Research On Representative Antibiotic Resistance Enes In Livestock Lagoons And Manures

The emerging increasingly antibiotic resistance genes (ARGs) in the environments have been considered a major threat for human health, and livestock are well-known to serve as important reservoirs for various ARGs. However, Researches on the prevalence and dissemination of antibiotic resistance genes in livestock lagoons and manures, and the potential of livestock waste lagoons to reduce antibiotic resistance genes are limited. In the present study,12tetracycline resistance genes and2sulfonamide resistance genes were determined in lagoons and manures sampled from various scale and type livestock in Hangzhou. All these resistance genes were detected in lagoons and manures samples using the Polymerase-chain-reaction (PCR). Then quantitative real-time PCR was further used to quantify three resistance mechanisms tetracycline resistance genes(tetA、tetC、tetG、tetL、tetM、tetO、tetQ、tetW、tetB、 tetX) and sulfonamide resistance genes(sul1、sul2), the class Ⅰ integron gene (intI1) was also monitored as an indicator of horizontal gene transfer potential and multiple antibiotic resistance. The results demonstrated that there was no distinct difference between tetracycline resistance genes and sulfonamide resistance genes in the same type livestock, and the relative abundance of these two resistance genes in manures and influent were10-1～10-4and10-2～10-4. Sulfonamide resistance genes were observed to be generally more recalcitrant than tetracycline resistance genes in wastewater treament. The positive correlations of bulk water quality constituents were identified with tetracycline resistance genes. Linear regression methods show that sulfonamide resistance genes had a close relationship with the class Ⅰ integron gene.