Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.245
Filtrar
1.
Huan Jing Ke Xue ; 41(1): 253-261, 2020 Jan 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854926

RESUMO

This study was carried out in the ozone (O3) and biological activated carbon (BAC) section of a drinking water plant to investigate the effects of O3 on microbial and effluent disinfection by-products (DBPs) in BAC during drinking water treatment. The water quality, dissolved organic matter (DOM) characteristics, microbial activity, and DBPs formation at different O3 concentrations were analyzed. Results showed that the effect of O3 on microorganisms is mainly that it increased the utilization efficiency of DOM. However, excessive O3 increased the amount of organic matter such as protein and microbial metabolites (SMPs) in the effluent. When the O3 concentration increased from 0 mg·L-1 to 2.0 mg·L-1, the survival rate of microorganisms in the BAC decreased from 95.10% to 62.60%. However, since O3 transforms organic matter into a biodegradable substance, we found that microbial activity increased by 62.52% and that the biofiltration of the BAC was enhanced. When the O3 concentration was further increased to 4.0 mg·L-1, the microbial survival rate decreased to 49.9% and the protein and SMPs produced by the microorganisms increased. This resulted in an increased formation of carbon-containing DBPs (C-DBPs) and nitrogen-containing DBPs (N-DBPs) by 41.93% and 7.18%, respectively. In summary, an appropriate dosage of O3 was beneficial for removing DOM by O3-BAC, but we found that an excessive O3 concentration caused the formation of new DBPs precursors.


Assuntos
Carvão Vegetal , Água Potável/microbiologia , Ozônio , Purificação da Água/métodos , Desinfecção/métodos , Poluentes Químicos da Água , Qualidade da Água
2.
J Environ Sci (China) ; 87: 331-340, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31791506

RESUMO

This study profiled the bacterial community variations of water from four water treatment systems, including coagulation, sedimentation, sand filtration, ozonation-biological activated carbon filtration (O3-BAC), disinfection, and the tap water after the distribution process in eastern China. The results showed that different water treatment processes affected the bacterial community structure in different ways. The traditional treatment processes, including coagulation, sedimentation and sand filtration, reduced the total bacterial count, while they had little effect on the bacterial community structure in the treated water (before disinfection). Compared to the traditional treatment process, O3-BAC reduced the relative abundance of Sphingomonas in the finished water. In addition, ozonation may play a role in reducing the relative abundance of Mycobacterium. NaClO and ClO2 had different effects on the bacterial community in the finished water. The relative abundance of some bacteria (e.g. Flavobacterium, Phreatobacter and Porphyrobacter) increased in the finished water after ClO2 disinfection. The relative abundance of Mycobacterium and Legionella, which have been widely reported as waterborne opportunistic pathogens, increased after NaClO disinfection. In addition, some microorganisms proliferated and grew in the distribution system, which could lead to turbidity increases in the tap water. Compared to those in the finished water, the relative abundance of Sphingomonas, Hyphomicrobium, Phreatobacter, Rheinheimera, Pseudomonas and Acinetobacter increased in the tap water disinfected with NaClO, while the relative abundance of Mycobacterium increased in the tap water disinfected with ClO2. Overall, this study provided the detailed variation in the bacterial community in the drinking water system.


Assuntos
Água Potável/microbiologia , Abastecimento de Água/estatística & dados numéricos , China , Desinfecção , Monitoramento Ambiental , Purificação da Água/métodos
3.
J Water Health ; 17(6): 944-956, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31850901

RESUMO

The incidence of infectious waterborne disease in Canada continues to be a public health issue and can be associated with the source of drinking water. Millions of Canadians relying on unregulated private well water are at increased risk of disease. This study examined relationships between well and owner characteristics and the frequency of microbial testing of private wells in two southern-Ontario counties. Using multi-level logistic regression models, testing frequency (i.e., at least once per year vs. less) was modeled, as both self-reported and laboratory-validated, for associations with owner and well characteristics. For the self-reported outcome, a previous adverse test result significantly increased the odds of being classified as a frequent tester, and owners with a well-head more than 16 inches (40.6 cm) above the ground were at significantly higher odds of being classified as frequent testers compared to those with well-heads less than 16 inches above the ground and those below ground level. For the model based on the laboratory-validated outcome, the odds of an owner being a frequent tester significantly varied with the length of occupancy and the occurrence of a previous adverse result. The absence of associations between other well characteristics and testing frequency suggests that well safety education could benefit these communities.


