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1.
Water Res ; 178: 115838, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-32361344

RESUMEN

Biofilm formation and removal from dead-ends is a particularly difficult and understudied area of water distribution system biology. In this work, we have built a model drinking water distribution system to probe the effect of different hydrodynamic flow regimes on biofilm formation and removal in the main pipe and in the dead-end. The test rig was built to include all major drinking water distribution system components with materials and dimensions used in standard plumbing systems. We have simulated the effect of stagnant, laminar, turbulent, and intense turbulent flushing conditions on the growth and removal of biofilms from the main pipe and the dead-end. The growth of the biofilm in the main pipe was not prevented at a volumetric flow rate of 9.4 L min-1 and flow velocity of 2 m s-1. Mature biofilms were more difficult to remove. Biofilms grown under shear stress conditions could withstand significantly higher shear stresses than those to which they were exposed to during growth. The biofilms grew twice as fast in the dead-end when flow in the main pipe was turbulent compared to stagnant conditions. Biofilms in the dead-end were not affected by the flushing conditions in the main pipe (Q = 52 L min-1, Re = 9.0 · 104). The computational fluid dynamics simulation suggests that biofilms cannot be hydrodynamically removed from the dead-end at depths that are larger than one pipe diameter. Biofilms beyond this limit present a possible source for reinoculation and recolonization of the rest of the water distribution system.


Asunto(s)
Agua Potable , Biopelículas , Hidrodinámica , Modelos Biológicos , Ingeniería Sanitaria , Microbiología del Agua , Abastecimiento de Agua
2.
Water Res ; 178: 115854, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-32361348

RESUMEN

Supplying safe drinking water in humanitarian emergencies is critical, and source water chlorination is a commonly implemented intervention to provide safe water. We evaluated three different source water chlorination programs (bucket, in-line, and piped water chlorination) in the ongoing humanitarian response in Cox's Bazar refugee camps in Bangladesh. We used a mixed-methods research protocol including key informant interviews, water point observations, focus group discussions, household surveys, and water quality testing. The three evaluated programs were implemented at different response stages and required different levels of staffing, infrastructure, and community mobilization work. In the bucket chlorination program, highly contaminated open well water was chlorinated, in in-line and piped water chlorination programs, groundwater was treated. Overall, 71% of bucket, 36% of in-line, and 60% of piped water chlorination households had stored water that met free chlorine residual (FCR) criteria, respectively. Additionally, 71% of bucket, 86% of in-line, and 91% of piped water chlorination households had stored water that met Escherichia coli (E. coli) criteria (<10 E. coli CFU/100 mL). Regression results indicate presence of FCR, serving water by pouring, and higher source water pH were associated with meeting E. coli criteria. Our results highlight: no individual program fully met international standards as implemented, although each partially met standards; the importance of understanding beneficiary preferences and behavior change campaigns; and, the benefits and drawbacks of each source water chlorination program must be considered before implementation. Overall, we found appropriate source water chlorination program choice is a continuum, depending on humanitarian phase and context. Therefore, we recommend continuing context- and phase-appropriate source water chlorination programs, emphasizing consistent and acceptable chlorine dosage, implementing programmatic improvements, and incorporating user preferences to reduce microbial contamination and consequently the risk of waterborne diseases.


Asunto(s)
Agua Potable , Purificación del Agua , Bangladesh , Urgencias Médicas , Escherichia coli , Halogenación , Humanos , Microbiología del Agua , Abastecimiento de Agua
3.
Water Res ; 178: 115671, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-32380294

RESUMEN

Shoreline sand harbors high concentrations of fecal indicator bacteria (FIB) that may be resuspended into the water column through washing and resuspension. Studies have explored coastal processes that influence this sand-water flux for FIB, but little is known about how microbial markers of contamination or the bacterial community interact in the sand-water interface. In this study, we take a three-tiered approach to explore the relationship between bacteria in sand, sediment, and overlying water at three shoreline sites and two associated rivers along an extended freshwater shoreline. Samples were collected over two years and analyzed for FIB, two microbial source tracking (MST) markers (Catellicoccus marimammalium, Gull2; Bacteroides HF183), and targeted metagenomic 16S rRNA gene analysis. FIB was much higher in sand than in water at all three sites. Gull2 marker was abundant in shoreline sand and water while HF183 marker was mostly present in rivers. Overall bacterial communities were dissimilar between sand/sediment and water, indicating little interaction. Sediment composition was generally unfavorable to bacterial resuspension. Results show that FIB and MST markers were effective estimates of short-term conditions at these locations, and bacterial communities in sand and sediment reflected longer-term conditions. Findings are useful for locating contamination sources and targeting restoration by evaluating scope of shoreline degradation.


Asunto(s)
Lagos , Calidad del Agua , Bacterias , Heces , Michigan , ARN Ribosómico 16S , Arena , Agua , Microbiología del Agua , Contaminación del Agua
4.
J Environ Manage ; 267: 110456, 2020 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-32421660

RESUMEN

To investigate how the aquatic bacterial community of a stratified reservoir drives the evolution of water parameters, the microbial community structure and network characteristics of bacteria in a stratified reservoir were investigated using Illumina MiSeq sequencing technology. A total of 42 phyla and 689 distinct genera were identified, which showed significant seasonal variation. Additionally, stratified variations in the bacterial community strongly reflected the vertical gradient and seasonal changes in water temperature, dissolved oxygen, and nutrition concentration. Furthermore, principal coordinate analysis indicated that most microorganisms were likely influenced by changes in water stratification conditions, exhibiting significant differences during the stratification period and mixing period based on Adonis, MRPP, and Anosim. Compared to the stratification period, 123 enhanced operational taxonomic units (OTUs; 29%) and 226 depleted OTUs (52%) were identified during the mixing period. Linear discriminant analysis effect size results showed that 15 major genera were enriched in the mixing period and 10 major genera were enriched in the stratification period. Importantly, network analysis revealed that the keystone species belonged to hgcI_clade, CL500-29, Acidibacter, Paucimonas, Flavobacterium, Prochlorothrix, Xanthomonadales, Chloroflexia, Burkholderiales, OPB56, KI89A_clade, Synechococcus, Caulobacter or were unclassified. Redundancy analysis showed that temperature, dissolved oxygen, pH, chlorophyll-α, total phosphorus, nitrate, and ammonia were important factors influencing the water bacterial community and function composition, which were consistent with the results of the Mantel test analysis. Furthermore, random forest analysis showed that temperature, dissolved oxygen, ammonia, and total dissolved phosphorous were the most important variables predicting water bacterial community and function community α- and ß-diversity (P < 0.05). Overall, these results provide insight into the interactions between the microbial community and water quality evolution mechanism in Zhoucun reservoir.


Asunto(s)
Agua Potable , Microbiota , Bacterias , Microbiología del Agua , Calidad del Agua
5.
Water Res ; 181: 115926, 2020 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-32417460

RESUMEN

Waterborne enteric viruses are an emerging cause of disease outbreaks and represent a major threat to global public health. Enteric viruses may originate from human wastewater and can undergo rapid transport through aquatic environments with minimal decay. Surveillance and source apportionment of enteric viruses in environmental waters is therefore essential for accurate risk management. However, individual monitoring of the >100 enteric viral strains that have been identified as aquatic contaminants is unfeasible. Instead, viral indicators are often used for quantitative assessments of wastewater contamination, viral decay and transport in water. An ideal indicator for tracking wastewater contamination should be (i) easy to detect and quantify, (ii) source-specific, (iii) resistant to wastewater treatment processes, and (iv) persistent in the aquatic environment, with similar behaviour to viral pathogens. Here, we conducted a comprehensive review of 127 peer-reviewed publications, to critically evaluate the effectiveness of several viral indicators of wastewater pollution, including common enteric viruses (mastadenoviruses, polyomaviruses, and Aichi viruses), the pepper mild mottle virus (PMMoV), and gut-associated bacteriophages (Type II/III FRNA phages and phages infecting human Bacteroides species, including crAssphage). Our analysis suggests that overall, human mastadenoviruses have the greatest potential to indicate contamination by domestic wastewater due to their easy detection, culturability, and high prevalence in wastewater and in the polluted environment. Aichi virus, crAssphage and PMMoV are also widely detected in wastewater and in the environment, and may be used as molecular markers for human-derived contamination. We conclude that viral indicators are suitable for the long-term monitoring of viral contamination in freshwater and marine environments and that these should be implemented within monitoring programmes to provide a holistic assessment of microbiological water quality and wastewater-based epidemiology, improve current risk management strategies and protect global human health.


