Agencies Working to Stop Spread of Colistin-Resistant Gene
CDC and HHS are involved. The Department of Defense notified stakeholders this week that its Multidrug-resistant Organism Repository and Surveillance Network 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 public health response is under way by units of the CDC and HHS after the Department of Defense notified stakeholders last week that its Multidrug-resistant Organism Repository and Surveillance Network at the Walter Reed Institute of Research had identified the first colistin-resistant mcr-1 E. coli in a person in the United States, according to a May 31 announcement by CDC and a May 26 blog post from HHS. They reported that E. coli bacteria carrying the MCR-1 gene was found in a urine sample from a Pennsylvania woman with no recent travel outside of the United States; the gene makes bacteria resistant to the antibiotic colistin, which is a last-resort drug to treat patients with multi-drug-resistant infections, including carbapenem-resistant Enterobacteriaceae (CRE), which exists on a small piece of DNA that can move from one bacterium to another, spreading antibiotic resistance among bacterial species. CDC and its federal partners have been hunting for the gene in the United States since it emerged in China last year.
The Pennsylvania State Health Department investigated and has determined the woman did not have CRE, and the bacteria identified is not resistant to all antibiotics, according to CDC, but it cautioned that the presence of the mcr-1 gene and its ability to share its colistin resistance with other bacteria such as CRE raise the risk that pan-resistant bacteria could develop.
"The investigation is currently focused on identifying 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," the agency reported.
Dr. David J. Smith, M.D., deputy assistant secretary of Defense for Health Readiness Policy and Oversight; Cathie Woteki, Ph.D., USDA under secretary for Research, Education & Economics; and Dr. Beth P. Bell, M.D., MPH, director of CDC's National Center for Emerging and Zoonotic Infectious Diseases, wrote in the blog post that, beginning in fall 2016, CDC's Antibiotic Resistance Lab Network will provide the infrastructure and lab capacity for seven to eight regional labs and labs in all states and seven major cities/territories to detect and respond to resistant organisms recovered from human samples . State labs will be able to detect new forms of antibiotic resistance, including mutations that allow bacteria to survive the effects of the last-resort drugs, and report those findings to CDC.
They explained that the National Antimicrobial Resistance Monitoring System, an HHS/USDA partnership known as NARMS, is continuing to search for evidence of colistin-resistant bacteria in the United States. After the 2015 detections in China, the NARMS teams began a two-pronged approach to search for evidence of colistin-resistant bacteria caused by mcr-1 in the United States; thus far, out of 949 animal samples screened, one strain of colistin-resistant E. coli was found in a pig intestinal sample. "The DNA sequence of this isolate revealed that the strain contained the mcr-1 gene on a plasmid. The scientists also determined that the mcr-1 carrying colistin-resistant E. coli is resistant to other antibiotics including ampicillin, streptomycin, sulfisoxazole, and tetracycline."
HHS, CDC, and the FDA also used whole genome sequencing technology to search for the gene in Salmonella, E. coli and Klebsiella taken from human and retail meat sources and, as of April 2016, more than 44,000 Salmonella and 9,000 E. coli/Shigella isolates from NARMS as well as the National Center for Biotechnology Information genomic database did not show the presence of the mcr-1 gene.
"The two detections of the mcr-1 gene in the U.S. provide a new clue into the antibiotic resistance landscape, and it also highlights how much we still do not understand," the trio wrote in their post. "Colistin is rarely used in human medicine compared to other antibiotics. It is often used to treat multi-drug resistant infections and its use is increasing. It is not used in animals in this country. As such, the new detection underscores the urgent need for more research in this area, and that's why the President's 2017 budget request also calls for Congress to fund the Agriculture and Food Research Initiative at its full level, allowing our nation's best and brightest scientists to help the NARMS partners get ahead of the fight to keep antibiotics effective and available. Earlier this month, USDA announced that it is seeking applications for $6 million in research funding to address antibiotic resistance through this program, but currently USDA must leave nine in ten applications for AFRI grants unfunded, keeping meaningful projects off the table."