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1.
Ecotoxicol Environ Saf ; 202: 110937, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800220

RESUMO

Cyanobacteria have been considered a major global threat because of their widespread ability to proliferate and contaminate inland and marine waters with toxic metabolites. For this reason, to avoid risks to humans and environmental health, regulatory legislation and guidelines have been established based on extensive toxicological data. However, most of what is known in this field come from works on microcystin (MC) variants, which effects were almost exclusively tested in metazoan models. In this work, we used acute end-point toxicological assays and high-resolution hybrid quadrupole time-of-flight mass spectrometer coupled with electrospray ionization source (ESI-Q-TOF-MS) analyses to evaluate the deleterious impact of aqueous extracts prepared from cultures of cyanobacteria and environmental bloom biomasses over a non-metazoan model organism, the cosmopolitan fresh/brackish water unicellular microeukaryote, Paramecium caudatum (Ciliophora). Our data suggest that all extracts produced time-dependent effects on P. caudatum survival, irrespective of their metabolite profile; and that this ciliate is more sensitive to extracts containing microginins than to extracts with only MCs, stressing that more toxicological investigations should be performed on the environmental impact of neglected cyanotoxins. Further, our data provide evidence that P. caudatum may be more sensitive to cyanotoxins than vertebrates, indicating that guidelines values, set on metazoans are likely to be inaccurate to protect organisms from basal food web positions. Thus, we highly recommend the widespread use of microeukaryotes, such as ciliates in environmental risk assessment frameworks for the establishment of more reliable cyanotoxin monitoring guideline values.


Assuntos
Cianobactérias/crescimento & desenvolvimento , Paramecium caudatum/fisiologia , Animais , Biomassa , Cilióforos , Cadeia Alimentar , Água Doce/microbiologia , Humanos , Microcistinas
2.
PLoS Negl Trop Dis ; 14(7): e0008437, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32701971

RESUMO

BACKGROUND: Leptospirosis is one of the most significant zoonoses across the world not only because of its impact on human and animal health but also because of the economic and social impact on agrarian communities. Leptospirosis is endemic in Sri Lanka where paddy farming activities, the use of draught animals in agriculture, and peridomestic animals in urban and rural areas play important roles in maintaining the infection cycle of pathogenic Leptospira, especially concerning animals as a potential reservoir. In this study, an environmental DNA (eDNA) metabarcoding methodology was applied in two different agro-ecological regions of Sri Lanka to understand the eco-epidemiology of leptospirosis. METHODOLOGY/PRINCIPAL FINDINGS: Irrigation water samples were collected in Kandy District (wet zone mid-country region 2) and Girandurukotte, Badulla District (intermediate zone low-country region 2); and analysed for the presence of pathogenic Leptospira, associated microbiome and the potential reservoir animals. Briefly, we generated PCR products for high-throughput sequencing of multiple amplicons through next-generation sequencing. The analysis of eDNA showed different environmental microbiomes in both regions and a higher diversity of Leptospira species circulating in Kandy than in Girandurukotte. Moreover, the number of sequence reads of pathogenic Leptospira species associated with clinical cases such as L. interrogans was higher in Kandy than in Girandurukotte. Kandy also showed more animal species associated with pathogenic bacterial species than Girandurukotte. Finally, several pathogenic bacterial species including Arcobacter cryaerophilus, responsible for abortion in animals, was shown to be associated with pathogenic Leptospira. CONCLUSIONS/SIGNIFICANCE: Leptospirosis has been considered to be endemic in wet regions, consistently, leptospiral sequences were detected strongly in Kandy. The great Leptospira species diversity in Kandy observed in this study shows that the etiological agents of leptospirosis in Sri Lanka might be underestimated. Furthermore, our eDNA metabarcoding can be used to discriminate bacterial and animal species diversity in different regions and to explore environmental microbiomes to identify other associated bacterial pathogens in the environment.


