Water Microbiome Research Articles

Biofloc technology significantly reshapes water microbiome and improves survival rates in Japanese eel (Anguilla japonica).

This study is significant as it addresses a critical gap in the application of Biofloc Technology (BFT) to Japanese eel (Anguilla japonica) aquaculture, a high-value species in East Asia. BFT's potential to reduce water consumption and enhance growth through the use of beneficial microorganisms presents a sustainable solution to the challenges of nitrogenous waste management in global aquaculture. Our research provides the first comprehensive analysis of how BFT influences both the growth and microbiome composition of Japanese eels compared with traditional flow-through systems. By identifying specific microbial residents potentially linked to improved feed consumption and growth, this study opens new avenues for optimizing BFT in eel farming. The findings contribute to the broader understanding of microbial roles in aquaculture, highlighting the potential for BFT to support more sustainable and productive aquaculture practices.

Aeromonas isolation reveals this genus's contribution to antimicrobial resistance fluxes across the wastewater-treated water-river interface.

Aeromonas spp. are common members of water and wastewater microbiomes, but some are listed as opportunistic pathogens and are often reported to carry antimicrobial resistance (AMR) genes. We aimed to assess the performance of isolation media for capturing their distribution and their role in AMR dissemination into aquatic environments. We investigated the abundance, diversity, and AMR profile of Aeromonas isolates from wastewater and receiving water bodies at five municipal wastewater treatment plants in Denmark using three isolation media. This was then compared with the diversity estimated from community-wide 16S rRNA gene amplicon sequencing and resistance patterns inferred from high-throughput qPCR of resistance genes. Isolates from ampicillin sheep blood agar were the most phylogenetically diverse, but the overall Aeromonas recovery on the three media was similarly good and matched the dominant amplicon sequence variants. While the dominant phylotypes were ubiquitous, some types were only detected in treated wastewater and the receiving rivers. The resistance prevalence was moderate and mostly to beta-lactams and tetracyclines. Isolates resistant to piperacilin-tazobactam, cefepime, and tetracycline downstream of the plants were linked to wastewater origin. Overall, our work demonstrates Aeromonas and Aeromonas-mediated AMR fluxes at the wastewater/environment interfaces and provides methodological bases for monitoring aeromonads in wastewater and surface waters.

Antimicrobial Resistance of Waste Water Microbiome in an Urban Waste Water Treatment Plant

Waste water treatment plants (WWTP) are considered as a hotspot for the acquisition and dissemination of antimicrobial resistance (AMR). The present study aimed to assess the AMR rate of the waste water microbiome in a selected WWTP and the treatment efficiency. Culture-dependent and PCR methods were used in the AMR study of raw and treated waste water (TWW) microbiomes. The population proportion of heterotrophic plate count (HPC) bacteria resistant to five antibiotic classes was assessed, as well as the AMR phenotype of a total of 238 Enterobacteriaceae and 259 Enterococcus spp. strains. Waste water treatment increased tetracycline- and ciprofloxacin-resistant bacteria by 67% and 61%, as well as the incidence of Enterobacteriaceae resistant to ciprofloxacin, co-trimoxazole, and cephalosporins. Multiple resistance increased, and 8.8% of TWW isolates exhibited an ESBL-producing phenotype, most often encoded by blaTEM and blaCTX-M genes. The most common resistance among Enterococcus spp. was to erythromycin and tetracycline, and despite the increased AMR rate among TWW isolates, only the increase in tetracycline resistance and the decrease in high-level gentamicin resistance were significant. All parameters analysed demonstrated limited removal of resistant HPC or faecal indicator bacteria in the studied WWTP and a positive selective effect towards some of them, most often to ciprofloxacin.

Daily sampling reveals household-specific water microbiome signatures and shared antimicrobial resistomes in premise plumbing

Daily sampling reveals household-specific water microbiome signatures and shared antimicrobial resistomes in premise plumbing

Bacterial Communities From Two Freshwater Aquaculture Systems in Northern Germany.

