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1.
Water Res ; 203: 117543, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34433109

RESUMO

According to the European Directives (UE) 2020/2184 and 2009/54/EC, which establishes the sanitary criteria for water intended for human consumption in Europe, water suitable for human consumption must be free of the bacterial indicators Escherichia coli, Clostridium perfringens and Enterococcus spp. Drinking water is also monitored for heterotrophic bacteria, which are not a human health risk, but can serve as an index of bacteriological water quality. Therefore, a rapid, accurate, and cost-effective method for the identification of these colonies would improve our understanding of the culturable bacteria of drinking water and facilitate the task of water management by treatment facilities. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is potentially such a method, although most of the currently available mass spectral libraries have been developed in a clinical setting and have limited environmental applicability. In this work, a MALDI-TOF MS drinking water library (DWL) was defined and developed by targeting bacteria present in water intended for human consumption. This database, made up of 319 different bacterial strains, can contribute to the routine microbiological control of either treated drinking water or mineral bottled water carried out by water treatment and distribution operators, offering a faster identification rate compared to a clinical sample-based library. The DWL, made up of 96 bacterial genera, 44 of which are not represented in the MALDI-TOF MS bacterial Bruker Daltonics (BDAL) database, was found to significantly improve the identification of bacteria present in drinking water.


Assuntos
Água Potável , Purificação da Água , Bactérias , Bases de Dados Factuais , Humanos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
2.
Water Res ; 201: 117090, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34111729

RESUMO

The introduction of SARS-CoV-2 containing human stool and sewage into water bodies may raise public health concerns. However, assessment of public health risks by faecally contaminated water is limited by a lack of knowledge regarding the persistence of infectious SARS-CoV-2 in water. In the present study the decay rates of viable infectious SARS-CoV-2 and SARS-CoV-2 RNA were determined in river and seawater at 4 and 20°C. These decay rates were compared to S. typhimurium bacteriophage MS2 and pepper mild mottle virus (PMMoV). Persistence of viable SARS-CoV-2 was temperature dependent, remaining infectious for significantly longer periods of time in both freshwater and seawater at 4°C than at 20°C. T90 for infectious SARS-CoV-2 in river water was 2.3 days and 3.8 days at 20°C and 4°C, respectively. The T90 values were 1.1 days and 2.2 days in seawater at 20°C and 4°C, respectively. In contrast to the rapid inactivation of infectious SARS-CoV-2 in river and sea water, viral RNA was relatively stable. The RNA decay rates were increased in non-sterilised river and seawater, presumably due to the presence of microbiota. The decay rates of infectious MS2, MS2 RNA and PMMoV RNA differed significantly from the decay rate of SARS-CoV-2 RNA, suggesting that their use as surrogate markers for the persistence of SARS-CoV-2 in the environment is limited.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , RNA Viral , Rios , Águas Residuárias
3.
Sci Total Environ ; 789: 147828, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34052479

RESUMO

Bathing water quality may be negatively impacted by diffuse pollution arising from urban and agricultural activities and wildlife, it is therefore important to be able to differentiate between biological and geographical sources of faecal pollution. crAssphage was recently described as a novel human-associated microbial source tracking marker. This study aimed to evaluate the performance of the crAssphage marker in designated bathing waters. The sensitivity and specificity of the crAss_2 marker was evaluated using faecal samples from herring gulls, dogs, sewage and a stream impacted by human pollution (n = 80), which showed that all human impacted samples tested positive for the marker while none of the animal samples did. The crAss_2 marker was field tested in an urban marine bathing water close to the discharge point of human impacted streams. In addition, the bathing water is affected by dog and gull fouling. Analysis of water samples taken at the compliance point every 30 min during a tidal cycle following a rain event showed that the crAss_2 and HF183 markers performed equally well (Spearman correlation ρ = 0.84). The levels of these marker and faecal indicators (Escherichia coli, intestinal enterococci, somatic coliphages) varied by up to 2.5 log10 during the day. Analysis of a high-tide transect perpendicular to the shoreline revealed high levels of localised faecal contamination 1 km offshore, with a concomitant spike in the gull marker. In contrast, both the crAss_2 and HF183 markers remained at a constant level, showing that human faecal contamination is homogenously distributed, while gull pollution is localised. Performance of the crAss_2 and HF183 assay was further evaluated in bimonthly compliance point samples over an 18-month period. The co-occurrence between the crAss_2 and HF183 markers in compliance sampling was 76%. A combination of both markers should be applied in low pollution impacted environments to obtain a high confidence level.


