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Guitard J, Brenier-Pinchart MP, Varlet-Marie E, Dalle F, Rouges C, Argy N, Bonhomme J, Capitaine A, Guégan H, Lavergne RA, Dardé ML, Pelloux H, Robert-Gangneux F, Yera H, Sterkers Y. Multicenter evaluation of the Toxoplasma gondii Real-TM (Sacace) kit performance for the molecular diagnosis of toxoplasmosis. J Clin Microbiol 2024; 62:e0142823. [PMID: 38470023 PMCID: PMC11005372 DOI: 10.1128/jcm.01428-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 02/20/2024] [Indexed: 03/13/2024] Open
Abstract
The molecular detection of Toxoplasma gondii DNA is a key tool for the diagnosis of disseminated and congenital toxoplasmosis. This multicentric study from the Molecular Biology Pole of the French National Reference Center for toxoplasmosis aimed to evaluate Toxoplasma gondii Real-TM PCR kit (Sacace). The study compared the analytical and clinical performances of this PCR assay with the reference PCRs used in proficient laboratories. PCR efficiencies varied from 90% to 112%; linearity zone extended over four log units (R2 > 0.99) and limit of detection varied from 0.01 to ≤1 Tg/mL depending on the center. Determined on 173 cryopreserved DNAs from a large range of clinical specimens, clinical sensitivity was 100% [106/106; 95 confidence interval (CI): 96.5%-100%] and specificity was 100% (67/67; 95 CI: 94.6%-100%). The study revealed two potential limitations of the Sacace PCR assay: the first was the inconsistency of the internal control (IC) when added to the PCR mixture. This point was not found under routine conditions when the IC was added during the extraction step. The second is a lack of practicality, as the mixture is distributed over several vials, requiring numerous pipetting operations. Overall, this study provides useful information for the molecular diagnosis of toxoplasmosis; the analytical and clinical performances of the Sacace PCR kit were satisfactory, the kit having sensitivity and specificity similar to those of expert center methods and being able to detect low parasite loads, at levels where multiplicative analysis gives inconsistently positive results. Finally, the study recommends multiplicative analysis in particular for amniotic fluids, aqueous humor, and other single specimens.
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Affiliation(s)
- Juliette Guitard
- Sorbonne University, INSERM, Centre de Recherche Saint-Antoine, Assistance Publique-Hôpitaux de Paris, Saint-Antoine Hospital Parasitology-Mycology Laboratory, Paris, France
- Molecular Biology group of the French National Reference Center for Toxoplasmosis, Montpellier, France
| | - Marie-Pierre Brenier-Pinchart
- Molecular Biology group of the French National Reference Center for Toxoplasmosis, Montpellier, France
- Parasitology-Mycology Laboratory, CHU Grenoble Alpes, Grenoble Alpes University, Grenoble, France
| | - Emmanuelle Varlet-Marie
- Molecular Biology group of the French National Reference Center for Toxoplasmosis, Montpellier, France
- Department of Parasitology-Mycology, University of Montpellier, CNRS, IRD, University Hospital Center (CHU) of Montpellier, MiVEGEC, Montpellier, France
| | - Frédéric Dalle
- Molecular Biology group of the French National Reference Center for Toxoplasmosis, Montpellier, France
- Parasitology-Mycology Laboratory, CHU Dijon, Dijon, France
| | - Celia Rouges
- Parasitology-Mycology Laboratory, Cochin Hospital, Paris, France
| | - Nicolas Argy
- Parasitology-Mycology Laboratory, Bichat Hospital, Paris, France
| | - Julie Bonhomme
- Parasitology-Mycology Laboratory, CHU Caen Normandie, Caen, France
| | - Agathe Capitaine
- Parasitology-Mycology Laboratory, CHU Caen Normandie, Caen, France
| | - Hélène Guégan
- Molecular Biology group of the French National Reference Center for Toxoplasmosis, Montpellier, France
- Parasitology-Mycology Laboratory, CHU Rennes, Rennes, France
| | - Rose-Anne Lavergne
- Nantes Université, CHU Nantes, Cibles et Médicaments des Infections et de l’Immunité, IICiMed, UR, Nantes, France
| | | | - Hervé Pelloux
- Molecular Biology group of the French National Reference Center for Toxoplasmosis, Montpellier, France
- Parasitology-Mycology Laboratory, CHU Grenoble Alpes, Grenoble Alpes University, Grenoble, France
| | - Florence Robert-Gangneux
- Molecular Biology group of the French National Reference Center for Toxoplasmosis, Montpellier, France
- Parasitology-Mycology Laboratory, CHU Rennes, Rennes, France
| | - Hélène Yera
- Parasitology-Mycology Laboratory, Cochin Hospital, Paris, France
- Parasitology-Mycology Laboratory, CHU Limoges, Limoges, France
| | - Yvon Sterkers
- Molecular Biology group of the French National Reference Center for Toxoplasmosis, Montpellier, France
- Parasitology-Mycology Laboratory, Cochin Hospital, Paris, France
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Franco PS, Scussel ACMO, Silva RJ, Araújo TE, Gonzaga HT, Marcon CF, Brito-de-Sousa JP, Diniz ALD, Paschoini MC, Barbosa BF, Martins-Filho OA, Mineo JR, Ferro EAV, Gomes AO. Systematic Review and Meta-Analysis of Congenital Toxoplasmosis Diagnosis: Advances and Challenges. J Trop Med 2024; 2024:1514178. [PMID: 38419946 PMCID: PMC10901580 DOI: 10.1155/2024/1514178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 10/21/2023] [Accepted: 02/06/2024] [Indexed: 03/02/2024] Open
Abstract
Objective To understand how congenital toxoplasmosis (CT) diagnosis has evolved over the years, we performed a systematic review and meta-analysis to summarize the kind of analysis that has been employed for CT diagnosis. Methods PubMed and Lilacs databases were used in order to access the kind of analysis that has been employed for CT diagnosis in several samples. Our search combined the following combining terms: "congenital toxoplasmosis" or "gestational toxoplasmosis" and "diagnosis" and "blood," "serum," "amniotic fluid," "placenta," or "colostrum." We extracted data on true positive, true negative, false positive, and false negative to generate pooled sensitivity, specificity, and diagnostic odds ratio (DOR). Random-effects models using MetaDTA were used for analysis. Results Sixty-five articles were included in the study aiming for comparisons (75.4%), diagnosis performance (52.3%), diagnosis improvement (32.3%), or to distinguish acute/chronic infection phases (36.9%). Amniotic fluid (AF) and placenta were used in 36.9% and 10.8% of articles, respectively, targeting parasites and/or T. gondii DNA. Blood was used in 86% of articles for enzymatic assays. Colostrum was used in one article to search for antibodies. In meta-analysis, PCR in AF showed the best performance for CT diagnosis based on the highest summary sensitivity (85.1%) and specificity (99.7%) added to lower magnitude heterogeneity. Conclusion Most of the assays being researched to diagnose CT are basically the same traditional approaches available for clinical purposes. The range in diagnostic performance and the challenges imposed by CT diagnosis indicate the need to better explore pregnancy samples in search of new possibilities for diagnostic tools. Exploring immunological markers and using bioinformatics tools and T. gondii recombinant antigens should address the research needed for a new generation of diagnostic tools to face these challenges.
