Enterocci in water

The term enterococci comprises a complex and diverse group of bacteria, including more than 30 different species, most of which are capable of interacting with humans. They are ubiquitous, being commonly found in the gut of humans, other mammalians and birds, as well as in soil, water and several foods for human consumption. Since enterococci are normal inhabitants of the gut of both humans and animals they are traditionally included among the fecal indicator bacteria (FIB) in waters for human use. Water is a major vehicle for pathogenic microorganisms and contaminated water is considered an important source of human infections either by direct consumption or by the use of contaminated water in food processing and preparation. Government authorities have defined the enterococcal load above which the risk of human disease is real and this is based on epidemiological studies linking gastrointestinal, respiratory and eye illness to the use of fecally contaminated water. Currently, the presence and quantitation of enterococci and other FIB in water are determined by culture methods. Criticisms have been levied against these methods: because they take a few days to complete, which is considered too long for the purposes of rapid, restrictive intervention but, overall, the demonstration that enterococci can survive in water longer than their culturability lasts means that today these methods for determining the microbiological quality of waters are no longer regarded as safe for protecting human health in that the proportion of enterococci in the viable but nonculturable (VBNC) state is undetected. For these reasons new non-culture methods are currently being evaluated and standardized. These methods, their preliminary applications and the expectations associated with them are discussed in this chapter.