A matter of time
Sykes thinks it's just a matter of time before CRE is recognized in animals. Because she and her colleagues are seeing more
multidrug-resistant gram-negative bacteria, they're starting to use carbapenems such as meropenem more in companion animal
medicine. "It's my concern that, as a result, we could select for CRE in veterinary patients as well," she says. "But there's
a possibility that the other pathway will occur, which is that they'll become so much more prevalent in humans that we'll
start seeing them colonizing pets too."
Papich says it's hard to predict how long it might take for CRE to affect veterinary patients. "Bacteria don't see any boundaries
between species," he says. "Eventually these highly resistant pathogens infecting humans get transferred to our animals, and
we end up with a similar problem."
J. Scott Weese, DVM, DVSc, DACVIM, of the University of Guelph's Ontario Veterinary College, says he has received anecdotal
reports of sporadic CRE infections in animals, mainly out of the southern United States. "The saving grace for us at the moment
is that CRE has not established much of a foothold yet in people in the community, but if or when it does, that means there
will be exposure of animals," he says. "And given the broad range of bugs that can acquire resistance genes and their potential
as enteric commensals, it certainly could spread in the animal population."
Papich says veterinarians who suspect CRE should use a laboratory that adheres to standards established by the Clinical Laboratory
Standards Institute (CLSI; see http://clsi.org/). "Although we do not have specific guidelines for testing animals at this time, laboratories should use the human testing
standards," Papich says. At a CLSI meeting this month, a special workshop will meet to develop guidelines for veterinary diagnostic
Whatever happens, the emergence of CRE has given the veterinary community an opportunity to discuss the importance of rational
antibiotic use and hospital infection control practices. "We have to remember that indiscriminate antibiotic use in an individual
patient, when it is done by thousands of other veterinarians and over the course of time in many animals, can actually be
to the detriment of all of our patients in the future," says Sykes.
Papich agrees. "It is an important concern because we have so few antibiotics left to treat these infections," he says. "We
do use the carbapenem antibiotics in companion animals. They have such a good spectrum of activity that veterinarians rely
on them when there are few other antibiotics that are effective."
1. CDC warns of 'nightmare' bacteria killing hospital patients. Available at:
2. Weese JS, Blondeau JM, Boothe D, et al. Antimicrobial use guidelines for treatment of urinary tract disease in dogs and cats:
Antimicrobial Guidelines Working Group of the International Society for Companion Animal Infectious Diseases. Vet Med Intl 2011.
CDC. Guidance for control of Carbapenem-resistant Enterobacteriaceae (CRE). 2012 CRE Toolkit. Available at: