How many people have a household cat as a pet? Yes, I am referring to that cute little kitty that is all curled up next to you. They might look friendly at first, but then something “rubs” them the wrong way. Next thing you know you’re grabbing your arm and screaming, “Ouch!” There is now a slight scratch that is throbbing with pain. A quick clean up and a band-aid is all the normal human being does to solve the problem. Little do you know, there could be a much more severe consequence.
Cat-scratch fever, or cat-scratch disease, is caused by Bartonella henselae, which is a normal flora of the cat’s saliva. B. henselae is also associated with bacteremia and endocarditis. Symptoms usually do not show for a few days following the incident. Once the symptoms start, however, they can last for a couple weeks. Symptoms of cat scratch fever include pain and swelling of the lymph nodes, general discomfort and body aches, and loss of appetite. Many times, cat scratch fever is never diagnosed. The symptoms are sometimes mild and not severe enough to warrant treatment. Cat scratch fever is not a very common disease. According to the U.S. Centers for Disease Control and Prevention, there are about 25,000 cases in the United States each year. However, there are likely many more cases that go undiagnosed or unreported.
In order to isolate this organism, the Isolator system is used for blood culture. It is plated out to fresh chocolate or 5% blood agar (rabbit or horse). The plates should be incubated at 350C in CO2 for up to 30 days. Bartonella henselae is a weak staining, gram-negative rod that stains better with a Gimenez. It appears irregular in shape, raised, whitish, and rough (cauliflower) like. The organism is catalase and oxidase negative as well as negative for all carbohydrates. The presumptive identification is based on colony growth after seven days with characteristic colony morphology, wet prep, catalase, and oxidase reactions.
I hope everyone has learned a little more about what to expect from the adorable kitty curled up by your side. Just remember for next time that if you get a scratch that does not appear normal, you might want to see your doctor for a possible infection of Bartonella henselae.
