Enterobacteriaceae Sepsis Outcome Programme annual report, 2013.

Area of Science:

• Medical Microbiology
• Infectious Diseases
• Antimicrobial Resistance Surveillance

Background:

• The Australian Group on Antimicrobial Resistance (AGAR) conducts periodic prevalence studies to track antimicrobial resistance in Gram-negative pathogens.
• The 2013 survey specifically focused on bloodstream infections, a critical area for monitoring treatment efficacy.

Purpose of the Study:

• To assess the prevalence of antimicrobial resistance in key Enterobacteriaceae species causing bloodstream infections in Australia.
• To analyze resistance patterns using both Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria.

Main Methods:

• A total of 4,958 Enterobacteriaceae isolates from bloodstream infections were tested.
• Commercial automated methods (Vitek® 2, BioMérieux; Phoenix™, BD) were employed for susceptibility testing.
• Results were interpreted using CLSI and EUCAST breakpoints (January 2014).

Main Results:

• Non-susceptibility to ceftriaxone was observed in 7.5% of Escherichia coli and 6.3% of Klebsiella pneumoniae.
• Ciprofloxacin non-susceptibility rates varied, with 10.3% of E. coli and 4.6% of K. pneumoniae affected.
• Piperacillin-tazobactam resistance ranged from 3.1% in E. coli to 17.3% in Enterobacter cloacae.
• Fourteen isolates harbored carbapenemase genes, including blaIMP, blaKPC, and blaNDM.

Conclusions:

• The 2013 survey highlights significant antimicrobial resistance in Enterobacteriaceae causing bloodstream infections in Australia.
• Emergence of carbapenemase genes (blaIMP, blaKPC, blaNDM) is a serious concern requiring ongoing surveillance.
• These findings underscore the need for continued monitoring and antimicrobial stewardship efforts.