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Affiliation(s)
- Priscila Silva Franco
- Universidade Federal de Uberlândia, Avenida João Naves de Ávila 2121, Uberlândia, Santa Mônica 38408-100, MG, Brazil
| | | | - Rafaela José Silva
- Universidade Federal de Uberlândia, Avenida João Naves de Ávila 2121, Uberlândia, Santa Mônica 38408-100, MG, Brazil
| | - Thadia Evelyn Araújo
- Universidade Federal de Uberlândia, Avenida João Naves de Ávila 2121, Uberlândia, Santa Mônica 38408-100, MG, Brazil
- Instituto René Rachou, Fundação Oswaldo Cruz, Avenida Augusto de Lima, 1715, Barro Preto 30190-002, Belo Horizonte, MG, Brazil
| | - Henrique Tomaz Gonzaga
- Universidade Federal de Uberlândia, Avenida João Naves de Ávila 2121, Uberlândia, Santa Mônica 38408-100, MG, Brazil
| | - Camila Ferreira Marcon
- Universidade Federal do Triângulo Mineiro, Rua Frei Paulino, 30, Nossa Sra. da Abadia 38025-180, Uberaba, MG, Brazil
| | - Joaquim Pedro Brito-de-Sousa
- Universidade Federal de Uberlândia, Avenida João Naves de Ávila 2121, Uberlândia, Santa Mônica 38408-100, MG, Brazil
- Instituto René Rachou, Fundação Oswaldo Cruz, Avenida Augusto de Lima, 1715, Barro Preto 30190-002, Belo Horizonte, MG, Brazil
| | - Angélica Lemos Debs Diniz
- Universidade Federal de Uberlândia, Avenida João Naves de Ávila 2121, Uberlândia, Santa Mônica 38408-100, MG, Brazil
| | - Marina Carvalho Paschoini
- Universidade Federal do Triângulo Mineiro, Rua Frei Paulino, 30, Nossa Sra. da Abadia 38025-180, Uberaba, MG, Brazil
| | - Bellisa Freitas Barbosa
- Universidade Federal de Uberlândia, Avenida João Naves de Ávila 2121, Uberlândia, Santa Mônica 38408-100, MG, Brazil
| | - Olindo Assis Martins-Filho
- Universidade Federal de Uberlândia, Avenida João Naves de Ávila 2121, Uberlândia, Santa Mônica 38408-100, MG, Brazil
- Instituto René Rachou, Fundação Oswaldo Cruz, Avenida Augusto de Lima, 1715, Barro Preto 30190-002, Belo Horizonte, MG, Brazil
| | - José Roberto Mineo
- Universidade Federal de Uberlândia, Avenida João Naves de Ávila 2121, Uberlândia, Santa Mônica 38408-100, MG, Brazil
| | - Eloisa Amália Vieira Ferro
- Universidade Federal de Uberlândia, Avenida João Naves de Ávila 2121, Uberlândia, Santa Mônica 38408-100, MG, Brazil
| | - Angelica Oliveira Gomes
- Universidade Federal do Triângulo Mineiro, Rua Frei Paulino, 30, Nossa Sra. da Abadia 38025-180, Uberaba, MG, Brazil
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Brenier-Pinchart MP, Filisetti D, Cassaing S, Varlet-Marie E, Robert-Gangneux F, Delhaes L, Guitard J, Yéra H, Bastien P, Pelloux H, Sterkers Y. Molecular Diagnosis of Toxoplasmosis: Multicenter Evaluation of the Toxoplasma RealCycler Universal PCR Assay on 168 Characterized Human Samples. J Mol Diagn 2022; 24:687-696. [PMID: 35452843 DOI: 10.1016/j.jmoldx.2022.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 01/20/2022] [Accepted: 03/04/2022] [Indexed: 10/18/2022] Open
Abstract
Real-time PCR plays a crucial role in the diagnosis of toxoplasmosis. In this multicenter study, the Toxoplasma RealCycler Universal assay was assessed for the diagnosis of toxoplasmosis by eight reference laboratories. DNAs from diverse clinical samples were included: 141 characterized samples from patients with different clinical forms of proven toxoplasmosis and 27 from patients without toxoplasmosis were tested in duplicate with the commercial assay. Final diagnosis was affirmed by each center by analysis of clinical settings and biological follow-up. Calibrated Toxoplasma gondii standards and 11 external quality control samples were also included. Discrepant results observed after the first run of commercial PCR were controlled by both reference and commercial PCR assays. Using the commercial assay, the detection threshold varied from 0.01 to 1 tachyzoites/mL, depending on the center. The relationship between crossing point and DNA concentration was linear over 4 log units (r2 > 0.99), and PCR efficiencies were satisfactory (89% to 104%). The results of the 11 external quality control samples were concordant after one retesting, but those for 3 clinical samples remained discrepant. Sensitivity and specificity were calculated at 97.8% (95% CI, 97.8%-100%) and 100% (95% CI, 87.2%-100%), respectively. Provided that PCRs are performed at least in duplicate to detect low parasitic loads, Toxoplasma RealCycler Universal PCR showed suitable performances to diagnose the different forms of toxoplasmosis.
