Stimulating the non-ARG harbored microbes with a specific carbon source can suppress the rebound of soil ARB after calcium peroxide application

The spread of antibiotic resistance genes poses a significant global environmental risk. Soil antibiotic-resistant bacteria (ARB) are a critical reservoir for antibiotic resistance genes in the environment, making them a focal point of concern. Traditional abatement techniques are not suitable for field applications at present. In this study, we investigated the removal of soil ARB using a combination of calcium peroxide and D-mannitol. Treatment with 2% CaO 2 alone effectively reduced the populations of sulfonamide-resistant bacteria, beta-lactam-resistant bacteria, macrolide-resistant bacteria, and tetracycline-resistant bacteria by over 90% under a soil water holding capacity of 90%. However, this reduction decreased significantly after 40 days due to CaO 2 depletion. To sustain the removal effect, we screened carbon sources and found that adding 1 mM D-mannitol 10 days after applying CaO 2 could maintain removal rates of 78.41%, 91.44%, 86.81%, and 90.39% after 40 days. Sequencing results revealed that while CaO 2 alone initially reduced ARB, it led to a rebound in genera such as Ochrobactrum and Lysinibacillus . In contrast, D-mannitol addition prevented this rebound and enriched non-ARB genera like Nitrososphaera , enhancing the overall removal effect. This study demonstrates that combining CaO 2 with D-mannitol is a promising strategy for efficient and sustained removal of soil ARB.