Critically important antimicrobial resistant E. coli in Australian pigs

Surveillance for antimicrobial resistance (AMR) plays a critical role in defining the presence, geographic and temporal distribution of AMR, which then informs control strategies. The quality of surveillance outputs affects the ability to make informed decisions about antimicrobial stewardship and other control measures that prevent further emergence and spread of resistant bacteria. Resistance to critically important antimicrobials (CIAs) is of the greatest concerns.

CIA-resistant bacteria can be introduced into a food-animal system either from humans, water, soil, pest animals, wild animals etc and is expected to result in passive carriage of low numbers of organisms. This is in contrast to emergence and amplification within the production system as a result of the selective pressure of antimicrobial use. Antimicrobial resistance surveillance that is performed for AMR in food animals usually does not have the ability to discern these pathways.

This research conducted a proof-of-concept study of AMR surveillance in regard to the detection and quantification of CIA-resistant E. coli within pigs using the novel Robotic Antimicrobial Susceptibility Platform Quantification protocol in combination with traditional antimicrobial susceptibility testing and genomic sequencing involving 10 pig farms.

Value for producers:

• Producers are generally good stewards in antimicrobial resistance

Recommendations: 

• Critically important antimicrobial resistant bacteria in the absence of direct antimicrobial use can still be introduced into farms through farm workers returning from overseas or incursions of wild birds.
   
• An introduction of antimicrobial resistant bacteria through livestock is unlikely given the strict national biosecurity regulations surrounding the importation of livestock and unprocessed animal products into Australia
   
•  It is important for on-going monitoring of antimicrobial resistant bacteria in livestock.