[Preliminary surveys about the use of "Mytilus galloprovincialis" as an accumulation matrix of bacteria in coastal waters]

A biomonitoring study using "Mytilus galloprovincialis" mussels was carried out, to estimate their possible employment as "natural indicators" of coastal bacterial pollution. The research was conducted from September 2001 to May 2002, twice in a month, near two coastal zones of Salento. We analysed both natural and cultivated mussels. The latter were placed in cages, after checking their starting level of microbiological pollution. The bacteriological analyses conducted simultaneously on mussels and their ambient water, were directed to the search of: total and faecal coliforms, faecal streptococci, Escherichia coli, Salmonella spp., Staphylococcus aureus and yeasts. In this preliminary study the mussels proved to be "sensitive indicators of faecal pollution", since they had an accumulation of the faecal indicators even if the water was not contaminated. Nevertheless a lower frequency in finding yeasts in the mussels (53.8%) in comparison with water (74.3%), the irregular presence of Salmonella spp. in water (3.75%) and its absence in bivalves, show the need of further studies, also through "in vitro" tests, in order to verify absorption/elimination kinetics of microorganisms.

[Microbiological monitoring of beach water: old and new parameters]

The survival of fecal coliforms, fecal streptococci, Salmonella enteritidis and Staphylococcus aureus in sea water (35@1000 salinity) in the dark and at room temperature was evaluated. Staphylococcus aureus has been regarded for a long time as the new parameter to add to the classic ones in order to define the quality and suitability to recreational use. At the sperimental condition considered the survival of fecal coliforms, fecal streptococci, Salmonella enteritidis, and Staphylococcus aureus resulted equal to 48 h, 88 h, 56 h, and 96 h respectively. Fecal coliforms resulted the most sensitive bacteria to osmotic shock while Staphylococcus aureus the most adaptable species. Our results seem to indicate the opportunity of reconsidering the microbiological parameters used for the control of beach water.