scholarly journals Confirmation of multi-parallel quantitative real-time PCR as the gold standard for detecting soil-transmitted helminths in stool

2021 ◽  
Author(s):  
Marina Papaiakovou ◽  
Nils Pilotte ◽  
Julia Dunn ◽  
David TJ Littlewood ◽  
Rubén O Cimino ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Gold Standard ◽  
Low Cost ◽  
Strongyloides Stercoralis ◽  
Diagnostic Methods ◽  
Quantitative Real Time Pcr ◽  
Soil Transmitted Helminths ◽  
Stool Samples ◽  
Kappa Agreement

AbstractDue to its simplicity and cost-effectiveness, microscopy has seen extensive field-use as the diagnostic standard for the detection of soil-transmitted helminths (STH) in stool samples. However, the sensitivity of microscopy-based detection is inadequate in reduced-transmission settings where worm burden is oftentimes low. Equally problematic, eggs of closely related species oftentimes have indistinguishable morphologies, leading to species misidentification. In light of these shortcomings, the purpose of this study was to demonstrate multi-parallel quantitative real-time PCR (qPCR) as the new “gold standard” for STH detection. Accordingly, stool samples from non-endemic participants were spiked with limited numbers of eggs or larvae (1 to 40) of five different species of STH. DNA extracts were tested using two unique multi-parallel real-time PCR-based diagnostic methods. These methods employed different target sequences (ribosomal internal transcribed spacer, or highly repetitive non-coding regions), to evaluate the detection of DNA from as little as one egg per sample. There was a statistically significant kendall correlation between egg/larvae counts and qPCR from both methods for Trichuris trichiura (0.86 and 0.872 for NHM and Baylor assays) and a strong correlation (0.602 and 0.631 for NHM and Baylor assays, respectively) for Ascaris lumbricoides. Less strong but still significant was the Kendall Tau-b value for A. duodenale (0.408 for both) and for S. stercoralis (0.483 and 0.653, respectively). In addition, using field stool samples from rural Argentina both assays had fair to moderate kappa agreement (0.329-0.454), except for Strongyloides stercoralis (0.121) that both assays had slight agreement. In spite of the small cohort of samples, both qPCR assays, targeting of two independent genomic regions, provided reproducible results and we believe that, low cost multi-parallel quantitative real-time PCR-based diagnostics should supplant microscopy as the new gold standard for stool-based detection of soil transmitted helminths in public-health and community settings.

scholarly journals Evaluation of Two DNA Extraction Methods for Detection of Strongyloides stercoralis Infection

2018 ◽  
Vol 56 (4) ◽  
Author(s):  
Beatrice Barda ◽  
Rahel Wampfler ◽  
Somphou Sayasone ◽  
Khampheng Phongluxa ◽  
Syda Xayavong ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Strongyloides Stercoralis ◽  
Extraction Methods ◽  
Molecular Techniques ◽  
Diagnostic Methods ◽  
Content Type ◽  
Stool Samples ◽  
Dna Extraction Methods ◽  
Baermann Method

ABSTRACT Strongyloides stercoralis is present worldwide, but its prevalence is still uncertain, mainly due to the lack of sensitivity of diagnostic methods. Molecular techniques are under development, but a standardized protocol is still unavailable. We compared the sensitivity of real-time PCR, using two extraction protocols, with that of the Baermann technique. Samples were collected in the framework of the baseline screening of a randomized clinical trial evaluating moxidectin against S. stercoralis in Lao People's Democratic Republic. Two stool samples from each participant were processed by the Baermann method, and one subsample was processed by PCR. DNA was extracted using the QIAamp DNA stool minikit based on the standard protocol for the QIAamp DNA minikit (QIA) and using a modification of the QIA procedure (POL). Subsequently, all extracted samples were analyzed by real-time PCR. Overall, 95 samples were analyzed by the three diagnostic methods. Sixty-nine (72.6%) samples were positive according to the Baermann method, 25 (26.3%) by the QIA method, and 62 (65.3%) by the POL method. The sensitivities were 86% (95% confidence interval [CI], 76.7 to 92.9), 31.0% (95% CI, 21.3 to 42.6), and 78.0% (95% CI, 66.8 to 86.1) for the Baermann, QIA, and POL methods, respectively. The sensitivities calculated for each day of the Baermann method separately were 60% (48.4 to 70.8%) and 64% (52.2 to 74.2%) for days 1 and 2, respectively. In conclusion, the POL method revealed a good performance and was comparable to the Baermann test performed on two stool samples and superior to the Baermann method performed on one stool sample. Additional studies are needed to standardize a PCR protocol for S. stercoralis diagnosis.

