Metagenome-assembled genomes provide insight into the metabolic potential during early production of Hydraulic Fracturing Test Site 2 in the Delaware Basin.

Demand for natural gas continues to climb in the United States, having reached a record monthly high of 104.9 billion cubic feet per day (Bcf/d) in November 2023. Hydraulic fracturing, a technique used to extract natural gas and oil from deep underground reservoirs, involves injecting large volumes of fluid, proppant, and chemical additives into shale units. This is followed by a "shut-in" period, during which the fracture fluid remains pressurized in the well for several weeks. The microbial processes that occur within the reservoir during this shut-in period are not well understood; yet, these reactions may significantly impact the structural integrity and overall recovery of oil and gas from the well. To shed light on this critical phase, we conducted an analysis of both pre-shut-in material alongside production fluid collected throughout the initial production phase at the Hydraulic Fracturing Test Site 2 (HFTS 2) located in the prolific Wolfcamp formation within the Permian Delaware Basin of west Texas, USA. Specifically, we aimed to assess the microbial ecology and functional potential of the microbial community during this crucial time frame. Prior analysis of 16S rRNA sequencing data through the first 35 days of production revealed a strong selection for a Clostridia species corresponding to a significant decrease in microbial diversity. Here, we performed a metagenomic analysis of produced water sampled on Day 33 of production. This analysis yielded three high-quality metagenome-assembled genomes (MAGs), one of which was a Clostridia draft genome closely related to the recently classified Petromonas tenebris. This draft genome likely represents the dominant Clostridia species observed in our 16S rRNA profile. Annotation of the MAGs revealed the presence of genes involved in critical metabolic processes, including thiosulfate reduction, mixed acid fermentation, and biofilm formation. These findings suggest that this microbial community has the potential to contribute to well souring, biocorrosion, and biofouling within the reservoir. Our research provides unique insights into the early stages of production in one of the most prolific unconventional plays in the United States, with important implications for well management and energy recovery.

Initial waterline contamination by Pseudomonas aeruginosa in newly installed dental chairs.

Water contamination in dental unit waterlines (DUWLs) is a potential source of healthcare-associated infection during dental care. The aim of this study was to evaluate the microbiological quality of DUWLs water from newly installed dental chairs in a French University Hospital. The microbiological quality of water from 24 new DUWLs initially disinfected by ICX Renew-prior to use of the dental units for patient treatment-was assessed for total culturable aerobic bacteria at 22°C and 36°C, Legionella sp., Pseudomonas aeruginosa, and total coliforms. Among the 24 samples analyzed, 21 were compliant with the water quality levels: 19 had no bacteria, and 2 contained only 4 and 1 CFU/mL for total culturable aerobic bacteria at 22°C and 36°C, respectively. Three samples were non-compliant due to contamination by P. aeruginosa (4, 2, and 2 CFU/100 mL). Controlling and preventing the microbiological contamination of DUWLs, especially by pathogenic bacteria, at the time of the installation of the new dental chairs are crucial to prevent healthcare-associated infection in dentistry. IMPORTANCE: Dental unit waterlines (DUWLs) of new dental chairs may be contaminated before their first clinical use, so an initial shock disinfection is crucial at the time of their installation. The microbiological analyses are crucial to control the water quality of DUWLs before their first clinical use because their disinfection does not guarantee the elimination of all bacteria.

From source to house: unraveling the seasonal effect of water distribution system on drinking water quality of poultry farms under Egyptian environmental condition.

Improvements in drinking water quality (DWQ) can lead, according to some estimates, to a 10% reduction of the world's disease load. The drinking water distribution system (DWDS) plays a crucial role in influencing DWQ and can contribute to the emergence of poultry-related epidemics. This study aims to monitor the variations in DWQ throughout the seasons within the DWDS of Egyptian poultry farms experiencing epidemics. The study assessed DWQ at four different points along the DWDS, including the water source (WS), water tank (WT), broiler drinker (BD), and layer drinker (LD), across 86 farms. Statistical analysis was employed to establish correlations between DWQ and the sampling points within the DWDS, as well as between water temperature (Tw.C°), ambient temperature (Ta.C°), and microbial DWQ. The survey revealed significant differences between Tw.C° and Ta.C°, with notable effect sizes (d = 0.89-1). Additionally, the results revealed significant differences in physicochemical DWQ between WS and house drinkers (HD), with medium to large effect sizes (d = 0.56-0.85). Furthermore, significant differences were identified in microbial DWQ between winter and summer, with a small to large effect size (d = 0.40-0.87). Notably, we recorded significant differences in microbial DWQ between WS and WT, with a small to medium effect size (d = 0.40-0.61), and between WT and BD, with a small to medium effect size (d = 0.48-0.53). Additionally, we found significant differences in microbial DWQ between WS and LD, with a medium effect size (d = 0.59-0.68). In conclusion, Tw.C° is influenced by seasonal variations in Ta.C°. While the physicochemical DWQ was unaffected by seasonal temperature variations, it was significantly impacted by the DWDS from WS to HD. In contrast, the microbial DWQ was strongly influenced by both seasonal temperature changes and DWDS.

