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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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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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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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Evaluation of serological and molecular tests used to identify Toxoplasma gondii infection in pregnant women attended in a public health service in São Paulo state, Brazil. Diagn Microbiol Infect Dis 2017; 89:13-19. [PMID: 28689893 DOI: 10.1016/j.diagmicrobio.2017.06.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 06/07/2017] [Accepted: 06/09/2017] [Indexed: 11/23/2022]
Abstract
Toxoplasmosis during pregnancy can have severe consequences. The use of sensitive and specific serological and molecular methods is extremely important for the correct diagnosis of the disease. We compared the ELISA and ELFA serological methods, conventional PCR (cPCR), Nested PCR and quantitative PCR (qPCR) in the diagnosis of Toxoplasma gondii infection in pregnant women without clinical suspicion of toxoplasmosis (G1=94) and with clinical suspicion of toxoplasmosis (G2=53). The results were compared using the Kappa index, and the sensitivity, specificity, positive predictive value and negative predictive value were calculated. The results of the serological methods showed concordance between the ELISA and ELFA methods even though ELFA identified more positive cases than ELISA. Molecular methods were discrepant with cPCR using B22/23 primers having greater sensitivity and lower specificity compared to the other molecular methods.
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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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Conventional polymerase chain reaction for the diagnosis of neurotoxoplasmosis: comparison of three sets of primers for the B1 gene using CSF samples. Diagn Microbiol Infect Dis 2012. [PMID: 23182076 DOI: 10.1016/j.diagmicrobio.2012.10.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Polymerase chain reaction (PCR) has made a significant improvement in the diagnosis of toxoplasmic encephalitis (TE). Nevertheless, a wide variety of targets and primers has been used in different assays, and few comparative studies had been carried out. The aim of the present study was to compare the efficiency of 3 conventional PCR methods by using 3 sets of primers targeting the repetitive B1 gene in the diagnosis of TE. Diagnostic sensitivity and specificity of PCR and nested-PCR protocols were assessed for 207 (nested-PCR/T1-T4), 200 (nested-PCR/S1-AS1), and 206 (PCR/B22-B23) cerebrospinal fluid (CSF) samples, including AIDS and HIV-negative patients. The diagnostic sensitivity of PCR and nested-PCR assays was 50.85%, 68.97%, and 72.41% for T1-T4, S1-AS1, and B22-B23, respectively. The diagnostic specificity was high for all the assays showing values between 95% and 97%. In general, the best results were obtained for the B22-B23 set of primers, suggesting their usefulness compared with 2 nested-PCR protocols and showing that this simple and rapid strategy may be the preferred one for the diagnosis of TE in AIDS patients.
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Rahumatullah A, Khoo BY, Noordin R. Triplex PCR using new primers for the detection of Toxoplasma gondii. Exp Parasitol 2012; 131:231-8. [PMID: 22561042 DOI: 10.1016/j.exppara.2012.04.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 03/31/2012] [Accepted: 04/11/2012] [Indexed: 11/19/2022]
Abstract
Molecular methods are used increasingly for the detection of Toxoplasma gondii infection. This study developed a rapid, sensitive, and specific conventional triplex PCR for the detection of the B1 gene and ITS1 region of T. gondii using newly designed primers and an internal control based on the Vibrio cholerae HemM gene. The annealing temperature and concentrations of the primers, MgCl(2), and dNTPs were optimized. Two sets of primers (set 1 and 2) were tested, which contained different segments of the T. gondii B1 gene, 529 repeat region and ITS1 region. A series of sensitivity tests were performed using parasite DNA, whole parasites, and spiked human body fluids. Specificity tests were performed using DNA from common protozoa and bacteria. The newly developed assay based on set 2 primers was found to be specific and sensitive. The test was capable of detecting as little as 10 pg T. gondii DNA, 10(4) tachyzoites in spiked body fluids, and T. gondii DNA in the organ tissues of experimentally infected mice. The assay developed in this study will be useful for the laboratory detection of T. gondii infection.
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Affiliation(s)
- Anizah Rahumatullah
- Institute for Research in Molecular Medicine, Universiti Sains Malaysia, Penang, Malaysia.