The microbial communities in aquaculture systems are primarily affected by changes in water quality, fish metabolism, feeding strategies and fish disease prevention treatments. Monitoring changes in aquatic microbiomes related to aquaculture activities is necessary to improve management strategies and reduce the environmental impact of aquaculture water discharge. This study assessed the effects of activities within two fish farms on water microbiome composition by analysing the water entering and leaving both systems. Additionally, pathogenic bacterial species associated with common fish diseases were identified. The abundance, diversity and identity of microorganisms were evaluated using 16S rRNA hypervariable gene region amplicon sequencing. Proteobacteria (38.2%) and Bacteroidetes (31.3%) were the most abundant phyla in all water samples. Changes in microbiome composition after passage through the fish tanks were observed in several taxa, such as Nitrospirae, Chloroflexi, Deferribacteres and Cyanobacteria. Flavobacterium sp. and Pseudomonas sp. were the predominant potential pathogens and heterotrophic bacteria detected in both farms. Several chemolithotrophic bacteria and archaea were found in the natural reservoir used for aquaculture activities, while water microbiomes in the aquaculture systems were generally dominated by heterotrophic organisms.

Vertical stratification of the water microbiome in an electric water heater tank: implications for premise plumbing opportunistic pathogens.

Hot water systems are the most frequent environment associated with the prevalence and growth of opportunistic premise plumbing pathogens (OPPPs). Previous studies identified water heaters as a source of waterborne diseases and concluded that design variables may contribute to their prevalence. A multifaceted approach was used to investigate the vertical stratification of the microbiome and selected OPPPs in an electric water heater tank connected to a home plumbing system simulator. Results show that the microbiome is highly diverse with evidence of temperature stratification and temporal structuring influenced by the partial drainage of the tank. Representatives of the Mycobacterium spp. were the most prevalent taxa, followed by Legionella spp., and a relatively low prevalence of free-living amoeba Vermamoeba vermiformis. Higher concentrations of Legionella pneumophila at the bottom of the tank indicated the potential growth and protection of this opportunistic pathogen at this location. Overall, partial drainage of the water tank (60% of the tank capacity) did not significantly mitigate the microbiome and selected OPPPs. The outcome of this study sheds light on the role of vertical stratification on water quality and demonstrates the resilience of the microbial community residing in an electric water heater tank and the implications for public health.

Seasonal succession, host associations, and biochemical roles of aquatic viruses in a eutrophic lake plagued by cyanobacterial blooms

Viruses are implicated to play key roles as biogeochemical mediators and ecological drivers in freshwater ecosystems. However, the dynamics of viruses and host associations throughout the seasons and during blooming periods in eutrophic freshwater ecosystems remain poorly understood. From the water microbiomes of planktonic biomass from Lake Taihu, a large eutrophic freshwater lake in China that experiences annual Microcystis-dominated harmful algal blooms (HABs), we recovered 41,997 unique viral clusters spanning a wide taxonomic range, including 15,139 Caudovirales clusters targeting bacteria and 1,044 NCLDV clusters targeting eukaryotes. The viral community exhibited clear seasonal succession, driven primarily by microbial communities (particularly Cyanobacteria and Planctomycetes) and environmental factors (mainly nutrients and temperature). Host prediction revealed that viral infection had a more distinct impact on bacteria-driven nitrogen pathways than on phosphate cycling. HAB-induced variations in microbial composition and environmental conditions affected viral strategies including viral lifestyles, host range, and virus-encoded auxiliary metabolic genes (vAMGs) distributions. Viruses infecting Proteobacteria and Actinobacteria showed an enhanced lysogenic lifestyle and a narrower host range during HAB peak in summer, while viruses infecting Bacteroidota adopted an opposite strategy. Notably, vAMGs were most abundant before the HAB outbreak in spring, compensating for bacterial metabolic processes of their hosts such as carbohydrates metabolism, photosynthesis, and phosphate regulation. The findings highlight the intricate relationships between viruses, host microbes, and the bloom-associated environment, underscoring the important biochemical roles viruses play in eutrophic freshwater ecosystems.