Asunto(s)
Enterovirus , Aguas Residuales , Monitoreo del Ambiente , Heces , Humanos , Microbiología del Agua , Calidad del Agua
6.
Sci Total Environ ; 730: 139126, 2020 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-32416507

RESUMEN

Solar water disinfection (SODIS) is a simple, inexpensive and sustainable Household Water Treatment (HWT) that is appropriate for low-income countries or emergency situations. Usually, SODIS involves solar exposure of water contained in transparent polyethylene terephthalate (PET) bottles for a minimum of 6 h. Sunlight, especially UVB radiation, has been demonstrated to photoinactivate bacteria, viruses and protozoa. In this work, an in-depth study of the optical and mechanical properties, weathering and production prices of polymeric materials has been carried out to identify potential candidate materials for manufacturing SODIS devices. Three materials were ruled out (polystyrene (PS), polyvinyl chloride (PVC) and polyethylene (PE)) and four materials were initially selected for study: polymethylmethacrylate (PMMA), polypropylene (PP), polycarbonate (PC) and polyethylene terephthalate (PET). These plastics transmit sufficient solar radiation to kill waterborne pathogens with production costs compensated by their durability under solar exposure. A predictive model has been developed to quantitatively estimate the radiation available for SODIS inside the device as a function of the material and thickness. This tool has two applications: to evaluate design parameters such as thickness, and to estimate experimental requirements such as solar exposure time. In this work, this model evaluated scenarios involving different plastic materials, device thicknesses, and pathogens (Escherichia coli bacterium, MS2 virus and Cryptosporidium parvum protozoon). The developed Solar UV Calculator model is freely available and can be also applied to other customized materials and conditions.


Asunto(s)
Luz Solar , Bacterias , Desinfección , Plásticos , Virus , Agua , Microbiología del Agua , Purificación del Agua
7.
Environ Monit Assess ; 192(5): 319, 2020 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-32356229

RESUMEN

In the Southern Nations, Nationalities, and Peoples' Region of Ethiopia, improved water is the main source of water for household purposes. Access to improved water closer to their homes benefits the community in many ways. It improves their health status, saves their time and energy, and improves their productivity in jobs and education they are engaged in. However, due to natural and human activities, improved water sources do not always deliver good quality of water. It can be contaminated by different pathogenic microorganisms and chemicals. The result indicated that 44.7% and 50.9% of the samples were contaminated with Escherichia coli and enterococci respectively, and from the sanitary condition survey, 57.6% of the water sources exhibited from intermediate- to very high-risk level. And the risk priority matrix identifies 95 (27.9%) samples with high risk and 54 (15.9%) of the samples with very high risk. The main risks identified at those unsafe water sources were that the drainage canals were blocked with mud, grass, leaves, and stones; animals drinking the overflow water and grazing in the proximity of water sources and feces such as cow dung were observed; inadequate protection of water sources such as absence of fences and diversion ditches; and stagnant water near the source. The study conducted in the Southern Nations, Nationalities, and Peoples' Region has clearly indicated that people may be at risk of being exposed to pathogens in half of the improved water sources when used for drinking based on the microbial indicator data or the sanitary inspection risk score. Though no correlation resulted from water quality and sanitary condition of sources, the risk priority matrix did enable prioritization of 54 very high-risk-level water sources for urgent targeted interventions from a total of 340 improved drinking water sources. From this, targeted interventions, improving water management practices, identifying and implementing effective water treatment options, providing sustainable energy sources for the supply of continuous water, and implementing climate resilience water safety planning, are recommended.


Asunto(s)
Agua Potable , Microbiología del Agua , Abastecimiento de Agua , Animales , Bovinos , Monitoreo del Ambiente , Etiopía , Femenino , Humanos , Calidad del Agua
8.
Environ Monit Assess ; 192(5): 324, 2020 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-32361854

