New Mechanisms of Highly-Resistant Bacteria Discovered

Carbapenems resistant Enterobacteriaceae may be spreading drug-resistant genes between species.

Findings from a new study suggest that a family of drug-resistant and potentially lethal carbapenems resistant Enterobacteriaceae (CRE) bacteria may be spreading faster than previously thought.

In a study published by the Proceedings of the National Academy of the Sciences, these bacteria were found in 4 US hospitals, where the investigators found a number of different CRE species.

When taking a closer look at the bacteria, the authors discovered numerous genetic traits that allow the bacteria to resist antibiotics. Interestingly, these bacteria are able to transfer their antibiotic-resistant traits amongst each other, which increases the difficulty of treating an infection.

These findings suggest that CRE is more widespread than previously thought, and the bacteria may be spread asymptomatically, according to the study. Surveillance of this harmful bacteria should be increased due to the threat of continuous evolution of drug resistance.

“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 senior study author William Hanage, PhD. “We need to look harder for this unobserved transmission within our communities and healthcare facilities if we want to stamp it out.”

CRE are highly-resistant to multiple types of antibiotics, including the last-resort drugs (carbapenems), and tend to spread in hospitals and long-term care facilities, the study authors wrote. According to the CDC, CRE cause 9300 infections and 600 deaths in the United States each year.

In the study, the investigators examined 250 samples of CRE from patients admitted to hospitals in order to gain a better understanding of the genetics of the bacteria. By understanding CRE’s genetics, the authors hoped to be able to define the frequency and characteristics of outbreaks, how strains are transmitted, and how resistance is spread.

Previous studies have only examined 1 CRE outbreak at a time.

The investigators found that different CRE species had extremely different carbapenems resistance genes that were easily transferred from species to species, which increases the difficulty of developing an effective treatment, according to the study.

Additionally, the authors discovered mechanisms of resistance that had not previously been seen, and they expect that more are to be found in further studies.

These findings underscore the need for research dedicated to uncovering the mechanisms of new forms of resistance as they continue to evolve, according to the study.

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