Cat scratch disease is a zoonotic febrile illness spread from a cat’s oral and pharyngeal flora by a scratch to humans, particularly to children. The disease is characterised by regional lymphadenopathy, fever and other systemic symptoms. A skin papule may be present at the inoculation site. The most common causative species of cat scratch fever is considered to be Bartonella henselae. Also called bacillary angiomatosis, cat scratch disease is associated with bacteraemia and endocarditis and may require prolonged therapy. What are the best investigations to confirm the diagnosis of a suspected case of cat scratch disease? angiomatosis)?
Many thanks in anticipation.
Beat reagards
Dr Sayed S Bukhari MD, FRCPath
Consultant in Infection
Midlands
UK
Dr. Buktari,
As you know, cat scratch fever may present in humans in subtle ways, or not so subtle. In terms of laboratory investigations, I know that Galaxy Laboratories in North Carolina, founded by Ed Breitwschwerdt, DVM is considered to have cutting edge technology in conducting laboratory testing for Bartonella. Reportedly they have developed a genus PCR that can be used on blood or serum, and may also be used to identify Bartonella in tissue slides. They also have a new method of doing blood cultures for Bartonella based on a specially designed medium BAPGM. Thy keep cultures for up to eight weeks. Breitschwerdt also does more esoteric tests in his private research lab --- but he developed Galaxy for commercial use because his research lab was being inundated with testing requests. Note that there can be strain differences in test construction, so it is possible to test positive on one IFA, and negative on another. It is an organism that does not stay in the bloodstream very long, or it can be present intermittently. I would do multiple sets of blood cultures and PCRs, and also the IFA. Some patients will test negative on everything because of the immune suppression the organism is known to cause, Although not presently noted in the literature, many patients with Bartonella will experience a Jarisch-Herxheimer reaction when administered appropriate antibiotics. Hope this is helpful. If you have further questions, you might consider sending an email to Galaxy --- [email protected]. I have no commercial or management ties to this lab, but admire their work. For some people, it is a chronic relapsing disease that they can't clear despite antibiotics.
http://www.galaxydx.com/web/
Well, an updated PCR testing method has been adopted by Galaxy Diagnostic group, called ePCR, where test samples are grown initially on BAPGM (Bartonella Alpha Proteolytic Growth Medium) then examined by PCR. This method could eliminate greatly false negative results obtained from traditional PCR testing.
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