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1.
Sci Total Environ ; 751: 141475, 2021 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-32890804

RESUMO

Enteric pathogens can be present in drinking water catchments due to several point and non-point sources of faecal contamination. Pathogen and contaminant signatures will decay due to environmental stresses, such as temperature, Ultra Violet (UV) radiation, salinity, and predation. In this study, we determined the decay of the culturable faecal indicator bacterium (FIB) Escherichia coli (E. coli), two sewage-associated marker genes (Bacteroides HF183 and crAssphage CPQ_056), and enteric pathogens (Campylobacter spp., human adenovirus 40/41, and Cryptosporidium parvum) in two freshwater laboratory microcosms using culture-based, quantitative PCR (qPCR) and vital dye (determine the fraction of viable Cryptosporidium oocysts) assays. Freshwater samples from the Lake Wappa and Lake Wivenhoe (Australia) were seeded with untreated sewage and C. parvum oocysts, and their declining concentrations were measured over a 28-day period. Moreover, 16S rRNA amplicon sequencing was also undertaken to determine the change/shift in sewage-associated bacterial communities using SourceTracker. Overall, culturable E. coli and the HF183 marker gene decayed significantly (p < 0.05) faster than did the qPCR measured enteric pathogens suggesting that the absence of culturable FIB or qPCR HF183 in water samples may not indicate the absence of pathogens. The decay of crAssphage was similar to that of HAdV 40/41 and other pathogens tested, suggesting crAssphage may be a better surrogate for enteric viruses in sub-tropical catchment waters. The decay rates were greater at 25 °C compared to 15 °C, suggesting that FIB and pathogens persist longer in the winter season compared to summer. Overall decay rates of the tested microorganisms in this microcosm study suggest that sub-tropical conditions, especially temperature, have a negative impact on the persistence of tested microorganisms. Sewage-associated bacterial communities also showed similar patterns. Based on the results, which showed differences in simulated summer and winter temperatures for pathogen decay, corresponding management options and treatment need to be adjusted accordingly to minimize human health risks effectively.


Assuntos
Criptosporidiose , Cryptosporidium , Animais , Austrália , Bactérias/genética , Monitoramento Ambiental , Escherichia coli , Fezes , Humanos , RNA Ribossômico 16S/genética , Esgotos , Microbiologia da Água
2.
Sci Total Environ ; 750: 141284, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33182170

RESUMO

Regular monitoring of drinking water quality is vital to identify contamination of potable water supplies. Testing for microbial contamination is important to prevent transmission of waterborne disease, but establishing and maintaining a water quality monitoring programme requires sustained labour, consumables and resources. In low resource settings such as developing countries, this can prove difficult, but measuring microbial contamination is listed as a requirement of reaching the UN's Sustainable Development Goal 6 for water and sanitation. A nine-month water quality monitoring programme was conducted in rural Malawi to assess the suitability of tryptophan-like fluorescence (TLF), an emerging method for rapidly detecting microbial contamination, as a drinking water quality monitoring tool. TLF data was compared with thermotolerant coliforms (TTCs, E. coli) and inorganic hydrochemical parameters. A large (n = 235) temporal dataset was collected from five groundwater drinking water sources, with samples collected once or twice weekly depending on the season. The results show that TLF can indicate a broader contamination risk but is not as sensitive to short term variability when compared to other faecal indicators. This is likely due to a broad association of TLF with elevated DOC concentrations from a range of different sources. Elevated TLF may indicate preferential conditions for the persistence of TTCs and/or E. coli, but not necessarily a public health risk from microbial contamination. TLF is therefore a more precautionary risk indicator than microbial culturing techniques and could prove useful as a high-level screening tool for initial risk assessment. For widespread use of TLF to be successful, standardisation of TLF values associated with different levels of risk is required, however, this study highlights the difficulties of equating TLF thresholds to TTCs or E. coli data because of the influence of DOC/HLF on the TLF signal.


