Ecological Kinetics and Evolutionary Dynamics of Antibiotic Resistance in Complex Environments

Fernando Baquero, Teresa M Coque, Jeronimo Rodríguez-Beltrán, Sonia Aracil-Gisbert, Ana Elena Pérez-Cobas

Antibiotic-resistant bacteria are common in the natural environment, including the microbiota of animal and human hosts. The local physical, chemical, and biological conditions of environmental patches and matrices vary in both qualitative and quantitative aspects. Often, these conditions diffuse in gradients, creating intersections that can either facilitate or inhibit the spread and evolution of antibiotic resistance (AbR). Ecological kinetics (EcoK) describes how these conditions and their combinations influence the abundance and transmission of antibiotic-resistant populations, as well as the mobile genetic elements that carry resistance genes. Evolutionary dynamics (EvoD) concern the effects of environmental conditions on genetic variation, the expression of resistance traits, and the evolvability of host bacteria, ultimately contributing to the emergence and selection of AbR. This study examines the influence of various environmental conditions, including temperature, oxygen availability, fluidity, humidity, osmolarity, acidity, particulate material, nutrients, organic matter, microbial density, and the presence of metals, pharmaceutical substances, biocides, pesticides, antibiotics, and antimicrobials produced by phytoplankton, plants, and animals, on EcoK and EvoD. This field remains scarcely understood, and further research is essential to identify high-risk areas where surveillance for the emergence and spread of AbR should be implemented.