Last-Resort Drugs Can’t Stop ‘Nightmare Bacteria’

(CN) – The threats posed by “nightmare bacteria” may be more severe and immediate than previously realized, as an increasing number are developing antibiotic-resistance genes while spreading asymptomatically in health care facilities.

New research published in the Proceedings of the National Academy of Sciences highlights a “riot of diversity” among these drug-resistant bacteria species and genes resistant to carbapenems, a class of last-resort antibiotics.

To determine the emerging public health issue, the team examined carbapenem resistant enterobacteriaceae-related infections in four U.S. hospitals. CRE species tend to spread in long-term care facilities and hospitals, leading to an estimated 9,300 infections and 600 deaths in the United States each year.

CRE bacteria are resistant to multiple antibiotics, including carbapenems, which are generally only used as a last-resort treatment when other antibiotics have failed.

These “nightmare bacteria” require enhanced surveillance partly due to their ability to spread without producing symptoms in patients, the researchers say.

“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,” said William Hanage, associate professor of epidemiology at Harvard University and senior author of the study. “We need to look harder for this unobserved transmission within our communities and health care facilities if we want to stamp it out.”

The researchers examined about 250 samples of CRE from hospitalized patients in order to form a snapshot of the genetic diversity of the species, find evidence of strains being transmitted within and between health care facilities, and define the frequency and characteristics of outbreaks.

Their findings show resistance genes are being transmitted between species of bacteria, with significant diversity found among CRE strains and carbapenem resistance genes.

The team also discovered resistance mechanisms that hadn’t been identified before – suggesting there are more to be discovered.

“The best way to stop CRE making people sick is to prevent transmission in the first place,” Hanage said. “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.”

A superbug resistant to all FDA-approved antibiotics recently caused the death of a Nevada woman in September, after she was infected with the bacterium Klebsiella pneumonaiae, the Centers for Disease Control and Prevention reported Friday.

The woman was likely infected following treatment for a broken leg and bone infection in India several years earlier, according to the CDC.

 

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