Assuntos
Água Potável , Monitoramento Ambiental , Escherichia coli , Fluorescência , Humanos , Malaui , Triptofano , Microbiologia da Água , Qualidade da Água , Abastecimento de Água
3.
Sci Total Environ ; 750: 142266, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33182211

RESUMO

Urbanization and population growth have created considerable sanitation challenges in cities and communities in many parts of Europe and the world. As such, it is imperative to identify the most environmentally-harmful microbiological and chemical sources of pollution, these being wastewater treatment plants (WWTPs) which release wastewater of low quality. In the present manuscript, an extensive study was performed of the sanitary conditions of river water and treated wastewater from seventeen WWTPs of various sizes along the Pilica River catchment in central Poland, with the aim of identifying "hot spots" in terms of most serious sources of sanitary hazards. The bacteriological risk for the river, including fecal indicator bacteria (FIB) such as coliforms, E.coli, enterococci, C. perfringens, and carbapenem-resistant Acinetobacter spp. (CRA) were assessed using classical microbiological methods, and the physicochemical parameters were also tested. The WWTPs, particularly the small ones (<2000 people equivalent, PE) demonstrated significant variation regarding the physicochemical parameters. Carbapenem-resistant Acinetobacter spp. bacteria growing at 42 °C were found in the effluent wastewaters of all tested municipal WWTPs, and in most of the Pilica River water samples, presenting a potential hazard to public health. A positive correlation was identified between E. coli and CRA abundance in treated wastewater; however, no such relationship was found in river water. It was found that seven small treatment plants discharged wastewater with very different microbiological parameters. Moreover, three small treatment plants serving only 0.56% of the population in the studied area continuously released extremely high microbiological contamination, constituting as much as 54-82% of fecal indicator bacteria loads in the area studied. Our findings show that this type of comprehensive analysis may enable assessment of the use of the entire catchment area, thus identifying the most serious threats to surface water quality and guiding the actions needed to improve the worst operating WWTPs.


Assuntos
Acinetobacter , Águas Residuárias , Carbapenêmicos , Cidades , Monitoramento Ambiental , Escherichia coli , Europa (Continente) , Fezes/química , Humanos , Polônia , Rios , Águas Residuárias/análise , Água , Microbiologia da Água
4.
Chemosphere ; 262: 127840, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32763570

RESUMO

This work assessed the effect of the antibiotics trimethoprim (TMP) and sulfamethoxazole (SMX) on the granulation process, microbiology, and organic matter and nutrient removal of an aerobic granular sludge (AGS) system. In addition, after the maturation stage, the impact of the redox mediator anthraquinone-2,6-disulfonate (AQDS) (25 µM) on the biotransformation of the antibiotics was evaluated. The reactor R1 was maintained as a control, and the reactor R2 was supplemented with TMP and SMX (200 µg L-1). The ability to remove C, N, and P was similar between the reactors. However, the structural integrity of the AGS was impaired by the antibiotics. Low TMP (∼30%) and SMX (∼60%) removals were achieved when compared to anaerobic or floccular biomass aerobic systems. However, when the system was supplemented with AQDS, an increase in the removal of TMP (∼75%) and SMX (∼95%) was observed, possibly due to the catalytic action of the redox mediator on cometabolic processes. Regarding the microbial groups, whereas Proteobacteria and Bacterioidetes increased, Planctomycetes decreased in both reactors. However, TMP and SMX presence seemed to inhibit or favor some genera during the formation of the granules, possibly due to their bactericidal action.


Assuntos
Microbiota/efeitos dos fármacos , Sulfametoxazol/toxicidade , Trimetoprima/toxicidade , Eliminação de Resíduos Líquidos , Antibacterianos , Bactérias/efeitos dos fármacos , Biomassa , Esgotos , Sulfametoxazol/química , Trimetoprima/química , Microbiologia da Água
5.
Sci Total Environ ; 752: 141775, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32890827

RESUMO

We evaluated the hygienic influence of onsite sanitation systems (OSSs) on drinking water wells in rural Sri Lanka by determining the safe setback distance between wells and the management of OSSs. Although previous studies have used bacterial indicators such as E. coli to evaluate the OSS impact, these parameters cannot assess the hygiene risk for waterborne pathogenic viruses (e.g. rotaviruses). Therefore, pepper mild mottle virus was selected as an indicator of human-specific faecal virus contamination. From a viral perspective, not only can the horizontal distance between a well and the nearest OSS reasonably represent hygiene safety, but the OSS sludge management can mitigate the contamination of wells even at short distances from the OSSs. Quantitative microbial risk assessment suggests that the infection risk of rotavirus was extremely high compared to the international standard. As proper management of OSSs would be key to reducing viral risk, it is necessary to reach out to the residents who are unaware of the importance and necessity of such management.


