Tenets of a holistic approach to drinking water-associated pathogen research, management, and communication

Proctor, Caitlin R.; Garner, Emily; Hamilton, Kerry A.; Ashbolt, Nicholas J.; Caverly, Lindsay J.; Falkinham, Joseph O.; Haas, Charles N.; Prévost, Michèle; Prevots, D. Rebecca; Pruden, Amy; Raskin, Lutgarde; Stout, Janet E.; Haig, Sarah–Jane

doi:10.1016/j.watres.2021.117997

Cited by 24 publications

(41 citation statements)

References 220 publications

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“…For example, most buildings in a recent survey did not comply with existing hot water system temperature guidance for opportunistic pathogen control (Singh et al, 2020). A holistic approach is needed to manage building water systems (Proctor et al, 2022) such that building managers can successfully comply with guidance. Therefore, under these conditions, given the labor and water resource limitations, the population being served, and the limited water quality benefits, regular flushing to maintain water quality during this low occupancy period was likely unjustified, but building managers should weigh costs and benefits given their local context.…”

Section: The Building Water Microbiome During Reduced Water Use and F...mentioning

confidence: 99%

“…Although many studies have used targeted approaches to study specific opportunistic pathogens in building water (Bargellini et al, 2011;Springston and Yocavitch, 2017;Haig et al, 2018;Aw et al, 2022;Dowdell et al, 2022), a holistic understanding of microbial communities in building water is lacking, which could provide insight into how to control the growth of microbial contaminants, especially during disturbances in operation (Proctor et al, 2022). Opportunistic pathogens (e.g., Legionella pneumophila, Mycobacterium avium, Pseudomonas aeruginosa) have become the leading cause of waterborne disease in the United States and other industrialized countries (Ashbolt, 2015;Falkinham et al, 2015, p. 201;Proctor et al, 2022), costing the United States $2.39 billion annually (Collier et al, 2021). In addition to pathogen occurrence during stagnation, growth of bacteria may lead to aesthetic issues and proliferation of other problematic microorganisms, such as nitrifiers.…”

Section: Introductionmentioning

confidence: 99%

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Is flushing necessary during building closures? A study of water quality and bacterial communities during extended reductions in building occupancy

et al. 2022

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Drinking water stagnation can lead to degradation of chlorine residual, bacterial growth (including of opportunistic pathogens and nitrifiers), and metals release from plumbing materials; however, few studies have characterized building water quality and bacterial communities during the extended stagnation periods that occurred during COVID-19 pandemic-related building closures. Additionally, despite a lack of evidence-based guidance, flushing fixtures has been recommended to restore building water quality. We aimed to evaluate the impacts of reduced building occupancy (>2 months) and weekly restorative flushing on drinking water quality, bacterial communities, and the occurrence of undesirable microorganisms in three university buildings. Reduced occupancy led to diminished chloramine and elevated intact cell counts, but values remained stable after additional weeks of limited water use. Flushing temporarily improved water quality, with chlorine and cell counts remaining stable for at least 1 day but returning to levels measured prior to flushing within 1 week. Alpha diversity was lower under more stagnant conditions, and fixture identity, not flushing, was the most influential factor on bacterial community composition, suggesting a strong influence from local biofilm. Although Mycobacterium, Legionella, Pseudomonas, Nitrosomonas, and Nitrospira were detected in samples via amplicon sequencing, concentrations measured via qPCR of M. avium complex, L. pneumophila, P. aeruginosa, and ammonia-oxidizing bacteria were very low or were undetected, supporting that stagnation alone did not lead to high occurrence of undesirable microorganisms. Findings from this study contribute to our understanding of the effects of stagnation on building water microbiomes and the efficacy of flushing to improve water quality. Under the conditions of this case study, repeated flushing on a weekly timescale during low occupancy periods was not sufficient to maintain chlorine residual and prevent bacterial growth in fixtures. Building managers need to weigh the temporary water quality benefits of flushing against the labor and water resources required considering local context.