Assuntos
Monitoramento Ambiental , Microbiologia da Água , Animais , Cães , Fezes , Humanos , Rios , Esgotos , Poluição da Água/análise
4.
Int J Food Microbiol ; 334: 108850, 2020 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-32919261

RESUMO

The complex and highly diverse microbial environment of drinking water, consisting mainly of bacteria at different metabolic states, is still underexplored. The aim of this work was to characterize the bacterial communities in tap water and bottled mineral water, the two predominant sources of drinking water in modern societies. A total of 11 tap water samples from a range of locations and distribution networks and 10 brands of bottled natural mineral water were analysed using two approaches: a) heterotrophic plate counts by matrix-assisted laser desorption/ionization time of flight mass-spectrometry (MALDI-TOF MS) for the culturable heterotrophic communities, and b) Illumina amplicon sequencing for total bacteria including non-culturable bacteria. Culturable heterotrophic bacteria were isolated in WPCA (ISO) agar at 22 ± 2 °C for 72 h and 2046 isolates were identified using MALDI-TOF MS. The Bruker Daltonics Library and a previously customized library (Drinking Water Library) were used as reference databases. For the total bacteria fraction, DNA was extracted from 6 L of water and submitted to Illumina 16S rRNA sequencing of the v4 region. Significant differences were observed between mineral and tap water, with a general dominance of Alphaproteobacteria (mainly the genus Blastomonas) in tap water and Gammaproteobacteria in mineral water with Acidovorax being the dominant genus in 3 out of 7 mineral water brands. The bacterial communities in the different brands of mineral water were highly diverse and characteristic of each one. Moreover, the season in which the water was bottled also affected the species distribution, with some of them identified in only one season. Among the culturable bacteria, the most abundant phylum was Proteobacteria (around 85% of the isolates), followed by Actinobacteria, Firmicutes and Bacteroidetes. Proteobacteria was also the most abundant phylum detected with Illumina sequencing (>99% of the reads). The two methods gave distinct results at the different taxonomic levels and could therefore have a complimentary application in the study of microbiota in mineral water environments. MALDI-TOF MS is a promising method for the rapid identification of heterotrophic bacteria in routine water analysis in the bottling industry. SIGNIFICANCE AND IMPACT OF THE STUDY: The complementarity of MALDI-TOF MS and NGS in the assessment of bacterial community diversity has been demonstrated in water intended for human consumption. The two methods are suitable for routine use in the water industry for water quality management.


Assuntos
Técnicas Bacteriológicas , Água Potável/microbiologia , Microbiota , Águas Minerais/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Técnicas Bacteriológicas/métodos , Meios de Cultura/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , RNA Ribossômico 16S/genética , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
5.
Sci Total Environ ; 739: 140242, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32758961

RESUMO

Antibiotic resistance represents the greatest challenge to healthcare systems around the world. As antibiotic resistance genes (ARGs) are shed in faeces, many studies have focused on how wastewater effluent contributes to ARG pollution in rivers. However, small urban streams and bathing waters not impacted by treated wastewater have received little attention though they may be important reservoirs of ARGs. The main objective of this study was to assess the extent to which ARG and faecal pollution impact small urban streams and bathing waters and to determine if there is a relationship between these contaminants. For one year, bi-monthly water samples were collected from two urban streams and Dublin city's three designated bathing waters. The Liffey Estuary, that receives treated wastewater, was also sampled. The sul1, tet(O), qnrS, blaTEM, blaSHV and blaCTX-M ARGs were quantified. E. coli and intestinal enterococci levels were determined and the source of faecal pollution (human, dog, gull) quantified by microbial source tracking. Our results show that the Liffey Estuary, the urban streams and the bathing waters are highly impacted by ARGs and human faeces. There were clear correlations between all of the studied faecal indicators and ARGs in the Liffey Estuary. In the urban streams relationships were observed for only some of the ARGs and faecal indicators, which is likely a result of non-continuous sewage leaks and overflows to the streams. Similarly, only some ARGs correlated with faecal indicators in the urban bathing waters. The source of ARGs in the bathing waters is likely to be multifaceted as we detected sporadic dog and gull faecal markers. This study demonstrates that small urban streams and bathing waters are reservoirs of ARGs and that they may pose a previously unrecognised public health risk as they have the potential to transmit enteric pathogens and antibiotic resistance determinants.