Assuntos
Saneamento , Vírus , Escherichia coli , Humanos , Higiene , População Rural , Sri Lanka , Microbiologia da Água , Abastecimento de Água , Poços de Água
6.
Sci Total Environ ; 752: 141846, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32892045

RESUMO

This paper examines seasonal variations in faecal contamination of drinking water sources in the Jirapa and Kassena-Nankana Municipalities of Ghana. Data collection involved a survey of 568 households, testing of faecal coliform concentrations in drinking water source samples (141 in the rainy season, 128 in the dry season), in-depth interviews with key water stakeholders, and field observation to identify sources of faecal contamination. From the water quality testing, faecal coliforms were detected in all source types, including 'treated' pipe-borne water. Contamination was significantly higher in the rainy season than in the dry season (P < 0.05) with 51.8% of water samples in the rainy season and 27.3% in the dry season failing to meet the World Health Organisation and Ghana Standard Authority guideline on faecal coliform concentrations in drinking water sources. The proportion of population at risk of faecal contamination in the rainy season was 41.5% compared to 33.1% in the dry season. We argue that in Ghana and Sub-Saharan Africa at large, water surveillance agencies risk underestimating population exposed to faecal contamination through drinking water sources if monitoring is only done in the dry season. To avoid this, we recommend seasonal monitoring of faecal concentration in drinking water sources. However, in periods of limited resources, monitoring is most appropriate in the rainy season when the risk of contamination is high.


Assuntos
Água Potável , Cidades , Água Potável/análise , Gana , Estações do Ano , Microbiologia da Água , Qualidade da Água , Abastecimento de Água
7.
Sci Total Environ ; 752: 141223, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32898796

RESUMO

Reclaimed water can significantly reduce household water consumption. However, microbial growth introduces several problems to reclaimed water, including health concerns, aesthetic deterioration and biofouling. Biological stability refers to the potential of organic matter or nutrients in water to support heterotrophic bacterial growth (HPC). Assimilable organic carbon (AOC) and biodegradable organic carbon (BDOC) are often used as indicators to evaluate the biological stability of water. This study investigated the effect of residual chlorine on the interaction between bacterial regrowth and AOC or BDOC and the variation of AOC after chlorine disinfection in reclaimed water. The results show that the HPC level is insensitive to AOC concentration when residual chlorine is >0.5 mg/L; however, the effects are more pronounced when residual chlorine is <0.5 mg/L. A residual chlorine concentration of >0.5 mg/L therefore maintains biological stability in reclaimed water. When residual chlorine was <0.5 mg/L, HPC levels were found to be limited when AOC was <128 µg/L or BDOC was <0.25 mg/L; and when residual chlorine was >0.5 mg/L, HPC levels were found to be limited when AOC was <796 µg/L or BDOC was <0.85 mg/L in reclaimed water. After chlorine disinfection, AOC contents initially increase and then decrease gradually, reaching minimum levels around day 20, and then increase in both greywater reclaimed water and mixed wastewater reclaimed water. Maintaining the chlorine demand and controlling the AOC level is critical for producing an effect on microbial regrowth and stabilising reclaimed water. The results of this study are conducive to the popularisation of reclaimed water use and also provide reference for reuse standards of reclaimed water.


Assuntos
Cloro , Purificação da Água , Carbono , Desinfecção , Água , Microbiologia da Água
8.
J Environ Manage ; 277: 111413, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33035938

