Molecular Methods for the Detection of Waterborne Pathogens - Waterborne Pathogens: Detection Methods and Applications - page 265

in genus-common genes. Furthermore, it may be possible to use different
enteric virus targets to differentiate between ongoing and recent fecal con-
tamination. 210 The persistence of these viruses relative to bacterial indicators
could be advantageous when tracking fecal contamination at a distance from
the source. Recent advances in viral detection by next-generation sequenc-
ing and metagenomics has enhanced the utility of enteric viruses for MST. 14
8.5. SUMMARY AND FUTURE OUTLOOK
Waterborne pathogens continue to infect and cause illnesses world-
wide. Routine analysis of water samples has paved the way to supplying
safe water for all to drink. Traditional techniques suffer from limitations,
including laborious sample preparation, bulky instrumentation, and slow
data readout. In view of the urgency for sensitive, specific, robust, and
rapid diagnostics, numerous advancements have been made in the area of
diagnostics.
The application of molecular methods to pathogen detection is major
breakthrough in the ability to demonstrate the responsibility of specific
agents as causes of disease. The use of culture-independent testing methods
for the detection of pathogens is well established in the clinical setting. 211
However, for environmental samples, the methodology lags behind due
to sample complexity, multiple organism contamination, and the inability
to culture the pathogens at all. For this reason, detection of fecal indica-
tor bacteria on selective culture media has been the gold standard. How-
ever, the inconsistency between waterborne pathogen presence and FIBs
has paved the way to alternative testing methods. Theoretically, molecular
methods have been advertised as being able to provide concise qualitative
and quantitative data on the presence of any microbial pathogenic organism
in drinking water, wastewater, and sewage samples. This review has sum-
marized some of the methods that have been proposed as alternatives to
indicator bacteria testing ( Table 8.1 ).
First of all, regardless of method to be used, the state of the sample
can affect the outcome of the testing. Environmental samples often contain
chemical contaminants, such as humic acids and metals, that need to be
diluted or removed prior to extraction of DNA/RNA, proteins, or fatty
acids because they can interfere with subsequent detection methods. This
is complicated by the fact that pathogens can be present at very low levels,
requiring the samples to be concentrated, which increases the likelihood