Abstract:

To investigate the transmission and attenuation of antibiotic resistance factors carried by poultry manure in field application experiments, and to better control the spread of antibiotic resistance risks during the resource utilization of livestock manure, a greenhouse-based farmland simulation experiment was conducted. Soil samples with different fertilization rates were monitored over time for changes in antibiotic resistance genes (ARGs). A total of 90 samples were collected, including untreated soil, fresh chicken manure, organic fertilizer and soil amended with these two types of manure. PCR was used to detect 14 representative ARGs corresponding to common antimicrobial resistance traits in poultry-derived microorganisms. The results showed that genes such as blaNDM, tetM, sul1, sul2, sul3 and aadA were detected in all sample types. The fexA and cfr genes were not detected in untreated soil samples, but were detected in manure, which led to contamination of the fertilized soil. However, the positive detection rate of these genes in soil decreased over time. Additionally, genes including blaTEM, blaCTX-M, ermA, ermB and floR were detected in untreated soil, but subsequent studies found reduced detection rates in soil amended with manure, particularly organic fertilizer. In conclusion, the current field experiments revealed that farmland soil amended with poultry manure carries a high risk of ARGs. While poultry manure introduces short-term ARG contamination to the soil, the application of organic fertilizer helps mitigate ARG pollution in the soil over time.

Key words: poultry, manure application experiment, experimental soil, antibiotic resistance genes, attenuation dynamics