| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 3406624 | Journal of Virological Methods | 2014 | 5 Pages |
•The ultracentrifugation step decreased the viral recovery in sludge samples.•The ultracentrifugation might be concentrating inhibitors of molecular detection.•Direct viral RNA extraction yielded higher genomic copies than ultracentrifugation.•Phages were detected in comparable concentrations to those of enteric viruses.•Studied phages might be used as enteric viral surrogates in sludge samples.
The aim of this study was to compare two viral extraction methods for the detection of naturally occurring Enteroviruses in raw sludge. The first method (M1) is based on an ultracentrifugation step. In the second one (M2), viral RNA was extracted directly after viral elution from suspended solids. Genomes of enteroviruses were quantified by a quantitative real time PCR (qRT-PCR) in sludge samples. Somatic coliphages and F-specific RNA phages, considered as viral indicators of enteric viruses in sludge, were enumerated by the double layer agar technique. Results showed that direct assay of RNA extraction yielded higher genomic copies of enteric viruses (with an average of 5.07 Log10 genomic copies/100 mL). After the ultracentrifugation assay in the second method, genomic copies number decreases (with an average of 4.39 Log10 genomic copies/100 mL). This can be explained by an eventual concentration of inhibitors existing in sludge samples. Phages enumeration results showed their presence in all sludge samples with an average of (5.69 Log10 PFU/100 mL) for somatic coliphages and (4 Log10 PFU/100 mL) for F-specific RNA phages. This emphasizes the use of somatic coliphages as viral indicators for enteroviruses in environmental samples and especially in raw sludge samples in wastewater treatment plants prior to agricultural use.
