Living with Legionella and Other Waterborne Pathogens

Falkinham, Joseph O.

doi:10.3390/microorganisms8122026

Cited by 29 publications

(35 citation statements)

References 60 publications

(78 reference statements)

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“…increased after overnight stagnation, i.e., 120.08% and 585.71% higher, respectively. This result was consistent with the previous reports [5,8,59] in which they indicated that the abilities of Mycobacteria sp. and other OPPPs to persist and survive in the pipeline environment were attributed to the ability of bio lms formation, the relative resistance to disinfectant, and the strong adaptability to oligotrophic conditions.…”

Section: Bacterial Community Structuresupporting

confidence: 94%

Impact of indoor heating and overnight stagnation on tap water: Dynamics in water quality, biomass, bio-activity and bacterial community structure

Zhang

Liu²,

Ma³

et al. 2022

Preprint

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The drinking water distribution system is an important link with water supply system and it affects the quality of the drinking water. Indoor pipeline water quality is regulated by physical, hydraulic and biological elements, such as indoor temperature and stagnation. In this study, full-length 16S rRNA gene sequencing and flow cytometry were used to assess the indoor heating and overnight stagnation on the variation in bacterial community structure and the Intact cell count. The results exhibited that the average intact cell count was 6.99 × 104 cells/mL and the low nucleic acid (LNA) bacteria was 4.48 × 104 cells/mL after stagnation. The average concentration of total and intracellular adenosine triphosphate (ATP) was 3.64 × 10-12 gATP/mL and 3.13 × 10-17 gATP/cell in stagnant water, respectively. The growth of LNA cells played a crucial role in increasing ATP. The dominant phylum was Proteobacteria with average abundance of 87.21%, followed by Actinobacteria (8.25%). Pseudomonas sp. and Mycobacterium sp. increased 1.2-fold and 5.8-fold in stagnant water. Structural equation model and redundancy analysis illustrated that temperature, residual chlorine and Fe concentration significantly affected bacterial count and bacterial community. Taking together, these results show responses of drinking water quality to overnight stagnation and indoor heating, and provide scientific basis for drinking water security management.

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Section: Bacterial Community Structuresupporting

confidence: 94%

Impact of indoor heating and overnight stagnation on tap water: Dynamics in water quality, biomass, bio-activity and bacterial community structure

Zhang

Liu²,

Ma³

et al. 2022

Preprint

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show abstract

“…The Ops found in the bathroom samples are well reported (Kelley et al 2013;Novak et al 2020;Falkinham. 2020b).…”

supporting

confidence: 72%

Structure of bacterial communities in Japanese-style bathrooms: Comparative sequencing of bacteria in shower water and showerhead biofilms using a portable nanopore sequencer

Fujiyoshi

Nishiuchi²,

Maruyama

2021

Preprint

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Showers are one of the main exposure routes to diverse microbes for end users in built environments. Bacteria in water are responsible for biofilm formation on surfaces, and the inside of a showerhead is a specific niche. Here, for the purpose of microbial characterization, source estimation and possibility of infection, the bacterial compositions of both shower water and showerhead biofilms in the same bathroom were determined and compared using a portable nanopore sequencer. The results suggest that specific bacteria in source water would primarily adhere to the surface of the showerhead where they subsequently form biofilms, and the community compositions within biofilms largely vary depending on environmental factors. The relative abundance of several pathogenic bacterial genera in both water and biofilm samples was low. We suggest that it is important to manage risk of infection in each household, and rapid on-site analysis of microbial communities will allow the realization.

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“…Legionella reside in many aquatic environments and can develop in water systems from buildings, including those harbouring vulnerable populations such as healthcare facilities and long-term care facilities [1][2][3]. L. pneumophila causes most of the Legionnaires' disease cases, a severe form of pneumonia associated with high morbidity for at risk populations such as the elderly or immunocompromised [3][4][5]. L. pneumophila is particularly adapted to hot water environments, with reported optimal temperatures for growth ranging between 25 • C and 45 • C, while temperatures of 50 • C and over have been shown to decrease the culturable L. pneumophila populations [3,5,6].…”

Section: Introductionmentioning

confidence: 99%

Compromised Effectiveness of Thermal Inactivation of Legionella pneumophila in Water Heater Sediments and Water, and Influence of the Presence of Vermamoeba vermiformis

et al. 2022

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Intermittent reduction of temperature set-points and periodic shutdowns of water heaters have been proposed to reduce energy consumption in buildings. However, the consequences of such measures on the occurrence and proliferation of Legionella pneumophila (Lp) in hot water systems have not been documented. The impact of single and repeated heat shocks was investigated using an environmental strain of L. pneumophila and a reference strain of V. vermiformis. Heat shocks at temperatures ranging from 50 °C to 70 °C were applied for 1 h and 4 h in water and water heaters loose deposits (sludge). The regrowth potential of heat-treated culturable L. pneumophila in presence of V. vermiformis in water heaters sludges was evaluated. A 2.5-log loss of culturability of L. pneumophila was observed in simulated drinking water at 60 °C while a 4-log reduction was reached in water heaters loose deposits. Persistence of Lp after 4 h at 55 °C was shown and the presence of V. vermiformis in water heater’s loose deposits resulted in a drastic amplification (5-log). Results show that thermal inactivation by heat shock is only efficient at elevated temperatures (50 °C) in both water and loose deposits. The few remaining organisms can rapidly proliferate during storage at lower temperature in the presence of hosts.

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Living with Legionella and Other Waterborne Pathogens

Cited by 29 publications

References 60 publications

Impact of indoor heating and overnight stagnation on tap water: Dynamics in water quality, biomass, bio-activity and bacterial community structure

Impact of indoor heating and overnight stagnation on tap water: Dynamics in water quality, biomass, bio-activity and bacterial community structure

Structure of bacterial communities in Japanese-style bathrooms: Comparative sequencing of bacteria in shower water and showerhead biofilms using a portable nanopore sequencer

Compromised Effectiveness of Thermal Inactivation of Legionella pneumophila in Water Heater Sediments and Water, and Influence of the Presence of Vermamoeba vermiformis

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