The effect of a sewage treatment plant effluent on the faecal coliforms and enterococci populations of the reception river waters

Abstract

Aims: A rural sewage treatment plant and the effect of its effluent on the enterococci and faecal coliforms populations of the receiving river waters was evaluated. Methods and Results: The enumeration of bacteria was performed by membrane filtration. Diversity and population similarity were analysed using the PhP-plates system. The treatment plant reduces the number of enterococci and faecal coliforms to values similar to those observed upstream. All water samples showed a high diversity for both bacterial populations. A high similarity in the composition and structure, was detected among all the samples. Conclusions: The impact of the disposal of treated sewage on the river did not modify the composition of either bacterial populations in the river water. Significance and Impact of the Study: The biochemical phenotyping of bacterial populations is a reliable tool for ecological and biodiversity studies. The obtained results provide a better understanding of the sewage treatment process and the impact of the treated sewage effluents in the environment.

Frequency of transferable multiple antibiotic resistance amongst coliform bacteria isolated from a treated sewage effluent in Antofagasta, Chile

“…composition of faecal coliforms in the receiving river (Vilanova et al 2002). However, when the identification of resistant coliform species in raw and treated waters are made, significant differences are found in species composition.…”

“…Furthermore the disposal of treated sewage into rivers, lakes, or elsewhere may or may not influence environmental bacterial populations (Vilanova et al 2002). Some studies have found that wastewater treatment can raise or lower the proportions of antibiotic resistant bacteria which carry antibiotic resistance plasmids (Andersen, 1994;Ohlsen et al 2003).…”

Host Species-Specific Metabolic Fingerprint Database for Enterococci and Escherichia coli and Its Application To Identify Sources of Fecal Contamination in Surface Waters

“…In this study, we used two types of plates specifically developed for typing of E. coli (PhP-RE plates) and enterococci strains (PhP-RF plates). The 11 substrates used for enterococci and E. coli have been described previously (24,30,51). The growth medium for PhP-RF contained 0.2% (wt/vol) proteose peptone (Oxoid), 0.05% (wt/vol) yeast extract (Oxoid), 0.5% (wt/vol) NaCl, and 0.011% (wt/vol) bromothymol blue, and for E. coli, it contained 0.1% (wt/vol) proteose peptone and 0.011% (wt/vol) bromothymol blue, according to the manufacturer's instructions.…”

“…A biochemical fingerprinting method known as the PhPlate system (PhPlate AB, Stockholm, Sweden) has been reported and used in many epidemiological and ecological studies (2,30,31,51). It measures the kinetics of bacterial metabolism in microtiter plates.…”

“…This system has a high discriminatory ability and reproducibility (30)(31)(32) and is shown to be comparable with many genotypic methods in comparative studies (30,31). The PhPlate system is simple to use and can be applied to studies involving large numbers of isolates and is therefore an excellent tool for studying the diversity (Di) and persistence of fecal indicator bacteria in surface waters (24,30,31,51). In this study, we used the PhPlate system to characterize two fecal indicator bacteria, enterococci and E. coli, from different host groups (i.e., animal species) to develop a metabolic fingerprint database to identify the source(s) of fecal contamination in a local creek.…”