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Affiliation(s)
- Marie-Pierre Brenier-Pinchart
- Parasitology-Mycology Laboratory, Centre Hospitalier Universitaire Grenoble Alpes and University of Grenoble Alpes, Grenoble, France; "Molecular Biology" Pole of the National Reference Center for Toxoplasmosis, Montpellier, France.
| | - Denis Filisetti
- "Molecular Biology" Pole of the National Reference Center for Toxoplasmosis, Montpellier, France; Parasitology-Medical Mycology Laboratory, Parasitology and Tropical Diseases Institute, University Hospitals and University of Strasbourg, Strasbourg, France
| | - Sophie Cassaing
- "Molecular Biology" Pole of the National Reference Center for Toxoplasmosis, Montpellier, France; Parasitology-Mycology Laboratory, Centre Hospitalier Universitaire de Toulouse and University of Toulouse, Toulouse, France
| | - Emmanuelle Varlet-Marie
- "Molecular Biology" Pole of the National Reference Center for Toxoplasmosis, Montpellier, France; Parasitology-Mycology Department, Centre Hospitalier Universitaire de Montpellier, Montpellier, France
| | - Florence Robert-Gangneux
- "Molecular Biology" Pole of the National Reference Center for Toxoplasmosis, Montpellier, France; Centre Hospitalier Universitaire de Rennes and Ecole des Hautes Etudes en Santé Publique, University of Rennes, Rennes, France
| | - Laurence Delhaes
- "Molecular Biology" Pole of the National Reference Center for Toxoplasmosis, Montpellier, France; Parasitology-Mycology Laboratory, Centre Hospitalier Universitaire de Bordeaux and Cardio-Thoracic Research Center, University of Bordeaux, Bordeaux, France
| | - Juliette Guitard
- "Molecular Biology" Pole of the National Reference Center for Toxoplasmosis, Montpellier, France; Parasitology Mycology Department, Saint-Antoine Hospital, Assistance Publique-Hôpitaux de Paris and Saint-Antoine Research Center, Sorbonne University, Paris, France
| | - Hélène Yéra
- "Molecular Biology" Pole of the National Reference Center for Toxoplasmosis, Montpellier, France; Parasitology-Mycology Laboratory, Cochin Hospital, Assistance Publique-Hôpitaux de Paris and University of Paris, Paris, France
| | - Patrick Bastien
- "Molecular Biology" Pole of the National Reference Center for Toxoplasmosis, Montpellier, France; Parasitology-Mycology Department, Centre Hospitalier Universitaire de Montpellier and MiVEGEC, Institut de Recherche pour Le Développement, University of Montpellier, Montpellier, France
| | - Hervé Pelloux
- "Molecular Biology" Pole of the National Reference Center for Toxoplasmosis, Montpellier, France; Parasitology-Mycology Laboratory, Centre Hospitalier Universitaire Grenoble Alpes and University of Grenoble Alpes, Grenoble, France
| | - Yvon Sterkers
- "Molecular Biology" Pole of the National Reference Center for Toxoplasmosis, Montpellier, France; Parasitology-Mycology Department, Centre Hospitalier Universitaire de Montpellier and MiVEGEC, Institut de Recherche pour Le Développement, University of Montpellier, Montpellier, France
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Robert MG, Brenier-Pinchart MP, Garnaud C, Fricker-Hidalgo H, Pelloux H. Molecular diagnosis of toxoplasmosis: recent advances and a look to the future. Expert Rev Anti Infect Ther 2021; 19:1529-1542. [PMID: 34112045 DOI: 10.1080/14787210.2021.1941867] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Toxoplasmosis is a globally distributed parasitic infection that can be particularly severe when opportunistic or congenital. Its diagnosis requires accurate and rapid techniques that rely mainly on serology and molecular methods. AREAS COVERED The aim of this review was to discuss the positioning of the molecular diagnosis of toxoplasmosis according to the different clinical situations possibly resulting from infection with T. gondii, and to detail recent developments in this technique. The English and French literature were searched with the following keywords: 'Toxoplasmosis', "Molecular diagnosis" and 'PCR'. EXPERT OPINION Molecular techniques have revolutionized the diagnosis of toxoplasmosis, and practices have considerably evolved over the past decades. However, there is still a high degree of inter-laboratory heterogeneity which impairs comparisons between results and studies. Efforts to standardize practices are underway.
