Meds and you

06 October 2015

Antibiotic-resistant 'superbug' threatens US cities

Seven US metropolitan areas are experiencing higher-than-expected levels of CRE, an antibiotic-resistant bacterium.

0

A relatively new antibiotic-resistant bacterium called CRE is making inroads in some major American cities, U.S. health officials report.

Surveillance of seven U.S. metropolitan areas found higher-than-expected levels of CRE in Atlanta, Baltimore and New York City, according to the U.S. Centres for Disease Control and Prevention.

Time to intervene

Lower-than-expected levels were found in Albuquerque, Denver and Portland, Oregon, while the Minneapolis rate was what the agency anticipated.

Read: What is antibiotic?

But CDC researchers were dismayed that they found active cases of CRE infection in every city they examined, said senior author Dr Alexander Kallen, a CDC medical officer.

The results support the CDC's decision to promote coordinated regional efforts to prevent the spread of CRE and other antibiotic-resistant germs, Kallen said.

"Here we are with an opportunity to intervene on one of these multidrug-resistant organisms just as it's about to emerge and it's still relatively uncommon," he said. "That is the time you want to intervene. It's much easier to control things and prevent the organism from becoming more common when it's rare."

Read: New antibiotic may overcome superbugs

About 9 percent of people died due to their infection from CRE, the researchers found. But some estimates have held that as many as 50 percent of CRE infections contribute to death if they lead to a bloodstream infection, Kallen said.

CRE, or Carbapenem-resistant Enterobacteriaceae, are a class of common bacteria that have developed resistance to some of the most widely used antibiotics, Kallen said. CRE were first reported in 2001.

Older and more toxic antibiotics

The best-known enterobacteriaceae are E. coli, a common cause of food poisoning, and Klebsiella pneumoniae, which can cause pneumonia and potentially fatal bloodstream infections, Kallen said.

CRE bacteria are able to produce an enzyme that breaks down antibiotics, forcing doctors to resort to older and more toxic antibiotics to stave off infections, he said.

Most CRE infections occur at a hospital. In fact, hospitalisation was the most common potential exposure to CRE, the study found. Patients' median (midpoint) age was 66.

But public health experts are worried that since enterobacteriaceae are so common in daily life, havoc could ensue if CRE starts to become transmitted outside of healthcare settings.

"We're seeing more and more patients in the community with an E. coli kidney infection that we have no oral therapy to treat," said Dr Mary Hayden, an associate professor of pathology at Rush University Medical Centre in Chicago. "If CRE gets into the community and starts causing regular old urinary tract infections in otherwise healthy people, it will have a significant impact because we don't have agents to treat those things."

Read: Warning against overuse of antibiotics

In the study, published 5 October in the Journal of the American Medical Association, the CDC conducted active surveillance of CRE in 2012 and 2013 among people living in the seven cities listed above.

The overall rate of CRE in those cities was 2.93 infections per 100,000 people, researchers found.

That's low compared with the antibiotic-resistant bug MRSA, and the opportunistic C. difficile bacteria, which causes potentially deadly diarrhoea in people whose digestive systems have been subjected to heavy antibiotics.

'Really good initial step'

However, CRE has become more common in a short amount of time, said Hayden, who wrote an accompanying editorial in the journal.

Read: How does an antibiotic work?

"I think we learned from those situations that these problems can spread very rapidly," she said. "If we look at what has happened with other similar antibiotic-resistant organisms, we can see what will happen with this unless we do something now."

To stop the spread of antibiotic-resistant bacteria, the CDC is promoting regional efforts in which hospitals, long-term care facilities and other health care offices communicate regularly about infections, Kallen said.

Many antibiotic-resistant bacteria spread in a community because they are carried by patients from one facility to another. Better coordination can prevent this spread by identifying patients and isolating them with good infection control, he said.

Hayden praised this study as a "really good initial step", but said she hopes it will be expanded to include many other metropolitan areas.

"This provides a nice national picture, but we could do better," she said.

Read more: 

New antibiotic breakthrough

Prevent antibiotic resistance 

Drug-resistant superbugs already around in 1915

Copyright © 2016 HealthDay. All rights reserved.