| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1468-1 | ||||
Resumo:Sewage sludge (SS) is a byproduct of wastewater treatment with potential agricultural use, but it is also known as an important reservoir of antibiotic resistance genes (ARGs) that poses risks for the human health and environmental safety. ARGs transfer among soil’s bacterial communities is mostly carried out by its mobile genetic elements (MGEs) through horizontal gene transfer (HGT). Thermophilic composting is a valuable approach for diminishing the presence of ARGs in SS and although performing it on industrial scale is essential for effectively managing the substantial quantities produced, the impact of industrial composting on the potential dissemination of ARGs through mobile genetic elements (MGEs) is still relatively scarce. Therefore, the objective of this study was to evaluate the relative abundance of MGEs genes on soils amended with fresh and industrially composted SS. For this, composted and fresh SS were placed in a clay soil alongside a control group with no soil amendments. MGEs genes were identified using high-throughput quantitative PCR (HT-qPCR), and their relative abundances were assessed in relation to bacterial 16S rRNA genes, revealing the presence of 8 genes from three distinct types. Soil amendment with either fresh or composted SS did not show significant effects on insertional sequence of MGE genes. However, composted SS decreased the relative abundance of transposon and integron genes, with an average reduction of approximately 58% and 86%, respectively. Compared to the control, MGE genes enhanced from 3.5 to 8.5-fold when fresh-SS and from -1.4 to 1.3-fold when composted-SS were amended to the soil. Therefore, fresh SS amendments can lead to a notable increase in MGE genes within the soil, potentially facilitating HGT of antimicrobial resistance genes and posing a threat to the natural resistome balance in soils. In contrast, composted SS amendments did not significantly affect MGE genes, seeming not enhancing the potential spread of antimicrobial resistance genes in soil, thus suggesting that industrial thermophilic composting holds promise as an alternative for SS management. Palavras-chave: antibiotic resistance genes, mobile genetic elements, horizontal gene transfer, composting, soils Agência de fomento:Cnpq; FAPESP | |||||