PCR Assays for “Orphan Diseases”

Dec 11, 2014 / Diagnostic Updates

There are a number of “seldom seen” or “orphan diseases” that may be difficult to culture or identify once isolated. We have recently added polymerase chain reaction (PCR) assays to specifically detect some of these organisms of high concern, including Brucella sp. and Francisella tularensis. Acceptable specimens include EDTA blood, used to detect DNA in septic infections, or fine-needle aspirates of spleen or lymph node, which are also suitable for culture. The Microbiology/Molecular section also has developed a PCR assay specific for Blastomyces dermatitidis. These specific PCR assays save time to arrive at an etiological diagnosis and implement treatment, without the constraints of pure culture or single organism infection required for successful direct 16S rRNA or 18S rRNA sequencing. The specific PCRs are also less expensive ($25 to $35) than sequencing. A limitation to the PCR is that we can identify only targeted pathogens, so we are expanding our primer stocks. If there is a pathogen for which you need a faster response time or to discuss new test development, please contact Dr. Carol Maddox: maddox@illinois.edu.