However, this approach detects the viral nucleic acids of both infectious and ubiquitin-Proteasome degradation non-infectious viruses. Therefore, it is important to develop and evaluate simple and efficient tools which make it possible to overcome the limitations of the traditional cell culture and PCR assays [9]. An approach based on an enzymatic treatment with RNAse combined with a proteinase K treatment was found to be successful in some cases in distinguishing between infectious and non-infectious viruses [10–12]. For bacteria, a relatively recent approach is the treatment of samples with the DNA-intercalating dyes ethidium
monoazide (EMA) or propidium monoazide (PMA) [13–17]. EMA and PMA are closely related ITF2357 nmr DNA intercalating dyes with a photo-inducible azide group that covalently cross-link to DNA through visible-light photoactivation. PMA has the advantage of being more selective than EMA for dead cells as it is more membrane-impermeant [18]. Recently, promising PMA / EMA treatments have also been tested for distinguishing between infectious and non-infectious RNA viruses [19, 20]. A study concluded that PMA-RT-PCR assays that include pretreatment of enteroviruses
and noroviruses with PMA prior to RT-PCR enable rapid differentiation between infectious and non-infectious enteric viruses when the virus particles are inactivated by heating at 72°C or 37°C or by using hypochlorite. However, unlike poliovirus, PMA treatment did not affect detection of heat-inactivated Norwalk virus by quantitative RT-PCR [21]. Another study found that EMA did not distinguish between infectious and non-infectious GDC-0449 nmr avian influenza virus particles [22]. Sánchez et al. [23] showed that PMA treatment previous to RT-qPCR detection is a promising alternative for assessing Celecoxib HAV infectivity. The usefulness of EMA or PMA for distinguishing between infectious and non-infectious RV and HAV was investigated. Both viruses were chosen for their cultivability and their differences in genomic organization. RV, the leading cause
of severe dehydrating diarrhea in infants and young children worldwide, are non-enveloped viruses that possess a genome with 11 segments of double-stranded RNA contained in a triple-layered protein capsid and belong to the Reoviridae. Hepatitis A virus (HAV) infection is the leading worldwide cause of acute viral hepatitis. HAV is a positive single-stranded non-enveloped RNA virus classified in the Hepatovirus genus of the Picornaviridae family. The purpose of this study was to develop a method based on pre-treatment-RT-qPCR assays in order to discriminate between infectious and non-infectious viruses (HAV, RV) following thermal inactivation. To this end, the binding of EMA and PMA to RV and HAV RNA was investigated. Then, a pre-treatment based on “PMA or EMA +/− surfactant RT-qPCR” was optimized for each virus. Finally, this method was applied to establish viral thermal inactivation kinetics through three RT-qPCR assays.