Abstract 
Background: Talaromyces (Penicillium) marneffei is an emerging pathogen that causes significant morbidity and mortality in immunocompromised patients in endemic regions, such as Southeast Asia. This study compared the diagnostic performance of a well-validated real-time quantitative PCR (qPCR) assay targeting the ITS1-5.8S-ITS2 region and a Platelia galactomannan (GM) assay for the diagnosis of talaromycosis marneffei (TSM) using serum samples from patients with or without HIV.
Methods: Thirty-six patients with TSM were enrolled for laboratory diagnosis using qPCR and GM assays. Serum samples were first tested by qPCR and later for the GM antigen using an ELISA assay. qPCR was carried out using an auto-mated quantitative fluorescence PCR cycler, and the results were analyzed using a receiver operating characteristic curve. Sensitivity and speciﬁcity of serum qPCR assay were calculated. GM levels were determined using Platelia Asper-gillus enzyme immunoassay. The GM optical density cutoff index was ≥0.5. The sensitivities of both diagnostic methods were compared using Fisher’s test.
Results: The results showed that this novel qPCR method is highly sensitive and speciﬁc for detection of T. marneffei DNA in serum samples; the limit of detection and species-specificity were five copies of DNA and 100%, respectively. In assaying serum samples from 36 patients with TSM, the sensitivity of the qPCR method was 86.11% (31/36), including 20/20 (100%) patients with fungemia and 11/16 (68.75%) without fungemia. For GM assay, the sensitivity was 80.56% (29/36) when the GM optical density cutoff index was ≥0.5, including 19/20 (95%) patients with and 10/16 (62.5%) without fungemia.
Conclusion: These results indicate that a novel qPCR assay and GM assay can be valuable tools in the diagnosis of T. marneffei infection. Serum is a convenient hematological sample source for T. marneffei DNA quantification. Combining GM and qPCR assays is a more accurate and appropriate method for diagnosis of T. marneffei infection in endemic areas.

5 / Evaluation of Quantitative Real-Time PCR and Platelia Galactomannan Assay for Diagnosis of Disseminated Talaromyces marneffei Infection