Antibiotics and Antibiotics Resistance Genes Dissemination in Soils

This chapter describes the dissemination of antibiotics and antibiotic resistance genes in soil. It starts with an overview of the current knowledge about the natural resistome in soil—mainly bacteria-producing antibiotics—and also the contribution of agriculture, animal husbandry and natural fertilization, and the use of water from the effluent to irrigate crop fields in dissemination of antibiotics in soil. The aspects related to the degradation of antibiotics in the environment and their dependence on environmental conditions are also discussed. Attention has also been paid to the complexity of the soil microbes in the biofilms community and different answers to subinhibitory concentrations of various antibiotics like the SOS response, biofilm formation, or changes in primary metabolism. The next part of this chapter focuses on antibiotic-resistant bacteria in soil and their dissemination. There are numerous examples of intrinsically resistant bacteria and also mechanisms of the acquisition or development of resistance to various antibiotics. Also emphasized is the role of antibiotic pressure leading to higher levels of resistance and the acquisition and exchange of genetic material also that from pathogenic bacteria introduced into the environment from medical settings, municipal wastewater systems, and animal husbandry facilities. The last part is dedicated to antibiotic resistance genes and the mechanism of their transfer and dissemination. This phenomenon is related to horizontal (or lateral) gene transfer through mobile genetic elements. The issue of dissemination of anthropogenically associated antibiotic resistance genes to soil is also discussed. Finally, a holistic model for understanding antibiotic resistance gene dynamics in soil is proposed.