Waterborne pathogens detection technologies: advances, challenges, and future perspectives.

The World Health Organization (WHO) estimated that pathogens like Escherichia coli, primarily linked to food and water contamination, are associated with 485,000 deaths from diarrheal diseases annually, translating to a staggering worldwide economic loss of nearly 12 billion USD per annum. International organizations like the WHO and United Nations Children's Fund (UNICEF) have established related guidelines and criteria for pathogenic detection technologies and driving the search for innovative and efficient detection methods. This comprehensive review examines the trajectory of waterborne pathogenic bacteria detection technologies from traditional techniques, i.e., culture-based methods, to current detection methods including various forms of polymerase chain reaction (PCR) techniques [qualitative real-time PCR, digital PCR, ELISA, loop-mediated isothermal amplification, next-generation sequencing (NGS)] and to emerging techniques, i.e., biosensors and artificial intelligence (AI). The scope of the review paper focuses on waterborne pathogenic bacteria that are recognized as human pathogens, posing tangible threats to public health through waterborne. The detection techniques' merits, constraints, research gaps and future perspectives are critically discussed. Advancements in digital droplet PCR, NGS and biosensors have significantly improved sensitivity and specificity, revolutionizing pathogen detection. Additionally, the integration of artificial intelligence (AI) with these technologies has enhanced detection accuracy, enabling real-time analysis of large datasets. Molecular-based methods and biosensors show promise for efficient water quality monitoring, especially in resource-constrained settings, but on-site practical implementation remains a challenge. The pairwise comparison metrics used in this review also offer valuable insights into quick evaluation on the advantages, limitations and research gaps of various techniques, focusing on their applicability in field settings and timely analyses. Future research efforts should focus on developing robust, cost-effective and user-friendly techniques for routine waterborne bacteria monitoring, ultimately safeguarding global water supplies and public health, with AI and data analysis playing a crucial role in advancing these methods for a safer environment.

Phase change materials for portable isothermal incubators as a solution to shorten effective analysis times in microbiological quality control of drinking water.

The microbiological quality control of water for human consumption of parameters relevant as E.coli and total coliforms does not start on the field despite the existence of test methods that could make it possible. One of the things that makes this difficult is the possibility of initiating an effective and reliable incubation at the sampling site. The appearance of isothermal media with phase change materials solves this limitation. When phase change materials combine a relatively high melting heat with a suitable melting temperature adapted to the application temperature, they become excellent materials for thermal protection and for thermal energy storage. Starting the test at the same sampling point means that the effective times to obtain a result are shorter, improving water quality control. On the other hand, operationally, it also allows longer sampling routes. Both aspects are essential for managers responsible for controlling water quality for human consumption. In this work, the evidence that demonstrates the feasibility of this approach is presented.

Characterizing Biofilm Interactions between Ralstonia insidiosa and Chryseobacterium gleum.

Ralstonia insidiosa and Chryseobacterium gleum are bacterial species commonly found in potable water systems, and these two species contribute to the robustness of biofilm formation in a model six-species community from the International Space Station (ISS) potable water system. Here, we set about characterizing the interaction between these two ISS-derived strains and examining the extent to which this interaction extends to other strains and species in these two genera. The enhanced biofilm formation between the ISS strains of R. insidiosa and C. gleum is robust to starting inoculum and temperature and occurs in some but not all tested growth media, and evidence does not support a soluble mediator or coaggregation mechanism. These findings shed light on the ISS R. insidiosa and C. gleum interaction, though such enhancement is not common between these species based on our examination of other R. insidiosa and C. gleum strains, as well as other species of Ralstonia and Chryseobacterium. Thus, while the findings presented here increase our understanding of the ISS potable water model system, not all our findings are broadly extrapolatable to strains found outside of the ISS. IMPORTANCE Biofilms present in drinking water systems and terminal fixtures are important for human health, pipe corrosion, and water taste. Here, we examine the enhanced biofilm of cocultures for two very common bacteria from potable water systems: Ralstonia insidiosa and Chryseobacterium gleum. While strains originally isolated on the International Space Station show enhanced dual-species biofilm formation, terrestrial strains do not show the same interaction properties. This study contributes to our understanding of these two species in both dual-culture and monoculture biofilm formation.

