Human CRE infections are 'untreatable,' experts say

How will this latest superbug impact veterinary patients?
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Jun 01, 2013

This spring, the director of the U.S. Centers for Disease Control and Prevention (CDC) called carbapenem-resistant Enterobacteriaceae (CRE) a "nightmare bacteria." "Our strongest antibiotics don't work, and patients are left with potentially untreatable infections," said Tom Frieden, MD, MPH, in a press release.

In the first half of 2012, nearly 200 U.S. healthcare facilities treated at least one patient infected with this new super breed.1 In a National Public Radio interview, the CDC's Michael Bell, MD, said, "This particular type of resistance has seemed to spread from one type of bacteria to another. It's able to hand off its blueprint for resistance to other types of bacteria, which raises the possibility that this kind of untreatable infection could become much more commonplace."

These types of bacteria don't get into human patients simply because of compromised immune systems, said Brad Spelberg, MD, of Harbor-UCLA Medical Center, in the same broadcast. "It's because we're providing very intensive care: putting plastic catheters into their bloodsteams so we can give life-saving medicines, inserting tubes into their lungs so we can have mechanical ventilators breathe for them or placing tubes in their bladders," he said. "When you break those types of anatomical barriers, it allows bacteria that normally don't get into those parts of your body to get in there."

Veterinary concerns

Fortunately, CRE have not been reported in dogs and cats to a great extent, if at all, says Jane E. Sykes, BVSc (Hons), PhD, DACVIM, of the University of California Davis School of Veterinary Medicine. Sykes is a member of the Antimicrobial Guidelines Working Group of the International Society for Companion Animal Infectious Diseases (ISCAID). "To our knowledge, we have never detected them here in our companion animal patient population at UC Davis."

However, the rate of resistance in other bacteria that infect dogs and cats has increased to scary proportions. In particular, Sykes has seen a dramatic rise in multidrug-resistant Staphylococcus pseudintermedius infections and infections by Enterobacteriaceae (Escherichia coli, Klebsiella) and Pseudomonas aeruginosa. "Methicillin-resistant Staphylococcus pseudintermedius infections can be resistant to almost every orally administered drug available, and these can be particularly serious when they cause orthopedic infections, such as tibial plateau leveling osteotomy infections," she says.

Some of these resistant bacteria, especially the gram-negative organisms, may also have the potential to colonize humans that are in contact with these pets, Sykes continues. "More than ever before, veterinarians need to be prudent in regard to antibiotic use and hospital infection-control protocols," she says.