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Affiliation(s)
- Marie Gladys Robert
- Service de Parasitologie-Mycologie, CHU Grenoble Alpes, Grenoble, France.,Université Grenoble Alpes, Institut pour l'Avancée des Biosciences (IAB), Grenoble, France
| | - Marie-Pierre Brenier-Pinchart
- Service de Parasitologie-Mycologie, CHU Grenoble Alpes, Grenoble, France.,Université Grenoble Alpes, Institut pour l'Avancée des Biosciences (IAB), Grenoble, France.,Centre National de Référence Toxoplasmose - Pôle Biologie Moléculaire, France
| | - Cécile Garnaud
- Service de Parasitologie-Mycologie, CHU Grenoble Alpes, Grenoble, France.,Université Grenoble Alpes, CNRS, CHU Grenoble Alpes, Grenoble INP, TIMC-IMAG, Grenoble, France
| | | | - Hervé Pelloux
- Service de Parasitologie-Mycologie, CHU Grenoble Alpes, Grenoble, France.,Université Grenoble Alpes, Institut pour l'Avancée des Biosciences (IAB), Grenoble, France.,Centre National de Référence Toxoplasmose - Pôle Biologie Moléculaire, France
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Multicenter Comparative Assessment of the TIB MolBiol Toxoplasma gondii Detection Kit and Four Laboratory-Developed PCR Assays for Molecular Diagnosis of Toxoplasmosis. J Mol Diagn 2021; 23:1000-1006. [PMID: 34082073 DOI: 10.1016/j.jmoldx.2021.05.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 04/19/2021] [Accepted: 05/06/2021] [Indexed: 11/21/2022] Open
Abstract
Toxoplasmosis can be a life-threatening infection, particularly during pregnancy and in immunocompromised patients. The biological diagnosis of toxoplasmosis is challenging and has been revolutionized by molecular detection methods. This article summarizes the data of a multicenter study involving four centers to assess the performances of a commercial PCR assay as compared with four in-house PCR assays using Toxoplasma gondii standards, 20 external quality control specimens, and 133 clinical samples. This clinical cohort includes well-characterized clinical samples corresponding to different clinical situations: confirmed congenital toxoplasmosis (44 samples), toxoplasmosis in immunocompromised patients (25 samples), and chorioretinitis (5 samples). Furthermore, 59 samples from patients without toxoplasmosis were included as negative controls. The analytical sensitivities of the five methods tested were very similar; and the limit of Toxoplasma DNA detection was around 0.01 T. gondii genome per reaction for all the methods. The overall concordance between the commercial PCR and the four in-house PCR assays was 97.7% (130/133). The clinical sensitivity and specificity were >98% and could be increased for the commercial kit when PCR was performed in multiplicate to detect low parasitic loads. In conclusion, the commercial PCR assay shows suitable performances to diagnose the different clinical forms of toxoplasmosis.
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Döşkaya M, Pullukçu H, Karakavuk M, Şahar EA, Taşbakan MS, Taşbakan MI, Yılmaz M, Can H, Döşkaya AD, Gürüz AY. Comparison of an in house and a commercial real-time polymerase chain reaction targeting Toxoplasma gondii RE gene using various samples collected from patients in Turkey. BMC Infect Dis 2019; 19:1042. [PMID: 31823777 PMCID: PMC6902542 DOI: 10.1186/s12879-019-4666-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 11/29/2019] [Indexed: 02/07/2023] Open
Abstract
Background Toxoplasma gondii is an opportunistic protozoan parasite that can infect all warm-blooded animals including humans and cause serious clinical manifestations. Toxoplasmosis can be diagnosed using histological, serological, and molecular methods. In this study, we aimed to detect T. gondii RE gene in various human samples by in house and commercial real time polymerase chain reactions. Methods A total of 38 suspected cases of toxoplasmosis [peripheral blood (n:12), amnion fluid (n:11), tissue (n:9), cerebrospinal fluid (n:5), and intraocular fluid (n:1)] were included to the study. An in house and a commercial RT-PCR were applied to investigate the T. gondii RE gene in these samples. Results The compatibility rate of the two tests was 94.7% (37/38). When the commercial RT-PCR kit was taken as reference, the sensitivity and specificity of in house RT-PCR test was 87.5 and 100%. When the in house RT-PCR test was taken as reference, the commercial RT-PCR kit has 100% sensitivity and 96.8% specificity. Incompatibility was detected in only in a buffy coat sample with high protein content. Conclusions Both the commercial and in house RT-PCR tests can be used to investigate T. gondii RE gene in various clinical specimens with their high sensitivity and specificity. In house RT-PCR assay can be favorable due to cost savings compared to using the commercial test.
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Affiliation(s)
- Mert Döşkaya
- Department of Parasitology, Ege University Faculty of Medicine, 35100, İzmir, Bornova, Turkey
| | - Hüsnü Pullukçu
- Department of Infectious Diseases, Ege University Faculty of Medicine, İzmir, Bornova, Turkey
| | - Muhammet Karakavuk
- Department of Parasitology, Ege University Faculty of Medicine, 35100, İzmir, Bornova, Turkey.,Ege University, Ödemiș Vocational High School, İzmir, Ödemiș, Turkey
| | - Esra Atalay Şahar
- Department of Parasitology, Ege University Faculty of Medicine, 35100, İzmir, Bornova, Turkey.,Department of Biotechnology, Ege University Faculty of Engineering, İzmir, Bornova, Turkey
| | - Mehmet Sezai Taşbakan
- Department of Chest Diseases, Ege University Faculty of Medicine, İzmir, Bornova, Turkey
| | - Meltem Işıkgöz Taşbakan
- Department of Infectious Diseases, Ege University Faculty of Medicine, İzmir, Bornova, Turkey
| | - Mümtaz Yılmaz
- Department of Internal Medicine, Ege University Faculty of Medicine, İzmir, Bornova, Turkey
| | - Hüseyin Can
- Department of Biology, Molecular Biology Section, Ege University Faculty of Sciences, İzmir, Bornova, Turkey
| | - Aysu Değirmenci Döşkaya
- Department of Parasitology, Ege University Faculty of Medicine, 35100, İzmir, Bornova, Turkey.
| | - Adnan Yüksel Gürüz
- Department of Parasitology, Ege University Faculty of Medicine, 35100, İzmir, Bornova, Turkey
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Vidal JE. HIV-Related Cerebral Toxoplasmosis Revisited: Current Concepts and Controversies of an Old Disease. J Int Assoc Provid AIDS Care 2019; 18:2325958219867315. [PMID: 31429353 PMCID: PMC6900575 DOI: 10.1177/2325958219867315] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 06/14/2019] [Accepted: 06/28/2019] [Indexed: 01/06/2023] Open
Abstract
Cerebral toxoplasmosis is the most common cause of expansive brain lesions in people living with HIV/AIDS (PLWHA) and continues to cause high morbidity and mortality. The most frequent characteristics are focal subacute neurological deficits and ring-enhancing brain lesions in the basal ganglia, but the spectrum of clinical and neuroradiological manifestations is broad. Early initiation of antitoxoplasma therapy is an important feature of the diagnostic approach of expansive brain lesions in PLWHA. Pyrimethamine-based regimens and trimethoprim-sulfamethoxazole (TMP-SMX) seem to present similar efficacy, but TMP-SMX shows potential practical advantages. The immune reconstitution inflammatory syndrome is uncommon in cerebral toxoplasmosis, and we now have more effective, safe, and friendly combined antiretroviral therapy (cART) options. As a consequence of these 2 variables, the initiation of cART can be performed within 2 weeks after initiation of antitoxoplasma therapy. Herein, we will review historical and current concepts of epidemiology, diagnosis, and treatment of HIV-related cerebral toxoplasmosis.
