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BMC Infectious Diseases Feb 2024Sexually transmitted infections (STIs) such as syphilis and HIV remain to be a significant public health issue worldwide. Dual rapid point-of-care tests (POCTs) have...
BACKGROUND
Sexually transmitted infections (STIs) such as syphilis and HIV remain to be a significant public health issue worldwide. Dual rapid point-of-care tests (POCTs) have shown promise for detecting antibodies to HIV and syphilis but have not been fully evaluated in the field. Our study supported the WHO ProSPeRo study on Sexually Transmitted Infection Point-of-Care Testing (STI POCT) by providing external quality assessment (EQA) for HIV and syphilis testing in reference laboratories and their associated clinical sites in seven countries.
METHODS
HIV/syphilis serum liquid and dried tube specimen (DTS) panels were prepared by CDC. Liquid panels were distributed to the reference laboratories for three rounds of testing using commercially and locally available laboratory-based serological tests. DTS panels were sent to the clinical testing sites for 8 rounds of POC testing using the Abbott SD BIOLINE HIV/Syphilis Duo test (hereafter referred to as SD BIOLINE) and the Chembio Dual Path Platform (DPP) HIV-Syphilis assay. EQA panels were tested at CDC using the Rapid Plasma Reagin (RPR) test and the Treponema pallidum Particle Agglutination assay (TP-PA) for syphilis antibodies. Genetic Systems HIV-1/HIV-2 Plus O EIA, Geenius HIV Supplemental Assay and the Oraquick Advance HIV test were used to detect HIV antibodies in the EQA panels. Results from the reference laboratories and POCT sites were compared to those obtained at the CDC and a percentage agreement was calculated.
RESULTS
Qualitative RPR and TP-PA performed at the reference laboratories demonstrated 95.4-100% agreement with CDC results while quantitative RPR and TP-PA tests demonstrated 87.7% and 89.2% agreement, respectively. A 93.8% concordance rate was observed for qualitative HIV testing in laboratories. EQA testing at clinical sites using dual tests showed 98.7% and 99.1% agreement for detection of HIV antibodies and eight out of 10 sites had > 95.8% agreement for syphilis testing. However, two clinical sites showed only 65.0-66.7% agreement for SD BIOLINE and 84.0-86.7% for DPP, respectively, for syphilis testing.
CONCLUSIONS
Overall, laboratories demonstrated high EQA performance in this study. Both HIV/syphilis POCTs gave expected results in the clinic-based evaluations using DTS. However, testing errors were identified in a few testing sites suggesting the necessity for continuous training and monitoring the quality of POC testing.
Topics: Humans; Syphilis; Treponema pallidum; HIV Antibodies; HIV Infections; Sensitivity and Specificity; Antibodies, Bacterial; Point-of-Care Testing; Syphilis Serodiagnosis; HIV-2; HIV-1; World Health Organization; Point-of-Care Systems
PubMed: 38418989
DOI: 10.1186/s12879-024-09027-3 -
JIMD Reports Nov 2023Measurement of plasma and dried blood spot (DBS) phenylalanine (Phe) is key to monitoring patients with phenylketonuria (PKU). The relationship between plasma and...
Measurement of plasma and dried blood spot (DBS) phenylalanine (Phe) is key to monitoring patients with phenylketonuria (PKU). The relationship between plasma and capillary DBS Phe concentrations has been investigated previously, however, differences in methodology, calibration approach and assumptions about the volume of blood in a DBS sub-punch has complicated this. Volumetric blood collection devices (VBCDs) provide an opportunity to re-evaluate this relationship. Paired venous and capillary samples were collected from patients with PKU ( = 51). Capillary blood was collected onto both conventional newborn screening (NBS) cards and VBCDs. Specimens were analysed by liquid-chromatography tandem mass-spectrometry (LC-MS/MS) using a common calibrator. Use of VBCDs was evaluated qualitatively by patients. Mean bias between plasma and volumetrically collected capillary DBS Phe was -13%. Mean recovery (SD) of Phe from DBS was 89.4% (4.6). VBCDs confirmed that the volume of blood typically assumed to be present in a 3.2 mm sub-punch is over-estimated by 9.7%. Determination of the relationship between plasma and capillary DBS Phe, using a single analytical method, common calibration and VBCDs, demonstrated that once the under-recovery of Phe from DBS has been taken into account, there is no significant difference in the concentration of Phe in plasma and capillary blood. Conversely, comparison of plasma Phe with capillary DBS Phe collected on a NBS card highlighted the limitations of this approach. Introducing VBCDs for the routine monitoring of patients with PKU would provide a simple, acceptable specimen collection technique that ensures consistent sample quality and produces accurate and precise blood Phe results which are interchangeable with plasma Phe.
