Is Staph Infection in Dogs Contagious?

Staph infection in dogs is a serious medical condition that warrants prompt medical treatment. Staph infections in both humans and dogs can usually be treated sufficiently with a round of antibiotics, but because some strains of staph infections can be life-threatening, many dog owners wonder if this type of infection can be transmitted to humans. Research has indicated that the transmission of staph between dogs and humans is highly unlikely, but in order to be truly reassured by this finding, dog owners need to understand exactly what staph infections are and how transmission of staph infections occur.

Staph Infections Explained

Staphylococcus is a bacterium, and there are two different strains of the staphylococcus bacterium:

  • intermedius 
  • aureus

Staph infections contracted by dogs are the result of the Staphylococcus intermedius bacterium. However, humans affected by staph infections are infected by the Staphylococcus aureus bacterium. So, while these are both strains of the staphylococcus bacterium, they are actually different organisms. It is thought by many veterinary professionals that humans are not susceptible to the intermedius strain, while dogs are not susceptible to the aureus strain. Veterinary research primarily confirms this theory, yet there are a few case studies in existence that reveal isolated transmissions of staph infections from dogs to humans.

Certain strains of Staphylococcus intermedius and Staphylococcus aureus bacteria have evolved and effectively altered their genetic codes to make themselves resistant to penicillin-based medications. This type of staph infection is recognized as Methicillin-Resistant Staphylococcus Aureus, or MRSA. It is important that dog owners be aware of the MRSA bacterium because its presence can make treatment much more difficult.

How Dogs Get Staph Infections

In order understand why staph infections are generally not considered contagious to humans, you need to understand how dogs actually contract this type of bacteria. Staphylococcus intermedius naturally lives on the skin of most dogs. It does not actually become harmful until the skin’s surface has been breached, which then allows the bacteria to enter and begin reproduction. In dogs, staph infections of this nature are usually the result of excessive scratching, hot spots or skin allergies. Such irritation of the skin makes the skin’s defenses weak, and the persistent scratching associated with these conditions eventually causes the dog to break through the skin. The Staphylococcus intermedius bacteria living on the skin is then able to penetrate and infect the dog.

How Humans Get Staph Infections

The ways in which humans contract staph infections is relatively the same as the ways dogs contract the infection. The Staphylococcus aureus bacterium lives naturally on the skin of many people. In fact, about 25% of the American population is carriers of the Staphylococcus aureus bacterium, most of whom are not aware. Typically, humans carry this bacterium either in the nares or on the surface of the skin. Again, any type of wound or open sore leaves causes susceptibility to developing the Staphylococcus aureus infection.