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Affiliation(s)
- José Ernesto Vidal
- Departamento de Neurologia, Instituto de Infectologia Emílio Ribas, São
Paulo, Brazil
- Departamento de Moléstias Infecciosas e Parasitárias, Hospital das Clínicas
HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
- Laboratório de Investigação Médica em Protozoologia, Bacteriologia e
Resistência Antimicrobiana (LIM 49), Instituto de Medicina Tropical, Universidade de São
Paulo, São Paulo, Brazil
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Varlet-Marie E, Sterkers Y, Perrotte M, Bastien P. A new LAMP-based assay for the molecular diagnosis of toxoplasmosis: comparison with a proficient PCR assay. Int J Parasitol 2018; 48:457-462. [PMID: 29476868 DOI: 10.1016/j.ijpara.2017.11.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 11/11/2017] [Accepted: 11/17/2017] [Indexed: 10/18/2022]
Abstract
Toxoplasmosis is generally a benign infection caused by the protozoan parasite Toxoplasma gondii but can have severe consequences in fetuses of mothers infected during pregnancy (congenital toxoplasmosis) and immunocompromised individuals. PCR-based diagnostic tests have become crucial for its diagnosis. However, this molecular diagnosis essentially relies upon laboratory-developed methods and suffers from a lack of standardization, leading to great variation in methods and performance among laboratories. With the need for accreditation of clinical microbiological laboratories, the use of commercial PCR kits has become an attractive alternative; but thorough evaluation of newly commercialized kits by proficient groups is necessary before any recommendation can be made to parasitology laboratories by health authorities or learned societies. Here, we compared the performance of an original commercial method, the Iam TOXO Q-LAMP (DiaSorin®), using Loop-mediated isothermal amplification (LAMP) technology, with our reference laboratory-developed method using real-time PCR. The kit was first tested using amniotic fluid (AF) and plasma samples (either negative or spiked with live T. gondii tachyzoites at different concentrations (from 7 to 105 tachyzoites/mL)). It was then assessed using a cohort of 11 AF, five placental and 32 blood clinical samples preserved at -20 °C. For the processing of placental/blood samples, a pretreatment step was used, which did not strictly follow the manufacturer's recommendations. The practical ease of use and compliance with good laboratory practices were also evaluated. Although the LAMP assay was less sensitive than the laboratory-developed method at very low parasite concentrations (0.1 T. gondii genome equivalents/mL), the two methods yielded identical results qualitatively and, in some instances, quantitatively, particularly for AF samples.
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Affiliation(s)
- Emmanuelle Varlet-Marie
- CHU (University Hospital Centre) of Montpellier/University of Montpellier, Research Unit "MIVEGEC", CNRS, IRD, Faculty of Medicine, Laboratoire de Parasitologie-Mycologie, Montpellier, France; Pôle "Biologie Moléculaire" du Centre National de Référence de la Toxoplasmose, France; University of Montpellier, Faculty of Pharmacy, Laboratoire de Biophysique & Bioanalyse, Montpellier, France
| | - Yvon Sterkers
- CHU (University Hospital Centre) of Montpellier/University of Montpellier, Research Unit "MIVEGEC", CNRS, IRD, Faculty of Medicine, Laboratoire de Parasitologie-Mycologie, Montpellier, France; Pôle "Biologie Moléculaire" du Centre National de Référence de la Toxoplasmose, France
| | | | - Patrick Bastien
- CHU (University Hospital Centre) of Montpellier/University of Montpellier, Research Unit "MIVEGEC", CNRS, IRD, Faculty of Medicine, Laboratoire de Parasitologie-Mycologie, Montpellier, France; Pôle "Biologie Moléculaire" du Centre National de Référence de la Toxoplasmose, France.
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Abstract
PURPOSE OF REVIEW Toxoplasmosis in immunocompromised patients is associated with a high mortality rate. Molecular techniques are important tools to diagnose acute disease in immunocompromised patients, but there are various methods with variable efficiency. Some of them have been validated for the diagnosis of congenital toxoplasmosis, but the impact of their use has not been evaluated in immunocompromised patients. RECENT FINDINGS Toxoplasmosis is of increasing importance in non-HIV immunocompromised patients. In addition, the picture of disease shows greater severity in South America, both in immunocompetent study participants and in congenitally infected infants. These epidemiological differences could influence the sensitivity of diagnostic methods. This review analyzes recent data on molecular diagnosis and compares them with older ones, in light of progress gained in molecular techniques and of recent epidemiological findings. Most recent studies were conducted in South America and used PCR targeting the B1 gene. PCR on blood could allow diagnosing a significant proportion of patients with ocular toxoplasmosis in Brazil. SUMMARY Quantitative PCR methods with specific probes should be used to improve sensitivity and warrant specificity. Performance of quantitative PCR targeting the repeated 529 bp sequence for the diagnosis of toxoplasmosis in immunocompromised patients needs evaluation in field studies in South America and in western countries.