A New Plant Active Polysaccharide from Nicotiana Improves the Lead-Led Impairment of Spatial Memory in Mice by Modulating the Gut Microbiota and IL-6.

Active polysaccharides from plants are broadly applied in the food and health industry. The purpose of this study is to identify a new plant active polysaccharide and to investigate its role in modulating spatial memory. Ultrasonics and DEAE-52 chromatography were used to separate and purify the plant active polysaccharide (PAP). Mice were exposed to 100 ppm of lead acetate from birth to 7 weeks old to establish the memory impairment model. PAPs with concentrations of 200 or 400 ppm were fed to the subject mice each day after weaning in a spatiotemporally separated fashion. At the end of the intervention, mice were examined using the Morris water maze test, microbiome sequencing, cytokine profiling and protein analysis. The derived active polysaccharide was constituted by β-anomeric carbon, indicating a new form of PAP. The PAP significantly ameliorates the memory impairment caused by postnatal lead exposure, as evidenced by the preferred coverage of the test mouse in the hidden platform, demonstrating salient neuroregulatory activity. In terms of the gut microbiome in response to PAP treatment, it was found that the 400 ppm PAP reversed the gut dysbiosis, producing a comparable structure to the intact animals, represented by the relative abundance of Firmicutes and Muribaculum, Desulfovibrio, etc. For cytokines, the PAP reversed the plasma levels of IL-6, suggesting an anti-inflammatory trend in the context of proinflammation caused by lead invasion. By injecting an IL-6 antagonist, Tocilizumab, into the deficient mice, the spatial memory was significantly repaired, which demonstrates the central roles of IL-6 in mediating the positive effect of the PAP. Finally, a histone modification mark, H3K27me3, was found to be potent in responding to the signals conveyed by the PAP. The PAP could improve the memory deficits by remodeling the gut-brain axis centered at the microbiota and IL-6, which is regarded as an important cytokine-modulating brain activity. This is an intriguing instance linking neuromodulation with the active polysaccharide, shedding light on the innovative applications of plant polysaccharides due to the scarcity of similar phenotypic connections.

Microbial community storm dynamics signal sources of "old" stream water.

Accurate characterization of the movement of water through catchments, particularly during precipitation event response, is critical for hydrological efforts such as contaminant transport modeling or prediction of extreme flows. Abiotic hydrogeochemical tracers are commonly used to track sources and ages of surface waters but provide limited details about transit pathways or the spatial dynamics of water storage and release. Alternatively, biotic material in streams is derived from thousands of taxa originating from a variety of environments within watersheds, including groundwater, sediment, and upslope terrestrial environments, and this material can be characterized with genetic sequencing and bioinformatics. We analyzed the stable water isotopes (δ18O and δ2H) and microbiome composition (16S rRNA gene amplicon sequencing) of the Marys River of western Oregon, USA during an early season storm to describe the processes, storage, and flowpaths that shape surface water hydrology. Stable water isotopes (δ18O and δ2H) typified an event response in which stream water is composed largely of 'old' water introduced to the catchment before the storm, a common though not well understood phenomenon. In contrast, microbial biodiversity spiked during the storm, consisting of early- and late-event communities clearly distinguishable from pre-event communities. We applied concentration-discharge (cQ) analysis to individual microbial taxa and found that most Alphaproteobacteria sequences were positively correlated (i.e., were mobilized) with discharge, whereas most sequences from phyla Gammaproteobacteria and Bacteroidota were negatively correlated with discharge (i.e., were diluted). Source predictions using the prokaryote habitat preference database ProkAtlas found that freshwater-associated microbes composed a smaller fraction of the microbial community during the stream rise and a larger fraction during the recession, while soil and biofilm-associated microbes increased during the storm and remained high during recession. This suggests that the "old" water discharged during the storm was likely stored and released from, or passed through, soil- and biofilm-rich environments, demonstrating that this approach adds new, biologically derived tracer information about the hydrologic pathways active during and after this event. Overall, this study demonstrates an approach for integrating information-rich DNA into water resource investigations, incorporating tools from both hydrology and microbiology to demonstrate that microbial DNA is useful not only as an indicator of biodiversity but also functions as an innovative hydrologic tracer.