scholarly journals Cryptosporidium spp. during chemotherapy: a cross-sectional study of 94 patients with malignant solid tumor

2021 ◽  
Vol 41 (5) ◽  
pp. 293-298
Author(s):  
Mehmet Karabey ◽  
Hüseyin Can ◽  
Tülay Öncü Öner ◽  
Mert Döşkaya ◽  
Sedef Erkunt Alak ◽  
...  
Keyword(s):  
Sample Size ◽  
Real Time ◽  
Solid Tumors ◽  
Real Time Pcr ◽  
Tertiary Care ◽  
Diagnostic Methods ◽  
Cross Sectional ◽  
Cryptosporidium Spp ◽  
Stool Samples ◽  
Pcr Targeting

BACKGROUND: Cryptosporidium spp . is a protozoan parasite that infects many vertebrate animals, including humans. Since Cryptosporidium spp . can cause chronic life-threatening diarrhea and severe malabsorption in immunocompromised patients, we investigated the prevalence of this parasite among patients undergoing chemotherapy for malignant solid tumors. OBJECTIVE: Investigate the prevalence of Cryptosporidium spp . in stool samples. DESIGN: Cross-sectional. SETTING: Tertiary care. PATIENTS AND METHODS: Stool samples were collected from adult patients with malignant solid tumors receiving chemotherapy and diarrhea. Cryptosporidium spp . prevalence was determined using Ziehl–Neelsen staining, ELISA, and real-time PCR targeting of the COWP gene. MAIN OUTCOME MEASURE: The prevalence of Cryptosporidium spp . in patients undergoing chemotherapy for malignant solid tumors. SAMPLE SIZE: 94 RESULTS: The prevalence was 2.1% (2/94), 5.3% (5/94), and 5.3% (5/94) as detected by Ziehl–Neelsen staining, real-time PCR and ELISA, respectively. The prevalence reached 8.5% (8/94) using all results obtained from the three methods. Among eight positive stool samples, four were positive by at least two different methods (Ziehl–Neelsen staining-ELISA or ELISA-real-time PCR) whereas the remaining four were positive by either ELISA or real-time PCR. CONCLUSION: These findings show the risk of cryptosporidiosis in cancer patients and the necessity to use at least two diagnostic methods during the diagnosis of cryptosporidiosis to reach more accurate and trustworthy results. LIMITATIONS: Further studies with a larger sample size are recommended. CONFLICT OF INTEREST: None.

scholarly journals Development of Conventional Multiplex PCR: A Rapid Technique for Simultaneous Detection of Soil-Transmitted Helminths

Pathogens ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 152 ◽  
Author(s):  
Vivornpun Sanprasert ◽  
Ruthairat Kerdkaew ◽  
Siriporn Srirungruang ◽  
Sarit Charuchaibovorn ◽  
Kobpat Phadungsaksawasdi ◽  
...  
Keyword(s):  
Multiplex Pcr ◽  
Real Time ◽  
Real Time Pcr ◽  
Intestinal Parasites ◽  
Simultaneous Detection ◽  
Diagnostic Tools ◽  
Multiple Infections ◽  
Parasitic Infections ◽  
Soil Transmitted Helminths ◽  
Stool Samples

