicrobial Resistance; Enterobacter; Escherichia coli; Klebsiella; antibiotic resistance; bacteraemia; gram-negative.