RESUMO
BACKGROUND: Respiratory infections are common reasons for hospital admission, and are associated with enormous economic burden due to significant morbidity and mortality. The wide spectrum of microbial agents underlying the pathology renders the diagnosis of respiratory infections challenging. Molecular diagnostics offer an advantage to the current serological and culture-based methods in terms of sensitivity, coverage, hands-on time, and time to results. OBJECTIVES: This study aimed to compare the clinical performance of three commercial kits for respiratory viral detection. STUDY DESIGN: The performance of FilmArray Respiratory Panel, AnyplexII RV16, and Argene was compared using clinical respiratory samples (nâ¯=â¯224, comprising 189 nasopharyngeal swabs in Universal Transport Medium (UTM) and 35 endotracheal aspirates), based on common overlapping targets across the platforms. Influenza A "equivocal" and "no-subtype" samples by FilmArray were further compared to a laboratory-developed Influenza A/B test. RESULTS AND CONCLUSIONS: The overall performance of all three platforms appeared to be comparable with regards to sensitivities (95.8-97.9%) and specificities (96.1-98.0%), detection of coinfections, and distinguishment of influenza from non-influenza cases. "Equivocal" and "no-subtype" samples by FilmArray mostly represented weak Influenza A by laboratory-developed test. Lower respiratory tract samples had comparable final-run success-rates and discordant-rates as compared to UTM. Coronavirus HKU1, which was not targeted by AnyplexII RV16, were detected as OC43. The expected test volume would be the main determinant for the selection of platform. Among the platforms, the FilmArray is the most automated but is of the lowest-throughput and has the highest reagent cost.
Assuntos
Técnicas de Diagnóstico Molecular , Kit de Reagentes para Diagnóstico/normas , Infecções Respiratórias/diagnóstico , Infecções Respiratórias/virologia , Vírus/genética , Coinfecção/diagnóstico , Coinfecção/virologia , Enterovirus/genética , Enterovirus/isolamento & purificação , Hospitalização , Humanos , Influenza Humana/diagnóstico , Reação em Cadeia da Polimerase Multiplex , Nasofaringe/virologia , Kit de Reagentes para Diagnóstico/economia , Rhinovirus/genética , Rhinovirus/isolamento & purificação , Sensibilidade e Especificidade , Vírus/classificação , Vírus/isolamento & purificaçãoRESUMO
BACKGROUND/PURPOSE: Screening for vancomycin-resistant enterococci (VRE) by culture takes days to generate results, while polymerase chain reaction (PCR) testing directly from clinical specimens lacks specificity. The aims of this study were to develop a real-time PCR to detect and identify Enterococcus faecium, Enterococcus faecalis, and vanA and vanB genes, and to evaluate the impact of this PCR on test-reporting times when performing it directly from suspect VRE isolates present on screening chromogenic media. METHODS: The tetraplex PCR primers were designed to amplify E. faecium, E. faecalis, and vanA and vanB genes, with melt-curve analysis of PCR products. Following analytical and clinical validation of the molecular assay, PCR testing was performed for target colonies present on VRE chromogenic media. PCR results were evaluated against conventional phenotypic identification and susceptibility testing, with the time to result being monitored for both modalities. RESULTS: A total of 519 colonies from clinical specimens were tested concurrently by real-time PCR and phenotypic methods. In all, 223 isolates were identified with phenotypic vancomycin resistance (vanA, n = 108; vanB, n = 105; non-vanA/vanB = 10), with complete agreement between PCR and phenotypic testing for vancomycin-resistant E. faecium and E. faecalis. The majority (88.6%) of PCR results were reported, on average, 24.8 hours earlier than those of phenotypic testing, with 68% reduction in total costs. CONCLUSION: The use of culture on selective media, followed by direct colony PCR confirmation allows faster and economical VRE screening.
Assuntos
Técnicas Bacteriológicas/métodos , Meios de Cultura/química , Infecções por Bactérias Gram-Positivas/diagnóstico , Programas de Rastreamento/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Enterococos Resistentes à Vancomicina/isolamento & purificação , Proteínas de Bactérias/genética , Carbono-Oxigênio Ligases/genética , Compostos Cromogênicos/metabolismo , Custos e Análise de Custo , Enterococcus faecalis/genética , Enterococcus faecalis/isolamento & purificação , Enterococcus faecium/genética , Enterococcus faecium/isolamento & purificação , Humanos , Reação em Cadeia da Polimerase Multiplex/métodos , Fatores de Tempo , Temperatura de Transição , Enterococos Resistentes à Vancomicina/genéticaRESUMO
The Xpert CT/NG is a rapid assay for detection of Neisseria gonorrhoeae and Chlamydia trachomatis. QC materials must be formulated to emulate human specimens, and are prohibitively expensive. A creative, cost-effective QC approach is proposed. The acceptable sample types for the Xpert CT/NG assay were extended to include eye swabs.