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Section: The Building Water Microbiome During Reduced Water Use and F...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Is flushing necessary during building closures? A study of water quality and bacterial communities during extended reductions in building occupancy

et al. 2022

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“…This lack of broad surveillance and method comparability has limited our understanding of typical L. pneumophila concentrations in commercial and public building plumbing, the impacts of water demand patterns in those buildings, and the effectiveness of various interventions for L. pneumophila mitigation. 33 Recent investigations into the impact of COVID-19 pandemic building closures have reported that building water quality overall was negatively impacted. 7,[44][45][46][47][48][49] However, studies have reported mixed results with respect to L. pneumophila, including no detection of L. pneumophila, 44,49 no change in occurrence as water use returned to normal levels, 45 a small increase (2x) in Legionella spp.…”

Section: (Which Was Not Certified By Peer Review)mentioning

confidence: 99%

“…[27][28][29][30] However, few studies have investigated its occurrence during extended periods of reduced water use. 22,26,[31][32][33] The quantification of L. pneumophila levels in potable water systems has traditionally been performed using plate culture methods. However, alternative methods such as the IDEXX Legiolert ® kit, a liquid culture method that yields results in most probable number (MPN) per volume, has become more widely used in recent years due to its ease of use and reported specificity for L. pneumophila.…”

Section: Introductionmentioning

confidence: 99%

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Legionella pneumophilaoccurrence in reduced-occupancy buildings in 11 cities during the COVID-19 pandemic

Dowdell

Greenwald

Joshi

et al. 2022

Preprint

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In spring 2020, reduced water demand was an unintended consequence of COVID-19 pandemic-related building closures. Concerns arose that contaminants associated with water stagnation, such as Legionella pneumophila, could become prevalent. To investigate this potential public health risk, samples from 26 reduced-occupancy buildings across 11 cities in the United States, Canada, and Switzerland were analyzed for L. pneumophila using liquid culture (Legiolert, n=258) and DNA-based methods (qPCR/ddPCR, n=138). L. pneumophila culture-positivity was largely associated with just five buildings, each of which had specific design or operational deficiencies commonly associated with L. pneumophila occurrence. Samples from free chlorine buildings had higher culture-positivity (37%) than chloramine buildings (1%), and 78% of culture-positive samples occurred when the residual was ≤0.1 mg/L Cl2. Although overall sample positivities using culture- and DNA-based methods were equivalent (34% vs. 35%), there was disagreement between the methods in 13% of paired samples. Few buildings reported any water management activities, and L. pneumophila concentrations in flushed samples were occasionally greater than in first-draw samples. This study provides insight into how building plumbing characteristics and management practices contribute to L. pneumophila occurrence during low water use periods and can inform targeted prevention and mitigation efforts.

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Acute Toxicity Assay Based on Electrochemical Method for Detection of Antibiotic Residues in Water

Dong

Chang

et al. 2022

Electroanalysis

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In this work, the bacteria suspended in solution or immobilized in the biofilm were employed to study whether bacterial electrochemistry can reflect the impacts of the antibiotic residues in water on microorganisms. In the sensing system with immobilized bacteria, the tested antibiotics of 10∼40 mg/L showed an opportunity to inhibit respiration over a short time and the combined effect of these antibiotics exhibited a complex dose‐dependence. The resistance was induced for the immobilized bacteria in the repeated measurement over a long‐term period, which was fortunately solved by refreshing the biofilm via a nutrient supplementation. In the solution system, bacterial respirations were promoted by the tested antibiotics even at concentrations up to 160 mg/L, but β‐glucosidase activity was inhibited by only 0.05 mg/L antibiotic. Cu2+ and Zn2+ were further inducted in the suspended system, and the combination of metals and antibiotics showed an obvious antagonistic effect. Real water detection indicated that the bacterial electrochemical method was expected to warn the water qualities with a sudden change by an appropriate testing condition.

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Tenets of a holistic approach to drinking water-associated pathogen research, management, and communication

Cited by 24 publications

References 220 publications

Is flushing necessary during building closures? A study of water quality and bacterial communities during extended reductions in building occupancy

Is flushing necessary during building closures? A study of water quality and bacterial communities during extended reductions in building occupancy

Legionella pneumophilaoccurrence in reduced-occupancy buildings in 11 cities during the COVID-19 pandemic

Acute Toxicity Assay Based on Electrochemical Method for Detection of Antibiotic Residues in Water

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