Assuntos
Antibacterianos , Rios , Animais , Cidades , Cães , Farmacorresistência Bacteriana , Escherichia coli , Fezes , Genes Bacterianos , Humanos , Águas Residuárias
6.
Sci Total Environ ; 736: 139573, 2020 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-32474276

RESUMO

Fecal pollution of water bodies poses a serious threat for public health and ecosystems. Microbial source tracking (MST) is used to track the source of this pollution facilitating better management of pollution at the source. In this study we tested 12 MST markers to track human, ruminant, sheep, horse, pig and gull pollution to assess their usefulness as an effective management tool of water quality. First, the potential of the selected markers to track the source was evaluated using fresh fecal samples. Subsequently, we evaluated their performance in a catchment with different impacts, considering land use and environmental conditions. All MST markers showed high sensitivity and specificity, although none achieved 100% for both. Although some of the MST markers were detected in hosts other than the intended ones, their abundance in the target group was always several orders of magnitude higher than in the non-target hosts, demonstrating their suitability to distinguish between sources of pollution. The MST analysis matched the land use in the watershed allowing an accurate assessment of the main sources of pollution, in this case mainly human and ruminant pollution. Correlating environmental parameters including temperature and rainfall with MST markers provided insight into the dynamics of the pollution in the catchment. The levels of the human marker showed a significant negative correlation with rainfall in human polluted areas suggesting a dilution of the pollution, whereas at agricultural areas the ruminant marker increased with rainfall. There were no seasonal differences in the levels of human marker, indicating human pollution as a constant pressure throughout the year, whereas the levels of the ruminant marker was influenced by the seasons, being more abundant in summer and autumn. MST analysis integrated with land use and environmental data can improve the management of fecal polluted areas and set up best practice.


Assuntos
Ecossistema , Rios , Animais , Monitoramento Ambiental , Fezes , Cavalos , Humanos , Ovinos , Suínos , Microbiologia da Água , Poluição da Água/análise , Qualidade da Água
7.
Food Microbiol ; 82: 1-10, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31027761

RESUMO

Natural mineral waters contain indigenous bacteria characteristic of each spring source. Once bottled, these communities change over time until the water is consumed. Bottle material is believed to play a major role in the succession of these populations, but very few studies to date have evaluated the effect of this material on bacterial communities. In this study, we examined the microbial community structure of three natural mineral waters over 3 months after bottling in glass and polyethylene terephthalate (PET) bottles. To this end, we used culture-dependent (heterotrophic plate count) and culture-independent methods (16S rRNA massive gene sequencing, denaturing gradient gel electrophoresis (DGGE) and fluorescent microscopy with vital dyes). Total and viable cell counts increased by around 1-2 log10 units between 1 and 2 weeks after bottling and then remained constant over 3 months for all waters regardless of the bottle material. DGGE fingerprints and 16S rRNA massive sequencing analysis both indicated that different communities were established in the waters two weeks after bottling in the different bottle materials. In conclusion, no differences in total, viable and culturable bacteria counts were observed between mineral waters bottled with PET or glass during shelf life storage. Nevertheless, in spite of changes in the communities, each water brand and material presented a distinct microbial community structure clearly distinguishable from the others, which could be interesting for traceability purposes.


Assuntos
Bactérias/isolamento & purificação , Água Potável/microbiologia , Armazenamento de Alimentos , Águas Minerais/microbiologia , Microbiologia da Água , Bactérias/classificação , Contagem de Colônia Microbiana , Variação Genética , Vidro , Sequenciamento de Nucleotídeos em Larga Escala , Metagenômica , Polietilenotereftalatos , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/genética
8.
J Water Health ; 15(6): 885-897, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29215353

RESUMO

The aim of this work was to assess the suitability of matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) for routine heterotrophic monitoring in a drinking water treatment plant. Water samples were collected from raw surface water and after different treatments during two campaigns over a 1-year period. Heterotrophic bacteria were studied and isolates were identified by MALDI-TOF MS. Moreover, the diversity index and the coefficient of population similarity were also calculated using biochemical fingerprinting of the populations studied. MALDI-TOF MS enabled us to characterize and detect changes in the bacterial community composition throughout the water treatment plant. Raw water showed a large and diverse population which was slightly modified after initial treatment steps (sand filtration and ultrafiltration). Reverse osmosis had a significant impact on the microbial diversity, while the final chlorination step produced a shift in the composition of the bacterial community. Although MALDI-TOF MS could not identify all the isolates since the available MALDI-TOF MS database does not cover all the bacterial diversity in water, this technique could be used to monitor bacterial changes in drinking water treatment plants by creating a specific protein profile database for tracking purposes.