PubMed: 37927487
DOI: 10.1002/jmd2.12398 -
The Lancet. Infectious Diseases May 2024The first licensed malaria vaccine, RTS,S/AS01, confers moderate protection against symptomatic disease. Because many malaria infections are asymptomatic, we conducted a...
Genotypic analysis of RTS,S/AS01 malaria vaccine efficacy against parasite infection as a function of dosage regimen and baseline malaria infection status in children aged 5-17 months in Ghana and Kenya: a longitudinal phase 2b randomised controlled trial.
BACKGROUND
The first licensed malaria vaccine, RTS,S/AS01, confers moderate protection against symptomatic disease. Because many malaria infections are asymptomatic, we conducted a large-scale longitudinal parasite genotyping study of samples from a clinical trial exploring how vaccine dosing regimen affects vaccine efficacy.
METHODS
Between Sept 28, 2017, and Sept 25, 2018, 1500 children aged 5-17 months were randomly assigned (1:1:1:1:1) to receive four different RTS,S/AS01 regimens or a rabies control vaccine in a phase 2b open-label clinical trial in Ghana and Kenya. Participants in the four RTS,S groups received two full doses at month 0 and month 1 and either full doses at month 2 and month 20 (group R012-20); full doses at month 2, month 14, month 26, and month 38 (group R012-14); fractional doses at month 2, month 14, month 26, and month 38 (group Fx012-14; early fourth dose); or fractional doses at month 7, month 20, and month 32 (group Fx017-20; delayed third dose). We evaluated the time to the first new genotypically detected infection and the total number of new infections during two follow-up periods (12 months and 20 months) in more than 36 000 dried blood spot specimens from 1500 participants. To study vaccine effects on time to the first new infection, we defined vaccine efficacy as one minus the hazard ratio (HR; RTS,S vs control) of the first new infection. We performed a post-hoc analysis of vaccine efficacy based on malaria infection status at first vaccination and force of infection by month 2. This trial (MAL-095) is registered with ClinicalTrials.gov, NCT03281291.
FINDINGS
We observed significant and similar vaccine efficacy (25-43%; 95% CI union 9-53) against first new infection for all four RTS,S/AS01 regimens across both follow-up periods (12 months and 20 months). Each RTS,S/AS01 regimen significantly reduced the mean number of new infections in the 20-month follow-up period by 1·1-1·6 infections (95% CI union 0·6-2·1). Vaccine efficacy against first new infection was significantly higher in participants who were infected with malaria (68%; 95% CI 50-80) than in those who were uninfected (37%; 23-48) at the first vaccination (p=0·0053).
INTERPRETATION
All tested dosing regimens blocked some infections to a similar degree. Improved vaccine efficacy in participants infected during vaccination could suggest new strategies for highly efficacious malaria vaccine development and implementation.
FUNDING
GlaxoSmithKline Biologicals SA, PATH, Bill & Melinda Gates Foundation, and the German Federal Ministry of Education and Research.
PubMed: 38723650
DOI: 10.1016/S1473-3099(24)00179-8 -
Plant Methods Feb 2024Herbaria are becoming increasingly important as archives of biodiversity, and play a central role in taxonomic and biogeographic studies. There is also an ongoing...