Assuntos
Água Potável/microbiologia , Microbiologia da Água/normas , Poços de Água , Água Potável/normas , Humanos , Modelos Logísticos , Ontário , Saúde Pública , Política Pública , Abastecimento de Água/normas
4.
J Water Health ; 17(5): 691-700, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31638021

RESUMO

A survey was conducted in the Czech Republic to determine whether serological responses to the 15/17-kDa and 27-kDa Cryptosporidium antigens had changed since the end of the communist era and if these responses were associated with drinking water sources. Sera from 301 blood donors residing in six areas served by various sources of drinking water were analysed by Western Blot (mini-immunoblots) to measure the IgG response. The intensity of response and percentage of persons with a strong response to the 27-kDa, but not the 15/17-kDa, antigen were higher than found 20 years earlier. A strong response to both the 15/17- and 27-kDa-antigens was higher than reported in other countries, and the probability of persons having a strong response was greater in areas with surface water sources than river-bank infiltration. Few cases of cryptosporidiosis were reported in spite of these high responses to Cryptosporidium antigens. These responses suggest a chronic low-level exposure from several sources that may be affording protection against symptoms and illness. Although strong serological responses were associated with surface water sources, drinking water is not likely to be the most important exposure for Cryptosporidium in the Czech Republic.


Assuntos
Criptosporidiose , Cryptosporidium , Água Potável/microbiologia , Microbiologia da Água , Abastecimento de Água/estatística & dados numéricos , Animais , República Tcheca , Monitoramento Ambiental , Estudos Soroepidemiológicos
5.
Lett Appl Microbiol ; 69(6): 431-437, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31622508

RESUMO

Cronobacter infections of infants are commonly regarded as due to the ingestion of contaminated feed. The aim of this study was to determine the occurrence of Cronobacter, total coliforms and Escherichia coli in different brands of natural mineral waters as sold in 20 l returnable bottles in Rio de Janeiro, Brazil. The quantification of total coliforms and E. coli was performed by Most Probable Number. The detection of Cronobacter was as according to the ISO 22964:2017 and Bacteriological Analytical Manual/FDA. Molecular characterization of Cronobacter isolates was performed by real-time PCR and by multi-locus sequence typing. The antibiotic susceptibility profile was determined and biofilm production was evaluated in polystyrene microplates. Total coliforms and E. coli were detected in 13 (39·4%) and 2 (6·1%) of the 33 lots analysed respectively, and were considered unsatisfactory for human consumption according to Brazilian law. One (3·0%) lot showed contamination by C. malonaticus ST440 (Cronobacter MLST Databases accession no. ID 2646). The strain was susceptible to all (n = 13) antibiotics tested and only formed a weak biofilm. Since there is a high consumption of natural mineral waters by elderly and immunosuppressed persons, epidemiological surveillance agencies should be aware of the risk that these waters may represent for these groups. SIGNIFICANCE AND IMPACT OF THE STUDY: Cronobacter malonaticus ST440 was isolated from 20 l bottled drinking natural mineral waters sold in markets in Rio de Janeiro State, Brazil, and can be a potential threat to human health, particularly for neonates. Thirteen lots (39·4%) were unsatisfactory for human consumption due to the presence of total coliforms and/or Escherichia coli.


Assuntos
Cronobacter/isolamento & purificação , Água Potável/microbiologia , Escherichia coli/isolamento & purificação , Águas Minerais/microbiologia , Idoso , Antibacterianos/farmacologia , Biofilmes , Brasil , Cronobacter/classificação , Cronobacter/efeitos dos fármacos , Infecções por Enterobacteriaceae/prevenção & controle , Escherichia coli/efeitos dos fármacos , Humanos , Recém-Nascido , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Reação em Cadeia da Polimerase em Tempo Real
6.
PLoS Negl Trop Dis ; 13(9): e0007672, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31487283

