Factors Influencing the Bacteriological Water Quality in Mountainous Surface and Groundwaters

Abstract

The presence of pathogenic bacteria in water, along with the factors that act upon them, constitutes a field that has been little investigated in natural environments. It is clear, however, that these pathogens do have a significant effect on the quality of drinking water. Selected bacteria such as Salmonella, Campylobacter, Yersinia, and Listeria were searched for in groundwaters of mainly mountainous regions. Waters of one or two brooks in the catchment area of each spring were also analysed. Our results show that Campylo bacter and Listeria are frequent in all of these waters, even when land use in the catchment area is extensive (mountain pastures). Salmonella, on the other hand, was never found. Factors influencing the presence of Campylobacter, Yersinia, and Listeria were tested using Spearman rank correlations. The results suggest that the presence in water of some species of these bacteria (C. jejuni, L. monocytogenes 4b, and L. ivanovii) is related to a contaminant input, i.e. to the presence of cattle in the catchment area. For other species (C. coli, L. monocytogenes 1/2a, and Yersinia enterocolitica), however, one is forced to admit that no such connection between the presence of these species and that of an identified, potential contaminant input exists. We are therefore obliged to conclude either that these bacteria multiply in a natural way in the environment, or that they are able to survive in it for a long time. Finally, the present study shows that pathogenic bacteria are not always accompanied by indicators of faecal contamination (Escherichia coli, entero cocci); for this reason, they could potentially pose a risk to public health.

Distribution and Characteristics of Listeria monocytogenes Isolates from Surface Waters of the South Nation River Watershed, Ontario, Canada

“…This finding implies that against the backdrop of other potential human and wildlife sources of contamination, dairy operations, which can consist of dairy barns, pasture lands, manure lagoons, and manured fields, are significant contaminant sources. This finding is consistent with those of previous studies (49,51), suggesting that similar landscape attribute relationships might have affinities beyond those reported for the environmental setting discussed in this study. Overall, the seasonal distribution of L. monocytogenes in agricultural watersheds will likely depend on the timing of manure applications (spring being the most important period in temperate climates) and the access of animals on pasture to watercourses.…”

“…Lineage distribution of L. monocytogenes water isolates varied with the season. Temperature was previously shown to influence the distribution of serovars in surface waters, with serovar 1/2a being significantly associated with cold periods and serovar 4b being significantly associated with higher air temperatures (51). These findings are in agreement with our results, where lineage II (i.e., serovar 1/2a) isolates were dominant during the fall whereas lineage I (i.e., serovar 4b) isolates were dominant in the summer.…”

“…Two studies have attempted to relate L. monocytogenes distribution in the environment to agricultural practices and showed that the presence of L. monocytogenes seemed to be associated with the presence of cattle in the catchment area (51) and to the proximity of bovine farms (49). In the present work, we used data mining methods (CART) to uncover relationships between land use variables (expressed as potential surrogates of point and nonpoint pollution sources) and L. monocytogenes-positive water samples.…”

Listeria monocytogenes lineages: Genomics, evolution, ecology, and phenotypic characteristics

“…However, certain serotypes seem to be associated with different environmental niches (Lyautey et al, 2007;Schaffter et al, 2004) and patient conditions (McLauchlin, 1990) as discussed in more detail below.…”

Review: Microbial biocenoses in pristine aquifers and an assessment of investigative methods

“…Faecal bacteria may also occur in pristine ground and surface waters that are not impacted by human activity; they can be attributed to wild animals (Niemi and Niemi 1991). Recent research revealed that small numbers of microbial pathogens, such as Legionella, might be detectable in pristine waters without any discernible contamination source, and without the presence of faecal indicator bacteria (Brooks et al 2004;Schaffter et al 2004). In some cases, microbial pathogens thus seem to be part of the "natural" biocenosis in groundwater.…”