Assuntos
Bactérias/isolamento & purificação , Água Potável/microbiologia , Monitoramento Ambiental/métodos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Purificação da Água/normas
9.
Mar Environ Res ; 129: 68-75, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28487162

RESUMO

Bryozoans are among the most abundant and diverse members of the Antarctic benthos, however the role of bioactive metabolites in ecological interactions has been scarcely studied. To extend our knowledge about the chemical ecology of Antarctic bryozoans, crude ether extracts (EE) and butanol extracts (BE) obtained from two Antarctic common species (Cornucopina pectogemma and Nematoflustra flagellata), were tested for antibacterial and repellent activities. The extracts were screened for quorum quenching and antibacterial activities against four Antarctic bacterial strains (Bacillus aquimaris, Micrococcus sp., Oceanobacillus sp. and Paracoccus sp.). The Antarctic amphipod Cheirimedon femoratus and the sea star Odontaster validus were selected as sympatric predators to perform anti-predatory and substrate preference assays. No quorum quenching activity was detected in any of the extracts, while all EE exhibited growth inhibition towards at least one bacterium strain. Although the species were not repellent against the sea star, they caused repellence to the amphipods in both extracts, suggesting that defence activities against predation derive from both lipophilic and hydrophilic metabolites. In the substrate preference assays, one EE and one BE deriving from different specimens of the species C. pectogemma were active. This study reveals intraspecific variability of chemical defences and supports the fact that chemically mediated interactions are common in Antarctic bryozoans as means of protection against fouling and predation.


Assuntos
Briozoários/fisiologia , Adaptação Fisiológica , Anfípodes , Animais , Regiões Antárticas , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Produtos Biológicos/metabolismo , Produtos Biológicos/farmacologia , Comportamento Alimentar , Comportamento Predatório , Estrelas-do-Mar
10.
J Environ Manage ; 182: 335-341, 2016 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-27497310

RESUMO

Reverse osmosis membrane filtration technology (RO) is used to treat drinking water. After RO treatment, bacterial growth is still observed in water. However, it is not clear whether those microorganisms belong to species that can pose a health risk, such as Pseudomonas spp. The goal of this study is to characterize the bacterial isolates from a medium that is selective for Pseudomonas and Aeromonas which were present in the water fraction before and after the RO. To this end, isolates were recovered over two years and were identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry. They were then biochemically phenotyped and the population similarity indexes were calculated. The isolates were analysed for their capacity to form biofilms in vitro and antimicrobial susceptibility. There were significant differences between the microbial populations in water before and after RO. Furthermore, the structures of the populations analysed at the same sampling point were similar in different sampling campaigns. Some of the isolates had the capacity to form a biofilm and showed resistance to different antibiotics. A successful level filtration via RO and subsequent recolonization of the membrane with different species from those in the feed water was found. Pseudomonas aeruginosa was not recovered from among the isolates. This study increases the knowledge on the microorganisms present in water after RO treatment, with focus in one of the genus causing problems in RO systems associated with human health risk, Pseudomonas.


Assuntos
Pseudomonas/fisiologia , Microbiologia da Água , Purificação da Água/métodos , Biofilmes , Filtração , Humanos , Membranas Artificiais , Osmose
11.
Int J Hyg Environ Health ; 219(7 Pt A): 577-584, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-26809219

