Sludge Water: The Potential Pathway of Antibiotic Resistance and Pathogenic Bacteria in Hospitals to the Environment

Bingxuan Zhao Rui Zhang ^* 宝林 金 Zuozhou Yu ^* Weicheng Wen ^* Tong Zhao Yue Quan ^* Jingya Zhou ^*

• Yanbian University, Yanji, China

Hospitals play a key role in the spread of antibiotic resistance genes (ARGs) and antimicrobial resistance (AMR). ARGs present in hospital wastewater tend to accumulate in activated sludge, with different ARGs exhibiting varying migration rates. As a result, sludge water produced during the activated sludge treatment process may serve as a significant source of ARGs in the environment. Despite this, research on the behavior of ARGs during sludge concentration and dewatering remains limited. This study hypothesized that ARGs might exhibit new behaviors in sludge water during sludge concentration. Using metagenomic analysis, we explored the distribution and migration risks of ARGs and human pathogenic bacteria (HPB) in sludge water, comparing them with those in hospital wastewater. The findings reveal a strong correlation between ARGs in sludge water and hospital wastewater, with subtypes like arlR, efpA, and tetR showing higher abundance in sludge water.Although the horizontal gene transfer potential of ARGs is greater in hospital wastewater, the resistance mechanisms and migration pathways are similar in both, though the HPB host associations differ. ARGs in both environments are primarily transmitted through coexisting mobile genetic elements (MGEs). This suggests that sludge water serves as a critical route for the release of hospitalderived ARGs into the environment, posing potential threats to public health and ecological safety.