Chapter 43, Problem 3CHI

Biofilms are known to form on surfaces in drinking water distribution networks. It is therefore important to understand how such biofilms develop and how long they last. A recent study followed the development of biofilms populated by the protists in the genera Giardia and Cryptosporidium, as well as a strain of Poliovirus and several bacteriophages. Attachment to, growth within, and detachment from model biofilms were measured in tap water flowing through a special reactor designed to simulate the type of turbulence found in a water distribution network.

Why were the investigators especially interested in biofilm stability? Also, why were they interested in bacteriophages? What special considerations do you think need to be addressed when studying protists with relatively complex life cycles? What method do you think would be most appropriate to detect the protists? What about detecting the viruses?

Read the original paper: Helmi, K., et al. 2008. Interactions of Cryptosporidium parvum, Giardia lamblia, vaccinal poliovirus type 1, and bacteriophages fX174 and MS2 with a drinking water biofilm and a wastewater biofilm. Ann. Rev. Microbiol. 74:2079.