Soil-transmitted helminths (STHs) are the most common intestinal parasites infecting humans worldwide. STH infections are a major cause of morbidity and disability. Accurate diagnostic tools are pivotal for assessing the exact prevalence of parasitic infections. Microscopic examination and culture techniques have been used to observe the presence of eggs or larvae of parasites in stool samples, but they are time-consuming and have low sensitivity. Therefore, accurate, simple, and inexpensive diagnostic techniques are still required for simultaneous detection of STH infections. Although molecular-based techniques, such as real-time PCR and multiplex real-time PCR, have been developed, they are not suitable for routine diagnosis due to the requirement for expensive reagents and instruments. In this study, we established a conventional multiplex PCR for simultaneous rapid detection of Ascaris lumbricoides, Necator americanus, and Strongyloides stercoralis in stool samples. Our results show that the multiplex PCR could detect the DNA of STHs at a very low target gene concentrations (lower than 1 pg) with no cross-amplification. Multiplex PCR had five times higher sensitivity than the formalin–ethyl acetate concentration technique (FECT) in the detection of multiple infections, and two times higher for detection of S. stercoralis. However, multiplex PCR was comparable to FECT in the detection of A. lumbricoides and N. americanus. In conclusion, this method could be used as an alternative method for the detection of STHs, especially for S. stercoralis.

Low-Cost Monitoring of Campylobacter in Poultry Houses by Air Sampling and Quantitative PCR

2014 ◽  
Vol 77 (2) ◽  
pp. 325-330 ◽  
Author(s):  
M. S. R. SØNDERGAARD ◽  
M. H. JOSEFSEN ◽  
C. LÖFSTRÖM ◽  
L. S. CHRISTENSEN ◽  
K. WIECZOREK ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Low Cost ◽  
Air Sampling ◽  
Quantitative Risk Assessment ◽  
Quantitative Real Time Pcr ◽  
Airborne Particle ◽  
Air Samples ◽  
Particle Count ◽  
Poultry Houses

The present study describes the evaluation of a method for the quantification of Campylobacter by air sampling in poultry houses. Sampling was carried out in conventional chicken houses in Poland, in addition to a preliminary sampling in Denmark. Each measurement consisted of three air samples, two standard boot swab fecal samples, and one airborne particle count. Sampling was conducted over an 8-week period in three flocks, assessing the presence and levels of Campylobacter in boot swabs and air samples using quantitative real-time PCR. The detection limit for air sampling was approximately 100 Campylobacter cell equivalents (CCE)/m3. Airborne particle counts were used to analyze the size distribution of airborne particles (0.3 to 10 μm) in the chicken houses in relation to the level of airborne Campylobacter. No correlation was found. Using air sampling, Campylobacter was detected in the flocks right away, while boot swab samples were positive after 2 weeks. All samples collected were positive for Campylobacter from week 2 through the rest of the rearing period for both sampling techniques, although levels 1- to 2-log CCE higher were found with air sampling. At week 8, the levels were approximately 104 and 105 CCE per sample for boot swabs and air, respectively. In conclusion, using air samples combined with quantitative real-time PCR, Campylobacter contamination could be detected earlier than by boot swabs and was found to be a more convenient technique for monitoring and/or to obtain enumeration data useful for quantitative risk assessment of Campylobacter.

scholarly journals Direct detection of Helicobacter pylori from biopsies of patients in Lagos, Nigeria using real-time PCR—a pilot study

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
A. Ajayi ◽  
T. Jolaiya ◽  
S. I. Smith
Keyword(s):  
Helicobacter Pylori ◽  
16S Rrna ◽  
Real Time ◽  
Real Time Pcr ◽  
Direct Detection ◽  
Low Cost ◽  
Treatment Options ◽  
Combined Cycle ◽  
Diagnostic Methods ◽  
H Pylori

Abstract Objective Prompt diagnosis of Helicobacter pylori infection is essential for proper treatment and eradication of the pathogen because prolonged infection could lead to gastric cancer. Sensitive and cost effective diagnostic methods are key to guiding treatment options that will reduce mortality. This study was aimed at detecting H. pylori from biopsies of peptic ulcer patients. Real-time PCR using TaqMan and EvaGreen assays targeting 16S rRNA and ureA genes were used to detect H. pylori DNA extracted from 40 biopsy samples comprising 20 biopsies obtained from the antrum and 20 from the corpus of 20 patients undergoing endoscopy for duodenal ulcer investigation in Lagos, Nigeria. Results H. pylori was detected in 80% of the biopsy samples by combined cycle threshold (Ct) and melting temperature (Tm) values. Mean Ct value for ureA gene ranged from 21.40 to 37.53 and 22.71 to 35.44 for 16SrRNA gene. Average melting temperatures (Tm) of 81.57 and 82.90 °C among amplicons of ureA and 16S rRNA were observed respectively. H. pylori DNA was generally detected in biopsies collected from antrum and corpus. Real-time PCR in the diagnosis of H. pylori can be considered a simple, low cost and efficient alternative or addition to the gold standard.

