This study reports the occurrence of different Vibrio and Salmonella species in 52 samples of Mytilus galloprovincialis collected from four sites along the Atlantic coast between Agadir and Essaouira (Anza, Cap Ghir, Imssouane and Essaouira). The level of Escherichia coli (E. coli) was also determined to evaluate the degree of microbial pollution in the investigated areas. In this study three methods were used : AFNOR NF EN ISO 6579 V08-013 for Salmonella spp., the provisional method routinely used by several laboratories (Institut Pasteur, Paris,…) for Vibrio cholerae and Vibrio parahaemolyticus in the seafood, and the most probable number method (MPN) using Norm ISO/TS 16649–3 (2005) for E. coli. The most frequently isolated Vibrios were Vibrio alginolyticus (90.4% of samples), followed by V. cholerae non O1 non O139 (15.4%) and V. parahaemolyticus (7.7%). Salmonella spp. was found in 15% of the samples. The number of E. coli ranged between 0.2/100 g and 1.8 103 /100 g of mussel soft tissues. This study indicates the potential sanitary risk associated with the presence of pathogenic bacteria in cultivated mussels in the two populous regions of southern Morocco, where shellfish production and maritime tourism are important to the local economy.

Many coastal cities around the world discharge their wastewaters into the marine environment. These wastewaters contain a high variety of pathogenic microorganisms that would have a role in the contamination of this ecosystem and may have potential risks for public health and environment. Using an environmental approach, we investigate the presence of Salmonella in wastewater treatment plants and its presence after the treatment in its receiving marine environment. In this environmental approach, we provide information about the inefficiency of wastewater treatment to remove Salmonella, especially that wastewater is considered as a good tank of high diversity of Salmonella serotypes. The identified Salmonella serotypes in the receiving marine environment almost coincide with those identified in wastewater. This characterization of Salmonella strains from wastewater and marine environment involves the direct impact of municipal wastewater discharges on this environment. Antibiotic susceptibility tests reveal generally the presence of multiresistant Salmonella strains in wastewater, which usually end up in the marine environment and may have a significant risk on the public health.