Isolation of gut associated bacteria from Callinectes amnicola (Crustacea: Portunidae) collected from two interconnecting tropical lagoons in Nigeria

The occurrence and relative distribution of bacterial flora associated with the gut of the crab Callinectes amnicola, as well as sediment and water, from Badagry and Epe Lagoons, were investigated. The water samples from the Epe Lagoon had the highest total bacteria count of 7.5±1.2 x 10⁷ cfug-¹, whereas the crab gut from the Badagry Lagoon had the lowest total bacteria count of 3.6±0.5 x 10⁷ cfug-¹. The analyzed plate counts from the gut of C. amnicola, included the total heterotrophic bacteria, total coliform and total faecal coliform which were greater in the Epe Lagoon than in the Badagry Lagoon although these differences were not significant (p>0.05). The values recorded for the EpeLaggon were 4.5±0.2 x 10⁷ cfug-¹, 3.4±0.1 x 10⁵ cfug-¹and 1.5±0.3 x 10⁵ cfug-¹for total heterotrophic bacteria, total coliform and total faecal coliform respectively. All the nine (9) identified isolates, with the exception of Streptococcus sp, were largely gram-negative bacteria, and included Escherichia coli, Salmonella typhi, Shigella sp., Proteus vulgaris, Pseudomonas aeruginosa, Bacillus sp., Aeromonas hydrophila and Vibrio cholera. Except for Shigella sp., which was absent in the Badagry Lagoon during the study period, the isolates found in this study were comparable in both locations. The most common isolates in the gut of C. amnicola obtained from the two interconnected lagoons were A. hydrophilaand E. coli. This study is useful for authorities to develop coastal contamination monitoring strategies and quantify the human health risks connected with the consumption of aquatic crabs.