Investigating interspecies transfer of antimicrobial resistance from compost and soil amendments to fresh produce in organic and conventional agricultural systems

Specifically, we propose to investigate the following interrelated farming operations: 1- the application of raw manure as fertilizer to produce ensiled forage for livestock and 2- the use of composted manure for the production of leafy greens. These practices are interrelated since the potential source of AR and pathogen contamination is the use of manure from animals that received multiple antibiotic doses. The overall objectives of the project will be:1) To determine the degree of interspecies transfer of AMR (manure →forage → compost →leafy greens →Ready to Eat Salads) focusing on on Shigatoxin Producing E. coli (STEC), Listeria monocytogenes (Lm) and fecal indicators);2) To establish the prevalence and persistence of AMR bacteria within manure-compost and compost-leafy green production systems, and3) To determine whether composting processes can reduce the transfer of AMR within resident microorganisms and those originating from manure applications.