RESUMEN

This study was carried out to assess the physicochemical and bacteriological contaminants of surface, shallow well and municipal borehole waters in part of the western Niger Delta as a way of safeguarding public health against waterborne diseases. A total of 72 water samples collected from the study area were analysed and their results show that the pH average value ranges from 6.2 in the dry to 8.5 in the rainy seasons for surface water, 6.6 and 8.3 for shallow well water and 6.5 to 8.4 for borehole water. The turbidity in surface water varies from 8.1 to 26.2 Formazin Attenuation Unit (FAU), 0.3 to 2.9 FAU in shallow well water and 0.4 to 4.8 FAU in borehole water. Electrical conductivity (EC) value varies from 1010 to 1840 µs/cm for surface water, 201 to 950 µs/cm for shallow well water and 670 to 1650 µs/cm for borehole water. Total dissolved solids range from 0.1 to 2.6 mg/l in surface water, 0.2 to 4.1 mg/l in shallow well water and 0.3 to 4.4 mg/l in borehole water. The value of the total hardness ranges from 44 to 120 mg in surface water, 46 to 96 mg in shallow well water and 70 to 130 mg in borehole water. The nitrate value ranges from 1.1 to 10.6 mg in surface water, 3.0 to 8.4 mg in shallow well water and 3.7 to 9.6 mg in borehole water. The value of sulphate content varies from 4.6 to 38.5 mg in surface water, 6.2 to 34.8 mg in shallow well water and 5.7 to 55.7 mg in borehole water. The value of phosphate concentrations in surface water varies from 1.0 to 9.0 mg, 0.7 to 3.4 mg in shallow well water and 1.0 to 4.7 mg in borehole water. The bacteriological analysis using the membrane filtration technique revealed the presence of faecal bacteria and total coliform counts. The presence of the analysed twin contaminants in the studied water resources reduced their water quality. The physicochemical and bacteriological data were subjected to statistical and correlation tests. It was concluded that their concentration levels were independent of intra-seasonal changes. The likely natural and artificial sources of contaminants are run-offs from fertilized lands, septic tanks, industrial discharges, sewage and waste disposal, algae blooms and erosion from natural deposits. The inherent risk is water-related diseases such as waterborne diseases, water-washed diseases, water-based diseases and diseases transmitted by water-related insect vectors. Water resources should be protected through proper sanitation systems, limiting of up-stream discharges, maintenance of wellheads, boiling and municipal water treatment plants. Educational advice should be given to the inhabitants on the dangers posed by continuous drinking of contaminated water. These measures will prevent disease outbreak and public health burden in the area.


Asunto(s)
Microbiología del Agua , Contaminantes Químicos del Agua , Recursos Hídricos , Monitoreo del Ambiente , Niger , Abastecimiento de Agua
9.
Water Res ; 178: 115814, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-32325219

RESUMEN

Drinking water supply wells can be contaminated by a broad range of waterborne pathogens. However, groundwater assessments frequently measure microbial indicators or a single pathogen type, which provides a limited characterization of potential health risk. This study assessed contamination of wells by testing for viral, bacterial, and protozoan pathogens and fecal markers. Wells supplying groundwater to community and noncommunity public water systems in Minnesota, USA (n = 145) were sampled every other month over one or two years and tested using 23 qPCR assays. Eighteen genetic targets were detected at least once, and microbiological contamination was widespread (96% of 145 wells, 58% of 964 samples). The sewage-associated microbial indicators HF183 and pepper mild mottle virus were detected frequently. Human or zoonotic pathogens were detected in 70% of wells and 21% of samples by qPCR, with Salmonella and Cryptosporidium detected more often than viruses. Samples positive by qPCR for adenovirus (HAdV), enterovirus, or Salmonella were analyzed by culture and for genotype or serotype. qPCR-positive Giardia and Cryptosporidium samples were analyzed by immunofluorescent assay (IFA), and IFA and qPCR concentrations were correlated. Comparisons of indicator and pathogen occurrence at the time of sampling showed that total coliforms, HF183, and Bacteroidales-like HumM2 had high specificity and negative predictive values but generally low sensitivity and positive predictive values. Pathogen-HF183 ratios in sewage have been used to estimate health risks from HF183 concentrations in surface water, but in our groundwater samples Cryptosporidium oocyst:HF183 and HAdV:HF183 ratios were approximately 10,000 times higher than ratios reported for sewage. qPCR measurements provided a robust characterization of microbiological water quality, but interpretation of qPCR data in a regulatory context is challenging because few studies link qPCR measurements to health risk.


Asunto(s)
Criptosporidiosis , Cryptosporidium , Agua Subterránea , Animales , Monitoreo del Ambiente , Heces , Humanos , Minnesota , Microbiología del Agua
10.
BMC Infect Dis ; 20(1): 295, 2020 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-32316920

RESUMEN

BACKGROUND: Soft tissue or skin infections due to nontuberculous mycobacteria (NTM) have been reported frequently and are mostly associated with trauma or cosmetic interventions like plastic surgery. However, infection with NTM as a result of a dental procedure have rarely been described and the lack of clinical suspicion and a clear clinical manifestation makes diagnosis challenging. CASE PRESENTATION: We report on three patients with a facial cutaneous sinus tract of dental origin, due to an infection with respectively Mycobacterium fortuitum, M. abscessus and M. peregrinum. The infection source was the dental unit waterlines (DUWLs), which were colonized with NTM. CONCLUSIONS: Water of the DUWL can pose a health risk. This report emphasizes the need for quality control and certification of water flowing through DUWLs, including the absence of NTM. Our report also shows the need for a rapid recognition of NTM infections and accurate laboratory diagnosis in order to avoid long-term ineffective antibiotic treatment.


