July 27, 2016

Multidrug-resistant Infections in Veterinary Clinics

Multidrug-resistant infections associated with veterinary facilities pose a risk to both animal patients and humans.
By Laurie Anne Walden, DVM, ELS
Multidrug-resistant infections associated with veterinary facilities pose a risk to both animal patients and humans, according to a review recently published in Veterinary Microbiology. More than 80% of US veterinary teaching hospitals have reported outbreaks of nosocomial infection.
“In modern veterinary medicine [healthcare-associated infections] represent an urgent but largely unresolved issue, and infection control remains in its infancy,” write the authors. “Multidrug-resistant pathogens…pose a significant challenge due to the apparent spread of these pathogens within veterinary environments.” Because infections acquired in the hospital may be drug resistant and are often transmissible between humans and nonhuman animals, they represent a risk for patients, owners, and hospital staff.
The most common veterinary healthcare-associated infections are surgical site infections, wound infections, central line–associated blood infections, and catheter-associated urinary tract infections. Companion species most often affected are dogs, cats, and horses. Pathogens of special concern are methicillin-resistant staphylococci (Staphylococcus aureus [MRSA] and S pseudintermedius [MRSP]), extended-spectrum beta-lactamase (ESBL)–producing Escherichia coli, and multidrug-resistant Salmonella

Methicillin-resistant Staphylococci 

Outbreaks of MRSA in horses were first reported in the late 1990s in Japan and the United States. In a German study published in 2014, between 41% and 63% of S aureus isolates from wound swabs of dogs, cats, and horses were methicillin resistant. MRSA does not appear to be host specific, and infection in dogs and cats could represent “spill-over” from human infections.
Epidemiological data on MRSP outbreaks is somewhat limited, but environmental exposure in veterinary hospitals is a probable source of infection, as illustrated by an outbreak in a veterinary teaching hospital in Finland. Because treatment options for MRSP are limited, infected veterinary patients may face euthanasia out of concern for their welfare. 

Extended-spectrum Beta-lactamase–producing E coli 

Many E coli produce beta-lactamases, enzymes that confer resistance to beta-lactam antibiotics (eg, penicillins and cephalosporins). ESBL-producing bacteria, which are resistant to additional antibiotic classes, were identified in humans in the 1980s. Infections with ESBL-producing E coli have been reported in dogs, cats, and horses since the late 1990s. 

Multidrug-resistant Salmonella 

Salmonella infection is an ongoing problem in food animals, and infections with serovars resistant to multiple drugs have also been reported in dogs, horses, and humans. Animal feed containing meat and human food from livestock sources have been implicated in outbreaks.

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