Antibiotic-Resistant Bacteria Found in 37 U.S. States

Half a world away, doctors in India are fighting outbreaks of bacterial infections that are resistant to more than 15 types of antibiotics. But closer to home, a similarly scary bug is making the rounds in intensive care and other long-term units of American hospitals.

In at least 37 states, Washington, D.C., and Puerto Rico, doctors have identified bacteria, including E. coli, that produce Klebsiella pneumoniae carbapenemase, or KPC—an enzyme that makes bacteria resistant to most known treatments. It's much more prevalent in America than bacteria that produce NDM-1, the enzyme that has Indian doctors "hell scared," and, according to Alexander Kallen, a medical officer at the Centers for Disease Control in Atlanta, the final outcome isn't much different: superbacteria that are hard to kill.

"It's got a slightly different structure than [NDM-1]," he says of KPC. "But the bottom line is they're two different ways to produce bacteria that are resistant to a wide range of antibiotics."

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That's bad news for infected patients—the mortality rate for patients infected with KPC-producing bacteria has been estimated to be as high as 50 percent. Doctors are advised to do their best to keep the bacteria from spreading, which explains why the problem is most prevalent in hospitals and other close-quarter medical units. Infected patients are often isolated.

KPC has been seen in a wide range of bacteria, including E. coli, Salmonella, and K. pneumonia, which often affects hospitalized patients.

These superbugs are resistant to nearly every weapon doctors can throw at them, including carbapenems, a class of antibiotic that the CDC calls the "last line of defense" against infections that are resistant to other types of antibiotics. There are a couple antibiotics that have been shown to kill these superbugs, but often at great risk to patients. In fact, the FDA has associated the use of these effective antibiotics with an "increased risk of death" in patients with pneumonia.

That leaves many doctors scratching their heads. KPC-bacteria often grow on medical equipment such as catheters and ventilators, so doctors can sometimes remove that equipment or perform surgery to try to eliminate the infection from a patient's body.

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CDC researchers, including Kallen, say that hospitals who haven't been vigilant about isolating patients with KPC-producing bacteria may have missed their chance. According to a paper co-authored by Kallen released last year, "failure to recognize CRE infections when they first occur in a facility has resulted in a missed opportunity to intervene before these organisms are transmitted more widely."

The good news is that, at least for now, KPC-producing bacteria generally only infects people who already have compromised immune systems. "It can move into the wider community," says Kallen, "but we haven't seen much of that yet."

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jkoebler@usnews.com

Twitter: @jason_koebler