Assuntos
Água Doce/microbiologia , Leptospira/isolamento & purificação , Leptospirose/epidemiologia , Leptospirose/microbiologia , Irrigação Agrícola , Animais , DNA Bacteriano/genética , DNA Ambiental/genética , Humanos , Leptospira/classificação , Leptospira/genética , Filogenia , Sri Lanka/epidemiologia , Zoonoses/microbiologia , Zoonoses/transmissão
3.
Arch Virol ; 165(10): 2393-2396, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32719957

RESUMO

Pseudomonas phages PaGz-1 and PaZq-1, two new phages infecting Pseudomonas aeruginosa, were isolated from fresh water in Guangdong province, China. The genomes of these two phages consist of 93,975 bp and 94,315 bp and contain 175 and 172 open reading frames (ORFs), respectively. The genome sequences of PaGz-1 and PaZq-1 share 95.8% identity with a query coverage of 94%, suggesting that these two phages belong to two different species. Based on results of nucleotide sequence alignment, gene annotation, and phylogenetic analysis, we propose PaGz-1 and PaZq-1 as representative isolates of two species in the genus Pakpunavirus within the family Myoviridae.


Assuntos
Genoma Viral , Myoviridae/genética , Fases de Leitura Aberta , Filogenia , Fagos de Pseudomonas/genética , Pseudomonas aeruginosa/virologia , Sequência de Bases , China , Água Doce/microbiologia , Ontologia Genética , Anotação de Sequência Molecular , Myoviridae/classificação , Myoviridae/isolamento & purificação , Fagos de Pseudomonas/classificação , Fagos de Pseudomonas/isolamento & purificação , Pseudomonas aeruginosa/isolamento & purificação , Alinhamento de Sequência , Sequenciamento Completo do Genoma
4.
Int J Syst Evol Microbiol ; 70(8): 4602-4609, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32658638

RESUMO

Two bacterial strains, 50A-KIRBAT and 50C-KIRBAT, were isolated from the same freshwater creek located near Salzburg, Austria. They showed 16S rRNA gene sequence similarities to Aquirufa nivalisilvae of 100 and 99.9 %, respectively. A genome-based phylogenetic reconstruction with amino acid sequences of 119 single-copy genes suggested that the new strains represent two new species of the genus Aquirufa. Pairwise calculated whole-genome average nucleotide identity (gANI) values ranging from 85.4 to 87.5 % confirmed this conclusion. Phenotypic, chemotaxonomic and genomic traits were investigated. Like strains of other Aquirufa species, 50A-KIRBAT and 50C-KIRBAT grew aerobically and chemoorganotrophically, were rod-shaped, red-pigmented and motile, most likely by gliding. They could be distinguished by slight differences in the chemotaxonomic features. We propose to establish for strain 50A-KIRBAT (=CIP 111735T=LMG 31080T) as type strain the name Aquirufa ecclesiirivi and for strain 50C-KIRBAT (=CIP 111736T=LMG 31501T) as type strain the name Aquirufa beregesia. Furthermore, the relationship between the type strains of Aquirufa nivalisilvae (59G-WUEMPELT) and Allopseudarcicella aquatilis (HME7025T) was investigated. Results of polyphasic analyses, especially a gANI value of 97.6 %, as well as the genome-based phylogenetic reconstruction, suggested that Allopseudarcicella aquatilis is a heterotypic synonym of Aquirufa nivalisilvae. According to rule 24b of the International Code of Nomenclature of Prokaryotes we propose to classify strain HME7025 as Aquirufa nivalisilvae and provide an emended description for the latter.


Assuntos
Cytophagaceae/classificação , Água Doce/microbiologia , Filogenia , Áustria , Técnicas de Tipagem Bacteriana , Composição de Bases , Cytophagaceae/isolamento & purificação , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
5.
Int J Syst Evol Microbiol ; 70(8): 4653-4660, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32672530

RESUMO

A novel non-phototrophic member of the genus Rhodoferax was obtained from freshwater. The purpose of this study was to analyse the genome of a nonphototrophic strain and propose a new species based on its phylogenetic, genomic, physiological and chemotaxonomic characteristics. The results of phylogenetic analysis based on 16S rRNA gene sequences supports that the strain, designated Gr-4T, has a close relationship to the genus Rhodoferax. The observed average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain Gr-4T and its closest related strains were 72.3-74.6 % and 21.9-22.8 %, respectively. These values were much lower than the species separation thresholds for ANI or dDDH of 95-96 and 70 %, respectively, and in fact fall in the intergeneric range. Strain Gr-4T does not contain RuBisCO-related genes, but does contain GS/GOGAT pathway-related genes enabling nitrate ammonification. A polyphasic study and a genomic-level investigation were done to establish the taxonomic status of strain Gr-4T. Based on the phylogenetic, genomic and physiological differences, it is proposed that the isolate be classified to the genus Rhodoferax as Rhodoferax aquaticus sp. nov. with isolate Gr-4T (=KCTC 32394T=JCM 19166T) as the type strain.


