Using a constraint-based regression method for relative quantification of somatic mutations in pyrosequencing signals: a case for NRAS analysis.

BACKGROUND: Pyrosequencing Allele Quantification (AQ) is a cost-effective DNA sequencing method that can be used for detecting somatic mutations in formalin-fixed paraffin-embedded (FFPE) samples. The method displays a low turnaround time and a high sensitivity. Pyrosequencing suffers however from two main drawbacks including (i) low specificity and (ii) difficult signal interpretation when multiple mutations are reported in a hotspot genomic region. RESULTS: Using a constraint-based regression method, the new AdvISER-PYRO-SMQ algorithm was developed in the current study and implemented into an R package. As a proof-of-concept, AdvISER-PYRO-SMQ was used to identify a set of 9 distinct point mutations affecting codon 61 of the NRAS oncogene. In parallel, a pyrosequencing assay using the Qiagen software and its AQ module was used to assess selectively the presence of a single point mutation (NRAS[Formula: see text] - Q61R-1) among the set of codon 61 mutations, and to analyze related pyrosequencing signals. AdvISER-PYRO-SMQ produced a lower limit of blank (0 %) than the AQ module of Qiagen software (5.1 %) and similar limit of detection were obtained for both software (5.6 vs 4.8 %). AdvISER-PYRO-SMQ was able to screen for the presence of 9 distinct mutations with a single pyrosequencing reaction whereas the AQ module was limited to screen a single mutation per reaction. CONCLUSION: Using a constraint-based regression method enables to analyze pyrosequencing signal and to detect multiple mutations within a hotspot genomic region with an optimal compromise between sensitivity and specificity. The AdvISER-PYRO-SMQ R package provides a generic tool which can be applied on a wide range of somatic mutations. Its implementation in a Shiny web interactive application (available at https://ucl-irec-ctma.shinyapps.io/Pyrosequencing-NRAS-61/) enables its use in research or clinical routine applications

MOESM2 of Using a constraint-based regression method for relative quantification of somatic mutations in pyrosequencing signals: a case for NRAS analysis

Additional file 2. Dataset NRAS-61.txt. A dataset to illustrate the use of the Shiny web interactive application. The dataset includes the pyro-signals (i.e.the raw peak heights) corresponding to four samples (A1, A2, A3, and A4)

Genomic characterisation of extended-spectrum β-lactamase-producing multidrug-resistant Escherichia coli in Rabat, Morocco.

Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli are an increasingly significant cause of hospital- and community-acquired infections worldwide. Whereas several reports have highlighted their increased prevalence also in North African countries, genomic data on isolates associated with these infections are still scarce. This study aimed to provide data on ESBL-producing E. coli isolates from patients with extraintestinal infections at the Military Teaching Hospital Mohamed V of Rabat, Morocco. Whole-genome sequencing was carried out on 18 ESBL-producing extraintestinal pathogenic E. coli (ExPEC) isolates for analysis of phylogenomic evolution, virulence factors and antimicrobial resistance genes. Data were compared with ExPEC lineages from several surrounding countries using multilocus sequence typing (MLST) and single nucleotide polymorphism-based phylogenetic approaches. The majority of E. coli isolates were ST131 (n = 15), followed by ST617 (n = 2) and a novel sequence type (ST10703) that is closely related to the pandemic ST405 clone. All ST131 isolates belonged to the O25b-ST131 pandemic clone. They harboured more virulence genes than their non-ST131 counterparts. IncF plasmid replicons and the bla β-lactamase gene were identified in all isolates. No ESBL-producing E. coli isolates carried any known carbapenemase gene. Our findings underscore the pre-eminence of ST131 as the major factor driving the expansion of ExPEC in the Rabat region while highlighting the potential links with isolates circulating in other neighbouring countries

A simple and fast spectroscopy-based technique for Covid-19 diagnosis

AbstractThe coronavirus pandemic, which appeared in Wuhan, China, in December 2019, rapidly spread all over the world in only a few weeks. Faster testing techniques requiring less resources are key in managing the pandemic, either to enable larger scale testing or even just provide developing countries with limited resources, particularly in Africa, means to perform tests to manage the crisis. Here, we report an unprecedented, rapid, reagent-free and easy-to-use screening spectroscopic method for the detection of SARS-CoV-2 on RNA extracts. This method, validated on clinical samples collected from 280 patients with quantitative predictive scores on both positive and negative samples, is based on a multivariate analysis of FTIR spectra of RNA extracts. This technique, in agreement with RT-PCR, achieves 97.8% accuracy, 97% sensitivity and 98.3% specificity while reducing the testing time post RNA extraction from hours to minutes. Furthermore, this technique can be used in several laboratories with limited resources.</jats:p

Correction: Experimental Treatment with Favipiravir for Ebola Virus Disease (the JIKI Trial): A Historically Controlled, Single-Arm Proof-of-Concept Trial in Guinea.

[This corrects the article DOI: 10.1371/journal.pmed.1001967.]

