Distribution, spread and detection methods of antibiotic resistance genes in livestock manure and soil system

Abstract:

There are increasing concerns about antibiotic resistance genes (ARGs) as emerging environmental contaminants. Antibiotics have been routinely utilized in livestock farming as feed additives to promote animal growth, prevent and treat diseases caused by various bacteria pathogens. Most of them could not be totally absorbed by animals but induce the development of antibiotic resistance bacteria (ARB) and ARGs in animal intestinal tracts. The residual antibiotics, ARB or ARGs are discharged with fecal. Therefore, animal wastes are important reservoirs of antibiotics, ARB, and ARGs. Antibiotic resistance may be transferred to the soil environment through composting and manure fertilization process. Furthermore, ARGs can disseminate in the environment by horizontal gene transfer, and even spread along the food chain, which poses a huge threat to the environment and human health. In this paper, the profiles of the occurrence, distribution and spread of ARGs in animal manure-soil system are reviewed in detail. The main detection methods of antibiotic resistance are discussed. Composting is still an effective way to reduce the spread of antibiotic resistance genes in animal manure and therefore should be an important consideration in the future.