Rapid Resin-based Method for Concentration of Rotavirus, Hepatitis A Virus and Adenovirus 40 from Tap Water

Introduction: Detection of low levels of viral contaminants in water represents a food safety challenge, due to the lack of rapid, simple and inexpensive methods for concentration of targets before detection.  Currently, most virus concentration methods are based on adsorption of viruses to filters by electrostatic interactions, followed by elution of viral particles and nucleic acid isolation for further molecular detection.  However, these systems display several shortcomings, including clogging, need for large volumes of eluent, low recovery efficiency and low sensitivity.

Purpose: Evaluate the performance of a newly developed resin-based concentration method to detect low concentrations of hepatitis A virus (HAV), adenovirus 40 (HAdV-40) and rotavirus (RV) in tap water.

Methods: Ten-liter tap water samples (n = 3) inoculated with different concentrations (10 to 10,000 TCID ₅₀ /10 l) of human adenovirus 40, hepatitis A virus and rotavirus were incubated for 120 minutes with 0.5g of anion exchange resin, followed by nucleic acids isolation directly from the resin.  Nucleic acids isolated from water before concentration and from the resin after concentration were analyzed by real time PCR or real time reverse transcriptase PCR, using commercially available detection kits (Ceeram®).

Results: Detection of enteric viruses from the resin after concentration was significantly (P < 0.001) improved compared to detection from water samples (average ΔCt = 12.1 for AdV-40, 4.3 for HAV and 7.0 for RV).  The lowest virus concentration detected using resin-based concentration was 10 TCID₅₀ /10 l for HAdV-40 and HAV, and 100 TCID ₅₀ /10 l for RV.  The resin-based virus concentration method compares favorably to other methodologies, considering that it displayed similar detection limits, but it was easier to perform and more cost effective.

Significance: The resin-based method rapidly and successfully concentrates different enteric viruses from water samples, ultimately enhancing molecular detection sensitivity.