BACKGROUND
Herbaria are becoming increasingly important as archives of biodiversity, and play a central role in taxonomic and biogeographic studies. There is also an ongoing interest in functional traits and the way they mediate interactions between a plant species and its environment. Herbarium specimens allow tracking trait values over time, and thus, capturing consequences of anthropogenic activities such as eutrophication. Here, we present an open, reproducible, non-destructive workflow to collect leaf trait data from herbarium specimens using near-infrared spectroscopy (NIRS), and a proof of concept for the reliability of this approach.
RESULTS
We carried out three experiments to test the suitability of non-destructive NIRS methods to predict leaf traits both for fresh and dried leaves: (1) With a fertilization experiment, we studied whether NIRS was able to capture changes in leaf N and leaf P during a fertilization experiment and we compared contents predicted by NIRS with results obtained from regular wet lab methods. Calibration models for leaf nitrogen and phosphorus contents had a quality of R = 0.7 and 0.5, respectively. We fitted calibration models for NIRS readings on fresh and dried leaf samples, both of which produced equally precise predictions compared to results from wet lab analyses. (2) We tested the effect of herbarium conservation on NIRS readings by simulating them through the application of six treatments combining freezing, drying and pesticide spraying in a factorial scheme and comparing these with untreated samples. No consistent changes were observed in the spectra quality before and after the simulated herbarium conditions. (3) Finally, we studied the effect of specimen storage duration using specimens from a 2018 study which were re-analyzed and compared with spectra obtained in 2021. No consistent changes in spectra were observed after the storage period.
CONCLUSIONS
The results demonstrate the reliability of NIRS to measure leaf N and P on herbarium samples. Together with the calibration method and dataset presented here, they provide a toolset allowing researchers to study the development of leaf traits and their response to environmental changes over decades and even centuries in a fast and non-destructive manner.
PubMed: 38303074
DOI: 10.1186/s13007-024-01146-x -
Plant Disease Sep 2023Epipremnum pinnatum (L.) Engl., (Araceae, Monocots) known as dragon-tail plant or centipede tongavine, is the most cultivated aroid species worldwide (Boyce 2004). In...
Epipremnum pinnatum (L.) Engl., (Araceae, Monocots) known as dragon-tail plant or centipede tongavine, is the most cultivated aroid species worldwide (Boyce 2004). In 2022, symptomatic dragon-tail plants, collected from plant nurseries in south Florida (e-Xtra Fig.1). Symptoms included round leaf spots often with a yellow halo and erupting pustules mainly distributed in the underside of the leaves. Visits to the nurseries revealed a 60% incidence of approximability 50 mature plants, with some leaves showing up to 30% of tissue damage. The putative pathogen was identified morphologically as Pseudocerradoa paullula (Syd. & P. Syd.) M. Ebinghaus & Dianese (Pucciniaceae, Basidiomycota) (Ebinghaus et al. 2022), characterized by the production of pseudosuprastomatal uredinia with globose to subglobose urediniospores, light-brown, echinulate (1 µm height), 24-31 µm diam with thick walls, 1.5-2.5 µm in height (n=30). Identical morphological features reported by Urbina et al. (2023) (e-Xtra Fig. 1). PCR amplification followed by Sanger sequencing of the internal transcribed spacer (ITS) and large subunit (LSU) of the ribosomal RNA genes (Aime 2006) together with LSU internal species specific primer (Urbina et al. 2023) were used to confirm the identification of the pathogen (GenBank ON887194-ON887196). MegaBlast (Chen et al. 2015) searches resulted in a >99% sequence similarity to a P. paullula specimen collected in Florida (2019-101665, GenBank ON887197). Host identification was made by using the Ribulose-1,5-bisphosphate carboxylase-oxygenase (rbcL. GenBank ON887186, ON887187) and Maturase K (matK) loci (GenBank ON887190, ON887191) (Fazekas et al. 2012). Both barcodes resulted in >99.13% sequence similarity to voucher J.R. Abbott 24912 FLAS (GenBank GU135198 and GU135036, respectively). Symptomatic dried specimens were deposited in the Plant Industry Herbarium (PIHG 16229 - 16232). Koch's postulates were fulfilled using urediniospores collected from an infected E. pinnatum sample that was kept in darkness at 4°C for seven days until inoculation. Eight potted dragon-tail plants were inoculated by hand rubbing urediniospores against upper and lower leaf surfaces and three plants were used as controls. All plants were misted with sterile water and covered with plastic bags (23 °C, >90% RH, 12/12 h daylight). Bags were removed 48 h after inoculation, plants were set in a climate-controlled greenhouse (~30 °C, ~65% RH, 12/12 h light cycle) and monitored daily for symptoms. Chlorotic spots appeared after 10 days, and pustules after 25 days while the non-inoculated controls remained symptomless. Aroid leaf rust is known to infect several aroid species, including dragon-tail (Shaw 1995), which some varieties capable to outdoors in USDA 9a hardiness zones (Wunderlin et al. 2023), but the rust fungus has not been observed on any species of Epipremnum in the landscape yet, suggesting that its susceptibility could be driven by plant growth conditions that favor pathogen infection (e.g., excess of humidity and nutrients, dense planting, overhead irrigation, etc.). Here we encourage dragon-tail plant growers to be aware of its susceptibility to P. paullula and to stay vigilant of the culture conditions to avoid plants from getting infected with this airborne pathogen.
PubMed: 37755418
DOI: 10.1094/PDIS-07-23-1360-PDN -
Journal of Pharmaceutical and... Apr 2024The detection of nitazenes in biological fluids is increasingly needed as they are repeatedly reported in intoxication and overdose cases. A simple method for the...
The detection of nitazenes in biological fluids is increasingly needed as they are repeatedly reported in intoxication and overdose cases. A simple method for the quantification of low levels of nine nitazene analogs and brorphine in Dried Blood Spots (DBS) was developed and validated. 10 μL of spiked whole blood is deposited on a Capitainer®B card and allowed to dry. The spot is punched out, and extracted with 500 μL methanol:acetonitrile (3:1 v/v) added with 1.5 μL of fentanyl-D5 as the internal standard. After stirring, sonication, and centrifugation of the vial, the solvent is dried under nitrogen, the extract is reconstituted in 30 μL methanol, and 1 μL is injected into a UHPLC-MS/MS instrument. The method validation showed linear calibration in the 1-50 ng/mL range, LOD values ranging between 0.3 ng/mL (isotonitazene) and 0.5 ng/mL (brorphine), average CV% and bias% within 15 % and 10 % for all compounds, respectively. The matrix effect due to blood and filter paper components was within 85-115 % while recovery was between 15-20 %. Stability tests against time and temperature showed no significant variations for storage periods up to 28 days. Room temperature proved to represent the best samples storage conditions. UHPLC-MS/MS proved capable to reliably identify all target analytes at low concentration even in small specimen volumes, as those obtained from DBS cards, which in turn confirmed to be effective and sustainable micro-sampling devices. This procedure improves the efficiency of toxicological testing and provides an innovative approach for the identification of the nitazene class of illicit compounds.
Topics: Tandem Mass Spectrometry; Methanol; Dried Blood Spot Testing; Chromatography, Liquid; Reproducibility of Results; Chromatography, High Pressure Liquid; Imidazoles; Piperidines
PubMed: 38280237
DOI: 10.1016/j.jpba.2024.115975 -
Plant Disease May 2024Since the emergence of Ug99 wheat stem rust in Uganda in 1998 (Pretorius et al. 2000), the threat of movement into South Asia has been a concern due to long-distance...