RESUMO

The study of bacterial communities throughout a drinking water treatment plant could provide a basic understanding of the effects of water processing that could then be used to improve the management of such plants. However, it is necessary to develop new analytical techniques that are sufficiently efficient, robust and fast for their effective and useful application in routine analysis. The aim of this study is therefore to assess the performance of matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS), as compared to the PhenePlate™ system, for routine analysis in a drinking water treatment plant. To this end we studied a total of 277 colonies isolated in different seasons and from different points throughout the water treatment process, including: raw water, sand filtration, ultrafiltration, reverse osmosis and chlorination. The colonies were analysed using MALDI-TOF MS by direct deposition of the cells on the plate. The colonies were also biochemically fingerprinted using the PhenePlate™ system, clustered according to their similarity and a representative strain was selected for 16S rRNA gene sequencing and API® gallery-based identification. The use of MALDI-TOF MS was reliable compared to the PhenePlate™ system and has the advantage of being faster and relatively cheap. Bacteria typing by MALDI-TOF MS is therefore a promising method to replace conventional routine phenotypic methods for the identification of bacteria in drinking water laboratories, thanks to its robustness. The major limiting factor for MALDI-TOF MS is the lack of a suitable mass spectra database; although each laboratory can develop its own library. This methodology will provide a tracking tool for companies to use in risk management and the detection of possible failures in both the water treatment processes and the distribution network, as well as offering characterization of the intrinsic microbial populations.


Assuntos
Bactérias/isolamento & purificação , Monitoramento Ambiental/métodos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Poluentes da Água/isolamento & purificação , Bactérias/classificação , Bactérias/genética , Técnicas de Tipagem Bacteriana , Água Potável , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Poluentes da Água/classificação , Purificação da Água
12.
Mar Environ Res ; 101: 52-59, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25232675

RESUMO

The antimicrobial activity of Antarctic bryozoans and the ecological functions of the chemical compounds involved remain largely unknown. To determine the significant ecological and applied antimicrobial effects, 16 ether and 16 butanol extracts obtained from 13 different bryozoan species were tested against six Antarctic (including Psychrobacter luti, Shewanella livingstonensis and 4 new isolated strains) and two bacterial strains from culture collections (Escherichia coli and Bacillus cereus). Results from the bioassays reveal that all ether extracts exhibited antimicrobial activity against some bacteria. Only one butanol extract produced inhibition, indicating that antimicrobial compounds are mainly lipophilic. Ether extracts of the genus Camptoplites inhibited the majority of bacterial strains, thus indicating a broad-spectrum of antimicrobial activity. Moreover, most ether extracts presented activities against bacterial strains from culture collections, suggesting the potential use of these extracts as antimicrobial drugs against pathogenic bacteria.


Assuntos
Anti-Infecciosos/farmacologia , Briozoários/metabolismo , Animais , Regiões Antárticas , Anti-Infecciosos/isolamento & purificação , Misturas Complexas/farmacologia , Testes de Sensibilidade Microbiana
13.
Vet Microbiol ; 173(1-2): 59-65, 2014 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-25085518

RESUMO

The complete genome sequencing of Bacillus toyonensis, the active ingredient of the feed additive Toyocerin(®), has revealed the presence of tetM and cat genes, a tetracycline and a chloramphenicol resistance gene, respectively. The aim of this study was to determine whether the use of Toyocerin(®) (viable spores of B. toyonensis) as a probiotic in feedstuff increased the abundance of tetracycline and chloramphenicol resistant bacteria in the intestinal tracts of piglets and Holstein bulls. To this end, qPCRs were designed to quantify the abundances of tetM and cat genes and B. toyonensis in the intestinal content of animals treated and non-treated with Toyocerin(®). Additionally, the culturable bacterial populations resistant to tetracycline or chloramphenicol were enumerated by plate counting. No statistical significances were detected between the concentrations of tetracycline or chloramphenicol resistant bacterial populations in treated and non-treated animals. The concentrations of tetM and cat in most of the treated animals were similar to those of B. toyonensis. Furthermore, tetM and cat genes were also detected in some non-treated animals, although in low concentrations. These results suggest that tetM and cat genes are already circulating among the commensal microbiota regardless of the use of Toyocerin(®). The use of Toyocerin(®) as a supplement in feedstuff does not increase the abundances of tetracycline and chloramphenicol resistant bacteria in the intestinal tracts of piglets and Holstein bulls beyond the contribution directly associated to the introduction of B. toyonensis spores through diet.


Assuntos
Ração Animal/microbiologia , Bacillus/fisiologia , Farmacorresistência Bacteriana/genética , Trato Gastrointestinal/microbiologia , Genes Bacterianos , Probióticos/administração & dosagem , Animais , Antibacterianos/farmacologia , Carga Bacteriana , Bovinos , Cloranfenicol/farmacologia , Resistência ao Cloranfenicol/genética , Masculino , Esporos Bacterianos/fisiologia , Suínos , Tetraciclina/farmacologia
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