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An updated literature review on maternal-fetal and reproductive disorders of Toxoplasma gondii infection. J Gynecol Obstet Hum Reprod 2017; 47:133-140. [PMID: 29229361 DOI: 10.1016/j.jogoh.2017.12.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 12/01/2017] [Accepted: 12/04/2017] [Indexed: 12/19/2022]
Abstract
BACKGROUND Toxoplasma gondii infection is one of the most prevalent infectious disease with worldwide distribution. Congenital toxoplasmosis is annually responsible for 1.20 million disability-adjusted life years around the world, but often it is overlooked many countries. METHODS We performed an updated review to summarize the current researches on fetal, neonatal and maternal consequences of T. gondii infection and also adverse effects of toxoplasmosis on women reproductive organs. RESULTS T. gondii infection could be cause of several abnormalities from hydrocephalus, microcephaly, deafness, abortion and still birth in fetal to psychomotor retardation, intellectual disability, hearing loss, slower postnatal motor development during the first year of life; and chorioretinitis, cryptogenic epilepsy and autism spectrum disorders in newborns. Moreover, this infection is related with neuropsychiatric disorders such as anxiety, schizophrenia spectrum disorders, depression, decreased weight, autoimmune thyroid diseases, self-directed violence, violent suicide attempts in mothers. This literature review emphasized that toxoplasmosis could be an important neglected factor endometritis, ovarian dysfunction, impaired folliculogenesis, ovarian and uterine atrophy, decrease in reproductive organs weight and reproductive performance in women. We reviewed role of the immunological profile such as pro-infiammatory cytokines and hormonal changes as main potential mechanisms related to this infection and development of maternal-fetal and reproductive disorders. CONCLUSION T. gondii is associated with several brain related disorders in both mothers and newborns, and also it is cause of several abnormalities in reproductive organs. Early diagnosis and treatment of the infection could be effective to significantly improve the clinical outcome.
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Abstract
Foodborne infections are a significant cause of morbidity and mortality worldwide, and foodborne parasitic diseases, though not as widespread as bacterial and viral infections, are common on all continents and in most ecosystems, including arctic, temperate, and tropical regions. Outbreaks of disease resulting from foodstuffs contaminated by parasitic protozoa have become increasingly recognized as a problem in the United States and globally. Increased international trade in food products has made movement of these organisms across national boundaries more frequent, and the risks associated with infections have become apparent in nations with well-developed food safety apparatus in place.
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Evaluation of Toxoplasma ELITe MGB Real-Time PCR Assay for Diagnosis of Toxoplasmosis. J Clin Microbiol 2017; 55:1369-1376. [PMID: 28202794 DOI: 10.1128/jcm.02379-16] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 02/05/2017] [Indexed: 11/20/2022] Open
Abstract
Molecular diagnosis of congenital toxoplasmosis or disseminated toxoplasmosis is based mainly on PCR. The repeated DNA element rep529 has become the main DNA target used in most PCR methods, whether laboratory developed or commercial. In this multicenter study, we evaluated the Toxoplasma ELITe MGB (Elitech) commercial kit by comparison with three reference quantitative PCR assays (RAs) used routinely in three proficient laboratories of the French National Reference Center for Toxoplasmosis network, using Toxoplasma calibrated suspensions diluted to obtain a range of concentrations from 0.1 to 10,000 parasites/ml. These suspensions were extracted with either the DNA extraction kit (EXTRAblood; Elitech) recommended by the manufacturer or the QIAamp DNA minikit (Qiagen). The Toxoplasma ELITe MGB assay was also evaluated on a panel of 128 clinical samples, including 56 amniotic fluid samples, 55 placenta samples, and various other samples, of which 95 originated from patients with proven toxoplasmosis. The ELITe MGB assay amplified low-concentration replicates (<10 parasites/ml) of calibrated suspensions less frequently than the RAs of 2/3 laboratories. Additionally, the combination of EXTRAblood and Toxoplasma ELITe MGB yielded poorer sensitivity than the combination of QIAamp DNA minikit and ELITe MGB for low parasite concentrations (P < 0.001 for 1 parasite/ml). On clinical samples, the sensitivity and the specificity of the commercial assay were 89% and 100%, respectively. The sensitivity ranged from 79% (placenta samples) to 100% (amniotic fluid samples). Overall, this study shows that the Toxoplasma ELITe MGB assay is suitable for the diagnosis of toxoplasmosis from non-cell-rich or non-hemoglobin-rich samples and that the EXTRAblood kit is not optimal.
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Chaumeau V, Andolina C, Fustec B, Tuikue Ndam N, Brengues C, Herder S, Cerqueira D, Chareonviriyaphap T, Nosten F, Corbel V. Comparison of the Performances of Five Primer Sets for the Detection and Quantification of Plasmodium in Anopheline Vectors by Real-Time PCR. PLoS One 2016; 11:e0159160. [PMID: 27441839 PMCID: PMC4956213 DOI: 10.1371/journal.pone.0159160] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 06/28/2016] [Indexed: 02/07/2023] Open
Abstract
Quantitative real-time polymerase chain reaction (qrtPCR) has made a significant improvement for the detection of Plasmodium in anopheline vectors. A wide variety of primers has been used in different assays, mostly adapted from molecular diagnosis of malaria in human. However, such an adaptation can impact the sensitivity of the PCR. Therefore we compared the sensitivity of five primer sets with different molecular targets on blood stages, sporozoites and oocysts standards of Plasmodium falciparum (Pf) and P. vivax (Pv). Dilution series of standard DNA were used to discriminate between methods at low concentrations of parasite and to generate standard curves suitable for the absolute quantification of Plasmodium sporozoites. Our results showed that the best primers to detect blood stages were not necessarily the best ones to detect sporozoites. Absolute detection threshold of our qrtPCR assay varied between 3.6 and 360 Pv sporozoites and between 6 and 600 Pf sporozoites per mosquito according to the primer set used in the reaction mix. In this paper, we discuss the general performance of each primer set and highlight the need to use efficient detection methods for transmission studies.