Asunto(s)
Cara/microbiología , Infecciones por Mycobacterium no Tuberculosas/diagnóstico , Micobacterias no Tuberculosas/aislamiento & purificación , Adolescente , Niño , ADN Viral/metabolismo , Femenino , Hongos/aislamiento & purificación , Humanos , Infecciones por Mycobacterium no Tuberculosas/microbiología , Mycobacterium fortuitum/genética , Mycobacterium fortuitum/aislamiento & purificación , Micobacterias no Tuberculosas/genética , Microbiología del Agua , Adulto Joven
11.
Water Res ; 176: 115729, 2020 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-32240845

RESUMEN

Recreational water quality guidelines protect the public from health risks associated with water recreation by helping to prevent unacceptable concentrations of pathogenic organisms in ambient water. However, illness risk is associated with both the concentration of pathogens in the water and the degree of contact with those pathogens. Different recreational activities can result in different levels of contact with ambient water containing water-borne pathogens. We conducted a systematic literature review and meta-analysis to evaluate risks of illness associated with different recreational activities and different levels of contact to ambient surface waters. We screened 8,618 potentially relevant studies for quantitative measures of risk using inclusion/exclusion criteria established in advance. We categorized recreational activities as swimming, sports-related contact, minimal contact, and sand contact. We combined relative risks using a random effects meta-analysis for adverse health outcome categories representing gastrointestinal illness, respiratory illness, skin, eye, ear, nose, throat, and cold/flu illness. We identified 92 studies meeting our inclusion criteria. Pooled risk estimates indicate significant elevation of gastrointestinal illness with the recreational activity categories swimming (2.19, 95% CI: 1.82, 2.63) and sports-related contact (2.69, 95% CI: 1.04, 6.92), and nonsignificant elevation of gastrointestinal illness with minimal contact (1.27, 95% CI: 0.74, 2.16). We also found a significant elevation of respiratory illness with swimming (1.78, 95% CI: 1.38, 2.29) and sports-related contact (1.49, 95% CI: 1.00, 2.24), and no elevation of respiratory illness with minimal contact (0.90, 95% CI: 0.71, 1.14). This study suggests that exposures associated with different types of recreational activities are important characteristics of the exposure pathway when assessing illness risk associated with recreation in ambient surface waters.


Asunto(s)
Piscinas , Microbiología del Agua , Recreación , Medición de Riesgo , Natación , Calidad del Agua
12.
Int J Syst Evol Microbiol ; 70(3): 1571-1577, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32228746

RESUMEN

The present study aimed to determine the taxonomic positions of strains designated R-5-52-3T, R-5-33-5-1-2, R-5-48-2 and R-5-51-4 isolated from hot spring water samples. Cells of these strains were Gram-stain-negative, non-motile and rod-shaped. The strains shared highest 16S rRNA gene sequence similarity with Vulcaniibacterium thermophilum KCTC 32020T (95.1%). Growth occurred at 28-55 °C, at pH 6-8 and with up to 3 % (w/v) NaCl. DNA fingerprinting, biochemical, phylogenetic and 16S rRNA gene sequence analyses suggested that R-5-52-3T, R-5-33-5-1-2, R-5-48-2 and R-5-51-4 were different strains but belonged to the same species. Hence, R-5-52-3T was chosen for further analysis and R-5-33-5-1-2, R-5-48-2 and R-5-51-4 were considered as additional strains of this species. R-5-52-3T possessed Q-8 as the only quinone and iso-C15:0, iso-C11:0, C16 : 0 and iso-C17 : 0 as major fatty acids. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unidentified polar lipids and two unidentified phospholipids. The genomic G+C content was 71.6 mol%. Heat shock proteins (e.g. Hsp20, GroEL, DnaK and Clp ATPases) were noted in the R-5-52-3T genome, which could suggest its protection in the hot spring environment. Pan-genome analysis showed the number of singleton gene clusters among Vulcaniibacterium members varied. Average nucleotide identity (ANI) values between R-5-52-3T, Vulcaniibacterium tengchongense YIM 77520T and V. thermophilum KCTC 32020T were 80.1-85.8 %, which were below the cut-off level (95-96 %) recommended as the ANI criterion for interspecies identity. Thus, based on the above results, strain R-5-52-3T represents a novel species of the genus Vulcaniibacterium, for which the name Vulcaniibacterium gelatinicum sp. nov. is proposed. The type strain is R-5-52-3T (=KCTC 72061T=CGMCC 1.16678T).


