Positive antibiotic and resistance genes in source water of three regions and correlation analysis
Intl1）、16S rRNA及6种ARGs进行了检测。ARGs包括1种大环内酯类（ ermB）、1种β内酰胺类（ bla TEM）、2种四环素类（ tetC、 tetQ）和2种磺胺类（ sul1、sul2）。 结果
P<0.05）。5大类抗生素中，A地的检出浓度范围为0.11~418.80 ng·L−1，B地为0.12~23.23 ng·L−1，C地为4.69~285.75 ng·L−1。三地水源水中6种ARGs的检出率均达到了100%。A地ARGs的绝对丰度范围为22.56~94355.91（每毫升拷贝数，后同），B地绝对丰度的范围为27.99~80584.32，C地绝对丰度的范围为41.99~111068.19。在三地水源水不同ARGs中， bla TEM的绝对丰度较高，次之是 sul1与 sul2。此外，三地水源水中 Intl1的绝对丰度也处于较高水平。相关性分析显示，三地水源水中各ARGs绝对丰度之间基本呈正相关；各类抗生素与其对应ARGs之间对应关系不明显；整合子 Intl1与 sul1、 sul2（ P< 0.05）之间均呈正相关关系。 结论
China is a big country in the production and use of antibiotics. The abuse of antibiotics enables bacteria in water environment to acquire resistance, and promotes the generation and spread of antibiotics resistance genes (ARGs). The problem of antibiotic-resistant bacteria is increasingly serious and has become a public security issue of global concern. Water environment is a huge reservoir of antibiotics and ARGs. It is of great significance to study the pollution of antibiotics and ARGs in water to protect water sources and optimize the biosecurity of drinking water.
To evaluate the detection of antibiotics and ARGs in typical water sources, and to explore the relationship between antibiotics and ARGs.
Water samples were collected in Heilongjiang, Liaoning, and Hubei provinces during the wet season (from August to October) in 2020. Ten water samples were collected from each of the three places, and a total of 30 water samples were collected in this study. Five kinds of antibiotics, including macrolides, quinolones, sulfonamides, tetracycline, and β-lactam, were detected by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The integron (
Intl1), 16S rRNA, and 6 kinds of ARGs were detected by quantitative real-time PCR (qPCR). The ARGs include one macrolide ARGs ( ermB), one β-lactam ARGs ( bla TEM), two tetracycline ARGs ( tetC, tetQ), and two sulfonamide ARGs ( sul1, sul2). Results
The types of detected antibiotics varied by the three regions, and the concentration ranges of the same antibiotics varied by the three regions (
P<0.05). The concentration ranges of selected five kinds of antibiotics were 0.11-418.80 ng·L−1 in region A, 0.12-23.23 ng·L−1 in region B, and 4.69-285.75 ng·L−1 in region C, respectively. The detection rates of all six ARGs were 100%. The absolute abundance of ARGs in region A ranged from 22.56 to 94355.91 copies·mL−1, that in region B ranged from 27.99 to 80584.32 copies·mL−1, and that in region C ranged from 41.99 to 111068.19 copies·mL−1. The absolute abundance of bla TEMwas higher among the ARGs, followed by sul1and sul2.In addition, the absolute abundance of Intl1was also at a high level. The results of correlation analysis showed that the abundance of ARGs was positively correlated with each other. There was no correlation between specific antibiotics and corresponding ARGs. There was a positive correlation between Intl1and sul1or sul2( P<0.05). Conclusion
The types and concentrations of antibiotics and the abundance of ARGs in source water vary greatly in the study areas. The association between antibiotics and ARGs is uncertain.
Intl1may play an important role in the horizontal transfer of sulfonamide resistance genes.