Molecular diagnosis of strongyloidiasis in tropical areas: a comparison of conventional and real-time polymerase chain reaction with parasitological methods

Paula, Fabiana Martins de; Malta, Fernanda de Mello; Marques, Priscilla Duarte; Sitta, Renata Barnabé; Pinho, João Renato Rebello; Gryschek, Ronaldo César Borges; Chieffi, Pedro Paulo

doi:10.1590/0074-02760140371

Cited by 28 publications

(37 citation statements)

References 12 publications

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“…The screening of patients with risk factors prior to immunosuppression is necessary to prevent hyperinfection (1,31). Studies that measured the clinical sensitivity of the PCR assay designed by Verweij et al compared to morphological identification have provided a benchmark for comparison with the LAMP assay (10)(11)(12)(13)(14)(15)17). The PCR and LAMP assays both targeted components of the ribosomal cistron, which is a single transcription unit (32).…”

Section: Discussionmentioning

confidence: 99%

“…While nucleic acid amplification tests (NAAT) do not require live larvae, their effectiveness may be reduced due to low numbers of larvae, reaction inhibition, and nucleases (8,9). Real-time PCR based on the primers developed by Verweij et al is the most characterized method, and clinical validation studies have demonstrated sensitivities from 33% to 93% and specificities of 85% to 99%, depending on the comparator methods (10)(11)(12)(13)(14)(15). A recent meta-analysis of clinical validation studies calculated a PCR sensitivity of 71.8% compared to morphological identification, while a study comparing PCR to a comprehensive range of stool culture and concentration methods determined a PCR sensitivity of Ͼ90% (16,17).…”

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confidence: 99%

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Comparison of Loop-Mediated Isothermal Amplification and Real-Time PCR Assays for Detection of Strongyloides Larvae in Different Specimen Matrices

et al. 2019

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Strongyloides stercoralis can cause disease that ranges from asymptomatic chronic infection to fatal hyperinfection. Diagnosis from stool can be challenging because the most sensitive conventional tests require live larvae to be effective and there can be low larval output in chronic infection. Nucleic acid amplification tests (NAAT) have been developed to complement existing diagnostic methods. We compared a recently developed loop-mediated isothermal amplification (LAMP) assay with a real-time PCR that has previously been validated with larval microscopy. The limits of detection-quantified using serial dilutions of DNA extracts from single Strongyloides ratti third-stage (L3) larvae spiked into approximately 250 l of 5 different S. stercoralis-negative stool specimens-were 10 Ϫ3 (1/5 replicates) and 10 Ϫ2 (1/5 replicates) dilutions for PCR and LAMP, respectively. PCR was positive for 4/5 replicates at 10 Ϫ2 . LAMP was compared to PCR using extracts from 396 stool specimens collected in Bangladesh and Australia, of which 53 were positive and 343 were negative by PCR. The positive percentage agreement of LAMP was 77.3% (95% score confidence interval [CI], 64.5 to 86.6). The negative percentage agreement was 100% (95% CI, 98.9 to 100). In a preliminary investigation, PCR and LAMP assays were positive using DNA extracted from serum (PCR, 3/16 extracts; LAMP, 2/16 extracts) and bronchoalveolar lavage fluid (PCR and LAMP, 2/2 extracts), demonstrating proof of concept. Compared to PCR, the lower number of positive results using the LAMP assay may have been due to reaction inhibitors and DNA degradation, and strategies to improve the LAMP assay are discussed.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Comparison of Loop-Mediated Isothermal Amplification and Real-Time PCR Assays for Detection of Strongyloides Larvae in Different Specimen Matrices

et al. 2019

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“…To investigate strongyloidiasis, ELISA and real-time PCR were performed on serum and stool samples of all patients. Real-time PCR was used to investigate the presence of the 18S rRNA gene of S. stercoralis instead of microscopy because PCR methods show excellent sensitivity and specificity compared to microscopic methods (21,23). In addition, ELISA, detecting anti-S. stercoralis antibodies in serum samples of patients, was used in combination with real-time PCR to support and increase the positivity.…”

Section: Discussionmentioning

confidence: 99%

Screening of immunocompromised patients at risk of strongyloidiasis in western Turkey using ELISA and real-time PCR

et al. 2017

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Background/aim: Strongyloides stercoralis causes life-threatening hyperinfection or disseminated strongyloidiasis in immunocompromised patients such as HIV-positive, organ transplantation, and cancer patients. This study investigated the presence of strongyloidiasis in immunocompromised patients for the first time in Turkey.Materials and methods: Serum and stool samples were collected from 108 patients (25.9% of them were chronic renal failure and 74.1% were renal transplantation patients) who were admitted to Ege University Medical School in İzmir, located in western Turkey. Serum samples were analyzed by ELISA (DRG, Germany) and the presence of 18S rRNA gene of S. stercoralis was detected in stool samples by real-time PCR. Results:The analysis of serum samples showed that only one patient was anti-S. stercoralis IgG antibody and real-time PCR positive (0.92%). The patient was treated twice with albendazole (400 mg/day for 3 days) at 2-week intervals. Follow up real-time PCR was negative and the patient became seronegative 6 months after the initial diagnosis. Conclusion:This screening showed that the prevalence of strongyloidiasis in this small group of patients who were at risk of strongyloidiasis was 0.92%. Overall, the results showed that more systematic studies are required in Turkey to show the prevalence of strongyloidiasis.

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“…the 18S rRNA small subunit (SSU); the internal transcribed spacer region 1 (ITS-1); the 28S rRNA gene; or the cyclooxygenase gene (cox1) 19,[23][24][25][26][27][28][29][30][32][33][34][35][36][37] . Published sensitivities and specificities for…”

Section: Pcrmentioning

confidence: 99%

The laboratory diagnosis of Strongyloides stercoralis

Watts¹,

Robertson²,

Bradbury

2016

Microbiol. Aust.

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It is estimated that over 30million people worldwide are infected by the nematode, Strongyloides stercoralis1. It is endemic in sub-tropical and tropical parts of Australia, with high rates of infection documented in some indigenous communities2. Due to the potential for chronic autoinfection, that may persist for decades, migration leads to the presence of the infection in non-endemic areas1. Transmission to humans is generally through the penetration of larvae through the skin, following contact with faecally contaminated soil1. Disease severity ranges from asymptomatic chronic carriage to an overwhelming illness, where large numbers spread throughout the body, usually triggered by immunosuppression1.

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Molecular diagnosis of strongyloidiasis in tropical areas: a comparison of conventional and real-time polymerase chain reaction with parasitological methods

Cited by 28 publications

References 12 publications

Comparison of Loop-Mediated Isothermal Amplification and Real-Time PCR Assays for Detection of Strongyloides Larvae in Different Specimen Matrices

Comparison of Loop-Mediated Isothermal Amplification and Real-Time PCR Assays for Detection of Strongyloides Larvae in Different Specimen Matrices

Screening of immunocompromised patients at risk of strongyloidiasis in western Turkey using ELISA and real-time PCR

The laboratory diagnosis of Strongyloides stercoralis

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