Comparison of commercial and in-house real-time PCR platforms for 15 parasites and microsporidia in human stool samples without a gold standard

Acta Tropica ◽  
2020 ◽  
Vol 207 ◽  
pp. 105516 ◽  
Author(s):  
Thomas Köller ◽  
Andreas Hahn ◽  
Enkhtsetseg Altangerel ◽  
Jaco J. Verweij ◽  
Olfert Landt ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Gold Standard ◽  
Stool Samples ◽  
Without A Gold Standard ◽  
Human Stool

scholarly journals Pneumocystis Jirovecii detection and comparison of multiple diagnostic methods with quantitative real-time PCR in patients with respiratory symptoms

2020 ◽  
Vol 27 (6) ◽  
pp. 1423-1427 ◽  
Author(s):  
Mohammad Y. Alshahrani ◽  
Mohammed Alfaifi ◽  
Irfan Ahmad ◽  
Ali Gaithan Alkhathami ◽  
Abdulrahim Refdan Hakami ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Respiratory Symptoms ◽  
Diagnostic Methods ◽  
Pneumocystis Jirovecii ◽  
Quantitative Real Time Pcr

DEVELOPMENT OF MULTIPLEX REAL-TIME PCR ASSAY FOR SIX PATHOGENS: RAPID TOOL FOR DIAGNOSIS OF BACTERIAL MENINGITIS

2019 ◽  
pp. 60-66
Author(s):  
Viet Quynh Tram Ngo ◽  
Thi Ti Na Nguyen ◽  
Hoang Bach Nguyen ◽  
Thi Tuyet Ngoc Tran ◽  
Thi Nam Lien Nguyen ◽  
...  
Keyword(s):  
Bacterial Meningitis ◽  
Real Time ◽  
Real Time Pcr ◽  
Diagnostic Methods ◽  
Type B ◽  
E Coli ◽  
Pcr Assays ◽  
Set Up ◽  
Etiological Agents ◽  
Suis Serotype

Introduction: Bacterial meningitis is an acute central nervous infection with high mortality or permanent neurological sequelae if remained undiagnosed. However, traditional diagnostic methods for bacterial meningitis pose challenge in prompt and precise identification of causative agents. Aims: The present study will therefore aim to set up in-house PCR assays for diagnosis of six pathogens causing the disease including H. influenzae type b, S. pneumoniae, N. meningitidis, S. suis serotype 2, E. coli and S. aureus. Methods: inhouse PCR assays for detecting six above-mentioned bacteria were optimized after specific pairs of primers and probes collected from the reliable literature resources and then were performed for cerebrospinal fluid (CSF) samples from patients with suspected meningitis in Hue Hospitals. Results: The set of four PCR assays was developed including a multiplex real-time PCR for S. suis serotype 2, H. influenzae type b and N. meningitides; three monoplex real-time PCRs for E. coli, S. aureus and S. pneumoniae. Application of the in-house PCRs for 116 CSF samples, the results indicated that 48 (39.7%) cases were positive with S. suis serotype 2; one case was positive with H. influenzae type b; 4 cases were positive with E. coli; pneumococcal meningitis were 19 (16.4%) cases, meningitis with S. aureus and N. meningitidis were not observed in any CSF samples in this study. Conclusion: our in-house real-time PCR assays are rapid, sensitive and specific tools for routine diagnosis to detect six mentioned above meningitis etiological agents. Key words: Bacterial meningitis, etiological agents, multiplex real-time PCR

Sign in / Sign up

Export Citation Format

Share Document