Control of Legionella Contamination with Monochloramine Disinfection in a Large Urban Hospital Hot Water System

Kandiah, Sheetal; Yassin, Mohamed; Hariri, Rahman; Ferrelli, Julliet; Fabrizio, Marie; Porter, Lorenda; Duda, Scott; Stout, Janet E.

doi:10.1016/j.ajic.2012.04.149

Cited by 5 publications

(4 citation statements)

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“…In terms of disinfection efficacy, our results are in line with what was previously reported by several authors in terms of monochloramine efficacy on Legionella control [ 33 , 37 , 53 , 54 , 55 , 56 , 57 ]. Although this study cannot prove its remediation properties thanks to the initial shock treatment, based on our observations we can state monochloramine effectiveness in ensuring a long-term control of Legionella proliferation, as demonstrated for the first time by a decade-long application experience.…”

Section: Discussionsupporting

confidence: 93%

Water Safety Plan, Monochloramine Disinfection and Extensive Environmental Sampling Effectively Control Legionella and Other Waterborne Pathogens in Nosocomial Settings: The Ten-Year Experience of an Italian Hospital

et al. 2023

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Legionella contamination control is crucial in healthcare settings where patients suffer an increased risk of disease and fatal outcome. To ensure an effective management of this health hazard, the accurate application of a hospital-specific Water Safety Plan (WSP), the choice of a suitable water disinfection system and an extensive monitoring program are required. Here, the ten-year experience of an Italian hospital is reported: since its commissioning, Legionellosis risk management has been entrusted to a multi-disciplinary Working Group, applying the principles of the World Health Organization’s WSP. The disinfection strategy to prevent Legionella and other waterborne pathogens relies on the treatment of domestic hot water with a system ensuring the in situ production and dosage of monochloramine. An average of 250 samples/year were collected and analyzed to allow an accurate assessment of the microbiological status of water network. With the aim of increasing the monitoring sensitivity, in addition to the standard culture method, an optimized MALDI-ToF MS-based strategy was applied, allowing the identification of Legionella species and other relevant opportunistic pathogens. Data collected so far confirmed the effectiveness of this multidisciplinary approach: the fraction of positive samples never overcame 1% on a yearly basis and Legionnaires’ Disease cases never occurred.

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Section: Discussionsupporting

confidence: 93%

Water Safety Plan, Monochloramine Disinfection and Extensive Environmental Sampling Effectively Control Legionella and Other Waterborne Pathogens in Nosocomial Settings: The Ten-Year Experience of an Italian Hospital

et al. 2023

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“…Among the antimicrobial agents of relatively most recent application in the disinfection of water, monochloramine seems to be more effective for Legionella remediation in hospital plumbing systems [3][4][5]. The present study shows the results obtained by the continuous injection of monochloramine for 1 year on domestic hot water (DHW) in two Italian hospitals heavily contaminated by Legionella.…”

Section: Introduction mentioning

confidence: 75%

“…Thus, due to the limited effectiveness (increase of the temperature of water in boilers, shock hyperchlorination) or the high costs (point-of-use water filters) or the ineffectiveness (H 2 O 2 ) of the controlling strategies adopted, at the beginning of 2014 a new control strategy had to be chosen. A scientific literature survey [3][4][5] and the risk assessment of the two hospitals directed the choice to the monochloramine.…”

Section: Resultsmentioning

confidence: 99%

“…Casini et al [5] found that at the initial monitoring phase before the start of the monochloramine disinfection, all the sampling sites resulted positive for L. pneumophila, while no sample resulted positive after treatment. In the US, at the end of 1 year of a monochloramine injecting system evaluation Kandiah et al [3] observed a reduction in water sample culture positivity rate from 53% to 0.35% for Legionella.…”

Section: Resultsmentioning

confidence: 99%

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Continuous Disinfection by Monochloramine on Domestic Hot Water System of Health-care Facilities for the Control of Legionella Contamination in Italy

