Adaptation of the bivalve embryotoxicity assay for the high throughput screening of emerging contaminants in Mytilus galloprovincialis.

Emerging contaminants (such as Endocrine disrupting chemicals-EDCs, brominated and perfluorinated compounds-BFRs and PFCs, pharmaceuticals) are chemicals currently not included in regulatory monitoring programs, and whose fate and biological impacts are poorly understood. Assessment of ecosystem health with respect to these chemicals is of particular concern also in the marine environment: in this respect, data on the effects on early life stages are important to establish the sensitivity of marine species. In this work, the acute (48 h) bivalve embryo toxicity test was applied for screening the developmental effects of different emerging contaminants in the Mediterranean mussel Mytilus galloprovincialis. The assay was adapted to 96-microwell plates, and standardized in order to obtain to normal D-shaped larvae with acceptability of test results based on negative control and positive control (copper) comparable with those reported in literature for Mytilus spp. The effects of different model compounds representative of EDCs (Nonylphenol-NP and Bisphenol A-BPA), BFRs (Tetrabromobisphenol A-TBBPA), PFCs (perfluorooctanoid acid-PFOA and perfluorooctane sulphonate-PFOAS) and pharmaceuticals (Ibuprofen-IBU, Diclofenac-DCF, Bezafibrate-BEZA) in a wide concentration range (0.01-0.1-1-10-100-1000 µg/L) were evaluated. The assay proved as a sensitive tool for high throughput screening of emerging contaminants in a marine species, leading to production of significant amounts of data that may be useful for regulatory purposes.

Development of a PCR protocol for the detection of Escherichia coli O157:H7 and Salmonella spp. in surface water.

Escherichia coli O157:H7 and Salmonella are pathogenic microorganisms that can cause severe gastrointestinal illness in humans. These pathogens may be transmitted in a variety of ways, including food and water. The presence of Salmonella and E. coli O157:H7 in surface waters constitutes a potential threat to human health when used for either drinking or recreation. As with most waterborne pathogens, Salmonella and E. coli O157:H7 are difficult to detect and enumerate with accuracy in surface waters due to methodological limitations. The aim of this study was to develop a protocol for the detection of Salmonella spp., E. coli O157:H7 and E. coli virulence genes (stx (1), stx (2) and eae) in water using a single enrichment step and PCR. In spiked water samples, PCR results showed high sensitivity (<3 CFU/L) for both microorganisms. The protocol developed in this study has been applied in different surface waters in association with microbiological and physical analysis. The frequency of PCR positive samples was 33% for Salmonella and 2% for E. coli O157:H7 producing intimin (eae) and Shiga-like toxin I (stx (1)). Moreover, the finding of amplicons corresponding to eae and stx (1) genes in the absence of E. coli O157:H7 suggested the possible presence of other pathogenic bacteria that carry these genes (e.g. EHEC, Shigella strains). The results obtained showed that the developed protocol could be applied as a routine analysis of surface water for the evaluation of microbiological risks.

[Microbiological risk associated with consumption of drinking water in developed countries]. / Rischio microbiologico associato al consumo di acqua potabile nei paesi industrializzati.

This article provides an overview of the waterborne disease (WBD) issue in developed countries (USA, Canada, UK and other European countries). The factors involved in the epidemiology of waterborne infection are analysed (microbial, social, environmental, etc.) and the main WBD etiological agents are described with particular interest to emerging pathogens (i.e. Cryptosporidium parvum, Legionella and Calicivirus). Microorganism characteristics related to water contamination risk are described and examples of waterborne outbreak are reported. A short account about the detection methods of these microorganisms in the water is given. In conclusion, some possible strategies to control waterborne microbiological risk in industrialised countries are discussed considering the application of the risk analysis and the HACCP system in the water production and the need of a WBD surveillance system.