Association of antimicrobial biodegradation with the evolution of antimicrobial resistance in ecosystems

The exacerbated antimicrobial contamination and the development of antimicrobial resistance have emerged as a significant environmental concern with global implications. The vigorous and diverse metabolic potential of microorganisms makes antimicrobial biodegradation a common occurrence in the environment. Biodegradation serves as a normal response of natural microbial communities to antimicrobials, offering flexibility for microbial growth diversity. The genes encoding antimicrobial degradation have two sides: inactivating antimicrobials and conferring bacteria resistance. Thus we come to the fork in the road pointing at one side to the genes as antimicrobial resistance genes worsening environmental resistance, and at the other end that antimicrobial biodegradation decelerates the evolution of environmental resistance by curtailing antimicrobial selection. This chapter discusses and elucidates the dual role of antimicrobial-degrading resistance genes in the antimicrobial-contaminated environment that has significant implications for the development of antimicrobial risk assessment strategies bridged by molecular biomarkers. In addition, the solution to this ecological paradox is an important foundation for developing theories and methods of endogenous and exogenous control of antimicrobials in water environments.