RESUMO

In the wet-dry tropics of Northern Australia, drinking water in remote communities is mostly sourced from bores accessing groundwater. Many aquifers contain naturally high levels of iron and some are shallow with surface water intrusion in the wet season. Therefore, environmental bacteria such as iron-cycling bacteria promoting biofilm formation in pipes or opportunistic pathogens can occur in these waters. An opportunistic pathogen endemic to northern Australia and Southeast Asia and emerging worldwide is Burkholderia pseudomallei. It causes the frequently fatal disease melioidosis in humans and animals. As we know very little about the microbial composition of drinking water in remote communities, this study aimed to provide a first snapshot of the microbiota and occurrence of opportunistic pathogens in bulk water and biofilms from the source and through the distribution system of three remote water supplies with varying iron levels. Using 16s-rRNA gene sequencing, we found that the geochemistry of the groundwater had a substantial impact on the untreated microbiota. Different iron-cycling bacteria reflected differences in redox status and nutrients. We cultured and sequenced B. pseudomallei from bores with elevated iron and from a multi-species biofilm which also contained iron-oxidizing Gallionella, nitrifying Nitrospira and amoebae. Gallionella are increasingly used in iron-removal filters in water supplies and more research is needed to examine these interactions. Similar to other opportunistic pathogens, B. pseudomallei occurred in water with low organic carbon levels and with low heterotrophic microbial growth. No B. pseudomallei were detected in treated water; however, abundant DNA of another opportunistic pathogen group, non-tuberculous mycobacteria was recovered from treated parts of one supply. Results from this study will inform future studies to ultimately improve management guidelines for water supplies in the wet-dry tropics.


Assuntos
Bactérias/isolamento & purificação , Água Potável/microbiologia , Austrália , Bactérias/classificação , Bactérias/genética , Biodiversidade , Biofilmes , Burkholderia pseudomallei/classificação , Burkholderia pseudomallei/genética , Burkholderia pseudomallei/isolamento & purificação , Burkholderia pseudomallei/fisiologia , Água Potável/química , Gallionellaceae/genética , Gallionellaceae/isolamento & purificação , Gallionellaceae/fisiologia , Ferro/análise , Filogenia , População Rural , Poluição da Água/análise , Abastecimento de Água
7.
J Dairy Sci ; 102(11): 9689-9701, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31447152

RESUMO

Sporeforming bacteria are responsible for the spoilage of several dairy products including fluid milk, cheese, and products manufactured using dried dairy powders as ingredients. Sporeforming bacteria represent a considerable challenge for the dairy industry because they primarily enter the dairy product continuum at the farm, survive processing hurdles, and subsequently grow in finished products. As such, strategies to reduce spoilage due to this group of bacterial contaminants have focused on understanding the effect of farm level factors on the presence of spores in bulk tank raw milk with the goal of reducing spore levels in raw milk, as well as understanding processing contributions to spore levels and outgrowth in finished products. The goal of the current study was to investigate sources of spores in the farm environment and survey farm management practices to identify variables using multimodel inference, a model averaging approach that eliminates the uncertainty of traditional model selection approaches, that affect the presence and levels of spores in bulk tank raw milk. To this end, environmental samples including feed, bedding, manure, soil, water, and so on, and bulk tank raw milk were collected twice from 17 upstate New York dairy farms over a 19-mo period and the presence and levels of various spore types (e.g., psychrotolerant, mesophilic, thermophilic, highly heat resistant thermophilic, specially thermoresistant thermophilic, and anaerobic butyric acid bacteria) were assessed. Manure had the highest level of spores for 4 out of 5 aerobic spore types with mean counts of 5.87, 5.22, 4.35, and 3.68 log cfu/g of mesophilic, thermophilic, highly heat resistant thermophilic, and specially thermoresistant thermophilic spores, respectively. In contrast, bulk tank raw milk had mean spore levels below 1 log cfu/mL across spore types. Multimodel inference was used to determine variables (i.e., management factors, environmental spore levels, and meteorological data from each sampling) that were important for presence or levels of each spore type in bulk tank raw milk. Analyses indicated that variables of importance for more than one spore type included the residual level of spores in milk from individual cows after thorough teat cleaning and forestripping, udder hygiene, clipping or flaming of udders, spore level in feed commodities, spore level in parlor air, how often bedding was topped up or changed, the use of recycled manure bedding, and the use of sawdust bedding. These results improve our understanding of how spores transfer from environmental sources into bulk tank raw milk and provide information that can be used to design intervention trials aimed at reducing spore levels in raw milk.


