大环内酯类抗生素的广泛应用,造成了抗生素耐药性污染,威胁河流生态健康。在这项研究中,五种大环内酯类抗生素(阿奇霉素,克拉霉素,罗红霉素,红霉素,和脱水红霉素A)在枣河的三个水文时期(4月,七月,和12月)。同时,抗生素抗性基因(ARGs)的变化,移动遗传元件(MGEs),使用宏基因组测序确定浮游细菌群落。观察到阿奇霉素和罗红霉素的明显污染梯度,旱季的浓度超过其他季节。阿奇霉素浓度最高(1.36μg/L)。MLS抗性基因的丰度在干旱季节沿枣河增加,而相反的趋势是在雨季。在旱季,MLS抗性基因与大环内酯类抗生素的水平之间存在显着相关性。值得注意的是,与参考站点相比,污水处理厂(WWTP)废水中转座酶的丰度在旱季和雨季均显着升高,而插入序列(IS)和质粒的丰度在旱季下降。暴露于含有大环内酯类抗生素的废水改变了浮游细菌群落的多样性。ARGs的细菌宿主似乎是假单胞菌,主要与多种药物亚型有关。此外,ARG亚型与MGEs(转座酶和istA)高度相关。偏最小二乘路径模型(PLS-PM)证明了MGE和ARGs丰度之间的正相关,表明水平基因转移(HGT)在枣河中ARGs传播中的重要性。环境变量,如TN和NO3--N,与MGE的丰度显着相关,ARGs,和细菌。总的来说,我们的发现可以提供有关河流中AZI和ROX污染梯度中微生物组和ARGs变化模式的见解。
The widespread application of macrolide antibiotics has caused antibiotic resistance pollution, threatening the river ecological health. In this study, five macrolide antibiotics (azithromycin, clarithromycin, roxithromycin, erythromycin, and anhydro erythromycin A) were monitored in the Zao River across three hydrological periods (April, July, and December). Simultaneously, the changes in antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and planktonic bacterial communities were determined using metagenomic sequencing. A clear pollution gradient was observed for azithromycin and roxithromycin, with the concentrations in the dry season surpassing those in other seasons. The highest concentration was observed for azithromycin (1.36 μg/L). The abundance of MLS resistance genes increased along the Zao River during the dry season, whereas the opposite trend was obtained during the wet season. A significant correlation between the levels of MLS resistance genes and macrolide antibiotics was identified during the dry season. Notably, compared with the reference site, the abundance of transposase in the effluent from wastewater treatment plants (WWTPs) was significantly elevated in both dry and wet seasons, whereas the abundance of insertion sequences (IS) and plasmids declined during the dry season. The exposure to wastewater containing macrolide antibiotics altered the diversity of planktonic bacterial communities. The bacterial host for ARGs appeared to be Pseudomonas, primarily associated with multidrug subtypes. Moreover, the ARG subtypes were highly correlated with MGEs (transposase and istA). The partial least-squares path model (PLS-PM) demonstrated a positive correlation between the abundance of MGEs and ARGs, indicating the significance of horizontal gene transfer (HGT) in the dissemination of ARGs within the Zao River. Environmental variables, such as TN and NO3--N, were significantly correlated with the abundance of MGEs, ARGs, and bacteria. Collectively, our findings could provide insights into the shift patterns of the microbiome and ARGs across the contamination gradient of AZI and ROX in the river.