The piranha gut microbiome provides a selective lens into river water biodiversity

Advances in omics technologies have enabled the in-depth study of microbial communities and their metabolic profiles from all environments. Here metagenomes were sampled from piranha (Serrasalmus rhombeus) and from river water from the Rio São Benedito (Amazon Basin). Shotgun metagenome sequencing was used to explore diversity and to test whether fish microbiomes are a good proxy for river microbiome studies. The results showed that the fish microbiomes were not significantly different from the river water microbiomes at higher taxonomic ranks. However, at the genus level, fish microbiome alpha diversity decreased, and beta diversity increased. This result repeated for functional gene abundances associated with specific metabolic categories (SEED level 3). A clear delineation between water and fish was seen for beta diversity. The piranha microbiome provides a good and representative subset of its river water microbiome. Variations seen in beta biodiversity were expected and can be explained by temporal variations in the fish microbiome in response to stronger selective forces on its biodiversity. Metagenome assembled genomes construction was better from the fish samples. This study has revealed that the microbiome of a piranha tells us a lot about its river water microbiome and function.

What is the Difference between Conventional Drinking Water, Potable Reuse Water, and Nonpotable Reuse Water? A Microbiome Perspective.

As water reuse applications expand, there is a need for more comprehensive means to assess water quality. Microbiome analysis could provide the ability to supplement fecal indicators and pathogen profiling toward defining a "healthy" drinking water microbiota while also providing insight into the impact of treatment and distribution. Here, we utilized 16S rRNA gene amplicon sequencing to identify signature features in the composition of microbiota across a wide spectrum of water types (potable conventional, potable reuse, and nonpotable reuse). A clear distinction was found in the composition of microbiota as a function of intended water use (e.g., potable vs nonpotable) across a very broad range of U.S. water systems at both the point of compliance (Betadisper p > 0.01; ANOSIM p < 0.01, r-stat = 0.71) and point of use (Betadisper p > 0.01; ANOSIM p < 0.01, r-stat = 0.41). Core and discriminatory analysis further served in identifying distinct differences between potable and nonpotable water microbiomes. Taxa were identified at both the phylum (Desulfobacterota, Patescibacteria, and Myxococcota) and genus (Aeromonas and NS11.12_marine_group) levels that effectively discriminated between potable and nonpotable waters, with the most discriminatory taxa being core/abundant in nonpotable waters (with few exceptions, such as Ralstonia being abundant in potable conventional waters). The approach and findings open the door to the possibility of microbial community signature profiling as a water quality monitoring approach for assessing efficacy of treatments and suitability of water for intended use/reuse application.

Impact of temperature and water source on drinking water microbiome during distribution in a pilot-scale study

This study utilized a pilot-scale distribution network to examine the impact of temperature increases (16 °C, 20 °C, 24 °C) and source variations (treated ground- and surface water) on bulk and biofilm communities over 137 days. Microbial characterization employed flow cytometry and 16 S rRNA gene-based amplicon sequencing to elucidate bulk-biofilm interactions. Bacterial bulk cell densities increased with higher temperatures, while water source variations significantly influenced bulk cell densities as well as the community composition. Additionally, growth curves were fitted on the flow cytometry results, and growth rates and carrying capacities were higher with treated groundwater at elevated temperatures. Conversely, biofilm cell densities remained unaffected by temperature. A mature biofilm was observed from day 70 onwards and a core biofilm microbiome, resilient to temperature and water source changes, was identified. These findings emphasize the importance of water source quality for maintaining biological stability in drinking water systems, particularly in the face of changing environmental conditions.

