Abstract

The Lagoon Ebrié in the city of Abidjan is a typical aquatic ecosystem that can be used to predict the existence and circulation of water pathogens. Phages are viruses that infect bacteria and can be used for the detection of their bacteria host. In this study, bacteria colonies were investigated in their natural habitat within the Lagoon by using phages as indicators. Their impact on pollution was also determined in different sites of the rural Lagoon in the city. Water samples were collected at different sites of the Lagoon for the detection of bacteria and phages. The virulence of phages was tested on bacteria host using diffusion on an agar plate. Our results showed three major bacterial strains; Pseudomonas aeruginosa, Escherichia coli, and Enterobacter cloacae. Twenty-four phages that infected five bacteria hosts were also isolated. The spectrum revealed that the phages have high virulence against E. coli, P. aeruginosa and E. cloacae by 82.5%, 71 and 70% respectively. The majority (83.3 %) of isolated phages produced lysis on Enterobacteriaceae. However, Vibrio phages were not detected in this study. These findings suggested the existence of multiple adaptations of phages and the persistence of diverse bacteria hosts in the Lagoon.  The phages that were detected confirmed the bacterial presence in the Lagoon, this portray the ecological system in operation and possible microbiological risks for the riverine populations.

Keys words: Lagoon Ebrie, pollution, indicators, phages, adaptation, Abidjan.