Assuntos
Indústria de Laticínios , Leite/microbiologia , Esporos Bacterianos/crescimento & desenvolvimento , Ração Animal/microbiologia , Animais , Bovinos , Indústria de Laticínios/métodos , Indústria de Laticínios/normas , Água Potável/microbiologia , Fazendas , Feminino , Abrigo para Animais/normas , Higiene , Estudos Longitudinais , Esterco/microbiologia , New York , Microbiologia do Solo
8.
Ethiop J Health Sci ; 29(3): 321-332, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31447500

RESUMO

Background: Multi-drug Resistant (MDR) bacteria could lead to treatment failure of infectious diseases and could be transferred by non-potable water. Few studies have investigated occurrence of Antibiotic Resistance Genes (ARGs) among bacteria including Aminoglycoside Modifying Genes (AMGs) from Drinking Water Distribution Systems (DWDS) in Nigeria. Here, we aimed at characterization of AMGs from DWDS from selected states in southwestern Nigeria. Methods: One hundred and eighty one (181) MDR bacteria that had been previously characterized using 16S rDNA and showed resistance to at least one aminoglycoside antibiotic were selected from treated and untreated six water distribution systems in southwestern Nigeria. MDR bacteria were PCR genotyped for three AMGs:aph (3″)c, ant (3″)b and aph(6)-1dd. Results: Out of 181 MDR bacteria genotyped, 69(38.12%) tested positive for at least one of the genotyped AMGs. Highest (50, 27.62%) detected gene was ant (3″)c followed by aph (3″)c(33, 18.23%). Combination of aph(3″)c and ant (3″)b in a single bacteria was observed as the highest (14, 7.73%) among the detected gene combination. Alcaligenes sp showed the highest (10/20) occurrence of ant (3″)b while aph(3″)c was the highest detected among Proteus sp (11/22). Other bacteria that showed the presence of AMGs include: Acinetobacter, Aeromonas, Bordetella, Brevundimonas, Chromobacterium, Klebsiella, Leucobacter, Morganella, Pantoae, Proteus, Providencia, Psychrobacter and Serratia. Conclusions: High occurrence of ant (3″)c and aph (3″)c among these bacteria call for urgent attention among public health workers, because these genes can be easily disseminated to consumers of these water samples if present on mobile genetic elements like plasmids, integrons and transposons.


Assuntos
Aminoglicosídeos/farmacologia , Antibacterianos/farmacologia , Água Potável/microbiologia , Farmacorresistência Bacteriana/genética , Microbiologia da Água , Bactérias/efeitos dos fármacos , Bactérias/genética , Farmacorresistência Bacteriana Múltipla/genética , Técnicas de Genotipagem , Nigéria
9.
Food Microbiol ; 84: 103257, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31421763

RESUMO

The viability of murine norovirus (MNV-1), bovine rotavirus (boRV), and hepatitis A virus (HAV) was evaluated at 21 °C, 4 °C, and -20 °C on stainless steel surfaces, in bottled water, and on blueberries for up to 21 days. After 14 days of incubation at 21 °C on stainless steel, a viability loss >4 log for MNV-1, >8 log for boRV, and >1 log for HAV was observed. Losses were observed for MNV-1 (>1 log) and HAV (>2 log) incubated in water at 21 °C for 21 days. No significant loss was detected for MNV-1 and HAV at 4 °C and -20 °C and for boRV at 21 °C, 4 °C, and -20 °C. On blueberries incubated at 4 °C and -20 °C, they all maintained their infectivity. After 7 days at 21 °C, a loss >2 log, a loss of 3 log, and no loss were observed for boRV, MNV-1, and HAV, respectively. After RNase pretreatment, the detection of extracted RNA from infectious and noninfectious samples suggested the protection of RNA inside the capsid. Even though they all are enteric viruses, their persistence varied with temperature and the nature of the commodity. It is therefore important to use more than one viral surrogate, during inactivation treatments or implementation of control measures.


