RESUMEN
BACKGROUND: The accuracy and reliability of rapid diagnostic tests are critical for monitoring and diagnosing SARS-CoV-2 infection in the general population. This study aimed to evaluate the analytical performance of the BIOSYNEX COVID-19 Ag BSS (Biosynex Swiss SA, Fribourg, Switzerland) antigen rapid diagnostic test (BIOSYNEX Ag-RDT), which targets the SARS-CoV-2 N-nucleocapsid protein for the diagnosis of COVID-19. The Ag-RDT was compared with a real-time RT-PCR (rtRT-PCR) as gold standard for performance measurement. METHODS: Two nasopharyngeal flocked swabs were prospectively collected simultaneously in March and April 2021 from 967 individuals aged ≥ 18 years tested for SARS-CoV-2 in two private laboratories, Paris, France. RESULTS: Overall, the Ag-RDT demonstrated high sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 81.8%, 99.6%, 96.6%, and 97.5%, respectively. The agreement (97.0%), reliability assessed using Cohen's κ-coefficient (0.87), and accuracy evaluated using Youden index (J) (81.6%) in detecting SARS-CoV-2 were high. The analytical performance of the Ag-RDT remained high when there was significant viral shedding (i.e., N gene Ct values ≤ 33 on reference RT-PCR). The sensitivity was only 55.2% in case of low or very low viral excretion (Ct > 33). CONCLUSIONS: The BIOSYNEX Ag-RDT is a promising, potentially simple diagnostic tool, especially in symptomatic COVID-19 patients with substantial viral excretion in the nasopharynx.
Asunto(s)
COVID-19 , Antígenos Virales , COVID-19/diagnóstico , Francia , Humanos , Nasofaringe , Sistemas de Atención de Punto , Estudios Prospectivos , Reacción en Cadena en Tiempo Real de la Polimerasa , Reproducibilidad de los Resultados , SARS-CoV-2/genética , Sensibilidad y EspecificidadRESUMEN
To assess the practicability (usability and satisfaction) and analytical performances of the VitaPCR™ SARS-CoV-2 Assay (Credo Diagnostics Biomedical Pte. Ltd.), a rapid point-of-care nucleic acid amplification test (NAAT), by reference to real-time reverse-transcription polymerase chain reaction (rRT-PCR) for respiratory viruses. The practicability of the VitaPCR™ Assay and Instrument was assessed from usability evaluation and a satisfaction questionnaire. Nasopharyngeal swabs were collected from 239 patients with coronavirus disease 2019 (COVID-19)-like illness during the second epidemic wave, in Paris, France. Overall, the usability of the VitaPCR™ Instrument was high. The satisfaction questionnaire indicated a high appreciation of the VitaPCR™ NAAT mainly for the short duration of analysis in only 20 min. A total of 140 and 99 samples were positive and negative for SARS-CoV-2 RNA by rRT-PCR, respectively. In the event of significant viral load (i.e., N gene Ct values 33), the platform's analytical performances dropped significantly, with lower sensitivity, concordance, and accuracy, while its specificity remained high. The VitaPCR™ SARS-CoV-2 Assay is an accurate rapid point-of-care NAAT, suitable for clinical practice for the rapid diagnosis of COVID-19, especially in patients with COVID-19-suspected symptoms.
Asunto(s)
Prueba de COVID-19/métodos , COVID-19/diagnóstico , Técnicas de Amplificación de Ácido Nucleico/métodos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , SARS-CoV-2/genética , COVID-19/epidemiología , Proteínas de la Envoltura de Coronavirus/genética , Proteínas de la Nucleocápside de Coronavirus/genética , ARN Polimerasa Dependiente de ARN de Coronavirus/genética , Francia/epidemiología , Humanos , Fosfoproteínas/genética , Pruebas en el Punto de Atención , Estudios Prospectivos , Sensibilidad y Especificidad , Encuestas y Cuestionarios , Carga Viral/métodosRESUMEN
The aim of this study was to determine the susceptibilities to macrolides of Group A streptococcal isolates from the European section of Turkey. In the case of resistant isolates, the patterns and genetic mechanisms of erythromycin resistance were studied. Seven (2.7%) of the 260 isolates were resistant to erythromycin. Four of them showed the M phenotype and harboured mefA genes whereas three isolates showed the inducible macrolide, lincosamide and streptogramin B resistance phenotype and harboured ermTR genes. In the European section of Turkey, the current resistance rate of Group A streptococci to macrolides remains low.
Asunto(s)
Antibacterianos/farmacología , Farmacorresistencia Bacteriana Múltiple/genética , Eritromicina/farmacología , Streptococcus pyogenes/efectos de los fármacos , Streptococcus pyogenes/genética , Europa (Continente)/etnología , Humanos , Pruebas de Sensibilidad Microbiana , Infecciones Estreptocócicas/tratamiento farmacológico , Infecciones Estreptocócicas/microbiología , TurquíaRESUMEN
The mechanisms of resistance to macrolides in seven group A streptococcal (Streptococcus pyogenes) isolates that were the cause of pharyngitis in children who were unsuccessfully treated with azithromycin (10 mg/kg of body weight/day for 3 days) were evaluated. All posttreatment strains were found to be genetically related to the pretreatment isolates by random amplified polymorphism DNA analysis and pulsed-field gel electrophoresis. Two isolates had acquired either a mef(A) or an erm(B) gene, responsible for macrolide efflux and ribosomal modification, respectively. Three isolates displayed mutations in the gene encoding the L4 ribosomal protein that is part of the exit tunnel within the 50S subunit of the bacterial ribosome. In the two remaining posttreatment strains, the mechanisms of macrolide resistance could not be elucidated.