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Affiliation(s)
- V. Chaumeau
- Centre hospitalier universitaire de Montpellier, Montpellier, France
- Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle, Institut de Recherche pour le Développement, Montpellier, France
- Centre for Advanced Studies for Agriculture and Food, Institute of Advanced Studies, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
- * E-mail: (V. Chaumeau); (V. Corbel)
| | - C. Andolina
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - B. Fustec
- Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle, Institut de Recherche pour le Développement, Montpellier, France
- Centre for Advanced Studies for Agriculture and Food, Institute of Advanced Studies, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
| | - N. Tuikue Ndam
- Institut de Recherche pour le développement, UMR216, Mère et enfant face aux infections tropicales, Paris, France
- Communauté d’Universités et d’Etablissements Sorbonne Paris Cité, Faculté de Pharmacie, Paris, France
| | - C. Brengues
- Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle, Institut de Recherche pour le Développement, Montpellier, France
| | - S. Herder
- UMR Intertryp, Institut de Recherche pour le Développement, Montpellier, France
- Department of Parasitology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand
| | - D. Cerqueira
- Centre for Advanced Studies for Agriculture and Food, Institute of Advanced Studies, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - T. Chareonviriyaphap
- Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
| | - F. Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - V. Corbel
- Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle, Institut de Recherche pour le Développement, Montpellier, France
- Centre for Advanced Studies for Agriculture and Food, Institute of Advanced Studies, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
- Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
- * E-mail: (V. Chaumeau); (V. Corbel)
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Shimokawa PT, Targa LS, Yamamoto L, Rodrigues JC, Kanunfre KA, Okay TS. HLA-DQA1/B1 alleles as putative susceptibility markers in congenital toxoplasmosis. Virulence 2016; 7:456-64. [PMID: 26856406 DOI: 10.1080/21505594.2016.1150401] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Host and parasite genotypes are among the factors associated with congenital toxoplasmosis pathogenesis. As HLA class II molecules play a key role in the immune system regulation, the aim of this study was to investigate whether HLA-DQA1/B1 alleles are associated with susceptibility or protection to congenital toxoplasmosis. One hundred and twenty-two fetuses with and 103 without toxoplasmosis were studied. The two study groups were comparable according to a number of socio-demographic and genetic variables. HLA alleles were typed by PCR-SSP. In the HLA-DQA1 region, the allele frequencies showed that *01:03 and *03:02 alleles could confer susceptibility (OR= 3.06, p = 0.0002 and OR= 9.60, p= 0.0001, respectively) as they were more frequent among infected fetuses. Regarding the HLA-DQB1 region, the *05:04 allele could confer susceptibility (OR = 6.95, p < 0.0001). Of the 122 infected fetuses, 10 presented susceptibility haplotypes contrasting with only one in the non-infected group. This difference was not statistically significant after correction for multiple comparison (OR = 9.37, p=0.011). In the casuistic, there were two severely damaged fetuses with high parasite loads determined in amniotic fluid samples and HLA-DQA1 susceptibility alleles. In the present study, a discriminatory potential of HLA-DQA1/B1 alleles to identify susceptibility to congenital toxoplasmosis and the most severe cases has been shown.
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Affiliation(s)
- Paulo Tadashi Shimokawa
- a Laboratory of Seroepidemiology and Immunobiology, Institute of Tropical Medicine, University of São Paulo , São Paulo , Brazil
| | - Lília Spaleta Targa
- a Laboratory of Seroepidemiology and Immunobiology, Institute of Tropical Medicine, University of São Paulo , São Paulo , Brazil
| | - Lidia Yamamoto
- a Laboratory of Seroepidemiology and Immunobiology, Institute of Tropical Medicine, University of São Paulo , São Paulo , Brazil
| | - Jonatas Cristian Rodrigues
- a Laboratory of Seroepidemiology and Immunobiology, Institute of Tropical Medicine, University of São Paulo , São Paulo , Brazil.,b LIM 48- Laboratory of Immunology, Department of Infectious and Parasitic Diseases, School of Medicine, University of São Paulo , São Paulo , Brazil
| | - Kelly Aparecida Kanunfre
- a Laboratory of Seroepidemiology and Immunobiology, Institute of Tropical Medicine, University of São Paulo , São Paulo , Brazil.,b LIM 48- Laboratory of Immunology, Department of Infectious and Parasitic Diseases, School of Medicine, University of São Paulo , São Paulo , Brazil
| | - Thelma Suely Okay
- a Laboratory of Seroepidemiology and Immunobiology, Institute of Tropical Medicine, University of São Paulo , São Paulo , Brazil
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Prusa AR, Kasper DC, Pollak A, Olischar M, Gleiss A, Hayde M. Amniocentesis for the detection of congenital toxoplasmosis: results from the nationwide Austrian prenatal screening program. Clin Microbiol Infect 2014; 21:191.e1-8. [PMID: 25596783 DOI: 10.1016/j.cmi.2014.09.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 09/18/2014] [Accepted: 09/18/2014] [Indexed: 10/24/2022]
Abstract
Prenatal diagnosis of congenital toxoplasmosis (CT) influences therapeutical management in pregnant women and their offspring. In Austria, a nationwide serological healthcare program to identify potential maternal toxoplasma infections during pregnancy exists. We assessed the clinical use of amniocentesis for toxoplasma-specific polymerase chain reaction (PCR) on amniotic fluid to detect CT. Data on serology, amniocentesis, PCR, complications, treatment, and paediatric clinical outcome were collected retrospectively among the birth cohort 1992-2008. There were 1386 women with amniocentesis, but only in 707 cases (51%) was acute maternal infection confirmed serologically. A high proportion (49%) of amniocenteses with negative PCR results in women with chronic infection or seronegativity were performed without clinical justification for the women or their foetuses. The positive and negative predictive values of PCR were 94.4% and 99.3%, respectively. Thirty-nine foetuses with CT, including four deaths, were reported. The five PCR-negative but infected infants were identified by the serological and clinical follow-up program. Thirty percent of amniocenteses were performed in the third trimester, and gestational age or treatment did not influence PCR sensitivity. Amniocentesis is indicated in women with acute maternal infection, and facilitated targeted therapies in pregnant women and their offspring. In women with late toxoplasma infection, negative amniotic fluid PCR made treatment of infants unnecessary. Serological and clinical follow-up of infants is important to confirm the infection status of the infant. Recommendations, based on our 17-year experience, to improve the current diagnostic strategies and to reduce unnecessary amniocentesis, are given.
