Evaluation of a rapid immunochromatographic test for the detection of Candida species from oropharyngeal samples

Abstract

Oropharyngeal candidiasis is the most common opportunistic fungal infectious disease. Culture methods and microscopy are used to detect the presence of Candida species in clinical specimens. We have previously developed an immunochromatographic test (ICT) to enable the simple and rapid diagnosis of candidiasis. In this study, we evaluated the performance of the ICT for the detection of Candida species from pharyngeal swabs and compared the results with those of the culture method. The isolated Candida species were identified using polymerase chain reaction-restriction fragment length polymorphism, and viable cell counts were determined using selective chromogenic agar. The detection rate of C. albicans was 63.3% and 0% among ≤102 and ≥ 106 colony-forming units (CFU)/mL of viable Candida cells from pharyngeal swabs, respectively. The detection rate of nonC. albicans Candida species, especially C. glabrata, increased commensurately from 16.7% at ≤102 CFU/mL to 75.0% at ≥106 CFU/mL. Among the 300 pharyngeal swabs analyzed, 59 cultures detected Candida species at a count of >103 CFU/mL (53 were ICT-positive). Of the remaining 241 culture-negative specimens, 219 were ICT-negative. The sensitivity, specificity, and accuracy of the ICT were 89.8%, 90.9%, and 90.7%, respectively. Taken together, the ICT evaluated can be made readily available for clinical use in detecting Candida.