Exploring the Impacts of Full-Scale Distribution System Orthophosphate Corrosion Control Implementation on the Microbial Ecology of Hydrologically Connected Urban Streams.

Many cities across the nation are plagued by lead contamination in drinking water. As such, many drinking water utilities have undertaken lead service line (LSL) replacement to prevent further lead contamination. However, given the urgency of lead mitigation, and the socioeconomic challenges associated with LSL replacement, cities have used phosphate-based corrosion inhibitors (i.e., orthophosphate) alongside LSL replacement. While necessary to ensure public health protection from lead contamination, the addition of orthophosphate into an aging and leaking drinking water system may increase the concentration of phosphate leaching into urban streams characterized by century-old failing water infrastructure. Such increases in phosphate availability may cascade into nutrient and microbial community composition shifts. The purpose of this study was to determine how this occurs and to understand whether full-scale distribution system orthophosphate addition impacts the microbial ecology of urban streams. Through monthly collection of water samples from five urban streams before and after orthophosphate addition, significant changes in microbial community composition (16S rRNA amplicon sequencing) and in the relative abundance of typical freshwater taxa were observed. In addition, key microbial phosphorus and nitrogen metabolism genes (e.g., two component regulatory systems) were predicted to change via BugBase. No significant differences in the absolute abundances of total bacteria, Cyanobacteria, and "Candidatus Accumulibacter" were observed. Overall, the findings from this study provide further evidence that urban streams are compromised by unintentional hydrologic connections with drinking water infrastructure. Moreover, our results suggest that infiltration of phosphate-based corrosion inhibitors can impact urban streams and have important, as-yet-overlooked impacts on urban stream microbial communities. IMPORTANCE Elevated lead levels in drinking water supplies are a public health risk. As such, it is imperative for cities to urgently address lead contamination from aging drinking water supplies by way of lead service line replacements and corrosion control methods. However, when applying corrosion control methods, it is also important to consider the chemical and microbiological effects that can occur in natural settings, given that our water infrastructure is aging and more prone to leaks and breaks. Here, we examine the impacts on the microbial ecology of five urban stream systems before and after full-scale distribution system orthophosphate addition. Overall, the results suggest that infiltration of corrosion inhibitors may impact microbial communities; however, future work should be done to ascertain the true impact to protect both public and environmental health.

Dental unit water content and antibiotic resistance of Pseudomonas aeruginosa and Pseudomonas species: a case study.

Background: Many studies consider the contamination of dental unit waterlines (DUWLs), but few of them have studied the possible presence of antibiotic resistant Pseudomonas aeruginosa in the DUWLs. Aims: Investigation of the presence of P. aeruginosa and Pseudomonas spp. strains in DUWLs and evaluation of their resistance to six antibiotics (ceftazidime, netilmicin, piperacillin/tazobactam, meropenem, levofloxacin, colistin sulfate) at a public dental clinic in Milan, Italy. Results: Dental units were contaminated by P. aeruginosa with loads of 2-1,000 CFU/L and were mainly located on the mezzanine floor, with a range of 46-54%, while Pseudomonas spp. were primarily found on the first and second floors, ranging from 50 to 91%. P. aeruginosa was antibiotic resistant in 30% of the strains tested, andPseudomonas spp. in 31.8% . Cold water from controls was also contaminated by these microorganisms. Conclusion: Monitoring antibiotic resistance in the water and adopting disinfection procedures on DUs are suggested within the Water Safety Plan.

[Evaluation of surface water quality in recreational areas, an integrative proposal of chemical and microbiological markers]. / Evaluación de la calidad de aguas superficiales en espacios recreacionales , una propuesta integradora de marcadores químicos y microbiológicos.

