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Alanio A, Gits-Muselli M, Lanternier F, Sturny-Leclère A, Benazra M, Hamane S, Rodrigues AM, Garcia-Hermoso D, Lortholary O, Dromer F, Bretagne S. Evaluation of a New Histoplasma spp. Quantitative RT-PCR Assay. J Mol Diagn 2021; 23:698-709. [PMID: 33706012 DOI: 10.1016/j.jmoldx.2021.02.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 01/05/2021] [Accepted: 02/11/2021] [Indexed: 12/22/2022] Open
Abstract
Laboratory diagnosis of histoplasmosis is based on various methods, including microscopy, culture, antigen, and DNA detection of Histoplasma capsulatum var. capsulatum or Histoplasma capsulatum var. duboisii. To improve sensitivity of existing real-time quantitative PCR (qPCR) assays, we developed a new RT-qPCR assay that allows amplification of whole nucleic acids of Histoplasma spp. validated on suspected cases. The limit of detection was 20 copies, and the specificity against 114 fungal isolates/species was restricted to Histoplasma spp. Whole nucleic acids of 1319 prospectively collected consecutive samples from 907 patients suspected of having histoplasmosis were tested routinely between May 2015 and May 2019 in parallel with standard diagnostic procedures performed in parallel. Forty-four had proven histoplasmosis attributable to H. capsulatum var. capsulatum (n = 40) or H. capsulatum var. duboisii (n = 4) infections. The results of RT-qPCR were positive in 43 of 44 patients (97.7% sensitivity) in at least one specimen. Nine of 863 cases (99% specificity) were RT-qPCR positive and therefore classified as possible cases. RT-qPCR was positive in 13 of 30 (43.3%) blood samples tested in proven cases. A positive RT-qPCR result in blood was significantly associated with H. capsulatum var. capsulatum progressively disseminated histoplasmosis with a positive RT-qPCR result in 92.3% of the immunocompromised patients with disseminated disease. This new Histoplasma RT-qPCR assay enabling amplification of H. capsulatum var. capsulatum and H. capsulatum var. duboisii is highly sensitive and allows the diagnosis of histoplasmosis advantageously from blood and bronchoalveolar lavage fluid.
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Affiliation(s)
- Alexandre Alanio
- Laboratoire de Parasitologie-Mycologie, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Assistance Publique-Hôpitaux de Paris, Paris, France; Molecular Mycology Unit, CNRS UMR2000, Institut Pasteur, Paris, France; National Reference Center for Invasive Mycoses and Antifungals, Institut Pasteur, Paris, France; UFR de Médecine, Hôpital Necker Enfants malades, Assistance Publique-Hôpitaux de Paris, IHU Imagine, Paris Descartes University, Université de Paris, Paris, France.
| | - Maud Gits-Muselli
- Laboratoire de Parasitologie-Mycologie, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Assistance Publique-Hôpitaux de Paris, Paris, France; Molecular Mycology Unit, CNRS UMR2000, Institut Pasteur, Paris, France; UFR de Médecine, Hôpital Necker Enfants malades, Assistance Publique-Hôpitaux de Paris, IHU Imagine, Paris Descartes University, Université de Paris, Paris, France
| | - Fanny Lanternier
- Molecular Mycology Unit, CNRS UMR2000, Institut Pasteur, Paris, France; National Reference Center for Invasive Mycoses and Antifungals, Institut Pasteur, Paris, France; UFR de Médecine, Hôpital Necker Enfants malades, Assistance Publique-Hôpitaux de Paris, IHU Imagine, Paris Descartes University, Université de Paris, Paris, France; Necker Pasteur Center for Infectious Diseases and Tropical Medicine, Hôpital Necker Enfants malades, Assistance Publique-Hôpitaux de Paris, IHU Imagine, Paris Descartes University, Université de Paris, Paris, France
| | | | - Marion Benazra
- Molecular Mycology Unit, CNRS UMR2000, Institut Pasteur, Paris, France
| | - Samia Hamane
- Laboratoire de Parasitologie-Mycologie, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Anderson Messias Rodrigues
- Laboratory of Emerging Fungal Pathogens, Department of Microbiology, Immunology and Parasitology, Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Dea Garcia-Hermoso
- Molecular Mycology Unit, CNRS UMR2000, Institut Pasteur, Paris, France; National Reference Center for Invasive Mycoses and Antifungals, Institut Pasteur, Paris, France
