[Incidence of bacterial contamination in the Ares-Betanzos estuary (NW Spain)].

The presence of bacterial indicators of fecal pollution and V. parahaemolyticus in the estuary of Ares-Betanzos (ría de Ares-Betanzos, NW of Spain) was investigated. Resistance patterns of coliform bacteria to eight antibacterial agents were also determined. In general, high numbers of indicator bacteria were found; for instance, heterotrophic bacteria ranged between 1.82 x 10(2) to 1.9 x 10(4) CFU/ml and up to 4.6 x 10(3)/100 ml fecal coliforms in surface waters and 1.2 x 10(4)/100 ml fecal streptococci in sediment could be found. Surface waters of sampling points 2 and 7, located at the inner part of the estuary, were more polluted than the corresponding ones in the mouth (sampling points, 1, 3, 4 and 9), whereas the sediment showed just the opposite distribution. An 88.5% of isolated coliforms were resistant to one or more antibacterial agents. The MAR index points to urban wastewaters as the probable origin of pollution. The low incidence of V. parahaemolyticus and the lack of correlation with any of the fecal indicator bacteria determined, discard its use as indicative of fecal pollution in marine environments.