The Environmental Contribution to Emerging Antibiotic Resistance

Antibiotic resistance in the modern era has reached near-epidemic levels, resulting in much more difficult treatment of previously well-managed pathogens. Previous understandings of how antibiotic resistance emerges failed to account for the function of the environment. Over the past 15 years, new research has provided a link between the environmental and clinical spheres of antibiotic use. This data suggests that environmental bacteria, particularly those found in livestock farming ecosystems, may significantly contribute to the overall flow of antibiotic resistance genes into human populations. The main force behind this is the utilization of antibiotics as growth promoters in animal feed supplements, seeding individual animals and their surroundings with low doses of antibiotics. Notable increases in resistance have been observed within areas that utilize these supplements, as well as in connected but unrelated systems. Waste management strategies are poorly implemented, leading to the dispersal of contaminated runoff into groundwater and riverine environments. Furthermore, existing waste processing is limited in efficacy, often releasing large amounts of unprocessed antibiotics as well as a concentrated population of resistant bacteria. Within these resistant populations, horizontal gene transfer has emerged as a vehicle for the distribution of resistance genes into other populations of bacteria. Due to the prevalence of these transfer events, a new role for the environment as a reservoir and incubator of resistance genes is proposed. Current strategies for managing the spread of antibiotic resistance are woefully inadequate, and the continued emergence of new resistance mechanisms due to negligence highlights the need for global, multidisciplinary solutions. To corral the spread of antibiotic resistance, a system is proposed that utilizes metagenomic monitoring and the enforcement of core global policies to slow the advance of resistance while waiting for novel treatment strategies to bear fruit.