The presence of the pathogenic microorganism Salmonella as well as indicator microorganisms (total and faecal coliforms, faecal streptococci, Clostridium perfringens, and coliphages) was investigated in three different aquatic environments affected by sewage discharges. The relationships between indicators and Salmonella depended mainly on the source of faecal discharges and on the survival capability of the microorganisms in aquatic environments. The microorganisms most closely related to Salmonella spp were faecal coliforms and C. perfringens, the latter yielding also the highest linear regression slope value. Detection percentages of Salmonella spp were high even at a low level of pollution, which allowed detection of the pathogens in the absence of classical indicator microorganisms in the sample.
The results obtained in the present study showed that there were no differences in survival rates between the serotypes of Salmonella tested. Moreover, Salmonella spp exhibited a similar persistence to E. coli in aquatic ecosystems, particularly in marine environment.