What is the "superbug" that has now killed three people, and how did it become a threat?
This week, North Carolina officials reported a person there died after being infected by the same nightmare bacteria that killed two in Los Angeles, Calif. A spokesperson for the Carolinas HealthCare System said 18 people there have been infected, and 15 of those were admitted with the superbug, while three acquired it at the hospital, according to CNN.
It is not clear how patients are contracting the suberbug.
In L.A., a hospitalized 18-year-old man and the family of a deceased 48-year-old woman came forward with lawsuits this week after they were infected with the superbug at UCLA Hospital in Los Angeles.
At that hospital, a total of 179 patients were exposed to the bug, called Carbapenem Resistant Enterobacteriaceae.
CRE is an umbrella term for bacteria that produce a powerful cocktail of antibiotic-chewing enzymes. In this case, those enzymes act as a countermeasure, destroying the antibiotic the antibiotic weapons relied on by doctors as a last resort.
“Right now we really don't have good effective antibiotics to treat them. If it becomes more widespread then it’s going to become a huge problem,” said Lee Riley, professor of infectious diseases at University of California, Berkeley.
The most common type of CRE-carrying bacteria is Klebsiella, an otherwise common bug that tends to live in the nose, mouth and gut. In hospitals, Klebsiella spreads through feces. It lingers on surfaces like doorknobs and equipment when people don’t sanitize properly.
Hospital infections are already responsible for 100,000 patient deaths each year in the United States, according to the CDC. Infections by CRE are still rare, but the chances of dying from once infected are as high as 50-50.
Infection is most common in a hospital, where a patient has an invasive medical device like a catheter or an endoscope.
While the manufacturer of the LA endoscopes is under investigation, contaminated equipment may not be the cause of all the infections, Riley said.
“My feeling is it’s the other way around, that the instrument is getting contaminated from the patients,” Riley said.
A patient can carry the CRE bacteria in his or her nose, mouth or intestines. It’s not likely to become an infection, though, unless the bacteria enters the bloodstream. An endoscope can put those bacteria where they don’t belong.
“People are talking about introducing disposable instruments, but I don't think that’s going to help.” Riley said.
CRE was first discovered in 2001. Since then, it’s spread to almost every state. About 4 percent of hospitals and 18 percent of long term care facilities in the U.S. experienced a CRE case in the first half of 2012, according to the Centers for Disease Control and Prevention.
CRE first became national news in 2011, following an outbreak at the National Institutes of Health Clinical Center in Bethesda, Maryland where 19 ICU patients were infected. The director of the CDC dubbed it “nightmare bacteria” in 2013.
Carbapenem antibiotics received FDA approval in 1985. They were designed to fight off bugs that were becoming resistant to penicillin-based antibiotics.
“The bacteria didn’t suddenly come up with these enzymes. This has been evolving over millions of years,” Riley said.
There are now more than 1,000 enzymes that chew up penicillin-based antibiotics, Riley said. But new developments in antibiotics haven’t been forthcoming.
“Drug companies have been somewhat reluctant to develop a new drug because it costs millions of dollars. These antibiotics become quickly useless, so what’s the incentive?” Riley said.
One challenge of CRE is that the bacteria don’t demonstrate their antibiotic-chewing enzymes right away. An initial test might show that the infection can be treated with normal antibiotics.
It’s only when the bacteria come into contact with the antibiotic that they start producing the enzymes, Riley said.
One way around that is to genetically test the bacteria, but many hospitals aren’t equipped to do that.
“Maybe this is not the right approach anymore, to keep making new antibiotics. Maybe we need to think of some other ways to combat these microbes,” Riley said. “The science needs to come up with a more out of the box approach.”
Gavin Stern is a national digital producer for the Scripps National Desk.