Assuntos
Mirtilos Azuis (Planta)/virologia , Água Potável/microbiologia , Vírus da Hepatite A/isolamento & purificação , Norovirus/isolamento & purificação , Rotavirus/isolamento & purificação , Aço Inoxidável/análise , Inativação de Vírus , Animais , Bovinos , Linhagem Celular , Desinfecção , Contaminação de Alimentos/análise , Vírus da Hepatite A/genética , Camundongos , Norovirus/genética , RNA Viral , Rotavirus/genética , Temperatura Ambiente
10.
Environ Pollut ; 254(Pt B): 113037, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31454567

RESUMO

Angola is one of the countries with a high rate of waterborne diseases, due to the scarcity and poor quality of water for human consumption. The watercourses are receptors of many effluents, mainly domestic sewage, due to a precarious or inexistent sanitation system and a small number of wastewater treatment plants. Therefore, this study aims: (i) to evaluate the water quality (physicochemical and microbiological parameters) of three Angolan rivers (Kwanza, Bengo and Dande) in locations where water is used as drinking water or abstracted for human consumption; (ii) to develop a new water quality index able to quantitatively express the water quality in those sites; and (iii) to assess the spatial distribution of water pollution through principal component analysis (PCA). Water quality assessment was performed by conducting four field surveys (campaigns I to IV); the first two campaigns took place in the dry season, while the last two ones took place in the rainy season. In the first two campaigns, the water quality was suitable to be treated for the production of drinking water, while in the last two campaigns, the water was unsuitable for that purpose (high levels of faecal coliforms were detected). The water quality index allowed to classify the water as generally excellent (campaigns I and II) and poor (campaigns III and IV). The rudimentary disinfection usually performed by individual water suppliers may improve the water quality, but it was not enough to achieve the parametric values required for human consumption in the rainy season (campaigns III and IV) except for Bengo sites. PCA identified sampling sites with the same water quality patterns, grouping into four groups (Kwanza sites) and two groups (Dande and Bengo sites). Therefore, the results of this study may support decision-makers as regards water supply management in the river stretches under study. The new developed Water Quality Index can support decision-makers in terms of water supply management, especially in countries with a high rate of waterborne diseases (e.g. Angola).


Assuntos
Água Potável/microbiologia , Monitoramento Ambiental/métodos , Poluentes Químicos da Água/análise , Angola , Água Potável/química , Fezes/química , Humanos , Chuva , Rios/química , Rios/microbiologia , Saneamento , Estações do Ano , Esgotos/análise , Águas Residuárias/análise , Água/análise , Microbiologia da Água , Poluição da Água/análise , Qualidade da Água , Doenças Transmitidas pela Água
11.
Sci Total Environ ; 686: 1238-1250, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31412520

RESUMO

In densely populated urban areas of many low-income countries, water scarcity, poor water quality, and inadequate wastewater management present complex challenges to ensuring health and wellbeing. This study was conducted in an impoverished peri-urban community in Dar es Salaam, Tanzania that experiences water scarcity and relies on domestic wells for drinking water. The objective of this study was to identify the sources of domestic well water contamination and assess the relationship and association of water contamination with three variables 1) the proximity of the well to a sanitation system, 2) well age, and 3) well depth. Out of the 71 wells tested, samples from >80% of wells contained Escherichia coli (E. coli) and 58% had nitrate levels above WHO guidelines. The average concentration of total dissolved solids (TDS) was 882 mg/L, which exceeded the WHO guideline of 600 mg/L. Bivariate correlation analysis showed a strong correlation between water contamination and proximity of the well to a sanitation system along with well depth. Univariate regression analysis confirmed the association of contaminants with distance of a well from a sanitation system and well depth (p < 0.05) but age of the well did not show any significant influence on water quality. Our findings indicate significant contamination of wells from nearby septic tanks and pit latrines. New regulatory mandates for the distance of domestic wells from sanitation systems are essential to prevent groundwater contamination and to protect human health.


Assuntos
Água Potável/análise , Água Potável/microbiologia , Escherichia coli/isolamento & purificação , Poluentes Químicos da Água/análise , Qualidade da Água , Poços de Água , Cidades , Nitratos/análise , Tanzânia , Abastecimento de Água
12.
Environ Sci Pollut Res Int ; 26(28): 29052-29064, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31392612