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Marques P, O’ Donovan J, Williams E, Gutierrez J, Worrall S, McElroy M, Proctor A, Brady C, Sammin D, Bassett H, Buxton D, Maley S, Markey B, Nally J. Detection of Toxoplasma gondii antigens reactive with antibodies from serum, amniotic, and allantoic fluids from experimentally infected pregnant ewes. Vet Parasitol 2012; 185:91-100. [DOI: 10.1016/j.vetpar.2011.10.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 10/12/2011] [Accepted: 10/19/2011] [Indexed: 10/15/2022]
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Marques PX, O’ Donovan J, Souda P, Gutierrez J, Williams EJ, Worrall S, McElroy M, Proctor A, Brady C, Sammin D, Basset H, Whitelegge JP, Markey BK, Nally JE. Amniotic and allantoic fluids from experimentally infected sheep contain immunoglobulin specific for Chlamydophila abortus. Vet Immunol Immunopathol 2011; 140:1-9. [DOI: 10.1016/j.vetimm.2010.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 10/29/2010] [Accepted: 11/01/2010] [Indexed: 11/29/2022]
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Polymerase chain reaction in the diagnosis of congenital toxoplasmosis: more than two decades of development and evaluation. Parasitol Res 2011; 108:505-12. [PMID: 21221639 DOI: 10.1007/s00436-010-2245-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2010] [Accepted: 12/21/2010] [Indexed: 10/18/2022]
Abstract
Toxoplasmosis, a protozoan disease caused by the coccidian parasite Toxoplasma gondii, is one of the most prevalent parasitic diseases of humans. Although most infections are subclinical and asymptomatic, it has a great importance with respect to immunocompromized hosts and congenitally infected newborns. The diagnosis of T. gondii infection has gained in great interest over the past decades with a wide variety of techniques being investigated from animal inoculation to advanced molecular techniques. This paper reviews and highlights the development and evaluation of polymerase chain reaction in the diagnosis of congenital toxoplasmosis in human population to present the redundant research on it in a chronologically simple approach.
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Gutierrez J, O’Donovan J, Williams E, Proctor A, Brady C, Marques P, Worrall S, Nally J, McElroy M, Bassett H, Sammin D, Buxton D, Maley S, Markey B. Detection and quantification of Toxoplasma gondii in ovine maternal and foetal tissues from experimentally infected pregnant ewes using real-time PCR. Vet Parasitol 2010; 172:8-15. [DOI: 10.1016/j.vetpar.2010.04.035] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 04/19/2010] [Accepted: 04/27/2010] [Indexed: 11/17/2022]
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12
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Accuracy of real-time polymerase chain reaction for Toxoplasma gondii in amniotic fluid. Obstet Gynecol 2010; 115:727-733. [PMID: 20308831 DOI: 10.1097/aog.0b013e3181d57b09] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To provide clinicians with information about the accuracy of real-time polymerase chain reaction (PCR) analysis of amniotic fluid for the prenatal diagnosis of congenital Toxoplasma infection. METHODS This was a prospective cohort study of women with Toxoplasma infection identified by prenatal screening in three centers routinely carrying out real-time PCR for the detection of Toxoplasma gondii in amniotic fluid. The data available were gestational age at maternal infection, types and dates of maternal treatment, results of amniocentesis and neonatal work-up and definitive infectious status of the child. We estimated sensitivity, specificity and positive and negative predictive values both overall and per trimester of pregnancy at the time of maternal infection. RESULTS Polymerase chain reaction analysis was carried out on amniotic fluid for 261 of the 377 patients included (69%). It was accurate with the exception of four negative results in children who were infected. Overall sensitivity and negative predictive value were 92.2% (95% confidence interval [CI] 81-98%) and 98.1% (95% CI 95-99.5%), respectively. There was no significant association with the trimester of pregnancy during which maternal infection occurred. Specificity and positive predictive values of 100% were obtained for all trimesters. CONCLUSION Real-time PCR analysis significantly improves the detection of T. gondii on amniotic fluid. It provides an accurate tool to predict fetal infection and to decide on appropriate treatment and surveillance. However, postnatal follow-up remains necessary in the first year of life to fully exclude infection in children for whom PCR results were negative. LEVEL OF EVIDENCE III.