Asunto(s)
Manantiales de Aguas Termales/microbiología , Filogenia , Xanthomonadaceae/clasificación , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/genética , Ácidos Grasos/química , Genes Bacterianos , Fosfolípidos/química , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Ubiquinona/química , Microbiología del Agua , Xanthomonadaceae/aislamiento & purificación
13.
Int J Syst Evol Microbiol ; 70(3): 1617-1622, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32228747

RESUMEN

A taxonomic study was carried out on strain SH27T, which was isolated from seawater collected around Xiaoshi Island, PR China. Cells of strain SH27T were Gram-stain-negative, non-motile, rod-shaped, orange-pigmented and grew at 15-37 °C (optimum, 28 °C), at pH 6.0-8.0 (pH 7.0) and in 1.0-7.0 % (w/v) NaCl (2.0-3.0 %). The isolate was positive for catalase, but negative for nitrate reduction, oxidase, indole production and urease. Carotenoid pigment was produced. Phylogenetic analysis based on the 16S rRNA gene placed strain SH27T in the genus Dokdonia with the closest relative being Dokdonia donghaensis KCTC 12391T, exhibiting 96.7 % 16S rRNA gene pairwise similarity. The results of genomic comparisons, including average nucleotide identity and digital DNA-DNA hybridization, showed 72.9 and 19.2 % identity to D. donghaensis KCTC 12391T, respectively. The major cellular fatty acids were iso-C15 : 0, iso-C15 : 1 G and iso-C17 : 0 3-OH. The major polar lipids were phosphatidylethanolamine and two unidentified lipids. Menaquinone-6 was the only respiratory quinone. The G+C content of the genomic DNA was 32.9 mol%. On the basis of the phenotypic and phylogenetic data, strain SH27T represents a novel species of the genus Dokdonia, for which the name Dokdonia sinensis sp. nov. is proposed, with the type strain SH27T (MCCC 1H00358T=CCTCC AB 2018323T=KCTC 62962T).


Asunto(s)
Flavobacterium/clasificación , Filogenia , Agua de Mar/microbiología , Técnicas de Tipificación Bacteriana , Composición de Base , China , ADN Bacteriano/genética , Ácidos Grasos/química , Flavobacteriaceae/clasificación , Flavobacterium/aislamiento & purificación , Hibridación de Ácido Nucleico , Fosfatidiletanolaminas/química , Pigmentación , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Vitamina K 2/análogos & derivados , Vitamina K 2/química , Microbiología del Agua
14.
Int J Syst Evol Microbiol ; 70(3): 1596-1604, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32228748

RESUMEN

We performed high-quality genome sequencing of eight strains of the species of the genus Tepidimonas and examined the genomes of closely related strains from the databases to understand why Tepidimonas taiwanensis is the only strain of this genus that utilizes glucose and fructose for growth. We found that the assimilation of these hexoses by T. taiwanensis was due to the presence of two transporters that are absent in all other genomes of strains of members of the genus Tepidimonas examined. Some strains lack genes coding for glucokinase, but the Embden-Meyerhof-Parnas pathway appears to be otherwise complete. The pentose phosphate pathway has a complete set of genes, but genes of the Entner-Doudoroff pathway were not identified in the genomes of any of the strains examined. Genome analysis using average nucleotide identity (ANIb), digital DNA-DNA hybridization (dDDH), average amino acid identity (AAI) and phylogenetic analysis of 400 conserved genes was performed to assess the taxonomic classification of the organisms. Two isolates of the genus Tepidimonas from the hot spring at São Pedro do Sul, Portugal, designated SPSP-6T and SPSPC-18 were also examined in this study. These organisms are mixotrophic, have an optimum growth temperature of about 50 ºC, utilize several organic acids and amino acids for growth but do not grow on sugars. Distinctive phenotypic, 16S rRNA gene sequence and genomic characteristics of strains SPSP-6T and SPSPC-18 lead us to propose a novel species based on strain SPSP-6T for which we recommend the name Tepidimonas charontis sp. nov. (=CECT 9683T=LMG 30884T).


Asunto(s)
Burkholderiales/clasificación , Manantiales de Aguas Termales/microbiología , Filogenia , Técnicas de Tipificación Bacteriana , Composición de Base , Burkholderiales/aislamiento & purificación , Hibridación Genómica Comparativa , ADN Bacteriano/genética , Ácidos Grasos/química , Hibridación de Ácido Nucleico , Portugal , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Microbiología del Agua
15.
Arch Virol ; 165(6): 1397-1407, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32307604

