Occurrence and distribution of fecal indicators and pathogenic bacteria in seawater and Perna perna mussel in the Gulf of Annaba (Southern Mediterranean)

The brown mussel Perna perna is a marine bivalve that is widely distributed and consumed along the east coast of Algeria. Due to its filter-feeding capacity, this mollusk can accumulate large quantities of pathogenic microorganisms from the surrounding waters, thus acting as bio-indicator of coastal environments. The objective of this study is to investigate the occurrence and distribution of fecal indicators and pathogenic bacteria in seawaters and mussels collected from four different sites in the Gulf of Annaba through physicochemical, biochemical and molecular analysis. The obtained results revealed that the levels of fecal indicator bacteria (FIB) were alarmingly high at Sidi Salem and Rezgui Rachid when compared with the two other sites (p < 0.05) and largely exceeded the permissible limits. Besides, P. perna collected from all sites were several fold more contaminated by these germs than seawater samples, notably, during the warm season of the study period. Biochemical and molecular analysis showed that isolated bacteria from both environmental compartments were mostly potentially pathogenic species such as E. coli, Salmonella, Staphylococcus, Klebsiella, Pseudomonas and Proteus. These principal findings demonstrate the strong involvement of anthropogenic activities on the microbiological quality of the Gulf and highlight the role of P. perna as an effective bio-indicator of the bacteriological quality of coastal waters.