Title: Association of Amoeba and Legionella in Non-Potable Water Systems
The objective is to determine if the relationship between Legionella and its amoeboid host is one of necessity or more opportunistic in nature.
- Is there a correlation between amoeba and Legionella in non-potable water?
- Is chlorine/other biocides effective against amoeba in non-potable water?
- Is the LIVE/DEAD® stain suitable for the determination and quantification of amoeba non-potable water?
Shivi Selvaratnam, Ph.D.
Legionella is an Opportunistic Waterborne Pathogen that exists as a free-living organism and an intracellular parasite in which several amoeba species serve as the host organism. Often the life cycle of Legionella is thought to be dependent upon the existence of an amoeboid host which, frequently, is present in a complex biofilm community. Whether this host-parasite relationship is a necessary or an opportunistic relationship is not well understood. We concluded from our previous study that TPC and Legionella concentrations in potable water are not correlated with amoeba concentrations. In this paper, we examine non-potable (cooling tower water) water systems for the presence of Legionella spp. and amoeba. We utilized conventional culture techniques to determine the presence of and quantify Legionella spp. and a LIVE/DEAD® stain to determine the presence of and quantify live and dead amoeba. Data was analyzed to determine if a correlation exists between the presence of amoeba and Legionella spp. in non-potable water samples, and (2) the effect of a biocides on amoeba in in vitro experiments.
Shivi Selvaratnam joined Weas Engineering in 2016 as the Senior Microbiologist and currently serves as the Lab Director of the Chemistry and Microbiology Labs. Shivi graduated with a Ph.D. in microbiology from Drexel University, PA and subsequently completed her post-doctorate at the University of Notre Dame, IN. She worked in academia for several years where she taught courses in microbiology and conducted research on the effects of pollutants on microbial communities in freshwater ecosystems. Prior to joining Weas Engineering, Shivi worked as a Technical Environmental Specialist at the Indiana Department of Environmental Management. Dr. Selvaratnam is the author of numerous publications and invited presentations.