Spatiotemporal distribution and influencing factors of antibiotic resistance genes in Zhanjiang Bay
YE Yingyi，HOU Qinghua*，LAN Donghe，ZHANG Jibiao
1.Laboratory for Coastal Ocean Variation and Disaster Prediction，Guangdong Ocean University，Zhanjiang 524088，China；2.College of Chemistry and Environmental Science，Guangdong Ocean University，Zhanjiang 524088，China
Abstract: In order to explore the spatial and temporal distribution characteristics of antibiotic resistance genes (ARGs) and the potential influence of environmental factors on their distribution in Zhanjiang Bay (109°40′-110°58′E, 20°13′-21°57′N), the seasonal abundance changes in sulfonamides, tetracyclines and fluoroquinolones ARGs (sul1, tetQ and qnrS), class 1 integron (intI1) and 16S rRNA genes were seasonally surveyed in surface sediments of Zhanjiang Bay by real-time quantitative PCR. It was found that the maximal average absolute abundance of ARGs genes in surface sediments in Zhanjiang Bay was observed in winter and the minimal in summer, with the maximal average relative abundance in summer, indicating that the distribution of ARGs had obvious seasonal distribution characteristics. In terms of the station distribution, the descending order of average absolute abundance of the three types of ARGs was expressed as Z21>Z04>Z06, and the average relative abundance as Z06>Z21>Z04, indicating that there was obvious spatial distribution characteristics in the distribution of ARGs. The Spearman correlation analysis revealed that there was significantly positive correlation between the absolute abundance of the three ARGs, intI1 and 16S rRNA genes (P<0.05), and that the relative abundance of intI1 was also shown to be significantly positively correlated with the relative abundance of sul1 (P<0.05). The correlation analysis between genes and environmental factors showed that the absolute and relative abundances of ARGs were related to tetracyclines and fluoroquinolone antibiotics, as well as heavy metals such as Mn and Cu. The results of redundancy analysis (RDA) and variation portioning analysis (VPA) of genes and environmental factors showed that heavy metals played an important role in the spatiotemporal distribution of ARGs. The distribution of ARGs in surface sediments in Zhanjiang Bay was potentially affected by the total amount of bacteria, intI1, physicochemical factors, antibiotics and heavy metals, with the maximal potential impact of heavy metals in environmental factors. The surrounding urban and industrial wastewater discharges are potential sources of pollution affecting its seasonal and spatial distribution.
2023, Vol. 38 