RESUMO

The quality assessment of water, supplied to the end user, is an essential part to assess the physical, chemical, and biological status of water, which impacts on human health. For the quality assessment of drinking water treatment plants and distribution systems of Hyderabad City and Mehran University of Engineering and Technology, Jamshoro, Pakistan, 13 surface drinking water samples were collected from three treatment plants, two of Hyderabad City, including WASA treatment plant and its distribution system (n = 5), Hala Nakka treatment plant and its distribution system (n = 6), and Mehran University Employees Cooperative Housing Society (MUECHS) treatment plant and its distribution system (n = 2). Physicochemical parameters of all drinking water samples were in the range compared to EPA and WHO guidelines, except in L-12 sample. Notably, no free-chlorine was detected in all samples. In metagenomics analysis, targeting V3-V4 hypervariable region of 16S rRNA gene, in QIIME2 environment, high bacterial prevalence was observed in all samples. On average, 348 OTUs were observed per sample. Among all samples, treated water sample from the Hala Nakka Treatment Plant (HNTR) was the most diverse sample in bacterial composition (Shannon 7.51 and Simpsons reciprocal indices 0.98). Overall, Proteobacteria, Bacteroidetes, Cyanobacteria, Verrucomicrobia, and Actinobacteria were the five most abundant phyla (relative abundances of 43.6, 37.9, 8.5, 2.5, and 2.4 percent, respectively). Notably, Cyanobacteria are well-known toxin producers which effect the human, and animal health. At genus level, Flavobacterium (4.86%) and Aquirestis (3.77%) were the most abundant genera. Functional predictions, based on 16S rRNA gene by PICRUSt, predicted 6909 KEGG orthologies, relating to 245 KEGG pathways. Among the predicted pathways of KEGG orthologies, pathways to human infections were also found. In conclusion, this study gave a deep insight into bacterial contamination in drinking water samples of Hyderabad City and MUECHS treatment plants and water quality status in Hyderabad and Mehran University of Engineering and Technology.


Assuntos
Água Potável/microbiologia , Monitoramento Ambiental , Metagenoma , Purificação da Água , Actinobacteria/genética , Bacteroidetes/genética , Cloro , Cidades , Cianobactérias/classificação , Habitação , Humanos , Metagenômica , Paquistão , Proteobactérias/genética , RNA Ribossômico 16S/genética , Universidades , Qualidade da Água
14.
Int J Food Microbiol ; 306: 108260, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31302488

RESUMO

The aim of this study was to determine the bacteriological quality of bottled water samples obtained from small purification plants located in Mexico City and to identify potentially pathogenic nontuberculous mycobacteria (NTM) species found in these samples. All 111 samples analyzed were positive for aerobic mesophilic bacteria (AMB) and 46 (41.4%) did not comply with Mexico's Official Guidelines. Sixty-nine (62.1%) and 23 (20.7%) water samples were positive for total coliforms (TC) and fecal coliforms (FC), respectively. A total of 81 (72.9%) of the water samples exceeded the maximum allowed limit stipulated in the guideline. Thirty-three (29.7%) of the purified water samples were positive for NTM, being recovered a total of 40 isolates. These NTM isolates were identified using three molecular markers (hsp65, rrs and rpoB genes) which corresponded to the fast-growing mycobacteria M. chelonae (n = 12), M. porcinum (n = 8), M. senegalense (n = 5), M. abscessus (n = 4), M. septicum (n = 4), M. wolinskyi (n = 3), M. mucogenicum (n = 2), M. fortuitum (n = 1) and M. sp. (n = 1). In seven purified water samples, two different NTM species were isolated simultaneously. Overall, these results showed that most of the purified bottled water samples analyzed in this study had unsatisfactory microbiological quality and some harbored NTM associated with illness. Our data could hasten health authorities to intensify efforts in the routine monitoring of activities in the purified bottled water industry in order to supply safe and healthy water to the public.


Assuntos
Água Potável/microbiologia , Enterobacteriaceae/isolamento & purificação , Micobactérias não Tuberculosas/isolamento & purificação , Purificação da Água , Qualidade da Água , Enterobacteriaceae/classificação , Enterobacteriaceae/genética , Humanos , Incidência , México , Micobactérias não Tuberculosas/classificação , Micobactérias não Tuberculosas/genética
15.
J Water Health ; 17(4): 517-531, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31313991

RESUMO

Insufficient potable water resources and poorly treated drinking water quality are the world's number one cause for preventable morbidity and mortality from water-related pathogenic microorganisms. Pathogenic microorganisms, including mycotoxigenic fungi, have been identified in treated drinking water. This paper presents a review of mycotoxigenic fungi as a health risk to the public as these fungi are responsible for allergies, cancers and opportunistic infections mainly to immunocompromised patients. The exacerbating factors contributing to fungal presence in water distribution systems, factors that lead to fungi being resistant to water treatment and treated drinking water quality legislations are also discussed. This paper provides a review on the prevalence of mycotoxigenic fungi and their implications to public health in treated drinking water, and the need for inclusion in treated drinking water quality regulations.