Phototrophs as the central components of the plastisphere microbiome in coastal environments

Upon entering the marine environment, plastics are colonized by a plethora of microorganisms to form a plastisphere, influencing the fate and transport of the plastic debris and the health of marine ecosystems. The assembly of marine plastisphere is generally believed to be dominated by stochastic processes. However, it remains elusive whether microbial interaction in the assembly of plastisphere microbial communities is conserved or not. We analyzed the plastisphere microbiomes of 137 plastic debris samples from intertidal zones at different geographical locations and habitats (seagrass, coral, mangrove, beach, and open ocean) and compared them with the surrounding sediment and seawater microbiomes. Microbial community structures of the plastisphere from different locations were more similar to each other but differed substantially from the surrounding sediment and water microbiomes, implying a common mechanism of plastisphere assembly. We used different machine learning algorithms (Multinomial Logistic Regression, Support Vector Machine, Decision Trees, Random Forest, and Artificial Neural Networks) to classify plastic debris samples with high sensitivity based on the microbiome composition. Eukaryotic and prokaryotic phototrophic organisms such as green algae, diatoms, and cyanobacteria, were found to be enriched on the plastic surfaces. Network analysis revealed the central role of the phototrophic organisms in the formation and sustenance of the plastispheres. We found that phototrophs served as core members interacting strongly with heterotrophic organisms in marine plastisphere, irrespective of the sampling location, habitats, and polymer types. This would explain the stochastic assembly of the plastisphere along with conserved properties driven by the phototrophs in the surrounding environment. Our results highlight the importance of phototrophic organisms in shaping the marine plastisphere microbial communities.

One Health Threat of Treated Wastewater Discharge in Urban Ohio Rivers: Implications for Surface Water and Fish Gut Microbiome and Resistome.

Wastewater treatment plants (WWTPs) are thought to be a major disseminating source of antibiotic resistance (AR) to the environment, establishing a crucial connection between human and environmental resistome. The objectives of this study were to determine how wastewater effluents impact microbiome and resistome of freshwater and fish, and identify potential AR-carrying clinically relevant pathogens in these matrices. We analyzed wastewater influent and effluent from four WWTPs in three metropolitan areas of Ohio, USA via shotgun metagenomic sequencing. We also sequenced river water and fish guts from three reaches (upstream, at the WWTP outfall, and downstream). Notably, we observed a decline in microbiome diversity and AR gene abundance from wastewater to the receiving river. We also found significant differences by reach and trophic level (diet) in beta-diversity of the fish gut microbiomes. SourceTracker revealed that 0.443 and 0.248 more of the of the fish gut microbiome was sourced from wastewater effluent in fish from the outfall and downstream locations, respectively, compared to upstream fish. Additionally, AR bacteria of public health concern were annotated in effluent and river water samples, indicating potential concern for human exposure. In summary, our findings show the continued role of wastewater as a significant AR reservoir and underscores the considerable impact of wastewater discharge on aquatic wildlife, which highlights the One Health nature of this issue.

Spatiotemporal distribution of environmental microbiota around animal farms adjacent to produce fields in central coast California