RESUMO

Surface waters listed on impaired waters (303 d) lists due to pathogen contamination pose a significant environmental and public health burden. The need to address impairments through the Total Maximum Daily Load (TMDL) process has resulted in method developments that successfully identify nonpoint fecal pollution sources by maximizing available resources to improve water quality. However, the ability of those methods to effectively and universally identify sources of fecal pollution requires further evaluation. The objective of this research was to assess the usefulness of a previously described multivariate statistical approach to identify common patterns influencing fate and transport of fecal pollutants from sources to receiving streams using the Tuckasegee River watershed in Western North Carolina as a test watershed. Two streams were routinely monitored using a targeted sampling approach to assess fecal pollution extent and identify nonpoint sources using canonical correlation and canonical discriminant analyses. Fecal pollution in the watershed varied spatially and temporally with significantly higher fecal coliform concentrations observed in Scott Creek (f = 9.49, p = 0.002) and during the summer months (f = 14.8, p < 0.0001). Canonical correlations described 62-67% of water quality variability and indicate that fecal pollution in portions of the watershed are influenced by stormwater runoff and fecal indicator bacteria resuspension from sediment, while fecal pollution in other portions are influenced by soil erosion and surface runoff. Canonical discriminant analyses indicate that LULC significantly influences the nature and extent of fecal pollution. These results demonstrate that chemical parameters are useful predictors of fecal pollution and can help identify nonpoint fecal pollution sources in relation to land use patterns and land management practices. This approach to water quality monitoring program design and data analysis may effectively and efficiently identify parameters that best predict fecal pollution to aid in development and implementation of effective TMDLs to remediate impaired waters.


Assuntos
Monitoramento Ambiental , Rios , Fezes , Análise Multivariada , North Carolina , Microbiologia da Água , Poluição da Água/análise , Qualidade da Água
10.
J Water Health ; 18(5): 766-775, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33095199

RESUMO

Coliforms are important bacterial contamination indicators in recreational waters. Little is known about the antibiotic resistance of coliforms from Southern California beaches. This study examined the numbers of coliforms as well as the incidence of antibiotic-resistant coliforms in beaches with restricted and non-restricted wave action by sampling from the shores of both types of beaches following dry and wet weather. Total coliforms were selected by membrane filtration onto mEndo agar and then enumerated. Randomly selected isolates from each location were screened for resistance to nine classes of antibiotics by disk diffusion, and the multiple antibiotic resistance (MAR) index was calculated. Numbers of total coliforms were significantly higher following rain compared to dry weather. Total coliform numbers were not significantly elevated at non-restricted wave action sites. Restricted wave action sites had a 78.5% increase in MAR index following wet weather compared to dry weather. Resistance to ampicillin was observed in almost 50% of isolates and was not significantly impacted by wave action or weather. Minimum inhibitory concentration testing revealed that many isolates were highly resistant to ampicillin. This study is the first to report on the antibiotic resistance of coliforms found in Southern California beaches and highlights the prevalence of ampicillin resistance.


Assuntos
Resistência Microbiana a Medicamentos , Microbiologia da Água , California/epidemiologia , Incidência , Testes de Sensibilidade Microbiana
11.
Nat Commun ; 11(1): 5364, 2020 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-33097697

RESUMO

Over the last ten years, satellite and geographically constrained in situ observations largely focused on the northern hemisphere have suggested that annual phytoplankton biomass cycles cannot be fully understood from environmental properties controlling phytoplankton division rates (e.g., nutrients and light), as they omit the role of ecological and environmental loss processes (e.g., grazing, viruses, sinking). Here, we use multi-year observations from a very large array of robotic drifting floats in the Southern Ocean to determine key factors governing phytoplankton biomass dynamics over the annual cycle. Our analysis reveals seasonal phytoplankton accumulation ('blooming') events occurring during periods of declining modeled division rates, an observation that highlights the importance of loss processes in dictating the evolution of the seasonal cycle in biomass. In the open Southern Ocean, the spring bloom magnitude is found to be greatest in areas with high dissolved iron concentrations, consistent with iron being a well-established primary limiting nutrient in this region. Under ice observations show that biomass starts increasing in early winter, well before sea ice begins to retreat. The average theoretical sensitivity of the Southern Ocean to potential changes in seasonal nutrient and light availability suggests that a 10% change in phytoplankton division rate may be associated with a 50% reduction in mean bloom magnitude and annual primary productivity, assuming simple changes in the seasonal magnitude of phytoplankton division rates. Overall, our results highlight the importance of quantifying and accounting for both division and loss processes when modeling future changes in phytoplankton biomass cycles.


