Sample Processing - Waterborne Pathogens: Detection Methods and Applications - page 103

parasites normally present in water samples. For example, during the out-
break of cryptosporidiosis in Östersund, Sweden, in 2010-2011, the highest
number of confirmed oocysts per 10 L of drinking water ever isolated was
0.05. 94
Flocculation has been applied to all types of microorganisms and new
materials are emerging. Polymers using biomaterial (e.g. chitosane and
lysine) can be used due to their affinity (e.g. weak interaction (e.g. elec-
trostatic and hydrogen bond)) with microbiological particles (containing
electrostatic charges and hydrophobic groups expressed variably as a func-
tion of pH and chemical and organic components of the water). However,
to be compatible with rapid on-site applications, they must be packaged in
an appropriate form (i.e. powder, magnetic beads, hollow fibers, or foam). 15
New materials is one area of development in sample processing, includ-
ing materials/chemicals for flocculation, filters (e.g. NanoCeram or glass
wool), elution protocols, and chemical additives or surface modifications
to prevent adsorption. More work is required to optimize the use of these
materials, to fully understand their interactions with pathogens, and perhaps
to work toward more cost-effective and greener materials.
Demands of new detection technologies impact sample processing, with
molecular methods being a key example. In viral detection, the advent of
molecular methods has driven a lot of work into development of proce-
dures for the isolation of virus samples that are free from interferents. The
traditional detection methods to identify bacteria by cultivation and para-
sites by microscopic observation means less focus has been placed on sample
processing for other end uses, although this is changing with recent work
reflecting developments in this area. However, replacing the use of tradi-
tional techniques for detection of bacteria and parasites by molecular detec-
tion only will require the development of methods that also show that the
organisms are indeed viable, and thus may be infectious as DNA is isolated
also from nonviable cells/(oo)cysts. This could be in the detection stages, as
discussed in subsequent Chapters, or perhaps in the development of sample
processing techniques to distinguish viable and nonviable pathogens.
Sample processing has not received as much research attention as detec-
tion technologies yet is a key part of the process often determining the
overall success of monitoring. Therefore it is essential to continue research
in this area, particularly in characterizing performance of different methods,
development of new materials and processes, and also in automation of
processes. This should offer the advantages of reduced reliance on operator
skill, reduced variability, and reduced risk of cross contamination of samples.