Performance evaluation of a newly developed molecular assay for the accurate diagnosis of gastroenteritis associated with norovirus of

The performance of a newly proposed fully automated cassette-based sample-to-results solution for norovirus (NoV) detection, InGenius Norovirus ELITe MGB®, was evaluated. A total of 120 selected archival stool samples from children hospitalized for acute gastroenteritis were used to compare the results to a reference real-time RT-PCR. The InGenius NoV assay showed optimal diagnostic accuracy (sensitivity, 100%; specificity, 95.7%) and was able to correctly detect the entire wide panel of epidemiologically relevant genotypes tested. These preliminary results suggest that the InGenius NoV assay can be recommended as a valuable method for accurate diagnosis of NoV GII infection in epidemic and sporadic gastroenteritis. Among gastroenteritis agents, noroviruses (NoVs) have a major clinical and financial impact on the populations of industrialized countries [1, 2]. Their low infectious dose (fewer than 20 virions) and their high genetic and antigenic variability make them responsible for sporadic cases and outbreaks in all age groups [3]. To date, seven NoV genogroups (GI–GVII) have been identified, and more than 40 genotypes within genogroups GI, GII, and GIV have been involved in human infections [4]. In the last decades, symptomatic infection in humans has been mostly sustained by a single genotype, GII.4, with different variants emerging every two to three years [5]. In recent years, novel non-GII.4 NoV strains have been observed as predominant genotypes in children hospitalized with acute gastroenteritis (AGE) in several countries [6–9]. NoVs are transmitted primarily through the fecal–oral route either by direct person-toperson spread or by consumption of contaminated food or water [10]. Severe NoV infection occurs in frail elderly persons, young children, and immunocompromised individuals. Hospitalization may be required to prevent dehydration, and isolation should be considered to avoid nosocomial outbreaks [10]. Given the rapid spread of NoVs, especially during outbreaks, timely diagnosis is essential to assist management and implementation of appropriate control measures [2]. Technical advancement during the past two decades, particularly with the aid of molecular methods, genetic engineering, and protein expression and assembly, have provided new tools and opportunities to investigate fastidious viral agents such as NoV. Rapid commercial assays, such as enzyme immunoassays (EIAs) and immunochromatographic assays (ICTs), although including combinations of several cross-reactive monoclonal and polyclonal antibodies, have shown limited usefulness for routine screening of NoV infection because of their inadequate sensitivity (<70%), [10, 11]. On the other hand, the specificity of such tests, although generally above 90%, is strongly affected by many parameters (such as outbreaks vs. sporadic cases, timing of collection relative to symptom onset, and patient demographics) [2, 10]. Viral genome amplification has many advantages over antigenic diagnostic methods, including higher throughput, adaptability to new strains, and production of data for molecular epidemiological surveillance [1, 12]. Moreover, due to its unsurpassed sensitivity and specificity, real-time reverse transcription (RT)-PCR is currently considered the method of choice for detecting NoV in clinical specimens [10]. Other popular molecular methods such as microarrays and high-throughput sequencing have major limitations, including cost, sensitivity, and complexity of data analysis, Handling Editor: Tim Skern. * Simona De Grazia simona.degrazia@unipa.it 1 Department of Health Promotion Sciences and Mother and Child Care “G. D’Alessandro”, University of Palermo, Via del Vespro, 133, 90127 Palermo, Italy