Assuntos
Biomassa , Fitoplâncton/crescimento & desenvolvimento , Estações do Ano , Água do Mar/microbiologia , Biodiversidade , Carbono/análise , Clorofila/análise , Clima , Ecologia , Camada de Gelo , Luz , Biologia Marinha , Meteorologia , Nutrientes , Oceanos e Mares , Dinâmica Populacional , Microbiologia da Água
12.
PLoS One ; 15(10): e0239594, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33021988

RESUMO

Beneficial microbes are all around us and it remains to be seen, whether all diseases and disorders can be prevented or treated with beneficial microbes. In this study, the presence of various beneficial bacteria were identified from the sediments of Indian major Rivers Ganga and Yamuna from nine different sites using a metagenomic approach. The metagenome sequence analysis using the Kaiju Web server revealed the presence of 69 beneficial bacteria. Phylogenetic analysis among these bacterial species revealed that they were highly diverse. Relative abundance analysis of these bacterial species is highly correlated with different pollution levels among the sampling sites. The PCA analysis revealed that Lactobacillus spp. group of beneficial bacteria are more associated with sediment sampling sites, KAN-2 and ND-3; whereas Bacillus spp. are more associated with sites, FAR-2 and ND-2. This is the first report revealing the richness of beneficial bacteria in the Indian rivers, Ganga and Yamuna. The study might be useful in isolating different important beneficial microorganisms from these river sediments, for possible industrial applications.


Assuntos
Sedimentos Geológicos/microbiologia , Metagenoma , Rios/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , DNA Bacteriano/genética , Índia , Microbiota , Filogenia , Microbiologia da Água
13.
BMC Infect Dis ; 20(1): 741, 2020 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-33036564

RESUMO

BACKGROUND: Cholera remains a major global health challenge. Uvira, in the Democratic Republic of the Congo (DRC), has had endemic cholera since the 1970's and has been implicated as a possible point of origin for national outbreaks. A previous study among this population, reported a case confirmation rate of 40% by rapid diagnostic test (RDT) among patients at the Uvira Cholera Treatment Centre (CTC). This study considers the prevalence and diversity of 15 enteric pathogens in suspected cholera cases seeking treatment at the Uvira CTC. METHODS: We used the Luminex xTAG® multiplex PCR to test for 15 enteric pathogens, including toxigenic strains of V. cholerae in rectal swabs preserved on Whatman FTA Elute cards. Results were interpreted on MAGPIX® and analyzed on the xTAG® Data Analysis Software. Prevalence of enteric pathogens were calculated and pathogen diversity was modelled with a Poisson regression. RESULTS: Among 269 enrolled CTC patients, PCR detected the presence of toxigenic Vibrio cholerae in 38% (103/269) of the patients, which were considered to be cholera cases. These strains were detected as the sole pathogen in 36% (37/103) of these cases. Almost half (45%) of all study participants carried multiple enteric pathogens (two or more). Enterotoxigenic Escherichia coli (36%) and Cryptosporidium (28%) were the other most common pathogens identified amongst all participants. No pathogen was detected in 16.4% of study participants. Mean number of pathogens was highest amongst boys and girls aged 1-15 years and lowest in women aged 16-81 years. Ninety-three percent of toxigenic V. cholerae strains detected by PCR were found in patients having tested positive for V. cholerae O1 by RDT. CONCLUSIONS: Our study supports previous results from DRC and other cholera endemic areas in sub-Sahara Africa with less than half of CTC admissions positive for cholera by PCR. More research is required to determine the causes of severe acute diarrhea in these low-resource, endemic areas to optimize treatment measures. TRIAL REGISTRATION: This study is part of the impact evaluation study entitled: "Impact Evaluation of Urban Water Supply Improvements on Cholera and Other Diarrheal Diseases in Uvira, Democratic Republic of Congo" registered on 10 October 2016 at clinicaltrials.gov Identification number: NCT02928341 .


