Evaluation of diagnostic methods for Candida albicans translocation in a mouse model: seminested polymerase chain reaction, blood culture, and serological assays.

Abstract

For the rapid diagnosis of systemic Candida infection, we compared the performance of an established seminested polymerase chain reaction (snPCR), serological tests for (1 --> 3)-beta-D-glucan assay and Candida mannan antigen assay, and blood culture in our murine model for Candida albicans translocation. In this mouse model, C. albicans disseminated to the liver from the intestine after day 6.5; the snPCR and blood culture results became positive from days 8 to 8.5 in about 60% of infected mice with culture-proven translocation, and in 100% on day 9. Both (1 --> 3)-beta-D-glucan and Candida mannan antigen were elevated in the serum as early as day 6.5 of infection, though they did not identify Candida species. Because the established snPCR can differentiate four clinically important Candida species and conventional microbiological methods require at least 48 h to identify Candida species in blood samples, the snPCR assay is advantageous for rapidly identifying Candida species in the blood. Therefore, the combination of the serological assays and the snPCR seems to be valuable for the early diagnosis of systemic C. albicans infection.