Sciences marines : recherche et développement

Abstrait

Enteroccoccus in Water, Sediment and Clams in a Tropical Environment,Maracaibo Lake, Venezuela

Marynes Montiel, Ricardo Silva, Jesús Núñez, Félix Morales, Hector Severeyn and Yajaira García

The genus Enterococcus has widespread extra enteric sources and reservoirs. It has been suggested that coastal and Great Lakes States adopt enterococci as an alternative indicator for the monitoring of recreational water quality. Limited information, however, is available about the presence of enterococci in Lake Maracaibo, which is an important estuary in Venezuela, with the income and interchange of the Caribbean Sea, and is used by the people for recreational purposes and the culture of marine organisms. In this study, the density and species composition of enterococci in sediment, clams and water were examined at Lake Maracaibo.Enterococci was enumerated by the Most Probable Number Technique (MPN), and isolated by standard methods. Results obtained by MPN analyses indicated that enterococci were present in all samples, and their densities were generally higher in clams than sediment and water with means of 1.0x106 MPN/100 g, 2.1x103 MPN/100 g, and 6.0x101 MPN/100 ml, respectively. Dominant Enterococcus species were E. faecalis (65%), E. casseliflavus (20%), E. sanguinicola (5%), E. faecium (5%), and unidentified strains (5%). Results suggest that some enterococci are able to persist in Lake Maracaibo, especially in clams and sediment, for a prolonged amount of time after being introduced.