Climate change affects the interactions between water systems, ecosystems, and the atmosphere. It also increases the risk of the presence of microorganisms which affect the systems that use these resources. The impact of the population on the water resources has become more evident in recent years, highlighting the close relationship between the levels of inorganic components and microbiological contamination of water and community health. The characterization of the variables that account for water pollution is a complex process. In this paper, it is proposed to quantified nitrites and phosphorous as chemical markers and fecal coliforms, genomic human adenovirus and/or picobirnavirus and infectious human enterovirus detection as microbiological markers for the prevention of water-borne infections in individuals exposed to superficial aqueous matrices by recreational activities.

El cambio climático afecta a las interacciones entre los sistemas hídricos, los ecosistemas y la atmósfera. También aumenta el riesgo de la presencia de microorganismos que afectan a los sistemas que utilizan estos recursos. El impacto de la población sobre los recursos hídricos se ha hecho más evidente en los últimos años, destacando la estrecha relación entre los niveles de componentes inorgánicos así como la contaminación microbiológica del agua y la salud de la comunidad. La caracterización de las variables que dan cuenta de la contaminación del agua es un proceso complejo. En este trabajo se propone la cuantificación de nitritos y fósforo como marcadores químicos y la detección de coliformes fecales, adenovirus humanos genómicos y/o picobirnavirus y enterovirus humanos infecciosos como marcadores microbiológicos para la prevención de infecciones de origen hídrico en individuos expuestos a matrices acuosas superficiales por actividades recreativas.

Candida species contamination in drinking groundwater from residence wells in three municipalities of midwestern Brazil and the potential human health risks.

Groundwater represents one of the largest safe drinking water sources worldwide; however, it has been threatened by increased human activities in recent years. Candida species express virulence factors that contribute to the establishment and worsening of infections, although little is known about the virulence profiles of these species in potable groundwater. The aim of this study was to detect the presence of yeasts in groundwater from residential wells and to evaluate the antifungal susceptibility profile, hydrolytic enzyme production, adhesion capacity, and biofilm formation of Candida spp. Fifty yeasts representing nine genera were isolated: Candida (48%), Meyerozyma (20%), Pichia (8%), Exophiala (8%), Clavispora (4%), Kodamaea (4%), Rhodotorula (4%), Hanseniaspora (2%), and Kazachstania (2%). Candida parapsilosis was the most commonly isolated species, and approximately 29% of the Candida isolates were resistant to at least one azole. All Candida isolates were able to produce hydrolytic enzymes and adhere to polystyrene, and most were classified as hydrophobic. Candida spp. can establish and form biofilms when cultivated in different media such as Sabouraud broth, water, and calcium hypochlorite. The use of contaminated groundwater for human consumption represents a possible route for the transmission of clinically relevant yeasts that can cause fungal infections, especially in immunocompromised individuals. Therefore, it is important to evaluate and establish effective measures for groundwater treatment to ensure the quality and safety for consumption.

Application of digital PCR for public health-related water quality monitoring.

Digital polymerase chain reaction (dPCR) is emerging as a reliable platform for quantifying microorganisms in the field of water microbiology. This paper reviews the fundamental principles of dPCR and its application for health-related water microbiology. The relevant literature indicates increasing adoption of dPCR for measuring fecal indicator bacteria, microbial source tracking marker genes, and pathogens in various aquatic environments. The adoption of dPCR has accelerated recently due to increasing use for wastewater surveillance of Severe Acute Respiratory Coronavirus 2 (SARS-CoV-2) - the virus that causes Coronavirus Disease 2019 (COVID-19). The collective experience in the scientific literature indicates that well-optimized dPCR assays can quantify genetic material from microorganisms without the need for a calibration curve and often with superior analytical performance (i.e., greater sensitivity, precision, and reproducibility) than quantitative polymerase chain reaction (qPCR). Nonetheless, dPCR should not be viewed as a panacea for the fundamental uncertainties and limitations associated with measuring microorganisms in water microbiology. With dPCR platforms, the sample analysis cost and processing time are typically greater than qPCR. However, if improved analytical performance (i.e., sensitivity and accuracy) is critical, dPCR can be an alternative option for quantifying microorganisms, including pathogens, in aquatic environments.

Global subtype diversity, spatial distribution patterns, and phylogenetic analysis of avian influenza virus in water.

