Ecological Kinetics and Evolutionary Dynamics of Antibiotic Resistance in Complex Environments

Antibiotic-resistant bacteria are common in natural environments, including the microbiota of animal and human hosts. The local physical, chemical, and biological conditions of environmental patches and matrices vary both qualitatively and quantitatively. Often, these conditions are found as gradients, creating intersections that can either facilitate or inhibit the spread and evolution of antibiotic resistance (AbR). Ecological kinetics (EcoK) describes how combinations of these conditions influence the abundance and transmission of antibiotic-resistant populations, as well as the mobile genetic elements that carry resistance genes. Evolutionary dynamics (EvoD) concerns 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 review examines the influence of numerous environmental conditions on EcoK and EvoD. This field remains poorly understood, and further research is essential to identify high-risk areas where surveillance for the emergence and spread of AbR should be implemented.