![]() Legionella level in response to disinfection treatment was also studied by taking into account the following water network characteristics: building area, annual water consumption, hospital activities involving the use of water, that can influence the Legionella contamination and the disinfectant exposure to distal outlets. These characteristics permitted us to study the activity of WTP 828 as three separate hot water networks (HWNs), modulating the dosage with respect to the level of Legionella contamination found. The plumbing system comprises a single cold water supply and three different hot water return lines. The hospital is comprised of three buildings connected to each other but were built and submitted to renovation works at different times. It shows a broad antimicrobial spectrum and has been shown to be active against bacteria, yeast, fungi, viruses, spores, proto-, and metazoans. H 2O 2 decomposes rapidly in different environmental conditions due to microbial catalase and peroxidase, and other than abiotic action, the decomposition is promoted by heavy metal, oxidative, and reductive reactions. ![]() It is compatible with different pipeline materials, and does not react with the organic constituents in the water to form dangerous residues with respect to chlorine, sodium hypochlorite (NaOCl), and monochloramine treatment. H 2O 2 is completely soluble in water and is stabilized in commercial formulation for disinfection treatment. The use of H 2O 2 as a biocide is widespread, and it is increasingly used as a general surface disinfectant in the medical, food, and industrial fields, as well as for water treatment. ĭifferent studies have focused in the last years on the role of oxidizing agents, notably hydrogen peroxide (H 2O 2), as disinfection treatments. During the chlorination, especially by hypochlorous acid and hypobromous acid, the reaction with naturally occurring organic matter present in raw water supplies, create many water DBPs, including the four primary trihalomethanes: chloroform (CHCl 3), bromodichloromethane (CHCl 2Br), dibromochloromethane (CHClBr 2), and bromoform (CHBr 3), that can have adverse effects on human health. However, increasing evidence suggests that humans are exposed to residual byproducts of water chlorination such as disinfection byproducts (DBPs) through drinking-water, oral, dermal, and inhalational contact. Although different studies have shown good performance using these methods to assess Legionella contamination, a reduction of effectiveness over a long-term period was consistently demonstrated. To perform Legionella control, plumbing water systems can be treated using chlorine as a shock hyperchlorination (residual chlorine concentration at distal outlets of 20–50 mg/L) or as continuous treatment using a concentration of 1–2 mg/L. The long-term effect of WTP828 on Legionella containment suggest the easy and safe application of this disinfectant, that combined with knowledge of building characteristics, an adequate environmental monitoring and risk assessment plan, become the key elements in preventing Legionella contamination and exposure.Ĭhlorine is the most common chemical disinfectant used in water (including drinking water), acts as an oxidizing agent, and reacts with several cellular constituents including the cell membrane of microbes. No relevant contamination was found for other parameters tested. WTP 828 induced a reduction in Legionella–positive sites (60% to 36%) and contamination levels (2.12 to 1.7 log 10 CFU/L), with isolates belonging to L. Legionella isolates were identified by serotyping and genotyping. aeruginosa), and a heterotopic plate count (HPC) at 36 ☌. The effectiveness of WTP828 was tested measuring physical-chemical and microbiological parameters such as Legionella, Pseudomonas aeruginosa ( P. This study focused on the activity of a new formulation of hydrogen peroxide and silver salts, WTP828, in the hospital hot water network (HWN) to contain Legionella contamination during two years of treatment. Different treatments are suggested to reduce Legionella risk, however long-term studies of their efficiency are lacking. Legionella surveillance is an important issue in public health, linked to the severity of disease and the difficulty associated with eradicating this bacterium from the water environment.
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