A family of highly drug-resistant and potentially deadly bacteria called carbapenem resistant Enterobacteriaceae (CRE) may be spreading more widely and more stealthily than previously thought, a new study warned Monday.
The study, published in the U.S. journal Proceedings of the National Academy of Sciences, examined about 250 samples of CRE from hospitalized patients in four hospitals in Boston and California and found a "riot of diversity," both among CRE species and among genes enabling the superbugs to resist antibiotics.
More importantly, these genes are transferring easily among various CRE species. In addition, the superbugs may well be transmitting from person to person without apparent symptoms.
"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 healthcare facilities if we want to stamp it out."
CRE are a class of bacteria that are resistant to multiple antibiotics, including carbapenems, which are considered last-resort drugs when other antibiotics have failed.
CRE, which tend to spread in hospitals and long-term care facilities, cause an estimated 9,300 infections and 600 deaths in the U.S. each year, according to the U.S. Centers for Disease Control and Prevention (CDC).
Tom Frieden, director of the CDC, has called them "nightmare bacteria" because they are resistant to some of the last-ditch treatments available to doctors battling resistant infections.
The new findings highlighted the need for increased genomic surveillance of these dangerous bacteria.
"The best way to stop CRE making people sick is to prevent transmission in the first place," said Hanage. "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."