This study aimed to identify different environmental microbiota in animal farms adjacent to produce fields and to understand their potential flow pattern. Soil and water samples were collected from 16 locations during the winter, spring, summer, and fall seasons. In addition, a high-resolution digital elevation model helped to create a stream network to understand the potential flow of the microbiome. Metagenomic analysis of the 16 S rRNA gene revealed that soil and water samples from the four seasons harbor diverse microbiome profiles. The phylogenetic relationship of operational taxonomic units (OTUs) is separated by a maximum of 0.6 Bray-Curtis distance. Similarly, the Principal Component Analysis (P = 0.001) demonstrated the soil and water microbiome clustering across different locations and seasons. The relative abundance of Proteobacteria, Bacteroidetes, and Firmicutes was higher in the water samples than in the soil samples. In contrast, the relative abundance of Actinobacteria and Chloroflexi was higher in the soil compared to the water samples. Soil samples in summer and water samples in spring had the highest abundance of Bacteroidetes and Firmicutes, respectively. A unique microbial community structure was found in water samples, with an increased abundance of Hydrogenophaga and Solirubrobacter. Genera that were significantly abundant at a 1% false discovery rate (FDR) among seasons and soil or water samples, include Nocardioides, Gemmatimonas, JG30-KF-CM45, Massilia, Gaiellales, Sphingomonas, KD4-96, Bacillus, Streptomyces, Gaiella, and Gemmatimonadaceae. The relative abundance of pathogenic genera, including Mycobacterium, Bacteroides, Nocardia, Clostridium, and Corynebacterium, were significantly (at 1% FDR) affected by seasons and environmental type. The elevation-based stream network model suggests the potential flow of microbiomes from the animal farm to the produce fields.

Examining the impact of agricultural drainage ditch management on in-stream bacterial communities involved in nitrogen cycling: insights from the Environmental Change One Health Observatory (ECO2)

IntroductionAgricultural drainage ditches are essential for maintaining flow efficiency and are often managed by brushing (i.e., vegetation clearing along ditch banks) and dredging. These maintenance practices not only impact flow but also the ditches’ capacity to process and assimilate agricultural chemicals. However, the influence of ditch management on microbial activities, essential in processing and transforming these contaminants, remains underexplored.MethodsWe conducted a four-year surface water sampling campaign in two long-established (over 40 years) agricultural drainage ditches situated in eastern Ontario, Canada. One drainage ditch underwent intensive bank brushing and channel dredging, while the other remained unmanaged. We assessed the impact of these contrasting ditch management practices on the diversity and compositional structure of surface water microbiome communities, with a particular focus on the distribution of genes associated with nitrogen (N) cycling, using shotgun metagenomics sequencing and an assembly-based metagenome approach.Results and discussionFrom 117 surface water samples, we reconstructed 157 metagenome-assembled genomes (MAGs), predominantly from the Patescibacteria superphylum. Brushing alone, conducted about 10 months prior to dredging, had an insignificant impact on the aquatic microbial community. However, dredging led to a significant reduction in community diversity and abundance of genes affiliated with denitrification, dissimilatory nitrate reduction to ammonia, and complete nitrification through comammox. Ditch management resulted in noticeable shifts in the microbial community, evidenced by the enrichment of taxa in Polaromonas, Emticicia, Flectobacillus, and Patescibacteria in the water of the managed ditch sites. The metagenomes of these taxa harbor genes involved in various nitrogen biotransformation pathways. Interestingly, following dredging, the levels of ammonia and ammonium, nitrite, and total Kjeldahl N in the managed ditch did not increase, but significantly decreased; likely due to ditch substrate removal and potentially increased flow efficiency and dilution. Being one of the few studies conducted to date, this study provided unique insights into the consequences of drainage ditch management on freshwater microbiomes involved in N cycling.

Drought influences the fungal community structure, diversity, and functionality inhabiting the grapevine xylem and enhances the abundance of Phaeomoniella chlamydospora

