Martin, Rebekah L.Harrison, KaraProctor, Caitlin R.Martin, AmandaWilliams, KristaPruden, AmyEdwards, Marc A.2020-09-282020-09-282020-09-22Martin, R.L.; Harrison, K.; Proctor, C.R.; Martin, A.; Williams, K.; Pruden, A.; Edwards, M.A. Chlorine Disinfection of Legionella spp., L. pneumophila, and Acanthamoeba under Warm Water Premise Plumbing Conditions. Microorganisms 2020, 8, 1452.http://hdl.handle.net/10919/100077Premise plumbing conditions can contribute to low chlorine or chloramine disinfectant residuals and reactions that encourage opportunistic pathogen growth and create risk of Legionnaires&rsquo; Disease outbreaks. This bench-scale study investigated the growth of <i>Legionella</i> spp. and <i>Acanthamoeba</i> in direct contact with premise plumbing materials&mdash;glass-only control, cross-linked polyethylene (PEX) pipe, magnesium anode rods, iron pipe, iron oxide, pH 10, or a combination of factors. Simulated glass water heaters (SGWHs) were colonized by <i>Legionella pneumophila</i> and exposed to a sequence of 0, 0.1, 0.25, and 0.5 mg/L chlorine or chloramine, at two levels of total organic carbon (TOC), over 8 weeks. <i>Legionella pneumophila</i> thrived in the presence of the magnesium anode by itself and or combination with other factors. In most cases, 0.5 mg/L Cl₂ caused a significant rapid reduction of <i>L. pneumophila</i>, <i>Legionella</i> spp., or total bacteria (16S rRNA) gene copy numbers, but at higher TOC (&gt;1.0 mg C/L), a chlorine residual of 0.5 mg/L Cl₂ was not effective. Notably, <i>Acanthamoeba</i> was not significantly reduced by the 0.5 mg/L chlorine dose.application/pdfenCreative Commons Attribution 4.0 Internationalopportunistic pathogensdrinking waterpremise plumbingbacteriachlorinechloramineArticle - Refereed2020-09-25https://doi.org/10.3390/microorganisms8091452