Experimental treatment with Favipiravir for Ebola Virus Disease (the JIKI Trial) : a historically controlled, single-arm proof-of-concept trial in Guinea

BACKGROUND:Ebola virus disease (EVD) is a highly lethal condition for which no specific treatment has proven efficacy. In September 2014, while the Ebola outbreak was at its peak, the World Health Organization released a short list of drugs suitable for EVD research. Favipiravir, an antiviral developed for the treatment of severe influenza, was one of these. In late 2014, the conditions for starting a randomized Ebola trial were not fulfilled for two reasons. One was the perception that, given the high number of patients presenting simultaneously and the very high mortality rate of the disease, it was ethically unacceptable to allocate patients from within the same family or village to receive or not receive an experimental drug, using a randomization process impossible to understand by very sick patients. The other was that, in the context of rumors and distrust of Ebola treatment centers, using a randomized design at the outset might lead even more patients to refuse to seek care. Therefore, we chose to conduct a multicenter non-randomized trial, in which all patients would receive favipiravir along with standardized care. The objectives of the trial were to test the feasibility and acceptability of an emergency trial in the context of a large Ebola outbreak, and to collect data on the safety and effectiveness of favipiravir in reducing mortality and viral load in patients with EVD. The trial was not aimed at directly informing future guidelines on Ebola treatment but at quickly gathering standardized preliminary data to optimize the design of future studies.METHODS AND FINDINGS:Inclusion criteria were positive Ebola virus reverse transcription PCR (RT-PCR) test, age ≥ 1 y, weight ≥ 10 kg, ability to take oral drugs, and informed consent. All participants received oral favipiravir (day 0: 6,000 mg; day 1 to day 9: 2,400 mg/d). Semi-quantitative Ebola virus RT-PCR (results expressed in "cycle threshold" [Ct]) and biochemistry tests were performed at day 0, day 2, day 4, end of symptoms, day 14, and day 30. Frozen samples were shipped to a reference biosafety level 4 laboratory for RNA viral load measurement using a quantitative reference technique (genome copies/milliliter). Outcomes were mortality, viral load evolution, and adverse events. The analysis was stratified by age and Ct value. A "target value" of mortality was defined a priori for each stratum, to guide the interpretation of interim and final analysis. Between 17 December 2014 and 8 April 2015, 126 patients were included, of whom 111 were analyzed (adults and adolescents, ≥13 y, n = 99; young children, ≤6 y, n = 12). Here we present the results obtained in the 99 adults and adolescents. Of these, 55 had a baseline Ct value ≥ 20 (Group A Ct ≥ 20), and 44 had a baseline Ct value < 20 (Group A Ct < 20). Ct values and RNA viral loads were well correlated, with Ct = 20 corresponding to RNA viral load = 7.7 log10 genome copies/ml. Mortality was 20% (95% CI 11.6%-32.4%) in Group A Ct ≥ 20 and 91% (95% CI 78.8%-91.1%) in Group A Ct < 20. Both mortality 95% CIs included the predefined target value (30% and 85%, respectively). Baseline serum creatinine was ≥110 μmol/l in 48% of patients in Group A Ct ≥ 20 (≥300 μmol/l in 14%) and in 90% of patients in Group A Ct < 20 (≥300 μmol/l in 44%). In Group A Ct ≥ 20, 17% of patients with baseline creatinine ≥110 μmol/l died, versus 97% in Group A Ct < 20. In patients who survived, the mean decrease in viral load was 0.33 log10 copies/ml per day of follow-up. RNA viral load values and mortality were not significantly different between adults starting favipiravir within <72 h of symptoms compared to others. Favipiravir was well tolerated.CONCLUSIONS:In the context of an outbreak at its peak, with crowded care centers, randomizing patients to receive either standard care or standard care plus an experimental drug was not felt to be appropriate. We did a non-randomized trial. This trial reaches nuanced conclusions. On the one hand, we do not conclude on the efficacy of the drug, and our conclusions on tolerance, although encouraging, are not as firm as they could have been if we had used randomization. On the other hand, we learned about how to quickly set up and run an Ebola trial, in close relationship with the community and non-governmental organizations; we integrated research into care so that it improved care; and we generated knowledge on EVD that is useful to further research. Our data illustrate the frequency of renal dysfunction and the powerful prognostic value of low Ct values. They suggest that drug trials in EVD should systematically stratify analyses by baseline Ct value, as a surrogate of viral load. They also suggest that favipiravir monotherapy merits further study in patients with medium to high viremia, but not in those with very high viremia.TRIAL REGISTRATION:ClinicalTrials.gov NCT02329054.Evaluation of the efficacy and of the antiviral activity of T-705 (favipiravir) duringEbola virus infection in non-human primates humansEbola Virus Disease - correlates of protection, determinants of outcome, and clinical managemen

JIKI trial: evolution of serum creatinine, aspartate aminotransferase, alanine aminotransferase, and creatine phosphokinase in adolescents and adults.

<p>The <i>x</i>-axis represents the time since first symptoms (for example, for a patient whose first symptom occurred 5 d before day 0, the baseline value dot is positioned at 5 d). Each line represents one patient. Dots represent baseline values, and X’s represent follow-up values. Red symbols represent patients who died; blue symbols represent patients who survived. Dark red lines represent patients with baseline Ct < 20 who died, light red lines represent patients with baseline Ct ≥ 20 who died, dark blue lines represent patients with baseline Ct < 20 who survived, and light blue lines represent patients with baseline Ct ≥ 20 who survived. Samples obtained more than 25 d after onset of symptoms are not represented.</p

JIKI trial: evolution of serum creatinine, transaminases, and creatine phosphokinase in the 11 adolescents and adults who had worsening in at least one biochemical parameter on favipiravir.

<p>(A) Patients who survived (<i>n</i> = 7). (B) Patients who died (<i>n</i> = 4). Each line represents one patient. All patients are identified with an ID number (from 1 to 7) or letter (from a to d) throughout the figures. For all 11 patients, all available data are shown. Dots represent baseline values, and X’s represent follow-up values. Dark blue lines represent patients with baseline Ct < 20 who survived. Light blue lines represent patients with baseline Ct ≥ 20 who survived. Light red lines represent patients with baseline Ct ≥ 20 who died. The <i>x</i>-axis represents the time since first symptoms (for example, for a patient whose first symptom occurred 5 d before admission to the treatment center, the baseline value dot is positioned at 5 d). Samples obtained more than 25 d after onset of symptoms are not represented. All 11 patients continued favipiravir.</p