Occurrence and distribution of antibiotics and resistance genes in greenhouse and open-field agricultural soils in China.

This study conducted a national scale survey to assess the levels and distributions of 13 commonly used antibiotics and nine antibiotic resistance genes (ARGs) in the greenhouse and open-field agricultural soils in China. The concentrations of antibiotics in the greenhouse and open-field soils were 428 ng/g (n = 51) and 193 ng/g (n = 51), respectively. The abundances of ARGs ranged from 1.15 × 10-7 to 9.78 × 10-2 copies/16S rRNA copies and from <LOD to 4.92 × 10-2 copies/16S rRNA copies in the greenhouse and open-field soils, respectively. The levels of antibiotics in the greenhouse were significantly higher than those in the open-field soils (p < 0.05). The concentrations of antibiotics in eastern and northern China were higher than those in the other regions of China. The abundances of ARGs were relatively higher in Guangdong, Shandong, Beijing, and Liaoning provinces. The sulII, tetA, tetG, tetO, and tetX in the greenhouse soils and sulII, tetG, and tetX in the open-field soils were significantly correlated with the levels of total antibiotics. The intI1 played a key role in the transfer of three classes of ARGs, especially in the greenhouse soils. These may indicate that the ARGs in the greenhouse could be easily affected by antibiotics and intI1 genes compared with those in the open-field soils. This study provides useful information to evaluate pollution of ARGs and contamination management in greenhouse agriculture in China.