RESUMEN

A new cyanophage, S-B05, infecting a phycoerythrin-enriched (PE-type) Synechococcus strain was isolated by the liquid infection method, and its morphology and genetic features were examined. Phylogenetic analysis and morphological observation confirmed that S-B05 belongs to the family Myoviridae of the order Caudovirales. Its genome was fully sequenced, and found to be 208,857 bp in length with a G + C content of 39.9%. It contained 280 potential open reading frames and 123 conserved domains. Ninety-eight functional genes responsible for cyanophage structuring and packaging, DNA replication and regulation, and photosynthesis were identified, as well as genes encoding 172 hypothetical proteins. The genome of S-B05 is most similar to that of Prochlorococcus phage P-TIM68. Homologues of open reading frames of S-B05 can be found in various marine environments, as revealed by comparison of the S-B05 genome sequence to sequences in marine viral metagenomic databases. The presence of auxiliary metabolic genes (AMGs) related to photosynthesis, carbon metabolism, and phosphorus assimilation, as well as the phylogenetic relationships based on AMGs and the complete genome sequence, reflect the phage-host interaction mechanism or the specific adaptation strategy of the host to environmental conditions. The genome sequence information reported here will provide an important basis for further study of the adaptive evolution and ecological role of cyanophages and their hosts in the marine environment.


Asunto(s)
Genoma Viral , Myoviridae/clasificación , Myoviridae/aislamiento & purificación , Agua de Mar/virología , Synechococcus/virología , Composición de Base , Secuencia de Bases , China , Especificidad del Huésped , Metagenómica , Myoviridae/ultraestructura , Sistemas de Lectura Abierta , Océano Pacífico , Filogenia , Microbiología del Agua , Secuenciación Completa del Genoma
16.
Environ Monit Assess ; 192(4): 259, 2020 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-32240379

RESUMEN

Bottled water as well as bottled water dispensers is widely used in the United Arab Emirates as a source of drinking water in residential, commercial, and institutional settings. The quality of such waters is of utmost concern as it has the potential to cause waterborne outbreaks, if (re)contaminated. Besides, bottled water dispensers could act as a source of contamination over time, if not cleaned properly on a regular basis. A cross-sectional study was conducted on 40 water samples collected from public and private bottled water dispensers in the emirates of Dubai and Sharjah. Samples were analyzed for heterotrophic plate count bacteria, fecal and total coliforms, and fungal growth. No total and fecal coliforms were detected in any of the samples. Heterotrophic plate counts (HPC) ranged between 0 and 100 CFU/100 ml, with an overall average of 31 CFU/100 ml. There was no significant difference between the HPC bacterial levels of public and private bottled water dispensers. However, a significant association (p < 0.05) was found between fungal growth and the location of the bottled water dispenser within the investigated sites. Survey outcomes also highlighted the need to spread awareness and knowledge amongst general public on basic cleanliness and hygiene practices contributing to safe drinking water and the need for stricter monitoring of public bottled water dispensers cleaning schedules.


Asunto(s)
Agua Potable/microbiología , Monitoreo del Ambiente , Recuento de Colonia Microbiana , Estudios Transversales , Enterobacteriaceae , Emiratos Árabes Unidos , Microbiología del Agua , Abastecimiento de Agua
17.
Environ Monit Assess ; 192(5): 276, 2020 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-32274591

RESUMEN

To assess the fate and behavior of engineered nanoparticles in the environment, it is important to examine the physicochemical and toxicological transformation of nanoparticles as they age in seawater. In this study, we investigated how aging and seawater conditions altered the physiochemical structure of nanoparticles and affected their interactions with bacteria. For this purpose, zinc oxide nanoparticles were aged under different seawater conditions by keeping them in 1%, 10%, and 100% seawater for 1 day and 20 days. The main physicochemical parameters (surface chemistry, chemical composition, particle size, and zeta potential) and toxicity of aged nanoparticles towards gram-negative Pseudomonas aeruginosa and gram-positive Staphylococcus aureus were examined. The results indicated that aged zinc oxide nanoparticles in various concentrations of seawater changed their surface chemistry, chemical composition, particle size, and zeta potentials. Growth inhibition results were observed in that the inhibition of gram-negative (Pseudomonas aeruginosa) bacteria was higher compared with the gram-positive (Staphylococcus aureus) bacteria, and Staphylococcus aureus activated with the aged zinc oxide nanoparticles. Also, the results showed that the key biochemical factors affected by the aging and seawater concentration.