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Affiliation(s)
- A-R Prusa
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - D C Kasper
- Research Core Unit for Pediatric Biochemistry and Analytics, Medical University of Vienna, Vienna, Austria.
| | - A Pollak
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - M Olischar
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - A Gleiss
- Centre for Medical Statistics, Informatics and Intelligent Systems, Medical University of Vienna, Vienna, Austria
| | - M Hayde
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
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Multicentric comparative assessment of the bio-evolution Toxoplasma gondii detection kit with eight laboratory-developed PCR assays for molecular diagnosis of congenital toxoplasmosis. J Clin Microbiol 2014; 53:29-34. [PMID: 25339393 DOI: 10.1128/jcm.01913-14] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The detection of Toxoplasma gondii in amniotic fluid is an essential tool for the prenatal diagnosis of congenital toxoplasmosis and is currently essentially based on the use of PCR. Although some consensus is emerging, this molecular diagnosis suffers from a lack of standardization and an extreme diversity of laboratory-developed methods. Commercial kits for the detection of T. gondii by PCR were recently developed and offer certain advantages; however, they must be assessed in comparison with optimized reference PCR assays. The present multicentric study aimed to compare the performances of the Bio-Evolution T. gondii detection kit and laboratory-developed PCR assays set up in eight proficient centers in France. The study compared 157 amniotic fluid samples and found concordances of 99% and 100% using 76 T. gondii-infected samples and 81 uninfected samples, respectively. Moreover, taking into account the classification of the European Research Network on Congenital Toxoplasmosis, the overall diagnostic sensitivity of all assays was identical and calculated to be 86% (54/63); specificity was 100% for all assays. Finally, the relative quantification results were in good agreement between the kit and the laboratory-developed assays. The good performances of this commercial kit are probably in part linked to the use of a number of good practices: detection in multiplicate, amplification of the repetitive DNA target rep529, and the use of an internal control for the detection of PCR inhibitors. The only drawbacks noted at the time of the study were the absence of uracil-N-glycosylase and small defects in the reliability of the production of different reagents.
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Abdel Aal AA, Attia SS, Hanafy NA, Al-Antably AS, Hassan MA, El-Sherbiny W, Nasr AS. Molecular Diagnosis of Toxoplasmosis in Non Immune Pregnant Females. Open Access Maced J Med Sci 2014. [DOI: 10.3889/oamjms.2014.071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND AND AIM: Infection with the protozoan parasite Toxoplasma gondii has a worldwide distribution. Congenital infection is the most important part of the disease burden due to Toxoplasma infection in humans. Early diagnosis of maternal infection helps to prevent severe complications of toxoplasmosis. In the present study, three PCR assays (conventional, nested & quantitative) were evaluated for diagnosis of recent toxoplasmosis based on detection of Toxoplasma B1 gene.MATERIAL AND METHODS: The present study was carried out on 150 pregnant females who were serologically negative for anti-Toxoplasma IgG and IgM antibodies.RESULTS: The results revealed that out of 12 true positive cases (by 2 out of the 3 PCR protocols), 8 cases were positive by cPCR, 11 cases were positive by nPCR and 12 cases were positive by qPCR. Accurate estimation of genomic Toxoplasma DNA in positive samples was achieved by qPCR. In general, PCR assays offer a sensitive alternative of serological methods for diagnosis of recent maternal toxoplasmosis. In addition, qPCR decreases the risk of contamination of PCR products being a closed tube method and helps in estimation of infection load.CONCLUSIONS: We recommend screening of high-risk pregnant women by qPCR for early diagnosis of toxoplasmosis and proper management.
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Characterization and multicentric validation of a common standard for Toxoplasma gondii detection using nucleic acid amplification assays. J Clin Microbiol 2014; 52:3952-9. [PMID: 25187637 DOI: 10.1128/jcm.01906-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The molecular diagnosis of toxoplasmosis essentially relies upon laboratory-developed methods and suffers from lack of standardization, hence the large diversity of performances between laboratories. Moreover, quantifications of parasitic loads differ among centers, a fact which prevents the possible prediction of the severity of this disease as a function of parasitic loads. The objectives of this multicentric study performed in eight proficient laboratories of the Molecular Biology Pole of the French National Reference Center for Toxoplasmosis (NRC-T) were (i) to assess the suitability of a lyophilized preparation of Toxoplasma gondii as a common standard for use in this PCR-based molecular diagnosis and (ii) to make this standard available to the community. High-quality written procedures were used for the production and qualification of this standard. Three independent batches of this standard, containing concentrations ranging from 10(4) to 0.01 T. gondii genome equivalents per PCR, were first assessed: the linear dynamic range was ≥ 6 log, the intra-assay coefficients of variation (CV) from a sample containing 10 T. gondii organisms per PCR were 0.3% to 0.42%, and the interassay CV over a 2-week period was 0.76% to 1.47%. A further assessment in eight diagnostic centers showed that the standard is stable, robust, and reliable. These lyophilized standards can easily be produced at a larger scale when needed and can be made widely available at the national level. To our knowledge, this is the first quality control assessment of a common standard which is usable both for self-evaluation in laboratories and for accurate quantification of parasitic loads in T. gondii prenatal infections.
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Murat JB, Fricker Hidalgo H, Brenier-Pinchart MP, Pelloux H. Human toxoplasmosis: which biological diagnostic tests are best suited to which clinical situations? Expert Rev Anti Infect Ther 2014; 11:943-56. [DOI: 10.1586/14787210.2013.825441] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Teixeira LE, Kanunfre KA, Shimokawa PT, Targa LS, Rodrigues JC, Domingues W, Yamamoto L, Okay TS. The performance of four molecular methods for the laboratory diagnosis of congenital toxoplasmosis in amniotic fluid samples. Rev Soc Bras Med Trop 2013. [DOI: 10.1590/0037-8682-0095-2013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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