Coniglio¹,

Andolfi²,

Faro³

et al. 2015

JHS

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Backgroud: The prevention of Legionella spp. colonization of water distribution systems is a critical issue in healthcare settings and only an effective disinfection of water systems and appropriate environmental surveillance strategies allow to prevent nosocomial legionellosis. Methods: Due to the temporary effectiveness (increase of the temperature of water in boilers and shock hyperchlorination), the high costs (point-of-use water filters) or the ineffectiveness (hydrogen peroxide, H 2 O 2 ) of the previous control procedures, 3 devices (one for each hot water loop) continuously injecting monochloramine have been installed in two different Italian hospitals heavily contaminated by Legionella pneumophila SG3 and SG6. Aim: To evaluate the efficacy of continuous disinfection by monochloramine for control of Legionella on domestic hot water (DHW) distribution system of health-care facilities. Findings: One month after the disinfection of DHW with monochloramine, the load of L. pneumophila SG3 and SG6 (previous mean count ranging from 10 3 to 10 5 CFU/L), as well as the Heterotrophic Plate Count (HPC) (previous mean count ranging from > 10 2 to > 10 4 CFU/mL), decreased at undetectable levels in 100% of the sampling points in the two hospitals. Conclusion: The results suggest that continuous injection of monochloramine on DHW systems can fully control L. pneumophila and HPC in contaminated hospitals since the beginning of its application.

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Shift in the Microbial Ecology of a Hospital Hot Water System following the Introduction of an On-Site Monochloramine Disinfection System

Baron

Vikram

Duda³

et al. 2014

PLoS ONE

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Drinking water distribution systems, including premise plumbing, contain a diverse microbiological community that may include opportunistic pathogens. On-site supplemental disinfection systems have been proposed as a control method for opportunistic pathogens in premise plumbing. The majority of on-site disinfection systems to date have been installed in hospitals due to the high concentration of opportunistic pathogen susceptible occupants. The installation of on-site supplemental disinfection systems in hospitals allows for evaluation of the impact of on-site disinfection systems on drinking water system microbial ecology prior to widespread application. This study evaluated the impact of supplemental monochloramine on the microbial ecology of a hospital’s hot water system. Samples were taken three months and immediately prior to monochloramine treatment and monthly for the first six months of treatment, and all samples were subjected to high throughput Illumina 16S rRNA region sequencing. The microbial community composition of monochloramine treated samples was dramatically different than the baseline months. There was an immediate shift towards decreased relative abundance of Betaproteobacteria, and increased relative abundance of Firmicutes, Alphaproteobacteria, Gammaproteobacteria, Cyanobacteria and Actinobacteria. Following treatment, microbial populations grouped by sampling location rather than sampling time. Over the course of treatment the relative abundance of certain genera containing opportunistic pathogens and genera containing denitrifying bacteria increased. The results demonstrate the driving influence of supplemental disinfection on premise plumbing microbial ecology and suggest the value of further investigation into the overall effects of premise plumbing disinfection strategies on microbial ecology and not solely specific target microorganisms.

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Control of Legionella Contamination with Monochloramine Disinfection in a Large Urban Hospital Hot Water System

Cited by 5 publications

References 0 publications

Water Safety Plan, Monochloramine Disinfection and Extensive Environmental Sampling Effectively Control Legionella and Other Waterborne Pathogens in Nosocomial Settings: The Ten-Year Experience of an Italian Hospital

Water Safety Plan, Monochloramine Disinfection and Extensive Environmental Sampling Effectively Control Legionella and Other Waterborne Pathogens in Nosocomial Settings: The Ten-Year Experience of an Italian Hospital

Continuous Disinfection by Monochloramine on Domestic Hot Water System of Health-care Facilities for the Control of Legionella Contamination in Italy

Shift in the Microbial Ecology of a Hospital Hot Water System following the Introduction of an On-Site Monochloramine Disinfection System

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