A PCR using primers aimed at the multicopy gene coding for the small
subunit rRNA and resulting in the synthesis of a 180-bp fragment was
evaluated for its use in diagnosing invasive candidiasis in comparison
with blood culture. With the use of a C. albicans-specific probe, +/- 10
to 15 C. albicans cells are detected in 100 microliters of whole blood by
Southern analysis. A DNase pretreatment was critical in the purification
process of yeast DNA from whole blood. Omission of the DNase pretreatment
decreased assay sensitivity 10-fold. PCR analysis of blood specimens
collected from mice with invasive candidiasis is more sensitive than blood
culture (100 versus 67%, respectively) at 72 h after intravenous (i.v.)
inoculation with C. albicans. Furthermore, the intensity of the
hybridization signals increased with the progression of infection. In
contrast, multiple blood samples from gastrointestinally colonized mice
were all negative by PCR, indicating that the PCR assay is also specific
and may, therefore, make a positive contribution to the detection and
follow-up of invasive candidiasis