Assuntos
Água Potável/microbiologia , Poluição da Água , Fungos , Humanos , Prevalência , Saúde Pública , Qualidade da Água
16.
J Water Health ; 17(4): 633-646, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31314000

RESUMO

Clean water provision remains a serious problem in low- and middle-income countries. In 2017, about 30% of the world population relied on unimproved water sources located outside of the dwellings. Often women and children are occupied in fetching water. This situation increases the prevalence of water-related diseases such as diarrhoea and reduces children's study time. School attendance may decrease due to the combined effects of diarrhoea and time spent on fetching water. We investigate the effects on school absenteeism and primary school enrolment in Indonesia, using a panel data set for 295 districts over the period 1994-2014. Districts with higher diarrhoea prevalence are found to have lower school enrolment (B: -0.202, sig p < 0.01) and higher school absenteeism (B: 2.334, sig p < 0.001). Districts where more households have access to private water facilities have higher school enrolment (B: 0.025, sig p < 0.01) and lower school absenteeism (B: -0.027, sig p < 0.01). More use of piped and bottled water in a district is associated with a lower diarrhoea prevalence (B: -0.004, sig p < 0.05). Policy-makers should take the benefits of improved water supply into account when making cost-benefit analyses regarding investments in water infrastructure.


Assuntos
Absenteísmo , Água Potável/microbiologia , Criança , Feminino , Humanos , Indonésia , Instituições Acadêmicas , Abastecimento de Água
17.
Sci Total Environ ; 689: 725-733, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31280154

RESUMO

Small scale ultrafiltration (UF) systems have been increasingly used in rural areas for drinking water supply, but their effectiveness in guarantying microbiological water safety at household level has rarely been assessed. Therefore, this study surveyed six representative villages where UF was utilized for full-scale drinking water supply for at least four years. At each village, the influent and the effluent from every stages of the treatment, as well as household tap water, were sampled and analyzed for microbiological indicating parameters, including total coliform count, Escherichia coli count, and heterotrophic plate count. The results were further assessed against current drinking water quality guidelines and standards. It was found that: (1) the qualification rate of household tap water samples varied substantially in the studied villages (0-75%), mainly due to the lack of post-disinfection and the occurrence of fecal contamination during water distribution; (2) UF appeared to be effective in controlling microbial contamination for small-scale systems with high-quality source water, while for systems using inferior source water, fecal contamination during water distribution necessitated continuous post-disinfection; and, (3) existing monitoring of membrane operational parameters cannot ensure microbial quality of treated water, and therefore, routine monitoring of microbial indicators in household water is recommended.


Assuntos
Água Potável/microbiologia , Enterobacteriaceae/isolamento & purificação , Ultrafiltração , Qualidade da Água , China , Escherichia coli/isolamento & purificação , Abastecimento de Água
18.
Biosens Bioelectron ; 142: 111508, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31325675

RESUMO

Incorporation of new readout methods with established analytical devices allows methodological innovations in analytical sciences. Herein, we present a new sensing platform by combining an ultrasensitive element analyzer, namely the laser-induced breakdown spectroscopy (LIBS) and a lateral flow strip (LFS). AgxAuy bimetallic nanoparticles (AgxAuyBNPs) are selected as the labels to deliver the optimal quantitative performance by analyzing the Ag (I) signal from the test (T) line of LFS. For prototypical application in pathogen detection, the LIBS-LFS sensor can achieve a detection limit of 1.6 cfu mL-1 of Staphylococcus aureus (S. aureus) within 10 min, which is superior to conventional methods. Importantly, the signals of AgxAuyBNPs for visual and LIBS analysis are stable and still readable after the detection is finished and the test strip is stored for up to 13 days, suggesting a potential for long-term data preservation. This combination of LIBS with LFS provides a new concept toward integrated nano/analytical devices that can benefit various application scenarios.


