Staphylococcus bacteria are commonly found on the skin and in the nostrils of both humans and animals. Dogs often carry these bacteria as part of their normal flora or are colonized without showing signs of illness. While transfer between species is possible, the risk increases when a dog is actively infected or when a person has broken skin or a weakened immune system.
Understanding Zoonotic Staph Strains
The Staph species most often associated with humans is Staphylococcus aureus (S. aureus), which is a common cause of skin and soft-tissue infections. Dogs, however, are primarily colonized by a different species, Staphylococcus pseudintermedius (S. pseudintermedius), which is a major opportunistic pathogen in canines. Both of these species can be transmitted between humans and dogs, making them zoonotic concerns.
A significant factor in the risk of Staph is antibiotic resistance, which complicates treatment. Methicillin-Resistant S. aureus (MRSA) is the human health concern, but dogs can carry this strain, often having acquired it from a human. The dog-adapted version is Methicillin-Resistant S. pseudintermedius (MRSP), which is increasingly seen in veterinary medicine and has been documented to cause infections in humans. MRSP is frequently multidrug-resistant, limiting treatment options for both pets and their owners.
How Staph Moves Between Dogs and Humans
Transmission of Staphylococcus bacteria, including resistant strains, relies heavily on close physical contact between the dog and human. The bacteria can be passed directly from a dog’s skin or saliva to a person, particularly if the dog is colonized or has an active infection like pyoderma or otitis.
Allowing a dog to lick open wounds or broken skin on a person is a high-risk activity that can directly transfer the bacteria. Transmission can also occur indirectly through contaminated items in the shared environment, such as bedding, towels, or furniture. Infection is most likely when the person has compromised skin barriers or a weakened immune system due to age or underlying medical conditions.
Essential Steps for Prevention
Reducing the risk of Staph transmission requires rigorous hygiene and managing contact with the dog. The single most effective preventative measure is frequent handwashing with soap and water after handling your pet, especially after touching areas like their mouth, nose, or anal region. An alcohol-based hand sanitizer can also be used when soap and water are unavailable.
You should avoid letting your dog lick your face or any area of broken or damaged skin, as saliva can be a vector for the bacteria. It is important to keep any cuts, scrapes, or surgical sites on both yourself and your pet covered with clean, dry bandages until they are fully healed. If your dog develops a skin infection, such as a rash or a moist, inflamed area, consult a veterinarian promptly for treatment. Prompt treatment ensures the infection is addressed quickly, limiting the shedding of bacteria into the shared environment.