[Distribution Characteristics of Antibiotic Resistance Genes in Vegetable Soils in Beijing]

In order to study the distribution characteristics and pollution status of antibiotic resistance genes (ARGs) in the vegetable soils, greenhouse and field soil samples in 11 organic vegetable bases with long-term manure amended in Beijing were collected. All samples were subjected to the determination of 13-type antibiotics and related ARGs. The experimental results showed that tetracycline residues were the highest among all antibiotics tested, followed by sulfanilamides. Antibiotic residues were higher in greenhouse soils than in field soils. For all soil samples, sulfanilamide resistance genes sul 1 and sul 2, as well as the tetracycline resistance gene tetL were observed with 100% detection frequencies. Detection frequency for class I integron (intI 1) in greenhouse soils was 1.5 times higher than that in field soils. The relative abundance for sul 2 and tetL in soil samples ranged 10^-4-10^-2 as found by quantitative PCR (qPCR) detection. The relative abundance of sul 2 was significantly positively correlated with the contents of sulfadimidine and doxycycline (P<0.05), and the relative abundance of tetL did not exhibit evident correlation with the contents of antibiotics tested. These results would contribute to understanding of the pollution status of ARGs in vegetable soils in Beijing, and to evaluation of currently agricultural practices based on ARGs.