Assuntos
Cólera/epidemiologia , Criptosporidiose/epidemiologia , Cryptosporidium/genética , Diarreia/epidemiologia , Surtos de Doenças , Escherichia coli Enterotoxigênica/genética , Infecções por Escherichia coli/epidemiologia , Vibrio cholerae/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Criança , Pré-Escolar , Cólera/microbiologia , Criptosporidiose/parasitologia , República Democrática do Congo/epidemiologia , Testes Diagnósticos de Rotina , Diarreia/microbiologia , Doenças Endêmicas , Infecções por Escherichia coli/microbiologia , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase Multiplex , Prevalência , Microbiologia da Água , Adulto Jovem
14.
Water Res ; 186: 116140, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-33096438

RESUMO

Predicting water quality and the human health risks associated with sewage-derived microbes requires understanding the fate and transport of these contaminants. Sewage-derived pathogen risks are typically assessed and monitored by measuring concentrations of fecal indicating bacteria (FIB), like Enterococcus sp. Previous research demonstrated that a high fraction of FIB is particle-associated, which can alter FIB dynamics within secondary water bodies. In this study, we experimentally quantified the effect of particle association on dark, temperature- and light-dependent growth and sinking rates of enterococci. Particle association significantly increased dark growth rates, light-dependent growth rates (i.e. decreased mortality), and sinking rates, relative to free-living enterococci. Simulations using a novel, 1-dimensional model parameterized by these rates indicate greater persistence (T90) for particle-associated enterococci in water bodies across a wide range of diffuse attenuation coefficients of light (Kd) and turbulent diffusivity (D) values. In addition, persistence of both fractions increased in simulated turbid and turbulent waters, compared to clear and/or quiescent conditions. Simulated persistence of both fractions also increased when enterococci discharges occurred later in a diel cycle (towards sunset, as opposed to sunrise), especially for the free-living population, because later discharges under our model conditions allowed both fractions to mix deeper before inactivation via sunlight. Model sensitivity testing revealed that T90 variability was greatest when dark growth rates were altered, suggesting that future empirical studies should focus on quantifying these rates for free-living and particle-associated sewage-derived microbes. Despite greater sensitivity of T90 to variability in dark growth rates, omitting light-dependent growth rates from simulations dramatically influenced T90 values. Our results demonstrate that particle association can increase enterococci persistence in receiving waters and highlight the importance of incorporating particle association in future water quality models.


Assuntos
Enterococcus , Escherichia coli , Fezes , Humanos , Esgotos , Microbiologia da Água , Qualidade da Água
15.
Environ Sci Process Impacts ; 22(10): 2058-2069, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33084698

RESUMO

Water infiltration into the subsurface can result in pronounced biogeochemical depth gradients. In this study, we assess metabolic potential and properties of the subsurface microbiome during water infiltration by analyzing sediments from spatially-segmented columns. Past work in these laboratory set-ups demonstrated that removal efficiencies of trace organic pollutants were enhanced by limited availability of biodegradable dissolved organic carbon (BDOC) associated with higher humic ratios and deeper sediment regions. Distinct differences were observed in the microbial community when contrasting shallow versus deeper profile sediments. Metagenomic analyses revealed that shallow sediments contained an enriched potential for bacterial growth and division processes. In contrast, deeper sediments harbored a significant increase in genes associated with the metabolism of secondary metabolites and the biotransformation of xenobiotic water pollutants. Metatranscripts further supported this trend, with increased potential for metabolic attributes associated with the biotransformation of xenobiotics and antibiotic resistance within deeper sediments. Furthermore, increasing ratios of humics in feed solutions correlated to enhanced expression of genes associated with xenobiotic biodegradation. These results provide genetic support for the interplay of dissolved organic carbon limitation and enhanced trace organic biotransformation by the subsurface microbiome.


Assuntos
Carbono , Genética Microbiana , Biodegradação Ambiental , Biotransformação , Sedimentos Geológicos , Microbiologia da Água
16.
PLoS One ; 15(9): e0238385, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32936810