Since the emergence of Ug99 wheat stem rust in Uganda in 1998 (Pretorius et al. 2000), the threat of movement into South Asia has been a concern due to long-distance dispersal capacity of airborne spores (Brown and Hovmøller 2002; Singh et al. 2008; Meyer et al. 2017). Increased preparedness by comprehensive rust surveillance efforts and development and deployment of resistant cultivars in advance of an incursion into South Asia has been one of the success stories of the Borlaug Global Rust Initiative (Sharma et al. 2013). In November 2023, an off-season rust survey was conducted in Marpha, Gandaki and Bagmati provinces in Nepal. Rust was only observed at two sites, Dangdunge of Dolakha district and Mude of Sindhupalchok district, where spring wheat was grown as fodder crop outside the main cropping season. Rust infected wheat leaves (10-15 leaves per site) were air dried and sealed in envelopes that were shipped under permit to the Global Rust Reference Center, Denmark. Bulk samples of stem rust, Puccinia graminis f.sp. tritici (Pgt), were recovered from both envelopes, and single pustule isolates were raised and multiplied on Morocco and McNair. Meanwhile, specimens of dry leaves were subjected to SSR genotyping according to standard procedures (Patpour et al. 2022). One distinct multi-locus Pgt genotype was observed, identical to and representing 99% of Ug99 isolates within Clade I collected in East Africa between 2012-2022. A Pgt single pustule isolate from each of the sampling sites were inoculated onto 20 internationally agreed stem rust differential lines using standard procedures, and 14 supplementary lines providing additional resolution of pathogen virulence (Patpour et al. 2022). The pathotyping was repeated in two independent experiments, which resulted in the infection type pattern of Pgt race TTKTT (Supplementary Table 1). Additional independent SSR genotype assays of recovered isolates confirmed the prevalent genotype of Clade I (Patpour et al. 2022; Szabo et al. 2022). This first detection of Ug99 race TTKTT in South Asia emphasizes the need for continued coordinated international surveillance efforts and utilization of diverse sources of resistance to control stem rust in wheat. New surveillance efforts in Nepal during February-March 2024 did not reveal additional cases of wheat stem rust. However, more detailed and sustained rust surveillance efforts, assessment of the vulnerability of current wheat crops to Ug99 and other races of stem-, stripe/yellow- and leaf rust, as well as intensified breeding for rust resistance throughout the region is strongly recommended to meet current and future plant health risks.
PubMed: 38812370
DOI: 10.1094/PDIS-03-24-0644-PDN -
Scientific Reports Sep 2023Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) led to a global pandemic of coronavirus disease 2019 (COVID-19). Early in the pandemic, efforts were made to...
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) led to a global pandemic of coronavirus disease 2019 (COVID-19). Early in the pandemic, efforts were made to test the SARS-CoV-2 antiviral efficacy of repurposed medications that were already approved and available for other indications, including hydroxychloroquine (HCQ) and azithromycin (AZI). To reduce the risk of SARS-CoV-2 exposure for clinical-trial study participants and to conform with lockdowns and social distancing guidelines, biospecimen collection for HCQ and AZI included at-home dried blood spot (DBS) collection rather than standard venipuncture by trained clinicians. In this study, we developed and validated the first sensitive and selective simultaneous LC-MS/MS method to accurately quantitate the concentration of HCQ, HCQ metabolites (Desethylchloroquine [DCQ], Bisdesethylchloroquine [BDCQ], Monodesethylhydroxychloroquine [DHCQ]) and AZI extracted from DBS. The validated method was successfully applied for the quantification of over 2000 DBS specimens to evaluate the pharmacokinetic profile of AZI, HQC, and its metabolites. This new method has a small sample volume requirement (~ 10 µL), results in high sensitivity (1 ng/mL), and would facilitate remotely conducted therapeutic drug monitoring.
Topics: Humans; Hydroxychloroquine; SARS-CoV-2; Azithromycin; Chromatography, Liquid; COVID-19; Tandem Mass Spectrometry; COVID-19 Drug Treatment; Communicable Disease Control
PubMed: 37777555
DOI: 10.1038/s41598-023-43185-9 -
Journal of Pharmaceutical and... Jun 2024Drug testing commonly use urine as a specimen and immunoassays for screening. The need for supervised urine collection has led to an interest in alternative specimens...