Asunto(s)
Nanopartículas del Metal , Nanopartículas , Óxido de Zinc , Antibacterianos , Bacterias , Monitoreo del Ambiente , Agua de Mar/química , Agua de Mar/microbiología , Microbiología del Agua
18.
Water Res ; 178: 115835, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-32330732

RESUMEN

Fecal coliform bacteria are a key indicator of human health risks; however, the spatiotemporal variability and key influencing factors of river fecal coliform have yet to be explored in a rural-suburban-urban watershed with multiple land uses. In this study, the fecal coliform concentrations in 21 river sections were monitored for 20 months, and 441 samples were analyzed. Multivariable regressions were used to evaluate the spatiotemporal dynamics of fecal coliform. The results showed that spatial differences were mainly dominated by urbanization level, and environmental factors could explain the temporal dynamics of fecal coliform in different urban patterns except in areas with high urbanization levels. Reducing suspended solids is a direct way to manage fecal coliform in the Beiyun River when the natural factors are difficulty to change, such as temperature and solar radiation. The export of fecal coliform from urban areas showed a quick and sensitive response to rainfall events and increased dozens of times in the short term. Landscape patterns, such as the fragmentation of impervious surfaces and the overall landscape, were identified as key factors influencing urban non-point source bacteria. The results obtained from this study will provide insight into the management of river fecal pollution.


Asunto(s)
Ríos , Urbanización , Bacterias , Monitoreo del Ambiente , Heces , Bacterias Gramnegativas , Humanos , Microbiología del Agua
19.
Water Res ; 176: 115700, 2020 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-32234605

RESUMEN

The risks of illness associated with bathing in UK coastal waters have not been quantified since the early 1990s. Efforts have been made since then to improve the quality of bathing waters. The aim of this study was to quantify the prevalence of symptoms of illness associated with sea bathing in bathers in England and Wales. A cross-sectional study was conducted between June 2014 and April 2015. An online survey collected information from sea bathers and non-bathers on their visits to beaches in England and Wales along with the occurrence of symptoms of illness. 2631 people (1693 bathers, 938 non-bathers) responded to the survey. Compared to non-bathers, bathers were more likely to report skin ailments (adjusted prevalence odds ratio (AOR) = 2.64, 95% confidence interval (CI) 1.23 to 5.65, p = 0.01), ear ailments (AOR = 3.77, 95% CI 1.84 to 7.73, p < 0.001), and any symptoms of illness (AOR = 3.73, 95% CI 2.63 to 5.29, p < 0.001). There was weak evidence of an increase in the odds of gastrointestinal illness (AOR = 1.59, 95% CI 0.96 to 2.65, p = 0.07), respiratory ailments (AOR = 2.44, 95% CI 0.92 to 6.48, p = 0.07) and eye ailments (AOR = 2.12, 95% CI 0.83 to 5.39, p = 0.11). While the study design does not allow inference of causality, we do observe an association between sea bathing in England and Wales and reported symptoms of ill health. This suggests that despite higher rates of compliance with water quality criteria among bathing waters nowadays, the odds of illness for bathers relative to non-bathers is similar in magnitude to estimates made in the 1990s.


Asunto(s)
Playas , Microbiología del Agua , Estudios Transversales , Inglaterra , Encuestas Epidemiológicas , Prevalencia , Gales
20.
Water Res ; 176: 115733, 2020 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-32234606

RESUMEN

Urban disaster response requires disposal of complex wastes. This study regards a case wherein high intensity rainfall fell over a remote mountainous area previously burned by wildfire, generating debris flows that devastated a downstream town. Sanitary sewers and homes with septic systems were damaged, releasing human waste into the debris flow field. Contaminated sediments, with their high fecal indicator bacteria (FIB) concentrations, were cleared from public rights-of-way and creek channels by local authorities, then disposed onto distant Goleta Beach for beach nourishment, causing immediate surf zone microbiological water quality exceedances. To determine potential public health threats, disposed sediments and surf zone waters were sampled and analyzed-relative to reference samples of mountain soil and raw sewage-for FIB, pathogens, human (HF183) and other host- (Gull2 TaqMan, and DogBact) associated DNA-based fecal markers, and bacterial community 16S rRNA gene sequences. Approximately 20% of disposed sediment samples contained the HF183 marker; sequencing suggested that all samples were contaminated by sewage. In an initial sediment disposal period, surf zone waters harbored intestinal bacterial sequences that were shared with disposed sediments and sewage. Yet surf zone bacterial communities returned to mostly marine clades within weeks. Taken together, multiple conventional and DNA-based analyses informed this forensic assessment of human waste contamination. In the future, similar analyses could be used earlier in disaster response to guide sediment disposal decisions towards continuously protecting beachgoer health.


Asunto(s)
Microbiología del Agua , Calidad del Agua , Ciudades , Heces , Sedimentos Geológicos , Humanos , ARN Ribosómico 16S
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