(photo credit: Marc Israel Sellem)
University of Virginia Health System researchers are the first in the world to
develop a new and faster method to track major infection-causing “superbugs” – a
major key in preventing the spread of deadly infections.
published in the November/December 2011 issue of the online journal mBio, comes
at a critical time.
Several newly discovered genes such as KPC
(Klebsiella pneumoniae carbapenemase) and NDM (New Delhi metallo-betalactamase)
have experts on alert for several reasons: their ability to easily transform
bacteria into antibiotic-resistant superbugs, their unprecedented ability to
cross over into different strains and species of bacteria, the ease with which
they can transfer to highly infectious bacteria, such as Salmonella and cholera
and the potential for these genes to easily establish themselves undetected in
“When you’re in a race against time to halt the spread
of these life-threatening infections, the traditional methods of detection and
tracking are very difficult and frankly take too long,” says UVA Medical Center
Epidemiologist Costi Sifri, MD, study principal investigator.Decoding
deadly hospital-acquired infections
The focus of their study was KPC, a gene
Sifri calls “perhaps the most important new resistance gene of the millennium.”
KPC has the ability to easily hitch a ride on movable genetic elements called
plasmids that then spread between pathogens, making them highly infectious and
Through their new method, Sifri’s research team was able to
quickly track the movement of plasmids carrying KPC between bacteria and
understand the spread of KPC bacteria at the molecular level.
traditional methods take several weeks or months to do this analysis and can
only be performed in specialized research laboratories, the method developed by
the UVA team takes only one to two days and can be performed by most modern
“We developed and successfully used a novel
technique to rapidly track the gene’s movement between patients and bacteria,”
says lead author Dr. Amy Mathers, assistant professor in the UVA School of
Medicine’s Division of Infectious Diseases and International Health.
were able to show that all cases in a cluster of hospital infections could be
traced back to a single patient. Most cases were linked by movement of the KPC
gene between different bacteria.”
Armed with this information, the
research team hopes to develop new strategies and tools to prevent the spread of
these highly resistant bacteria to other patients.
associated with this new gene are called CRE, or Carbapenem- Resistant
Enterobacteriaceae, and include E. coli and Klebsiella, among others. Infections
caused by CRE are associated with very high mortality rates, Sifri
says.A global health threat
“These pathogens are widely considered a
major healthcare threat in the United States and worldwide,” says Sifri.
“Monitoring their origin and spread is critical to preventing serious outbreaks
in hospitals, other healthcare facilities, and potentially the general
In fact, another drug resistant gene called NDM emerged
last year as a cause of significant disease in India and may be acquired through
drinking water. The pathogen spread quickly and was carried to the U.S. and
“Carbapenems have become essential antibiotics for the
treatment of many infections in hospitals today, and their potential loss as a
reliably effective class of antibiotics is a serious public health threat,"
Sifri says. "The more rapidly we can detect CRE and understand movement of KPC
gene in hospitalized patients, the more quickly we can intervene to prevent CRE
spread to other patients and bacteria. This is fundamentally important for
maintaining the effectiveness of this important class of
The study “Molecular Dissection of an Outbreak of
Carbapenem-Resistant Enterobacteriaceae Reveals Intergenus KPC Carbapenemase
Transmission through a Promiscuous Plasmid,” can be found online in the mBio
November/December 2001 issue.
This article was first published at www.newswise.com