Assuntos
Comamonadaceae/classificação , Água Doce/microbiologia , Filogenia , Técnicas de Tipagem Bacteriana , Composição de Bases , Comamonadaceae/isolamento & purificação , DNA Bacteriano/genética , Ácidos Graxos/química , Genes Bacterianos , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , República da Coreia , Análise de Sequência de DNA
6.
PLoS One ; 15(7): e0235441, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32614866

RESUMO

Although seagrasses are economically and ecologically critical species, little is known about their blade surface microbial communities and how these communities relate to the plant host. To determine microbial community composition and diversity on seagrass blade surfaces and in the surrounding seawater,16S rRNA gene sequencing (iTag) was used for samples collected at five sites along a gradient of freshwater input in the northern Gulf of Mexico on three separate sampling dates. Additionally, seagrass surveys were performed and environmental parameters were measured to characterize host characteristics and the abiotic conditions at each site. Results showed that Thalassia testudinum (turtle grass) blades hosted unique microbial communities that were distinct in composition and diversity from the water column. Environmental conditions, including water depth, salinity, and temperature, influenced community structure as blade surface microbial communities varied among sites and sampling dates in correlation with changes in environmental parameters. Microbial community composition also correlated with seagrass host characteristics, including growth rates and blade nutrient composition. There is some evidence for a core community for T. testudinum as 21 microorganisms from five phyla (Cyanobacteria, Proteobacteria, Planctomycetes, Chloroflexi, and Bacteroidetes) were present in all blade surface samples. This study provides new insights and understanding of the processes that influence the structure of marine phyllosphere communities, how these microbial communities relate to their host, and their role as a part of the seagrass holobiont, which is an important contribution given the current decline of seagrass coverage worldwide.


Assuntos
Bactérias/classificação , Água Doce/microbiologia , Hydrocharitaceae/microbiologia , Microbiota , Folhas de Planta/microbiologia , Água do Mar/microbiologia , Bactérias/genética , Golfo do México , Interações entre Hospedeiro e Microrganismos , Hydrocharitaceae/fisiologia , Filogenia , Folhas de Planta/fisiologia , RNA Ribossômico 16S/genética , Salinidade , Áreas Alagadas
7.
Artigo em Inglês | MEDLINE | ID: mdl-32640873

RESUMO

Each year, large amounts of plastic waste are generated and must be appropriately disposed. In this work, we studied the feasibility of using plastics as wetland substrates as an alternative plastic waste disposal method and the ability of the constructed wetland to remove pharmaceuticals and personal care products (PPCPs) from contaminated water. Wetland microcosms were constructed using polycarbonate, polyethylene terephthalate, quartz sand, and ceramsite substrates. Lake water spiked with methyl-paraben, ibuprofen, triclosan, 4-methybenzylidene camphor, carbamazepine, and 17α-ethinyl estradiol at 5 µg L-1 was continuously loaded to the microcosms with a hydraulic retention time of approximately 11 days. After 70 days, methyl-paraben, triclosan, and 4-methybenzylidene camphor were effectively removed regardless of the substrate. However, ibuprofen, carbamazepine, and 17α-ethinyl estradiol were partially removed, and the removal efficiency was the best in wetlands with ceramsite substrate. Carbamazepine was the most persistent among the tested compounds. Phospholipid fatty acid (PLFA) analysis revealed that ceramsite supported the highest microbial biomass per bulk volume of substrate followed by quartz sand, polycarbonate, and polyethylene terephthalate, which might be related to the PPCP removal potential of the wetland microcosms.