Grapevine productivity worldwide is increasingly threatened by global warming, potentially exacerbating water scarcity. This study examines drought's effects on grapevine xylem's fungal communities, particularly regarding Phaeomoniella chlamydospora, linked to esca and Petri diseases. Investigating one-year-old grafted grapevines under varied water regimes, including severe, moderate, and no water deficit, the research assesses how drought influences fungal diversity, structure, and interactions within the xylem. Utilizing ITS high-throughput amplicon sequencing and droplet-digital PCR, the study tracks changes in fungal composition and P. chlamydospora prevalence over two growing seasons. The induced water stress not only altered the diversity and composition of the fungal microbiome in the xylem vessels but also affected co-occurrence networks, resulting in less complex networks with fewer correlations between taxa, potentially increasing grapevine vulnerability to various biotic and abiotic stresses. Severe water deficit significantly reduced microbial diversity, leading to a shift in the abundance of pathotrophs such as P. chlamydospora in the xylem. This underscores the interconnectedness between water stress, microbiome dynamics, and plant health. The combination of compromised plant defenses, altered physiological conditions, and shifts in the surrounding microbial community may create conditions conducive to increased P. chlamydospora abundance in the xylem vessels of young vines following water stress.

Microbiota of laboratory channel catfish skin mucosa and aquaria water exposed to chloramine-T trihydrate.

Here, we describe the skin mucosa microbiome of channel catfish (Ictalurus punctatus) before and after exposure to chloramine-T trihydrate. We also describe the aquaria water microbiome after the post-treatment period. These data provide a unique baseline description of skin mucosa and aquaria water microbiome from catfish reared in research aquaria.

Comparative analysis of chlorine-resistant bacteria after chlorination and chloramination in drinking water treatment plants

Chlorine-resistant bacteria (CRB) in drinking water treatment plants (DWTPs) jeopardize water quality and pose a potential risk to human health. However, the specific response of CRB to chlorination and chloramination remains uncharacterized. Therefore, we analyzed 16 S rRNA sequencing data from water samples before and after chlorination and chloramination taken between January and December 2020. Proteobacteria and Firmicutes dominated all finished water samples. After chloramination, Acinetobacter, Pseudomonas, Methylobacterium, Ralstonia, and Sphingomonas were the dominant CRB, whereas Ralstonia, Bacillus, Acinetobacter, Pseudomonas, and Enterococcus were prevalent after chlorination. Over 75% of the CRB e.g. Acinetobacter, Pseudomonas, Bacillus, and Enterococcus were shared between the chlorination and chloramination, involving potentially pathogens, such as Acinetobacter baumannii and Pseudomonas aeruginosa. Notably, certain genera such as Faecalibacterium, Geobacter, and Megasphaera were enriched as strong CRB after chloramination, whereas Vogesella, Flavobacterium, Thalassolituus, Pseudoalteromonas, and others were enriched after chlorination according to LEfSe analysis. The shared CRB correlated with temperature, pH, and turbidity, displaying a seasonal pattern with varying sensitivity to chlorination and chloramination in cold and warm seasons. These findings enhance our knowledge of the drinking water microbiome and microbial health risks, thus enabling better infectious disease control through enhanced disinfection strategies in DWTPs.

Tap water microbiome shifts in secondary water supply for high-rise buildings

In high-rise buildings, secondary water supply systems (SWSSs) are pivotal yet provide a conducive milieu for microbial proliferation due to intermittent flow, low disinfectant residual, and high specific pipe-surface area, raising concerns about tap water quality deterioration. Despite their ubiquity, a comprehensive understanding of bacterial community dynamics within SWSSs remains elusive. Here we show how intrinsic SWSS variables critically shape the tap water microbiome at distal ends. In an office setting, distinct from residential complexes, the diversity in piping materials instigates a noticeable bacterial community shift, exemplified by a transition from α-Proteobacteria to γ-Proteobacteria dominance, alongside an upsurge in bacterial diversity and microbial propagation potential. Extended water retention within SWSSs invariably escalates microbial regrowth propensities and modulates bacterial consortia, yet secondary disinfection emerges as a robust strategy for preserving water quality integrity. Additionally, the regularity of water usage modulates proximal flow dynamics, thereby influencing tap water's microbial landscape. Insights garnered from this investigation lay the groundwork for devising effective interventions aimed at safeguarding microbiological standards at the consumer's endpoint.