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.

A significant proportion of shrimps marketed and consumed in Morocco are caught in the coastal region of the city of Agadir. This study provides interesting data of prevalence of Vibrio spp. in raw shrimps as well as better understanding of their potential virulence. It is apparent from this study that genes and primers used in multiplex PCR for identification and detection of virulence factors, can be used to monitor shrimps for the presence of potentially pathogenic strains of Vibrio cholerae and Vibrio parahaemolyticus. The results highlight the added value of using a chromogenic medium for research and isolation of pathogenic Vibrio in seafood, more specific and accurate than TCBS.