Presence of norovirus sequences in bottled waters is questionable

Norovirus in Bottled Water Associated with Gastroenteritis Outbreak, Spain, 2016

In April 2016, an outbreak of gastrointestinal illness (4,136 cases) occurred in Catalonia, Spain. We detected high levels of norovirus genotypes I and II in office water coolers associated with the outbreak. Infectious viral titer estimates were 33–49 genome copies/L for genotype I and 327–660 genome copies/L for genotype II.

Viruses in Water Environment

Development of PCR method had a great impact on studies on viruses in water environment, and now it makes possible to determine various kind of viruses from river, marine water and water/wastewater treatment systems, though there are still needs to improve accuracy of quantification. Now we know that river water may contain 1000copy/L of norovirus. The infectious risk management for recreational water has been left and not updated, hence we need develop better management system based on scientific knowledge.

Attachment of enteric viruses to bottles

Storage of water that was deliberately contaminated with enteric viruses in polyethylene terephthalate (PET) bottles led to a rapid decrease of the apparent viral load, thereby hampering the development of samples for a collaborative evaluation of viral detection methods for bottled water. To determine if this decrease was due to spontaneous inactivation or to adhesion, an elution protocol was developed and combined with a rapid and sensitive real-time reverse transcription-PCR-based method to quantify adsorbed norovirus (NV), hepatitis A virus (HAV), and rotavirus (RV) on bottle walls. The NV retention on PET bottle walls after 20 and 62 days reached an average level of 85% and 95% of the recovered inoculum, respectively. HAV and RV also showed adsorption onto PET bottles, reaching 90% and 80%, respectively, after 20 days of storage. NV and RV attachment was demonstrated to be dependent on the presence of autochthonous flora, whereas HAV adsorption was independent of it. Application of the elution and viral detection protocol to 294 commercially available water bottles obtained from 25 different countries did not give any positive result, thereby providing further evidence that the sources used for this product are free from enteric viruses and support for the theory that bottled water is not a vehicle for viral diseases.

Occurrence of bacterial indicators and bacteriophages infecting enteric bacteria in groundwater in different geographical areas

AIMS

The aim of this research was to determine the suitability of coliphages (bacteriophages) for assessing the microbial quality of groundwater.

METHODS AND RESULTS

The number of several bacterial indicators (faecal coliforms, Escherichia coli, enterococci and spores of sulfite-reducing clostridia) and bacteriophages (somatic coliphages, F-specific RNA bacteriophages and bacteriophages infecting Bacteroides fragilis) were determined in groundwater of aquifers in various geographical areas. Results show that the relative abundance, determined as percentages of positive detections, of the bacterial indicators and bacteriophages varies depending on the aquifer.

CONCLUSIONS

A single bacterial indicator may not be enough to assess microbiological quality in certain aquifers. One bacterial indicator and a bacteriophage parameter provide more information than two bacterial indicators.

SIGNIFICANCE AND IMPACT OF THE STUDY

Coliphages (CPH) provide different information from that provided by bacterial indicators on the microbial quality of groundwater in different geographical areas. Easy, fast and inexpensive methods for the detection of CPH are feasible in both industrialized and developing countries.