The current COVID-19 pandemic highlights the need for zoonotic infectious disease surveillance. Avian influenza virus (AIV) poses a significant threat to animal and public health due to its pandemic potential. Virus-contaminated water has been suggested as an important AIV spread mechanism among multiple species. Nevertheless, few studies have characterized the global AIV subtype diversity and distribution in environmental water. Therefore, this study aims to provide an updated descriptive and phylogenetic analysis of AIVs isolated in water samples from high risk-sites for influenza outbreaks (i.e. live bird markets, poultry farms, and wild bird habitats) on a global scale. The descriptive analysis evidenced that 21 subtypes were reported from nine countries between 2003 and 2020. Fourteen AIV subtypes were solely reported from Asian countries. Most of the viral sequences were obtained in China and Bangladesh with 47.44% and 23.93%, respectively. Likewise, the greatest global AIV subtype diversity was observed in China with 12 subtypes. Live bird markets represented the main sampling site for AIV detection in water samples (64.1%), mostly from poultry cage water. Nevertheless, the highest subtype diversity was observed in water samples from wild bird habitats, especially from the Izumi plain and the Dongting Lake located in Japan and China, respectively. Water from drinking poultry troughs evidenced the greatest subtype diversity in live bird markets; meanwhile, environmental water used by ducks had the highest number of different subtypes in poultry farms. Maximum-likelihood phylogenetic trees of hemagglutinin (HA) and neuraminidase (NA) genes showed that some sequences were closely related among different poultry/wild bird-related environments from different geographic origins. Therefore, the results suggest that even though the availability of gene sequences in public-access databases varies greatly among countries, environmental AIV surveillance represents a useful tool to elucidate potential viral diversity in wild and domestic bird populations.

Threat in water for drinking and domestic use: Nontuberculous mycobacteria.

Objective: Nontuberculous mycobacteria (NTM) have been recognized as a diverse group of organisms that are ubiquitous in environmental sources. In most regions of the world, NTM are not reportable as a public health disease, so epidemiological data are not easily available. However, data in published studies note increasing trends at the rate of NTM isolation from different geographic regions of the world. Increasing NTM isolation may have important public health implications. The aim of our study is the investigation of NTM from water resources and networks in Düzce, Turkey. Methods: NTM are common in water resources and water networks. They can cause waterborne infections in humans. A total of 120 water samples measured of chlorine and pH levels were decontaminated and filtered. Then, the filters were placed in the culturing media. Statistical Analysis Used: Chi-square and t-test were used for the statistical analysis. Results: NTM were detected in 20 (16.6%) samples. Nine of them (45%) were Mycobacterium fortuitum, three (15%) were Mycobacterium gordonae, three (15%) were Mycobacterium szulgai, two (10%) were Mycobacterium lentiflavum, two (10%) were Mycobacterium chelonae, and one (5%) was Mycobacterium peregrinum. Conclusions: These environmental bacteria can cause serious illnesses in both immunocompetent and especially immunocompromised individuals. For the correct treatment of these patients, it is important to determine NTM in clinical samples. Surveillance is necessary to know the source of NTM infection, to identify and type the strains, and to establish effective control measures such as disinfection, maintenance, and modernization of water systems.

Microbial pathogens and contaminants of emerging concern in groundwater at an urban subsurface stormwater infiltration site.

Urban stormwater may contain a variety of pollutants, including viruses and other pathogens, and contaminants of emerging concern (pharmaceuticals, artificial sweeteners, and personal care products). In vulnerable geologic settings, the potential exists for these contaminants to reach underlying aquifers and contaminate drinking water wells. Viruses and other pathogens, as well as other contaminants of emerging concern, were measured in stormwater and groundwater at an urban site containing a stormwater cistern and related subsurface infiltration gallery, three shallow lysimeter wells, and a monitoring well. Five of 12 microbial targets were detected more than once across the eight rounds of sampling and at multiple sampling points, with human-specific Bacteroides detected most frequently. The microbial and chemical contaminants present in urban stormwater were much lower in the water table monitoring well than the vadose zone lysimeters. There may be numerous causes for these reductions, but they are most likely related to transit across fine-grained sediments that separate the water table from the vadose zone at this location. Precipitation amount prior to sample collection was significantly associated with microbial load. A significant relation between microbial load and chloride-bromide ratio was also observed. The reduction in number and concentrations of contaminants found in the monitoring well indicates that although geologically sensitive aquifers receiving urban stormwater effluent in the subsurface may be prone to contamination, those with a protective cap of fine-grained sediments are less vulnerable. These results can inform stormwater infiltration guidance relative to drinking water wells, with an emphasis on restricting infiltration near water supply wells finished in geologically sensitive aquifers to reduce public health risks.

