What is AMR?
People and animals diagnosed with bacterial infections will typically be treated with antibiotic, or antimicrobial, agents to eliminate disease causing organisms and restore health. Antimicrobials target bacteria-specific processes that are essential to their growth and survival. Unfortunately, bacteria can sometimes fight back by developing or acquiring mechanisms that prevent the antibiotic from reaching its target, or that actively destroy the antimicrobial agent. Such organisms can no longer be killed by the antibiotic, and are therefore termed antimicrobial resistant (AMR) bacteria.
Antibiotic resistant pathogenic bacteria can survive in the presence of clinical concentrations of medically important antibiotics. These resistant pathogens are thought to contribute to many thousands of deaths worldwide, and it is popular to claim that “excessive” or “miss-use” of antibiotics are the primary drivers for this problem. In fact, if resistant strains of bacteria are present when an antibiotic is used, the resistant strains will survive at the expense of the susceptible strains whether we consider this “prudent” or miss-use. It is fine to encourage “prudent use” a means to help reduce this selection pressure, but we can do more to address this problem.
If antibiotic use selects for resistant bacteria, this means that the number of these bacteria will increase, potentially many orders-of-magnitude; and with numbers this large, the chance of transmission to other people, animals, and locations will increase dramatically compared to an “unamplified” population. This observation highlights the under-appreciated fact that bacterial dispersal is a key variable of the antibiotic-resistance challenge. Preventing transmission of resistant strains means that when resistant strains “emerge” in a population, they will pose less risk to other people.
Transmission of enteric/gut bacteria inherently involves an environmental component such as the hands of a heathcare providers and other people, or through contact with surfaces, fecal waste, contaminated soil, food or water. The central focus of antibiotic resistance research at the School of Global Animal Health considers the environmental selection and transmission of antibiotic-resistant enteric bacteria. This encompasses the fate of bacteria in the environment, but also the activity of antibiotic residues and their impact on resistant bacteria in the environment. Ultimately, we test ideas about how to block these selection and transmission events everywhere from food animal environments, to homes and in hospitals. This takes our researchers from the lab, to the farm, to urban settlements as we identify pathways of transmission while developing and testing ideas to reduce both the abundance and transmission of antibiotic-resistant bacteria.