BACKGROUND
Drug testing commonly use urine as a specimen and immunoassays for screening. The need for supervised urine collection has led to an interest in alternative specimens and a need for using mass spectrometry methods already for screening. In addition, mass spectrometry methods allow for broad multipanel screening which of great value because of the increased number of substances that needs to be covered has increased over time. One alternative specimen of interest for drugs of abuse testing is dried blood spots (DBS) and this work aimed at developing multipanel screening methods based on selected reaction monitoring liquid chromatography - mass spectrometry for both urine and dried finger blood as specimens.
MATERIALS AND METHODS
The urine method comprised 37 analytes and utilised salted out liquid/liquid extraction in 96-well format, respectively, and the blood method comprised 35 analytes, a 10 µL volumetric DBS device and a two-step solvent extraction procedure. In both cases stable isotope labelled internal standards were used for almost all analytes.
RESULTS
The methods were validated according to forensic standard. The lowest reporting limits were generally set at 100 ng/mL for urine and 1 ng/mL for blood and the accuracy and imprecision were within limits of 15 and 20%. The methods were applied in a clinical study on patients receiving methadone maintenance treatment for opioid dependence. Methadone was detected in all urine and DBS samples, for urine sometimes below the commonly applied screening cutoff limit of 300 ng/mL. In 20 out of 99 cases no other drug was detected in any specimen. The most commonly other detected substances were pregabalin, amphetamine, alprazolam, zopiclone and THCCOOH. Findings in urine and DBS generally agreed well but more positives were detected in DBS.
CONCLUSION
Multipanel methods using liquid chromatography - mass spectrometry suitable for clinical drug screening were successfully developed for urine and blood collected by finger-pricking and stored as DBS.
Topics: Humans; Chromatography, Liquid; Liquid Chromatography-Mass Spectrometry; Tandem Mass Spectrometry; Methadone; Dried Blood Spot Testing
PubMed: 38457867
DOI: 10.1016/j.jpba.2024.116075 -
International Journal of Neonatal... Aug 2023To investigate COVID-19 surveillance among pregnant women, the California Genetic Disease Screening Program conducted a screening performance and seroprevalence...
To investigate COVID-19 surveillance among pregnant women, the California Genetic Disease Screening Program conducted a screening performance and seroprevalence evaluation of maternal SARS-CoV-2 antibodies detected in banked newborn dried blood spots (DBS). We obtained seropositive results for 2890 newborn DBS from cohorts in 2020 and 2021 using Enable Bioscience's Antibody Detection by Agglutination-PCR (ADAP) assay for SARS-CoV-2 antibodies. To infer maternal infection, we linked 312 women with a known laboratory-confirmed COVID-19 episode with their newborn's DBS SARS-CoV02 antibody result. Among 2890 newborns, we detected 453 (15.7%) with SARS-CoV-2 antibodies in their DBS. Monthly snapshot statewide seroprevalence among neonates was 12.2% (95% CI 10.3-14.1%, =1156) in December 2020 and 33.3% (95% CI 29.1-37.4%, = 26) in March 2021. The longest time recorded from COVID-19 infection to a seropositive neonatal result was 11.7 months among the 312 mothers who had an available SARS-CoV-2 PCR test result. Approximately 94% (153/163) of DBS were seropositive when a known maternal infection occurred earlier than 19 days before birth. The estimated relative sensitivity of DBS to identify prevalent maternal infection was 85.1%, specificity 98.5% and PPV 99.2% ( = 312); the sensitivity was lowest during the December 2021 surge when many infections occurred within 19 days of birth. Fifty pre-pandemic specimens (100% seronegative) and 23 twin-pair results (100% concordant) support an intrinsic specificity and PPV of ADAP approaching 100%. Maternal infection surveillance is limited by a time lag prior to delivery, especially during pandemic surges.
PubMed: 37606480
DOI: 10.3390/ijns9030043