Microbiological quality of water from public drinking fountains in northwestern São Paulo, Brazil / Qualidade microbiológica da água de bebedouros públicos no noroeste de São Paulo, Brasil

Objective: The present study aimed to evaluate the microbiological quality of the water and the maintenance and physical structure of public drinking fountains located in the city of Araçatuba ­ SP. Methods: To assess the presence or absence of Escherichia coli and total coliforms in the drinking water 41 samples were randomly collected. Thirteen samples were collected in the year 2018 and 28 samples in 2019. Results: All samples collected in the year 2018 showed no total coliforms and E. coli. However, the samples collected in the year 2019 showed coliforms in 10% (3/28). All the drinking fountains analyzed demonstrated to be inadequate in at least one of the qualitative criteria considered. Conclusion: Our results indicate that are necessary periodic maintenance of the public drinking fountains and the monitoring of its water since these parameters serve as indicators of the integrity of the drinking water distribution system.

Objetivo: O presente estudo teve como objetivo avaliar a qualidade microbiológica da água, a manutenção e estrutura física de bebedouros públicos localizados no município de Araçatuba - SP. Métodos: Para avaliar a presença ou ausência de Escherichia coli e coliformes totais na água de consumo, 41 amostras foram coletadas aleatoriamente. Treze amostras foram coletadas no ano de 2018 e 28 amostras em 2019. Resultados: Todas as amostras coletadas no ano de 2018 não apresentaram coliformes totais e E. coli. Porém, as amostras coletadas no ano de 2019 apresentaram coliformes em 10% (3/28). Todos os bebedouros analisados demonstraram ser inadequados em pelo menos um dos critérios qualitativos considerados. Conclusão: Nossos resultados indicam que são necessários a manutenção periódica dos bebedouros públicos e o monitoramento de sua água, visto que esses parâmetros servem como indicadores da integridade do sistema de distribuição de água potável.

Análise microbiológica e correlação do ph da água dos bebedouros utilizada para o consumo humano em escolas do município de Alagoa Grande ­ Paraíba / Microbiological analysis of the water of drinking fountains used for human consumption in schools of the county of Alagoa Grande ­ Paraíba

Introdução: a análise microbiológica das águas em escolas é de suma importância, visto que crianças em idade escolar são extremamente vulneráveis podendo desenvolver doenças por causa das condições do seu sistema gastrointestinal. Objetivo: avaliar os parâmetros microbiológicos da água de bebedouros destinados ao consumo humano de escolas de Alagoa Grande ­ PB. Metodologia: foram realizadas avaliações microbiológicas das águas disponíveis nos bebedouros, analisando a potabilidade, bem como as torneiras destes, fazendo levantamento da quantidade de fungos e bactérias encontrados. Os testes foram realizados nos laboratórios do Centro Universitário Maurício de Nassau ­ Campina Grande. Resultados: 24% das amostras estudadas apresentaram positividade para o grupo coliforme e termotolerante, portanto, não estão em estado potável para o consumo, e que a manutenção da limpeza dos bebedouros que armazenam a água está deficiente, revelando elevado número de microrganismos e presença de contaminação de todos. Conclusão: as higienizações dos aparelhos, bem como o monitoramento da água consumida nas escolas, são essenciais no controle de doenças que obviamente prejudicam o rendimento escolar dos alunos. As escolas em parcerias com instituições de saúde devem se mobilizar no sentido de capacitar e educar os funcionários que realizam a limpeza dos bebedouros, os alunos e a comunidade que os utilizam, visando a colaboração de todos para melhorar a qualidade da água consumida.

Introduction: the microbiological testing of water available in schools is of paramount importance, as school-age children are extremely vulnerable to developing diseases because of their gastrointestinal system conditions, which underscore the importance of water quality in schools and proper maintenance of the same. The water for consumption is that which is called potable water. The water that do not fit into the standards of potability can lead to pathologies to humans through their consumption. The main pathologies carried by the waters are typhoid fever, cholera, salmonellosis, shigellosis, poliomyelitis, hepatitis A, verminoses, amebiasis and giardiasis. The present study aimed to evaluate the microbiological quality of water from drinking fountains intended for human consumption in schools in Alagoa Grande-PB. Metodology: the microbiological analyzes were carried out of the water available in the drinking fountain, analyzing the potability, as well as the taps of these, surveying the amount of fungi and bacteria found. The tests were executed in the laboratories of the Mauricio de Nassau Faculty ­ Campina Grande and it was found that. Resulting: 24% of the samples studied presented positivity to the coliform and thermotolerant group, therefore, were not in the potable state for consumption, and that the cleaning of the water fountains is deficient, revealing presence of a high numbers of microorganisms. The fact that the coliform group and thermotolerants were not detected in the other water samples analyzed does not mean that the water is totally safe, since high numbers of fungal and bacterial colonies were found in the nozzles of the drinking fountains. Conclusion: the results showed that the hygiene of the devices, as well as the monitoring of the water consumed in schools, are essential in the control of diseases that obviously impair the students' school performance. The schools in partnerships with health institutions should mobilize to train and educate water cleaners, students, and the community that use them, in order to collaborate with each other to improve the quality of water consumed.

