The potentially deadly, drug-resistant “superbug,” carbapenem-resistant Enterobacteriaceae (CRE), is more widespread in U.S. hospitals than previously thought, an earlier-released study has found. 
Researchers looked for cases of infections caused by CRE in a sample of 4 U.S. hospitals – 3 in the Boston area and 1 in California – and identified numerous varieties of the bacterium. 
Each year, CRE bacteria sicken about 9,300 people and claim the lives of 600 people in the United States, according to the CDC. Those numbers are climbing. CRE bacteria, in particular, have been called “nightmare bacteria” by CDC Director Tom Frieden because they often continue to thrive even in the face of “last-resort” antibiotics – drugs reserved for the toughest infections. 
In the study, the researchers also found that CRE has a plethora of genetic traits that make it resistant to antibiotics, and these traits can be easily transferred between the many CRE species.
The study documented the identical gene in different species. William Hanage, associate professor of epidemiology at Harvard Chan School and senior author of the study, says that “the extent to which this has happened is really quite surprising,” He added that the team “found 2 cases of high-level resistance we could not explain.”
He compared it to dark matter:
“We know it’s there because we can see its effects, but what’s actually making it happen at the moment is unknown. If I were to criticize my own work, I would say it is a shame that we weren’t able to get more hospitals and more samples from elsewhere within the health care systems.”
Based on the findings, the researchers believe that CRE is more common than previously thought, and that it may be transmitted from person to person without causing symptoms.
In fact, Dr. Alex Kallen, a medical officer in the CDC’s Division of Healthcare Quality Promotion, said “the most common source of transmission with CRE is asymptomatic.” For that reason, the team writes in Proceedings of the National Academy of Sciences, there needs to be increased surveillance of CRE. 
A healthy person might be able to carry CRE (it resides in the gastrointestinal tract) without developing an infection. However, if the bacterium is transferred to someone with a compromised immune system, it can be deadly.  
“We often talk about the rising tide of antibiotic resistance in apocalyptic terms. But we should always remember that the people who are most at risk of these things would be at risk for any infection, because they are often among the frailer people in the health care system. 
While the typical focus has been on treating sick patients with CRE-related infections, our new findings suggest that CRE is spreading beyond the obvious cases of disease. We need to look harder for this unobserved transmission within our communities and health care facilities if we want to stamp it out. 
The best way to stop CRE making people sick is to prevent transmission in the first place. If it is right that we are missing a lot of transmission, then only focusing on cases of disease is like playing whack-a-mole; we can be sure the bacteria will pop up again somewhere else.”
On a related front, it has come to light that a Nevada woman in her 70’s died months ago from a CRE infection that none of the 26 antibiotics available in the United States would touch. Dr. James Johnson, a professor of infectious diseases at the University of Minnesota, said of the case:
“I think this is the harbinger of future badness to come.” 
Johnson added that it’s hard to believe nobody else in the country is carrying the same strain. He said that when people ask him “How close are we to the edge of the cliff?,” he tells them: “We’re already falling off the cliff.”
Last fall, a Reuters investigation revealed that thousands of U.S. deaths due to superbugs go unreported each year, because in many cases it is not indicated on death certificates.
 USA Today