Microbial pollutants can also serve as indicators of
water quality. For instance total and faecal coliforms,
and the entercocci - faecal streptococci are the indicator
organisms currently used in the public health arena as
they indicate fecal contamination [3] and presence of
enteric pathogens in surrounding water [4]. Indicator
organisms are always used to determine the relative
risk of the possible presence of a particular pathogen in wastewater [5]. Coliform bacteria include all aerobic
and facultative anaerobic, gram-negative, nonsporeforming,
rod-shaped bacteria that ferment lactose
with gas formation, and comprises mainly species of
the genera Citrobacter, Enterobacter and Klebsiella and
also includes Faecal coliforms, of which Escherichia coli
is the predominant species [6] and Faecal streptococci.
These are found naturally in the soil, as well as in faeces.
Usually between 60% and 90% of total coliforms are faecal
coliforms. E. coli are a particular species of bacteria that
may or may not be pathogenic but are ubiquitous in the
human intestinal tract. Faecal streptococci is an indicator
in tropical conditions and especially used to compare the
survival with that of Salmonellae