Proactive Efforts by U.S. Federal Agencies Enable Early Detection of New Antibiotic Resistance

June 1, 2016 — 

Just over a year ago, President Obama released a National Action Plan for Combating Antibiotic Resistant Bacteria. As part of that plan, he also charged the Department of Defense (DoD), Department of Agriculture (USDA) and Department of Health and Human Services (HHS) with co-chairing a Presidential Advisory Council on Combating Antibiotic-Resistant Bacteria (Advisory Council). In the past year, our three agencies and the Council have held numerous stakeholder meetings, made new discoveries, and undertaken new research to preserve the effectiveness of antibiotics. [Source: USDA Blog, May 26, 2016]

In recent weeks, our three agencies have made some important discoveries regarding antibiotic resistance in the United States. Earlier this week, the Department of Defense notified stakeholders that its Multidrug-resistant Organism Repository and Surveillance Network (MRSN) at the Walter Reed Institute of Research had identified the first colistin-resistant mcr-1 E. coli in a person in the United States. A USDA and HHS search for colistin-resistant bacteria in food animals, retail meats and people also has found colistin-resistant E. coli in a single sample from a pig intestine.

These discoveries are of concern because colistin is used as a last-resort drug to treat patients with multi-drug resistant infections. Finding colistin-resistant bacteria in the United States is important, as it was only last November that scientists in China first reported that the mcr-1 gene in bacteria confers colistin resistance. Following the revelation in China, scientists across the globe began searching for other bacteria containing the mcr-1 gene, and the bacteria have since been discovered in Europe and Canada. The mcr-1 gene exists on a plasmid, a small piece of DNA that is not a part of a bacterium’s chromosome. Plasmids are capable of moving from one bacterium to another, spreading antibiotic resistance between bacterial species.

The patient with colistin-resistant E. coli was treated in an outpatient military treatment facility in Pennsylvania. Biologic samples were sent to the Walter Reed National Military Medical Center for initial testing and then to MRSN for genetic sequencing to identify the mcr-1 gene.

Our three departments take the emergence of this resistance gene very seriously. A coordinated public health response is underway to try to prevent its spread. For example, to respond to the DoD finding of mcr-1 in a human isolate, HHS’s Centers for Disease Control and Prevention is working with DoD, the Pennsylvania Department of Health, local health departments, and others to identify close contacts, including household and healthcare contacts, of the Pennsylvania patient to determine whether any of them may have been at risk for transmission of the bacteria containing the mcr-1 gene. Similarly, USDA is conducting traceback work to determine the sampled pig’s farm of origin

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