An expert on antibiotic resistance at the Centers for Disease Control and Prevention (CDC) has told reporters that it’s likely more people will be found carrying a newly discovered “superbug,” according to an article in the Washington Post. The bacterium, found in the urine of a Pennsylvania woman, is resistant to antibiotics of last resort.
The CDC expert, Dr. Beth Bell, also said that officials investigating the Pennsylvania superbug case don’t know how the resistant strain of Escherichia coli wound up in the woman’s body, and they may never find out. The E. coli bacteria contained a gene––mcr-1––that makes it resistant to the antibiotic colistin, which is used as a last resort against superbugs that can already withstand other antibiotics.
The discovery alarmed public health officials because it’s the first time that the colistin-resistant mcr-1 gene has been found in an individual in the United States. Experts are worried that colistin resistance will spread to other bacteria through the mcr-1 gene, leading to superbugs that can cause untreatable infections.
“We don't know a lot about this particular gene,” Bell admitted during a telephone briefing.
U.S. officials have been hunting for the mcr-1 gene since November 2015, she said, after Chinese and British researchers found the resistant strain in pigs and raw pork and in a small number of people in China. The strain was later discovered in Europe.
In the U.S., “it’s likely that more of these [cases] will be found,” Bell said. “We are a globally interconnected world, and people and bacteria travel around the globe.”
“The risk to the public at this point is pretty much minimal,” she added.
According to researchers at the U.S. Department of Agriculture (USDA) and at the Department of Health and Human Services, testing of hundreds of livestock and retail meats turned up the same colistin-resistant bacteria in a sample from a pig intestine in the U.S. The USDA said it is working to identify the farm from which the pig came.
The Pennsylvania woman was treated on April 26 at an outpatient military facility, according to Defense Department officials. Samples were sent to the Walter Reed National Military Medical Center for initial testing. The tests confirming the presence of the mcr-1 gene were performed at the Walter Reed Army Institute of Research in Silver Spring, Maryland.
Source: Washington Post; May 31, 2016.