Microbial Contamination of Dental Unit Waterlines and Potential Risk of Infection: A Narrative Review.

Several studies have revealed that dental unit waterlines (DUWLs) are often contaminated by large numbers of various micro-organisms (bacteria, fungi, protozoa, viruses). Microbial contamination in DUWLs may originate from the mains water piped into the dental unit, the suck-back of patients' saliva into the line due to the lack of adequate valves, and contamination from bottled water systems. Some of the main determinants of microbial contamination in DUWLs are: a very small lumen size (0.5-2 mm) of the tubing used, high surface-to-volume ratio (6:1), low throughput and the materials of which the tubing is made, water stagnation outside of working hours. The environmental conditions present inside the conduits of the dental unit may facilitate the proliferation of micro-organisms and the consequent formation of biofilm on the interior surface of the pipes of DUWLs. During the use of handpieces, particularly high-speed rotating instruments, a spray is thrown up in the form of aerosols or spatters containing biological material (saliva, blood and dental plaque) and micro-organisms. This means that the health of both dental staff and patients could be at risk of infection. The risk of cross-infections in dental settings can be tackled by implementing combined interventions to prevent the contamination of DUWLs.

Sediment re-suspension as a potential mechanism for viral and bacterial contaminants.

Pathogenic enteric viruses and bacteria tend to occur in higher concentrations and survive longer in aquatic sediments than suspended in the water column. Re-suspension of these organisms can result in a significant degradation of overlying water quality. Additionally, the re-suspension of microbial pathogens in artificial irrigation canals could endanger the consumption of fresh and ready-to-eat produce. Irrigation water has been implicated in numerous fresh produce outbreaks over the last 30 years. This study aimed to quantify the proportions of bacterial and viral re-suspension from sediment in a recirculating flume with varying velocities. MS2 coliphage and Escherichia coli were found to re-suspend at rates that were not significantly different, despite organism size differences. However, E. coli re-suspension rates from sand and clay were significantly different. This suggests that likely sediment-associated particles were recovered with the organisms attached. Similar re-suspension rates are hypothesized to be due to the dynamics of sediment transport, rather than that of the organisms themselves. This study also indicated that the re-suspension of sediment at very low velocities (e.g., less than 10 cm/s), could impact the microbiological quality of the overlaying water. Results from this study conclude that sediment could be a viable mechanism for irrigation water contamination.

Efficacy of BRS® and Alpron®/Bilpron® Disinfectants for Dental Unit Waterlines: A Six-Year Study.

Biofilms in dental unit waterlines (DUWL) are a potentially significant source of contamination posing a significant health risk as these may come into contact with patients and dental staff during treatment. The aim of this study was to evaluate the microbiological quality of DUWL water treated by Biofilm-Removing-System® (BRS®) and Alpron®/Bilpron® disinfectant solutions for six years in a French university hospital. The microbiological quality of water supplied by 68 dental units-initially shock treated with BRS®, then continuously treated by Alpron® with sterile water during working days and Bilpron® during inactivity period, and combined with purging every morning and after each patient-was assessed biannually during six years for total culturable aerobic bacteria at 22 °C and 36 °C, Legionella sp., Pseudomonas aeruginosa, and total coliforms. A total of 628 samples were analyzed, 99.8% were compliant with extended microbiological levels, and we never detected pathogen bacteria like Legionella sp. and P. aeruginosa. Only one sample (0.2%) was noncompliant with the level of total culturable aerobic bacteria at 36 °C, which exceeded 140 colony forming units per mL. The protocol implemented in our university hospital gives excellent results and enables control of the microbiological quality of DUWL water in the long term.