Library of prefabricated locked nucleic acid hydrolysis probes facilitates rapid development of reverse-transcription quantitative real-time PCR assays for detection of novel influenza A/H1N1/09 virus

Abstract

BACKGROUND: The emergence of a novel pandemic human strain of influenza A (H1N1/09) has clearly demonstrated the need for flexible tools enabling the rapid development of new diagnostic methods. METHODS: We designed a set of reverse-transcription quantitative real-timePCR(RT-qPCR) assays based on the Universal ProbeLibrary (UPL) - a collection of 165 presynthesized, fluorescence-labeled locked nucleic acid (LNA) hydrolysis probes - specifically to detect the novel influenza A virus. We evaluated candidate primer/UPL-probe pairs with 28 novel influenza A/H1N1/09 patient samples of European and Mexican origin. RESULTS: Of 14 assays in the hemagglutinin (HA) and neuraminidase (NA) genes, 12 detected viral nucleic acids from diluted patient samples without need for further optimization. We characterized the diagnostic specificity of the 2 best-performing assays with a set of samples comprising various influenza virus strains of human and animal origin that showed no crossreactivity. The diagnostic sensitivity of these 2 primer/probe combinations was in the range of 100-1000 genomic copies/mL. In comparison to a reference assay recommended by the German health authorities, the analytical sensitivities and specificities of the assays were equivalent. CONCLUSIONS: Facing the emergence of novel influenza A/H1N1/09, we were able to develop, within 2 days, a set of sensitive and specific RT-qPCR assays for the laboratory diagnosis of suspected cases. H1N1/09 served as a model to show the feasibility of the UPL approach for the expedited development of new diagnostic assays to detect emerging pathogens.