The fertilization of agricultural soil by organic amendment that may contain antibiotics, like manure, can transfer bacterial pathogens and antibiotic-resistant bacteria to soil communities. However, the invasion by manure-borne bacteria in amended soil remains poorly understood, being hardly observed. Here, we assessed the invasions of manure-borne bacteria during a coalescence event between manure and soil, in different soils and in the presence or absence of antibiotics. To this end,

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... ms of four different soils were amended or not with manure at an agronomical dose and/or exposed or not to the antibiotic sulfamethazine (SMZ). After one month of incubation, the diversity, structure and composition of bacterial communities of the soils were assessed by 16S rDNA sequencing. The invasion of manure-borne bacteria was still perceptible one month after the soil amendment. The results obtained with the soil already amended in situ with manure six months prior to the experiment suggest that some of the bacterial invaders were established in the community over the long term. Even if differences were observed between soils, the invasion was mainly attributable to some of the most abundant OTUs of manure (mainly Firmicutes). SMZ exposure had a limited influence on soil microorganisms. It was significant in only one soil, where it enhanced the invasion potential of some manure-borne invaders.