Assuntos
Cosméticos/análise , Preparações Farmacêuticas/análise , Plásticos/química , Resíduos Sólidos , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Áreas Alagadas , China , Estudos de Viabilidade , Água Doce/microbiologia
8.
Int J Syst Evol Microbiol ; 70(6): 3878-3887, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32511086

RESUMO

A polyphasic taxonomic study was carried out on strains CHu50b-3-2T and CHu40b-3-1 isolated from a 67 cm-long sediment core collected from the Daechung Reservoir at a water depth of 17 m, Daejeon, Republic of Korea. The cells of the strains were Gram-stain-negative, non-spore-forming, non-motile and rod-shaped. Comparative 16S rRNA gene sequence studies showed a clear affiliation of two strains with γ-Proteobacteria, which showed the highest pairwise sequence similarities to Lysobacter hankyongensis KTce-2T (96.5 %), Lysobacter pocheonensis Gsoil193T (96.3 %), Lysobacter ginsengisoli Gsoil 357T (96.1 %), Lysobacter solanacearum T20R-70T (96.1 %), Lysobacter brunescens KCTC 12130T (95.4 %) and Lysobacter capsici YC5194T (95.3 %). The phylogenetic analysis based on 16S rRNA gene sequences showed that the strains formed a clear phylogenetic lineage with the genus Lysobacter. The major fatty acids were identified as summed feature 9 (iso-C17 : 1 ω9c and/or C18 : 1 10-methyl), iso-C15 : 0, iso-C16 : 0 and iso-C17 : 0. The respiratory quinone was identified as ubiquinone Q-8. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and an unidentified phospholipid. The genomic DNA G+C content was determined to be 66.8 mol% (genome) for strain CHu50b-3-2T and 66.4 mol% (HPLC) for strain CHu40b-3-1. Based on the combined genotypic and phenotypic data, we propose that strains CHu50b-3-2T and CHu40b-3-1 represent a novel species of the genus Lysobacter, for which the name Lysobacter profundi sp. nov. is proposed. The type strain is CHu50b-3-2T (=KCTC 72973T=CCTCC AB 2019129T). Besides Lysobacter panaciterrae Gsoil 068T formed a phylogenetic group together with strain Luteimonas aquatica RIB1-20T (EF626688) that is clearly separated from all other known Lysobacter strains. Based on the phylogenetic relationships together with fatty acid compositions, Lysobacter panaciterrae Gsoil 068T should be reclassified as a member of the genus Luteimonas: Luteimonas aquatica comb. nov. (type strain Gsoil 068T=KCTC 12601T=DSM 17927T).


Assuntos
Água Doce/microbiologia , Sedimentos Geológicos/microbiologia , Lysobacter/classificação , Filogenia , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Lysobacter/isolamento & purificação , Fosfolipídeos/química , RNA Ribossômico 16S/genética , República da Coreia , Ubiquinona/química
9.
Toxicon ; 184: 136-142, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32540220

RESUMO

The first data on the distribution of microcystin genes among natural populations of different species of Microcystis from Russian reservoirs were obtained. It was statistically established that the occurrence of mcy gene-containing colonies of M. aeruginosa, M. viridis, and M. novacekii was significantly higher than that of M. wesenbergii and M. flos-aquae. It has been shown that M. wesenbergii from the water bodies in Russia and Eurasia is not capable of producing microcystins. These results are discussed with respect to various mechanisms that could explain the distribution of microcystin genes among the various Microcystis morphospecies, such as the compensation of microcystin functions by the synthesis of other secondary oligopeptides and the presence of dense mucilaginous envelopes surrounding the colonies of M. wesenbergii. No correlation was found between colony size and the frequency of mcy genes for individual morphospecies M. aeruginosa and M. flos-aquae.