RESUMO

A lack of replicable test systems that realistically simulate hot water premise plumbing conditions at the laboratory-scale is an obstacle to identifying key factors that support growth of opportunistic pathogens (OPs) and opportunities to stem disease transmission. Here we developed the convectively-mixed pipe reactor (CMPR) as a simple reproducible system, consisting of off-the-shelf plumbing materials, that self-mixes through natural convective currents and enables testing of multiple, replicated, and realistic premise plumbing conditions in parallel. A 10-week validation study was conducted, comparing three pipe materials (PVC, PVC-copper, and PVC-iron; n = 18 each) to stagnant control pipes without convective mixing (n = 3 each). Replicate CMPRs were found to yield consistent water chemistry as a function of pipe material, with differences becoming less discernable by week 9. Temperature, an overarching factor known to control OP growth, was consistently maintained across all 54 CMPRs, with a coefficient of variation <2%. Dissolved oxygen (DO) remained lower in PVC-iron (1.96 ± 0.29 mg/L) than in PVC (5.71 ± 0.22 mg/L) or PVC-copper (5.90 ± 0.38 mg/L) CMPRs as expected due to corrosion. Further, DO in PVC-iron CMPRs was 33% of that observed in corresponding stagnant pipes (6.03 ± 0.33 mg/L), demonstrating the important role of internal convective mixing in stimulating corrosion and microbiological respiration. 16S rRNA gene amplicon sequencing indicated that both bulk water (Padonis = 0.001, R2 = 0.222, Pbetadis = 0.785) and biofilm (Padonis = 0.001, R2 = 0.119, Pbetadis = 0.827) microbial communities differed between CMPR versus stagnant pipes, consistent with creation of a distinct ecological niche. Overall, CMPRs can provide a more realistic simulation of certain aspects of premise plumbing than reactors commonly applied in prior research, at a fraction of the cost, space, and water demand of large pilot-scale rigs.


Assuntos
Água Potável/efeitos adversos , Água Potável/microbiologia , Engenharia Sanitária/instrumentação , Microbiologia da Água , Biofilmes/crescimento & desenvolvimento , Fenômenos Químicos , Cobre/química , Desenho de Equipamento , Humanos , Ferro/química , Microbiota/genética , Modelos Biológicos , Infecções Oportunistas/etiologia , Infecções Oportunistas/microbiologia , Cloreto de Polivinila/química , RNA Ribossômico 16S/genética , Temperatura , Abastecimento de Água
17.
PLoS One ; 15(9): e0238998, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32941473

RESUMO

The frequent contact people have with liquids containing pathogenic microorganisms provides opportunities for disease transmission. In this work, we quantified the transfer of bacteria-using E. coli as a model- from liquid to skin, estimated liquid retention on the skin after different contact activities (hand immersion, wet-cloth and wet-surface contact), and estimated liquid transfer following hand-to-mouth contacts. The results of our study show that the number of E. coli transferred to the skin per surface area (n [E. coli/cm2]) can be modeled using n = C (10-3.38+h), where C [E. coli/cm3] is the concentration of E. coli in the liquid, and h [cm] is the film thickness of the liquid retained on the skin. Findings from the E. coli transfer experiments reveal a significant difference between the transfer of E. coli from liquid to the skin and the previously reported transfer of viruses to the skin. Additionally, our results demonstrate that the time elapsed since the interaction significantly influences liquid retention, therefore modulating the risks associated with human interaction with contaminated liquids. The findings enhance our understanding of liquid-mediated disease transmission processes and provide quantitative estimates as inputs for microbial risk assessments.


Assuntos
Adsorção/fisiologia , Dermatopatias Bacterianas/transmissão , Pele/microbiologia , Fenômenos Biológicos , Transmissão de Doença Infecciosa/prevenção & controle , Escherichia coli/patogenicidade , Mãos , Humanos , Modelos Teóricos , Água/química , Microbiologia da Água
18.
Mar Pollut Bull ; 160: 111546, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32898736

RESUMO

Urban beaches are frequently impacted from multiple sources of fecal contamination. This along with high beach usage underscores the importance of appropriate management that protects swimmer health. The USEPA has enabled the use of QMRA as a tool for quantifying swimmer health risk and setting site-specific water quality objectives. This study illustrates the challenges associated with human and non-human source identification and how these challenges influence the decision of whether QMRA at typical urban beaches for water quality management is appropriate. In this study, a similar and correlated spatial relationship with elevated Enterococcus and avian-specific markers was observed, suggesting shorebirds as a primary source of FIB. However, human-associated markers were also detected frequently but at low concentrations. Ultimately, a QMRA was not conducted because pathogen loading from potential human sources could not be confidently quantified, having consequences for health risk in receiving waters where recreational contact occurs.


