Role and prevalence of antibiosis and the related resistance genes in the environment.

Abstract

It becomes increasingly clear that the basis of antibiotic resistance problemamongbacterialpathogensisnotconfinedtotheborders of clinical microbiology but has broader ecological and evolutionary associations. This Research Topic “Role and prevalence of antibiosis and the related resistance genes in the environment” in Frontiers in Microbiology: Antimicrobials, Resistance, and Chemotherapy presents the examples of occurrence and diversity of antibiotic resistance genes (ARGs) in the wide range of environments, from the grasslands of the Colombian Andes, to the dairy farms and small animal veterinary hospitals in the United Stated, and to the various environments of Continental Europe and Indochina. Besides, various genetic mechanisms and selection/co-selection factors contributing to the dissemination and maintenance of ARGs are presented. The topic is finalized by the mathematical modeling approach to access the probability of rare horizontal gene transfer (HGT) events in bacterial populations. The opinion article by Martinez (2012) summarizes our present understanding of the cycle of ARGs acquisition by bacterial pathogens. The environmental microbiota harbors a vast diversity of genes, which we usually classify as conferring resistance to antibiotics. In natural ecosystems, however, their role may be different and not necessarily associated with this function. Yet, if the certain metabolic genes are acquired by commensal/pathogenic microbiotaand appeared to be conferring selective advantage under the pressure of antibiotics, their primary functionunderthesenewecologicalcircumstances becomesresistance to antibiotics. Moreover, uponthe amplification under the antibiotic selective pressure, these ARGs are released into the environment thus contributing to the rise of antibiotic resistance in other ecological compartments.