Diversity of Salmonella spp. and fungi in northern Greek rivers and their correlation to fecal pollution indicators

The prevalence and diversity of Salmonella spp., filamentous fungi, and yeasts and their correlation with fecal pollution indicators (total coliforms, fecal coliforms, enterococci) and total heterotrophic bacteria counts were investigated in 95 water samples from the northern Greek rivers Aliakmon and Axios. Salmonella spp. were isolated in 27.4% of the samples and a total of 19 serotypes were identified. The frequency of Salmonella isolation was higher in the Axios (36.8%) than in the Aliakmon (21.0%) river. Significantly (P<0.001) more Salmonella spp. were recovered during warm (41.4%) than cold (5.4%) months. Salmonella-positive samples showed significantly higher counts of total heterotrophic bacteria and coliforms. Filamentous fungi were isolated from 98.9% and yeasts from 17.9% of the samples with respective mean counts of 2.36×103 and 1.28×102 cfu/100 mL. Totals of 23 genera of filamentous fungi and 3 genera of yeasts were identified. The most frequent filamentous fungi were Penicillium and Aspergillus, while Candida was the most prevalent yeast. A significant (P<0.001) positive correlation of the fecal pollution indicators was demonstrated only for filamentous fungi. The results of this study indicate that these rivers may be potential pathways for human and other animal contamination with Salmonella spp., filamentous fungi, and yeasts, which contribute to the pollution of marine waters and the surrounding environment.