Assuntos
Microbiologia da Água , Poluição da Água , Praias , Monitoramento Ambiental , Fezes , Humanos , Medição de Risco , Poluição da Água/análise , Qualidade da Água
19.
PLoS One ; 15(9): e0239273, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32976495

RESUMO

One hundred and twenty-two Mycobacterium chimaera strains isolated in Italy from cardiac surgery-related patients, cardiac surgery-unrelated patients and from heater-cooler units, were submitted to whole-genome sequencing and to subsequent SNP analysis. All but one strains isolated from cardiac surgery-related patients belonged to Subgroup 1.1 (19/23) or Subgroup 1.8 (3/23). Only 28 out of 79 strains isolated from heater-cooler units belonged to groupings other than 1.1 and 1.8. The strains isolated from cardiac surgery-unrelated patients were instead distributed across the phylogenetic tree. Our data, the first on isolates from Italy, are in agreement with a recent large genomic study suggesting a common source, represented by strains belonging to Subgroups 1.1 and 1.8, of cardiac surgery-related Mycobacterium chimaera infections. The strains belonging to groupings other than 1.1 and 1.8 isolated from heather-cooler units evidently resulted from contaminations at hospital level and had no share in the Mycobacterium chimaera outbreak. One Mycobacterium chimaera strain investigated in this study proved distant from every previously known Mycobacterium chimaera Groups (1, 2, 3 and 4) and we propose to assign to a novel group, named "Group 5".


Assuntos
Infecção Hospitalar/microbiologia , Infecções por Mycobacterium não Tuberculosas/genética , Infecções por Mycobacterium/genética , Mycobacterium/isolamento & purificação , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Infecção Hospitalar/genética , Surtos de Doenças , Contaminação de Equipamentos , Feminino , Genômica , Humanos , Itália/epidemiologia , Masculino , Mycobacterium/patogenicidade , Infecções por Mycobacterium/epidemiologia , Infecções por Mycobacterium/microbiologia , Infecções por Mycobacterium não Tuberculosas/epidemiologia , Infecções por Mycobacterium não Tuberculosas/microbiologia , Micobactérias não Tuberculosas/genética , Micobactérias não Tuberculosas/patogenicidade , Polimorfismo de Nucleotídeo Único/genética , Microbiologia da Água , Sequenciamento Completo do Genoma
20.
PLoS One ; 15(9): e0238438, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32881972

RESUMO

Vibrio cholerae is a natural inhabitant of aquatic ecosystems worldwide, typically residing in coastal or brackish water. While more than 200 serogroups have been identified, only serogroups O1 and O139 have been associated with epidemic cholera. However, infections other than cholera can be caused by nonepidemic, non-O1/non-O139 V. cholerae strains, including gastroenteritis and extraintestinal infections. While V. cholerae can also survive in freshwater, that is typically only observed in regions of the world where cholera is endemic. We recently isolated V. cholerae from several locations in lakes and rivers in northwest Ohio. These isolates were all found to be non-O1/non-O139 V. cholerae strains, that would not cause cholera. However, these isolates contained a variety of virulence genes, including ctxA, rtxA, rtxC, hlyA, and ompU. Therefore, it is possible that some of these isolates have the potential to cause gastroenteritis or other infections in humans. We also investigated the relative motility of the isolates and their ability to form biofilms as this is important for V. cholerae survival in the environment. We identified one isolate that forms very robust biofilms, up to 4x that of our laboratory strains. Finally, we investigated the susceptibility of these isolates to a panel of antibiotics. We found that many of the isolates showed decreased susceptibility to some of the antibiotics tested, which could be of concern. While we do not know if these isolates are pathogenic to humans, increased surveillance to better understand the public health risk to the local community should be considered.


Assuntos
Água Doce/microbiologia , Vibrio cholerae/genética , Proteínas de Bactérias/genética , Cólera/epidemiologia , Ecossistema , Humanos , Ohio/epidemiologia , Reação em Cadeia da Polimerase , Vibrio cholerae/isolamento & purificação , Vibrio cholerae/metabolismo , Virulência/genética , Fatores de Virulência/genética , Microbiologia da Água
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