| Heavy metals and antibiotics are important typical environmental pollutants,while overuse of antibiotics and environmental emissions which stress the value of the resistant bacteria colonization,resulting in the spread and proliferation of resistance genes in the environment in recent years,as antibiotic resistance genes(ARGs)--an emerging contaminant caused widespread concern.Heavy metal pollution associated with industrialization and human development process and deteriorating,studies had found that arsenic,mercury heavy metal pollution was significantly associated with certain antibiotic resistance gene isoforms abundance of heavy metal pollution.In some areas of heavy metal pollution,bacteria not only had the resistance to heavy metals,and also resistant to many antibiotics.This study selected a typical heavy metal contaminated areas-Hunan section of the Xiangjiang River,field sampling and laboratory studies combined,which concerned the distribution of ?-lactam resistance genes in heavy metal contaminated areas,fate and the dissemination of proliferation,and study resistance gene fate under the influence of heavy metals,antibiotics and water quality and geochemical factor.In this study,13 representative sampling sites were selected in Xiangjiang River,and the surface water sample and sediment sample were collected in each site.In order to investigate the level of antibiotic and heavy metals in Xiangjiang River,the concentrations of 2 antibiotics and 6 heavy metals were detected by HPLC-MS/MS and ICP-MS,respectively.Furthermore,DNA extraction of every sample was performed to analysis the concentration of 16 Sr RNA and ?-lactam antibiotic resistance genes using qualitative PCR and real-time quantitative PCR.In addition,the ?-lactam antibiotic-resistant bacteria in sediment were isolated and identified by 16 Sr RNA sequencing and BLAST in Gen Bank database.The results revealed that the AMP concentration ranges from 80.1 ng/L to 1396.7 ng/L in water samples,and from 156.2 ng/g.to 2000.3 ng/g in sediment samples.The concentrations of heavy metals in Xiangjiang are higher than that in other rivers,and Pb,Cu and Zn are the most polluted metal ions in Xiangjiang River.The q PCR results showed that the absolute abundance levels of the ?-lactam resistance genes ranged from 0 copies/m L to 6.95 × 106 copies/m L in the water samples and from 1.01 × 101 to 2.25 × 108 copies/g in sediment samples.Moreover,there is a significant correlation(p <0.05)between the concentration of Hg and the absolute abundance of bla TEM-1 gene as well as bla CMY-2 gene.Meanwhile,the bla OXA-1 gene have a significant positive correlation(p <0.05)with Cu and Pb.This study analyzed heavy metal pollution in the area and lactam resistance gene in the region upstream of cleaner water and sediment samples.We also examined the influence of antibiotics,heavy metals and water quality on resistance gene amplification,dissemination and proliferation in the environment.This study revealed that heavy metals promote proliferation of certain resistance genes subtypes,and also discussed the impact of water quality and geochemical factor to the dissemination of proliferation factor antagonistic genes,as well as some heavy metals and antibiotics synergies to the trend of resistance genes,and explored the possible mechanisms on synergies promoting proliferation and spread of resistance genes. |
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