Fecal Streptococci/Enterococci in Aquatic Environments

Abstract

Introduction: Definition and Taxonomic Position Identification Habitat and Clinical Significance Fecal Pollution of Natural Water Environments Epidemiological Studies Survival of Fecal Streptococci/Enterococci in Aquatic Environments Enumeration Techniques

New Perspectives in Monitoring Drinking Water Microbial Quality

“…They comprise species of different sanitary significance and survival characteristics and, in addition, the proportions of the species of this group are not the same in animal and human faeces [8,10,11]. Enterococcus faecalis and Ent.…”

“…In addition, the classical microbial indicators proposed present several shortcomings and they cannot be used in all water types. In this instance, other indicators, named “Alternative”, should be used to determine the possible threat to public health [3,10,11,26]. …”

“…Nevertheless, sulphite-reducing clostridia are considered ubiquitous in aquatic sediments and the spore form explains their persistence, although they can be used as indicators of remote or non-point faecal pollution or to evaluate the virus and cyst inactivation in the drinking water disinfection processes [10,11,83]. However, the WHO [3,24,82] does not recommend clostridia for routine distribution system monitoring because, due to their length of survival, they may be detected long after (and far from) the pollution event, leading to possible false alarms.…”

“…Faecal streptococci, enterococci and intestinal enterococci are three synonyms used to refer to species described as members of the genus Enterococcus , which also fulfil Sherman’s criteria (growth at 10 °C and 45 °C, resistance to 60 °C, growth at pH 9.6 and at 6.5% NaCl, and reduction of 0.1% methylene blue) [ 8 , 10 , 11 ]. They comprise species of different sanitary significance and survival characteristics and, in addition, the proportions of the species of this group are not the same in animal and human faeces [ 8 , 10 , 11 ]. Enterococcus faecalis and Ent.…”

“…In previous studies, we and other authors, have reviewed the definitions of index and indicator organisms used to evaluate the microbiological quality of water [ 3 , 8 – 12 ], as well as the relevance of some of them, e.g., faecal streptococci, or their relationship with pathogenic bacteria, e.g., Salmonella , also involved in drinking water outbreaks [ 9 , 10 , 13 ]. The specific methods used for the analysis of indicators have also been reviewed in detail [ 8 , 12 , 14 ], so in this update we will review recent advances in relation to indicator/index organisms.…”