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Mesquita RT, Ziegler ÂP, Hiramoto RM, Vidal JE, Pereira-Chioccola VL. Real-time quantitative PCR in cerebral toxoplasmosis diagnosis of Brazilian human immunodeficiency virus-infected patients. J Med Microbiol 2010; 59:641-647. [PMID: 20150319 DOI: 10.1099/jmm.0.016261-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cerebral toxoplasmosis is the most common cerebral mass lesion in AIDS patients in Brazil, and results in high mortality and morbidity, despite free access to HAART (highly active antiretroviral treatment). Molecular diagnosis based on conventional PCR (cnPCR) or real-time quantitative PCR (qrtPCR) has been indispensable for definitive diagnosis. We report here the evaluation of qrtPCR with blood and cerebrospinal fluid (CSF) samples from AIDS patients in Brazil. This prospective study was conducted for 2 years, analysing DNA samples extracted from 149 AIDS patients (98 blood and 51 CSF samples) with confirmed clinical and radiological diagnosis. The laboratory diagnosis included cnPCR (with the B22/B23 primer set) and indirect immunofluorescence (IF). For qrtPCR, two primer sets were simultaneously designed based on described genes and using a 6-carboxyfluorescein dye-labelled TaqMan MGB (minor groove binder) probe. One was B1Tg, which amplified a sequence from the B1 gene. The other was the RETg, which amplified a PCR product of the 529 bp sequence. The overall cnPCR and qrtPCR results were: positive results were observed in 33.6% (50) patients. The sensitivities were 98% for cnPCR (B22/B23), and 86 and 98% for qrtPCR (B1Tg and RETg, respectively). Negative reactions were observed in 66.4% patients. The specificities were 97% for cnPCR and qrtPCR (B1Tg), and 88.8 % for RETg. These data show that RETg PCR is highly sensitive as it amplifies a repeat region with many copies; however, its specificity is lower than the other markers. However, B1Tg PCR had good specificity, but lower sensitivity. Among the patients, 20 had blood and CSF collected simultaneously. Thus, their results permitted us to analyse and compare molecular, serological and clinical diagnosis for a better understanding of the different scenarios of laboratorial and clinical diagnosis. For nine patients with confirmed cerebral toxoplasmosis diagnosis, four scenarios were observed: (i) and (ii) negative molecular diagnosis for CSF and positive for blood with variable IF titres for the sera and CSF (negative or positive); (iii) positive molecular diagnosis with CSF and negative with blood; and (iv) positive molecular diagnosis in both samples. In the latter two situations, normally the IF titres in sera and CSF are variable. Other opportunistic infections were shown in 11 patients. Despite the IF titres in sera and CSF being variable, all of them had negative molecular diagnosis for both samples. qrtPCR allows for a rapid identification of Toxoplasma gondii DNA in patient samples; in a minority of cases discrepancies occur with the cnPCR.
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Affiliation(s)
- Rafael T Mesquita
- Laboratório de Parasitologia, Instituto Adolfo Lutz, Sao Paulo, SP, Brazil
| | - Ângela P Ziegler
- Departamento de Neurologia, Instituto de Infectologia Emílio Ribas, Sao Paulo, SP, Brazil
| | - Roberto M Hiramoto
- Laboratório de Parasitologia, Instituto Adolfo Lutz, Sao Paulo, SP, Brazil
| | - Jose E Vidal
- Serviço de Extensão ao Atendimento de Pacientes HIV/AIDS, Divisão de Moléstias Infecciosas e Parasitárias, Hospital das Clínicas da Faculdade de Medicina da Universidade de Sao Paulo, Sao Paulo, SP, Brazil.,Departamento de Neurologia, Instituto de Infectologia Emílio Ribas, Sao Paulo, SP, Brazil
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Detection of Toxoplasma gondii oocysts in water sample concentrates by real-time PCR. Appl Environ Microbiol 2009; 75:3477-83. [PMID: 19363083 DOI: 10.1128/aem.00285-09] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PCR techniques in combination with conventional parasite concentration procedures have potential for the sensitive and specific detection of Toxoplasma gondii oocysts in water. Three real-time PCR assays based on the B1 gene and a 529-bp repetitive element were analyzed for the detection of T. gondii tachyzoites and oocysts. Lower sensitivity and specificity were obtained with the B1 gene-based PCR than with the 529-bp repeat-based PCR. New procedures for the real-time PCR detection of T. gondii oocysts in concentrates of surface water were developed and tested in conjunction with a method for the direct extraction of inhibitor-free DNA from water. This technique detected as few as one oocyst seeded to 0.5 ml of packed pellets from water samples concentrated by Envirocheck filters. Thus, this real-time PCR may provide a detection method alternative to the traditional mouse assay and microscopy.
