Chapter 3.1.1 : Current and Developing Methods for the Detection of Microbial Indicators in Environmental Freshwaters and Drinking Waters

Abstract:

Fecal contamination of freshwaters and drinking waters may result in serious risks to public health that include gastrointestinal and respiratory illnesses, eye and skin infections, many caused by enteric pathogens. The microbiological quality of freshwaters and drinking waters is usually monitored by the detection of traditional indicators that include total and thermotolerant coliforms, Escherichia coli, and Enterococcus spp. Culture methods are usually employed to detect bacterial indicators, but emerging techniques that include the detection of bacteriophages, as well as PCR-based methods amplifying bacterial 16S or 23S rRNA genes also have been developed. Molecular methods targeting indicator bacteria may reduce the time needed to take action to reduce the impact that fecal contamination of freshwaters and drinking waters represent to public health. In freshwaters used for recreation and consumption, identifying the source of the fecal contamination is important in order to reduce or eliminate its impact to pubic health. Microbial Source Tracking (MST) methods have been developed to identify the possible source (e.g. animal vs human) of the fecal contamination and include amplification of nucleic acids of traditional indicator bacteria. While bacterial indicators have successfully been used to protect public health for the last 100 years, and variations on the theme will be in use for decades to come, the target microorganisms would probably need to be revisited, because of the little information we have about their ecology.