| | - Olivier Lortholary
- Molecular Mycology Unit, CNRS UMR2000, Institut Pasteur, Paris, France; National Reference Center for Invasive Mycoses and Antifungals, Institut Pasteur, Paris, France; UFR de Médecine, Hôpital Necker Enfants malades, Assistance Publique-Hôpitaux de Paris, IHU Imagine, Paris Descartes University, Université de Paris, Paris, France; Necker Pasteur Center for Infectious Diseases and Tropical Medicine, Hôpital Necker Enfants malades, Assistance Publique-Hôpitaux de Paris, IHU Imagine, Paris Descartes University, Université de Paris, Paris, France
| | - Françoise Dromer
- Molecular Mycology Unit, CNRS UMR2000, Institut Pasteur, Paris, France; National Reference Center for Invasive Mycoses and Antifungals, Institut Pasteur, Paris, France
| | - Stéphane Bretagne
- Laboratoire de Parasitologie-Mycologie, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Assistance Publique-Hôpitaux de Paris, Paris, France; Molecular Mycology Unit, CNRS UMR2000, Institut Pasteur, Paris, France; National Reference Center for Invasive Mycoses and Antifungals, Institut Pasteur, Paris, France; UFR de Médecine, Hôpital Necker Enfants malades, Assistance Publique-Hôpitaux de Paris, IHU Imagine, Paris Descartes University, Université de Paris, Paris, France
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Alvarado P, Pérez-Rojas Y, Zambrano EA, Gonzatti MI, Roschman-González A. Improved serodiagnosis of histoplasmosis by use of deglycosylated extracellular released antigens of Histoplasma capsulatum. J Microbiol Methods 2020; 175:105981. [PMID: 32534998 DOI: 10.1016/j.mimet.2020.105981] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 06/07/2020] [Accepted: 06/07/2020] [Indexed: 11/15/2022]
Abstract
The diagnosis of histoplasmosis depends on various approaches: direct clinical examination, fungus isolation from cultures of clinical samples, histopathological evaluation, and serological testing. In serodiagnostic assays, the Histoplasma capsulatum H and M antigenic glycoproteins have been extensively used. However, both antigens showed limitations attributed mainly to their cross-reactivity with glycoproteins from other pathogenic fungi, which compromises specificity, and generates false positives, misdiagnosis, and therapeutic failure. In this work, we deglycosylated extracellular released antigens from the Venezuelan 7090 H. capsulatum clinical isolate, using chemical and enzymatic methods and evaluated their effectiveness by indirect enzyme-linked immunosorbent assay (ELISA) with sera from patients with either histoplasmosis or PCM. Prior to deglycosylation, the extracellular released antigen showed 62% of sensitivity 66% of specificity and 68% of cross-reactivity with paracoccidioidomicosis sera. The chemically deglycosylated extracellular released antigen, for 8 or 18 h showed 72 and 52% sensitivity with 98% and 92% specificity, respectively. Moreover, cross-reactivity with Paracoccidioides decreased to 4 and 16%, following deglycosylation for 8 or 18 h, respectively. The enzymatically treated antigen showed 52% of sensitivity, 92% of specificity and 8% cross-reactivity against Paracoccidioides. Deglycosylation of the H. capsulatum antigen improves its specificity and decreases its cross-reactivity against Paracoccidioides when using indirect ELISA for serodiagnosis. Therefore, it is recommended to deglycosylate the fungal extracellular released antigen for clinical serodiagnosis, and to monitor humoral immune responses during therapy of patients with the different clinical forms of histoplasmosis.
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Affiliation(s)
- Primavera Alvarado
- Laboratorio de Micología, Instituto de Biomedicina "Dr. Jacinto Convit", Caracas, Venezuela.
| | - Yenis Pérez-Rojas
- Grupo de Bioquímica e Inmunología de Hemoparásitos, Universidad Simón Bolívar, Venezuela
| | - Edgar Armando Zambrano
- Laboratorio de Bioquímica de Parásitos, Instituto de Biomedicina. "Dr. Jacinto Convit", Caracas, Venezuela
| | - Mary I Gonzatti
- Grupo de Bioquímica e Inmunología de Hemoparásitos, Universidad Simón Bolívar, Venezuela
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