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Okay TS, Yamamoto L, Oliveira LC, Manuli ER, Andrade Junior HFD, Del Negro GMB. Significant performance variation among PCR systems in diagnosing congenital toxoplasmosis in São Paulo, Brazil: analysis of 467 amniotic fluid samples. Clinics (Sao Paulo) 2009; 64:171-6. [PMID: 19330240 PMCID: PMC2666456 DOI: 10.1590/s1807-59322009000300004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Accepted: 11/01/2008] [Indexed: 12/02/2022] Open
Abstract
INTRODUCTION Performance variation among PCR systems in detecting Toxoplasma gondii has been extensively reported and associated with target genes, primer composition, amplification parameters, treatment during pregnancy, host genetic susceptibility and genotypes of different parasites according to geographical characteristics. PATIENTS A total of 467 amniotic fluid samples from T. gondii IgM- and IgG-positive Brazilian pregnant women being treated for 1 to 6 weeks at the time of amniocentesis (gestational ages of 14 to 25 weeks). METHODS One nested-B1-PCR and three one-round amplification systems targeted to rDNA, AF146527 and the B1 gene were employed. RESULTS Of the 467 samples, 189 (40.47%) were positive for one-round amplifications: 120 (63.49%) for the B1 gene, 24 (12.69%) for AF146527, 45 (23.80%) for both AF146527 and the B1 gene, and none for rDNA. Fifty previously negative one-round PCR samples were chosen by computer-assisted randomization analysis and re-tested (nested-B1-PCR), during which nine additional cases were detected (9/50 or 18%). DISCUSSION The B1 gene PCR was far more sensitive than the AF146527 PCR, and the rDNA PCR was the least effective even though the rDNA had the most repetitive sequence. Considering that the four amplification systems were equally affected by treatment, that the amplification conditions were optimized for the target genes and that most of the primers have already been reported, it is plausible that the striking differences found among PCR performances could be associated with genetic diversity in patients and/or with different Toxoplasma gondii genotypes occurring in Brazil. CONCLUSION The use of PCR for the diagnosis of fetal Toxoplasma infections in Brazil should be targeted to the B1 gene when only one gene can be amplified, preferably by nested amplification with primers B22/B23.
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Affiliation(s)
- Thelma Suely Okay
- Laboratory of Medical Investigation, Instituto da Criança, Faculdade de Medicina da Universidade de São Paulo - São Paulo/SP, Brazil.
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Nagy B, Varkonyi T, Molvarec A, Lazar L, Hupuczi P, Gabor Than N, Rigo J. Leptin gene (TTTC)n microsatellite polymorphism in pre-eclampsia and HELLP syndrome. Clin Chem Lab Med 2009; 47:1033-7. [DOI: 10.1515/cclm.2009.243] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Caner A, Döşkaya M, Karasu Z, Değirmenci A, Guy E, Kiliç M, Zeytunlu M, Francis J, Bozoklar A, Gürüz Y. Incidence and diagnosis of active toxoplasma infection among liver transplant recipients in Western Turkey. Liver Transpl 2008; 14:1526-32. [PMID: 18825713 DOI: 10.1002/lt.21558] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Toxoplasmosis is a serious and potentially life-threatening disease in liver transplant recipients while they are immunosuppressed. We report the clinical and laboratory findings related to active toxoplasma infection associated with 40 immunosuppressed liver transplant procedures that took place over a 12-month period at a major transplant unit in Izmir, Turkey. Twenty-seven (67.5%) of the 40 transplant recipients were found to be seropositive for toxoplasma infection and therefore at risk of reactivated infection. From the serological status of the donors, which was ascertained in 38 of 40 cases, we identified 3 (7.9%) of 38 transplants to be from a seropositive donor to a seronegative recipient. In 10 (26.3%) of 38 transplants, both the donor and recipient were seronegative, and this excluded toxoplasma as a risk. A comparison of real-time polymerase chain reaction (PCR) and nested PCR was undertaken in combination with a range of serological assays (the Sabin-Feldman dye test, enzyme immunoassay immunoglobulin M, and immunosorbent agglutination assay immunoglobulin M). Ethylene diamine tetraacetic acid blood samples from 3 of the 30 recipients at risk from toxoplasma were found positive by PCR, but only 1 of these was found positive in both assays. Among the 3 PCR-positive patients, immunoglobulin M and immunoglobulin G antibody levels increased in only 1 patient. Correlations between symptoms, laboratory findings, and clinical management (use of anti-toxoplasma therapy) are presented. Our findings suggest that toxoplasma presents a significant risk to our liver transplant population and that PCR is a helpful addition in identifying active infections and hence in informing clinical management decisions.
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Affiliation(s)
- Ayşe Caner
- Department of Parasitology, Ege University Medical School, Bornova/Izmir, Turkey
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Quantitative real-time PCR is not more sensitive than "conventional" PCR. J Clin Microbiol 2008; 46:1897-900. [PMID: 18400914 DOI: 10.1128/jcm.02258-07] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Nagy B, Lázár L, Nagy G, Bán Z, Papp Z. Detection of Toxoplasma gondii in amniotic fluid using quantitative real-time PCR method. Orv Hetil 2007; 148:935-8. [PMID: 17509974 DOI: 10.1556/oh.2007.27971] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Bevezetés:
A
Toxoplasma gondii (T. gondii)
által okozott fertőzés általában tünetmentes, vagy csak enyhe panaszokat okoz. A terhesekre azonban veszélyt jelent a parazita. A
T. gondiiv
al fertőzött anyáról a kórokozó transplacentalisan a magzatot is megfertőzheti és congenitalis toxoplasmosist okozhat, amely súlyos magzati elváltozásokat idézhet elő. A korai diagnózis a kezelés sikerét növeli. A congenitalis toxoplasmosis kimutatható szerológiai és molekuláris biológiai módszerekkel.
