Influence of Environmental and Anthropogenic Factors on Microbial Ecology and Sanitary Threat in the Final Stretch of the Brda River

Abstract

Ecology of aquatic microorganisms depends on a number of environmental parameters. The additional influence of anthropogenic factors is connected with sanitary risk, particularly in urban areas. The study was aimed at assessing the impact of physicochemical and biological parameters on the abundance and activity of bacterioplankton under different spatio-temporal conditions in the urbanized section of the Brda River. The evaluation of sanitary pollution of water was accompanied by the assessment of antibiotic resistance of isolated faecal strains determined using the disk diffusion method. The results indicate that the location of sampling sites significantly affected by the distribution of faecal Escherichia coli and enterococci in the studied part of the river. On the other hand, there were no significant seasonal changes in respiratory activity or abundance of planktonic bacteria. In addition, the abundance of bacterioplankton was not correlated with all measured physico-chemical parameters, though it was correlated with the organic carbon oxidation rate. Depending on the sampling site, bacterial cells with damaged membranes constituted between 8% and 20% of the population. Antibiograms showed the absence of multi-drug resistant strains. Enterococci exhibited the highest resistance to imipenem (45%), while Escherichia coli, to cefoxitin (31%).

Fecal Indicator Bacteria Transport from Watersheds with Differing Wastewater Technologies and Septic System Densities

“…The lack of a significant temporal trend in the higher density septic watersheds may suggest that spatial differences in septic system density exhibit a stronger influence on river FIB communities than temporal fluctuations. Past studies also found that spatial variability affected river bacterioplankton communities more than seasonal variation [39][40][41][42][43]. FIB communities may be affected by, but not limited to, changes in salinity [40], reduced river flow and sedimentation rates [42], and land use [24,40,41,43].…”