Staphylococci are common bacteria generally found on the skin and mucous membranes, especially of the nose, throat, and anus. There are many species of staphylococcus; the three most commonly isolated from cats are S. aureus, S. simulans, and S. intermedius with S. aureus and S. intermedius the most frequently isolated from superficial skin infections. In humans, various types of S. aureus produce conditions such as abscesses, boils, and toxins, including those that cause some forms of food poisoning.
What influences staph infections?
Staph is a normal inhabitant on the skin, according to William Miller, VMD, professor of dermatology at the Cornell University College of Veterinary Medicine. The healthy cat is very resistant to staph infections. The only real increase in susceptibility to infection occurs if the cat has underlying itchy skin disease like allergy, says Miller, who is board certified by the American College of Veterinary Dermatology.
Also, a cat with an immunosuppressive disease, like that caused by FeLV or FIV infection, or one that is receiving corticosteroids, may be predisposed to a staph skin infection. In addition, any break in the skin, such as trauma from abrasions, cuts, or scratches, may make the cats skin more prone to staph infection. In the process of grooming, very often the cat abrades the skin. This is no big deal for a normal cat, but for an immunosuppressed cat it can be a very big deal.
Environment can influence staph infection. Miller notes that when the humidity and temperature go up, the number of bacteria multiply on the skin surface, especially in moist areas such as between the thighs or in the genital area – but they dont penetrate the skin. Just because there are increased numbers of staph on the skin surface does not mean youre going to get a staph infection. Puncture wounds from bites or claws are a frequent cause of infection. The resulting abscesses can be caused by staph, but the bacteria usually obtained from such abscesses are microbes that reside in cats mouths, e.g., Pasteurella.
Abscess often the first sign
Staph infections in the cat are very unusual. Cats really dont get skin infections very often; as a matter of fact, theyre pretty rare, except for bite wound abscesses, says Miller. If an abscess is present, the cats guardian may notice a painful, red swelling. Often, the first sign a person notices is a moist area on the hair coat, evidence the abscess has burst and released pus; occasionally this is accompanied by a patch of dead skin and fur falling away. The cat may be lethargic and have a fever. Abscesses usually occur about the head, neck, or legs – areas most often bitten during a cat fight.
We usually swab a sample from the infected area onto a slide, stain it, and examine it under a microscope. If there are small, spherical bacteria present, thats staph, says Miller. Its usually not necessary to send a sample to the laboratory to see what bacteria grow and which antibacterial medications are the most effective. We treat on an empiric basis because we know the antibacterial medications that staph is sensitive to.
Antibiotic treatment effective
Along with correcting any underlying problems when possible, antibacterial therapy is the primary treatment for staph infections. For most infections it will be medication given by mouth – pills or pediatric liquids like Clavamox, says Miller. Its not usually in the form of a cream or salve because the cat licks it off. Most staph infections respond to Cefa-tabs , Cefa-drops, or Baytril. Theres a wide variety of effective antibacterials, so the choice depends on what the cat will accept and what the practitioner has in his or her office. Antibacterial resistance is not a problem in cats with staph infections at this time.
If you suspect your cat has a skin infection, Miller says, dont try home remedies. The cat needs to see the veterinarian not only to treat the infection effectively, but also to find out why it occurred. Its a very peculiar thing for a cat to have a skin infection.