摘要

  抗生素的广泛和不当过度使用导致抗生素抗性基因 (ARG) 的流行。作为典型的半封闭大陆架海，渤海被认为是中国污染最严重的海域之一。然而，关于渤海沉积物中ARGs空间分布的综合研究尚未见报道。在渤海海域进行了大规模采样。评估了 ARG（6 类，29 个 ARG 亚型）、1 类整合子整合酶基因（intI1）、hmt-DNA 和 16S rRNA 基因的丰度。在沿海地区检测到 IntI1 的丰度较高，范围从 2.8 × 105 到 2.5 × 108 拷贝/克。不同采样点的总 ARGs 丰度变化超过 3 个数量级，最大值为 4.9 × 108 拷贝/克。磺胺类耐药基因普遍存在且丰富，丰度为5.7×104～1.8×107拷贝/g，喹诺酮类耐药基因在不同样品中差异较大。等高线图显示，在莱州湾、渤海湾以南和中部海盆以东，ARGs 更为丰富。大多数目标 ARG 亚型以 100% 的检测频率被检测到。 sul1、sul2和tetX基因的绝对丰度和相对丰度均较高，而β-内酰胺类ARG亚型的丰度较低。主成分分析（PCA）和冗余分析（RDA）表明，不同样品中ARGs丰度不存在显着差异，沉积物质量在ARGs分布中起重要作用。对细菌群落进行了调查，并确定了 ARG 与细菌之间的 768 个强大而重要的联系。通过网络分析揭示了 ARGs 的可能宿主，沿海地区的相对丰度高于海洋。

  Extensive and improper overuse of antibiotics resulted in the prevalence of antibiotic resistance genes (ARGs). As the typical semi-enclosed continental shelf sea, the Bohai Sea has been considered as one of the most polluted marine areas in China. However, no comprehensive investigation on the spatial distribution of ARGs in sediments from the Bohai Sea has been reported. A large-scale sampling was performed in the Bohai Sea areas. The abundances of ARGs (6 classes, 29 ARG subtypes), class 1 integron-integrase gene (intI1), hmt-DNA and 16S rRNA gene were evaluated. IntI1 was detected with higher abundances in coastal areas ranging from 2.8 × 105 to 2.5 × 108 copies/g. The total ARGs abundances varied over 3 orders of magnitude in different sampling sites with the maximum at 4.9 × 108 copies/g. Sulfonamides resistance genes were ubiquitous and abundant with the abundances ranging from 5.7 × 104 to 1.8 × 107 copies/g, and quinolones resistance genes varied greatly in different samples. The contour map demonstrated that ARGs were more abundant in the Laizhou Bay, the south of Bohai Bay and the eastern of central sea basin. Most of the target ARG subtypes were detected with 100% detection frequencies. The genes of sul1, sul2 and tetX were detected with both higher absolute and relative abundance, while the abundance of β-lactams ARG subtypes was lower. Principal component analysis (PCA) and redundancy analysis (RDA) indicated that no significant differences in the ARGs abundance existed in different samples, and the sediment qualities played important roles in the distribution of ARGs. Bacterial communities were investigated and 768 strong and significant connections between ARGs and bacteria were identified. The possible hosts of ARGs were revealed by network analysis with higher relative abundance in coastal areas than the sea.

  https://www.sciencedirect.com/science/article/abs/pii/S0048969720312237