Assuntos
Técnicas Biossensoriais/instrumentação , Nanopartículas Metálicas/química , Fitas Reagentes/análise , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/isolamento & purificação , Animais , Técnicas Biossensoriais/economia , Água Potável/microbiologia , Desenho de Equipamento , Análise de Alimentos/economia , Análise de Alimentos/instrumentação , Microbiologia de Alimentos , Ouro/química , Humanos , Lasers , Limite de Detecção , Leite/microbiologia , Fitas Reagentes/economia , Prata/química , Análise Espectral/economia , Análise Espectral/instrumentação , Infecções Estafilocócicas/diagnóstico
19.
Chemosphere ; 235: 327-335, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31265978

RESUMO

The presence of pharmaceuticals in water sources, including in drinking water (DW), is increasingly being recognized as an emerging and global concern for the environment and public health. Based on the principles of the "One Health" initiative, the present work aims to understand the effects of clofibric acid (CA), a lipid regulator, on the behavior of a selected bacterium isolated from drinking water (DW). Biofilms of the opportunistic pathogen Stenotrophomonas maltophilia were exposed to CA for 12 weeks at 170 and 17000 ng/L. The effects of CA were evaluated on planktonic S. maltophilia susceptibility to chlorine and antibiotics (amoxicillin, ciprofloxacin, erythromycin, kanamycin, levofloxacin, oxacillin, spectinomycin, tetracycline and trimethoprim-sulfamethoxazole), biofilm formation, motility, siderophores production and on the adhesion and internalization of the human colon adenocarcinoma cell line (HT-29). It was found that CA did not affect planktonic S. maltophilia tolerance to chlorine exposure. Additionally, no effects were observed on biofilm formation, motility and siderophores production. However, biofilms formed after CA exposure were more tolerant to chlorine disinfection and lower CFU reductions were obtained. Of additional concern was the effect of CA exposure on S. maltophilia increased tolerance to erythromycin. CA exposure also slightly reduced S. maltophilia ability to invade HT-29 cells. In conclusion, this work reinforces the importance of studying the effects of non-antibiotic contaminants on the behavior of environmental microorganisms, particularly their role as drivers affecting resistance evolution and selection.


Assuntos
Biofilmes/efeitos dos fármacos , Ciprofloxacino/farmacologia , Ácido Clofíbrico/farmacologia , Stenotrophomonas maltophilia/efeitos dos fármacos , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Água Potável/microbiologia , Tolerância a Medicamentos , Células HT29 , Humanos , Stenotrophomonas maltophilia/patogenicidade , Stenotrophomonas maltophilia/ultraestrutura , Virulência
20.
Anal Chim Acta ; 1078: 151-160, 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31358213

RESUMO

Herein, we report a new signal amplification scheme for quantitative biochemical analysis based on gold nanoparticle (GNPs) catalyzed polymerization of transparent silane solution to milky white and turbid siloxane. Using immunoassay as a proof of concept, GNP labeled immunoprobe was used to bind captured antigen and catalyse the polymerization reaction allowing sensitive biochemical investigation. The polymerization reaction was optimized for standard 96 well polystyrene microtiter plates and we discovered that sodium lactate acts as an enhancer in the polymerization reaction as it reduces detection time to merely 30 min. The sensing strategy was applied to detection and quantification of Salmonella Typhimurium in water and egg samples and the platform showed excellent visibly quantifiable analytical response up to 100 cells mL-1. Furthermore, clinical utility and potential of the method was validated by detecting Vi capsular polysaccharide (Vi antigen) responsible for typhoidal Salmonellosis in human serum in sandwich format with a detection limit of 1 ng mL-1. The method serves as the first report towards nanoparticle triggered polymerization for development of rapid and low cost quantitative biochemical assay.


Assuntos
Ouro/química , Imunoensaio/métodos , Nanopartículas Metálicas/química , Polissacarídeos Bacterianos/sangue , Salmonella typhimurium/isolamento & purificação , Siloxanas/síntese química , Animais , Anticorpos/imunologia , Galinhas , Água Potável/microbiologia , Ovos/microbiologia , Contaminação de Alimentos/análise , Humanos , Limite de Detecção , Tamanho da Partícula , Polimerização , Polissacarídeos Bacterianos/imunologia , Estudo de Prova de Conceito , Salmonella typhimurium/imunologia , Silanos/química , Temperatura Ambiente
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA