Ecology

Antibiotic resistance, driven by the overuse of antibiotics, is a huge threat to public health in Canada. At the same time, infections are a major cause of death and increase health care costs. Critically ill patients are particularly susceptible to infections caused by antibiotic-resistant organisms and have an even higher rate of death.

Significant tension exists between avoiding inappropriate antibiotic use and preventing life-threatening infections. One intervention used to prevent infections and reduce deaths is selective decontamination of the digestive tract (SDD), a preventive antibiotic regimen. Health care professionals have refrained from using SDD owing to fears that increased use of antibiotics will drive antibiotic resistance. Whether these fears are justified is unknown. Currently, we deny patients a potentially lifesaving preventive therapy out of concern for the risk of antibiotic resistance. Therefore, further study is imperative to determine the balance of benefit and harm of this regimen.

We are funded by the Canadian Institutes of Health Research’s Strategy for Patient-Oriented Research (SPOR) to study whether SDD saves the lives of patients to whom it is delivered. Yet, this question is only one of the two key questions we need to answer before this treatment is implemented. We also need to know whether this regimen drives antibiotic resistance, thus potentially putting other patients’ lives at risk due to difficult-to-treat infections caused by antibiotic-resistant organisms. The microbiome is the key to understanding how and why antibiotics could drive antibiotic resistance.

We are commencing the SPOR-funded randomized controlled trial. Alongside this trial, we propose to perform a study of the impact of antibiotic usage on antibiotic resistance patterns in ICUs by studying the microbiome. If this treatment can save lives without causing antibiotic resistance, then this study could have global impact through lives saved and infections prevented, and by reducing health care costs.