Effect of Manure Application on Abundance of Antibiotic Resistance Genes and Their Attenuation Rates in Soil: Field-Scale Mass Balance Approach

Abstract

The development of models for understanding antibiotic resistance gene (ARG) persistence and transport is a critical next step toward informing mitigation strategies to prevent the spread of antibiotic resistance in the environment. A field study was performed that used a mass balance approach to gain insight into the transport and dissipation of ARGs following land application of manure. Soil from a small drainage plot including a manure application site, an unmanured control site, and an adjacent stream and buffer zone were sampled for ARGs and metals before and after application of dairy manure slurry and a dry stack mixture of equine, bovine, and ovine manure. Results of mass balance suggest growth of bacterial hosts containing ARGs and/or horizontal gene transfer immediately following slurry application with respect to ermF, sul1, and sul2 and following a lag (13 days) for dry-stack-amended soils. Generally no effects on tet(G), tet(O), or tet(W) soil concentrations were observed despite the presence of these genes in applied manure. Dissipation rates were fastest for ermF in slurry-treated soils (logarithmic decay coefficient of -3.5) and for sul1 and sul2 in dry-stack-amended soils (logarithmic decay coefficients of -0.54 and -0.48, respectively), and evidence for surface and subsurface transport was not observed. Results provide a mass balance approach for tracking ARG fate and insights to inform modeling and limiting the transport of manure-borne ARGs to neighboring surface water.

Fate and transport of tylosin-resistant bacteria and macrolide resistance genes in artificially drained agricultural fields receiving swine manure

“…The drought conditions in the summer of 2012 in Northeast Iowa may have caused additional stress to bacteria hosting the resistance genes and therefore hastened the return of overall concentrations to those found in no-manure control plot soils (Cools et al, 2001;Byappanahalli et al, 2012). The reduction in ermB and ermF genes in soil over winter are similar to those reported previously (Garder et al, 2014;Fahrenfeld et al, 2014). Enterococci concentrations in tile drainage were not significantly different (p N 0.10) across tillage or manure treatments.…”

Long-term field application of sewage sludge increases the abundance of antibiotic resistance genes in soil

“…Although chemical fertilizer had some effects on soil ARGs, these effects, not surprisingly, are weaker when compared with sewage sludge or chicken manure, considering that manure is rich in ARGs and ARBs , Jiang et al, 2002Ghosh and LaPara, 2007) and most ARGs are discharged from the municipal wastewater treatment process in the form of sewage sludge (Munir et al, 2011). However, land application of animal manure or sewage sludge does not universally increase ARGs in soils (Zhou et al, 2010) and this increase is not maintained long-term (Fahrenfeld et al, 2014). For instance, manure from three dairy farms did not increase cultivable chlortetracycline-resistant bacteria when land-applied to soil (Ghosh and LaPara, 2007).…”

Distribution of antibiotic resistance genes (ARGs) in anaerobic digestion and land application of swine wastewater

“…Marti et al (2014) indicated that genes of sul1, ermB, strB, intI1 and IncW repA increased significantly in the week following application and then declined, but the ermB could not decline to background level after 1 year period with application of swine manure. Fahrenfeld et al (2014) reported that ermF, sul1 and sul2 dissipated to background levels within 2 months following (2014) a Antibiotic resistance mechanism is categorized according to Blair et al (2014); ribosomal protection protein genes of tetracycline, modified dihydropteroate synthase enzyme genes, and 23S rRNA methyltransferase genes are classified into target site protection mechanism. b [ represents increased and Y represents decreased after anaerobic digestion.…”