Cél:
A
T. gondii
kimutatása a kvantitatív valós idejű PCR-módszerrel magzatvízből.
Módszerek:
A magzatvízből a DNS-t szilika adszorbciós módszerrel izoláltuk. A
T. gondii
kimutatása 74 mintából történt meg kvantitatív valós idejű PCR-módszerrel.
Eredmények:
A szerzők 74 magzatvízmintából hat esetben mutatták ki a parazita jelenlétét.
Konklúzió:
A kvantitatív valós idejű PCR-módszer megnöveli a kimutatás gyorsaságát és érzékenységét, valamint lehetőséget nyújt a kórokozó mennyiségi meghatározására is. Ez új utat nyithat a prognózis megállapítására, valamint a kezelés eredményességének a monitorizálására.
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Affiliation(s)
- Bálint Nagy
- Semmelweis Egyetem, Altalános Orvostudományi Kar, I. Szülészeti és Nogyógyászati Klinika, Budapest.
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Maubon D, Brenier-Pinchart MP, Fricker-Hidalgo H, Pelloux H. [Real-time PCR in the diagnosis of toxoplasmosis: the way to standardisation?]. ACTA ACUST UNITED AC 2007; 55:304-11. [PMID: 17303349 DOI: 10.1016/j.patbio.2006.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2006] [Accepted: 11/15/2006] [Indexed: 11/24/2022]
Abstract
Severity of toxoplasmosis is highly correlated to the immune status of the infected individual. Foetus and immunocompromised patient are mostly at risk to develop life threatening forms. In this situation, serological diagnosis gives poor information. DNA detection using polymerase-chain-reaction technology (PCR) has significantly improved the management of this disease. Even so, the growing number of conventional PCR assays has finally led to variable performance results. Real-Time PCR (RT-PCR) in toxoplasmosis has been developed since 2000. This new technology can improve standardisation. Moreover, quantification of parasitic load in samples becomes possible. This review describes the main RT-PCR procedures actually under use and the studies comparing different target genes. The effective benefit of quantification is also discussed. Reducing number of procedures and more systematic external quality control should be considered, in order to improve reliability in PCR results, which has undoubtedly become a major tool in toxoplasmosis diagnosis.
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Affiliation(s)
- D Maubon
- Parasitologie-mycologie, département des agents infectieux, centre hospitalier universitaire, BP 217, 38043 Grenoble, cedex 09, France.
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Kaiser K, Van Loon AM, Pelloux H, Ferrandiz J, Picot S, Wallace P, Peyron F. Multicenter proficiency study for detection of Toxoplasma gondii in amniotic fluid by nucleic acid amplification methods. Clin Chim Acta 2007; 375:99-103. [PMID: 16860303 DOI: 10.1016/j.cca.2006.06.016] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2006] [Revised: 06/14/2006] [Accepted: 06/14/2006] [Indexed: 01/01/2023]
Abstract
UNLABELLED A proficiency panel was designed to assess the performance of nucleic acid amplification technologies for the detection of Toxoplasma gondii in amniotic fluid. METHODS The proficiency panel consisted of five lyophilised coded samples in a range of concentration between 5 to 1000 parasites/ml and a negative control. The distribution also included a questionnaire on the applied methods. RESULTS Thirty-three laboratories in 17 countries participated and returned a total of 38 data sets. The percentage of data sets achieving correct results on all panel samples was 42.1%, whereas two or more incorrect or equivocal results were reported for 36.8%. The lowest concentration (5 parasites/ml) was not identified correctly in 15 (39.5%) data sets. False positive results were reported by two laboratories both of which had not included a step in their procedure to rule out contamination. In 32 (84.2%) data sets an "in-house" method was used, and in 6 (15.8%) sets a commercial assay was applied. CONCLUSIONS Overall, the results of this study demonstrate the need for improvements in both sensitivity and specificity of molecular detection methods of T. gondii and for the development of international reference materials to help laboratories with the development and validation of their assays.
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Affiliation(s)
- Karine Kaiser
- Parasitology Laboratory, Hôpital de la Croix Rousse, Lyon, France
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