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PCR assay quicker but less sensitive at penicilliosis diagnosis


 

FROM MYCOSES

References

A real-time PCR assay was effective at rapidly diagnosing penicilliosis caused by Talaromyces marneffei, according to Thuy Le, MD, and her associates.

Sensitivity of the assay was better when samples were collected from plasma prior to antifungal therapy. In a group of 27 HIV-infected patients from whom samples were collected prior to antifungal therapy, the assay detected the T. marneffei MP1 gene in 19 samples, while in a group of 23 HIV-infected patients from whom samples were collected within 48 hours of antifungal therapy, the assay successfully detected the MP1 gene in 12 samples.

Surface of a Penicillium marneffei colony. James Gathany, CDC

Surface of a Penicillium marneffei colony.

In an additional sample of 20 HIV-infected patients without penicilliosis, the assay found no signals of the T. marneffei MP1 gene in any of the tested plasma samples, giving a specificity of 100%. All testing was completed within 5-6 hours, significantly less than the 5 days needed for Bactec system testing.

“This real-time PCR assay should not replace the need for conventional microbiology methods in diagnosing penicilliosis. However, in conjunction with culturing, it can be used as a rapid rule-in test that can make a significant difference in patient management by allowing antifungal therapy to begin sooner, particularly in patients without skin lesions, and has the potential to improve the outcomes of T. marneffei–infected patients,” the investigators concluded.

Find the full study in Mycoses (doi: 10.1111/myc.12530).

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