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Serodiagnosis of Penicillium marneffei infection
K Y Yuen1, S S Wong, D N Tsang
1Department of Microbiology, Queen Mary Hospital, University of Hong Kong.
Abstract:
Diagnosis of Penicillium marneffei infection is often made late. We evaluated an indirect immunofluorescent antibody test for P marneffei in serum from 103 patients with persistent fever and from 78 normal subjects. Germinating conidia (initial tissue-invasion phase) and yeast-hyphae (tissue multiplication phase) forms were used as antigen. All 8 documented P marneffei cases (8%) had an IgG titre of 160 or more; the other 95 patients and all the healthy controls had an IgG titre of 40 or below. Blood culture was positive in only 1 case with HIV infection. Biopsy and culture of tissues were necessary for confirmation in the other 7 cases. The test could provide rapid presumptive diagnosis and supplement conventional culture.
Insights
Diagnosing Penicillium marneffei infection can be delayed. An indirect immunofluorescent antibody test shows promise for rapid presumptive diagnosis of Penicillium marneffei, aiding early detection in patients with persistent fever.
Area of Science:
- Medical Mycology
- Infectious Diseases
- Immunology
Background:
- Penicillium marneffei infection diagnosis is frequently delayed, impacting patient outcomes.
- Timely diagnosis is crucial for effective management of this opportunistic fungal infection.
Purpose of the Study:
- To evaluate an indirect immunofluorescent antibody test (IFAT) for diagnosing Penicillium marneffei infection.
- To assess the utility of IFAT in differentiating infected patients from healthy controls.
Main Methods:
- An indirect immunofluorescent antibody test (IFAT) was developed using germinating conidia and yeast-hyphae forms of P. marneffei as antigen.
- Serum samples from 103 patients with persistent fever and 78 healthy individuals were tested.
- IgG antibody titres were determined and compared with culture and biopsy results.
Main Results:
- All 8 confirmed cases of P. marneffei infection showed high IgG titres (≥160).
- The remaining 95 patients and all healthy controls had low IgG titres (≤40).
- Blood culture was positive in only one HIV-infected patient; other cases required tissue biopsy and culture for confirmation.
Conclusions:
- The indirect immunofluorescent antibody test (IFAT) can provide a rapid presumptive diagnosis for Penicillium marneffei infection.
- IFAT serves as a valuable supplementary tool to conventional diagnostic methods like blood culture and tissue biopsy.
- Early detection through IFAT may improve patient management and outcomes for P. marneffei infections.