Assuntos
Água Doce/microbiologia , Microcistinas/genética , Genes Bacterianos , Microcystis , Oligopeptídeos , Federação Russa
10.
Protist ; 171(3): 125740, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32544844

RESUMO

We report the discovery of three new species of freshwater metopid ciliates, Pileometopus lynni gen. et sp. nov., Castula flexibilis gen. et sp. nov., and Longitaenia australis gen. et sp. nov. Based on morphologic features and the 18S rRNA gene phylogeny, we transfer two known species of Metopus to the new genus Castula, as C. fusca (Kahl, 1927) comb. nov. and C. setosa (Kahl, 1927) comb. nov. and another known species is herein transferred to the new genus Longitaenia, as L. gibba (Kahl, 1927) comb. nov. Pileometopus is characterized by a turbinate body shape, a dorsal field of densely spaced dikinetids, a bipartite paroral membrane, and long caudal cilia. A distinctive morphologic feature of Castula species is long setae arising over the posterior third of the body (as opposed to a terminal tuft). Longitaenia spp. are characterized by an equatorial cytostome and long perizonal ciliary stripe relative to the cell length. Based on phylogenetic analyses of 18S rRNA gene sequences, we identify and briefly discuss strongly supported clades and intraspecific genetic polymorphism within the order Metopida.


Assuntos
Cilióforos/classificação , Filogenia , Cilióforos/citologia , Cilióforos/isolamento & purificação , Água Doce/microbiologia , Filogeografia , RNA Ribossômico 18S/genética
11.
PLoS Genet ; 16(6): e1008866, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32530914

RESUMO

Escherichia coli is mostly a commensal of birds and mammals, including humans, where it can act as an opportunistic pathogen. It is also found in water and sediments. We investigated the phylogeny, genetic diversification, and habitat-association of 1,294 isolates representative of the phylogenetic diversity of more than 5,000 isolates from the Australian continent. Since many previous studies focused on clinical isolates, we investigated mostly other isolates originating from humans, poultry, wild animals and water. These strains represent the species genetic diversity and reveal widespread associations between phylogroups and isolation sources. The analysis of strains from the same sequence types revealed very rapid change of gene repertoires in the very early stages of divergence, driven by the acquisition of many different types of mobile genetic elements. These elements also lead to rapid variations in genome size, even if few of their genes rise to high frequency in the species. Variations in genome size are associated with phylogroup and isolation sources, but the latter determine the number of MGEs, a marker of recent transfer, suggesting that gene flow reinforces the association of certain genetic backgrounds with specific habitats. After a while, the divergence of gene repertoires becomes linear with phylogenetic distance, presumably reflecting the continuous turnover of mobile element and the occasional acquisition of adaptive genes. Surprisingly, the phylogroups with smallest genomes have the highest rates of gene repertoire diversification and fewer but more diverse mobile genetic elements. This suggests that smaller genomes are associated with higher, not lower, turnover of genetic information. Many of these genomes are from freshwater isolates and have peculiar traits, including a specific capsule, suggesting adaptation to this environment. Altogether, these data contribute to explain why epidemiological clones tend to emerge from specific phylogenetic groups in the presence of pervasive horizontal gene transfer across the species.


Assuntos
Escherichia coli/genética , Evolução Molecular , Transferência Genética Horizontal , Variação Genética , Genoma Bacteriano/genética , Animais , Animais Selvagens/microbiologia , Austrália , Galinhas/microbiologia , Farmacorresistência Bacteriana/genética , Escherichia coli/isolamento & purificação , Escherichia coli/patogenicidade , Fezes/microbiologia , Água Doce/microbiologia , Tamanho do Genoma , Humanos , Doenças Inflamatórias Intestinais/microbiologia , Sequências Repetitivas Dispersas/genética , Mucosa Intestinal/microbiologia , Carne/microbiologia , Anotação de Sequência Molecular , Filogenia , Microbiologia do Solo , Fatores de Virulência/genética , Sequenciamento Completo do Genoma
12.
Arch Microbiol ; 202(9): 2367-2371, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32572518

RESUMO

A novel Bacillus strain, designated SYSU G01002T, was isolated from a sediment sample collected from tepid spring in Tengchong, Yunnan province, south-west PR China. The 16S rRNA gene sequence analysis showed that the strain SYSU G01002T shared the highest sequence identity with the type strain of Bacillus alkalitolerans (97.7%). Strain SYSU G01002T grew at pH 6.0-8.0 (optimum, pH 7.0), at 28-55 °C (optimum, 45 °C) and in the presence of 0-2.5% (w/v) NaCl (optimum in the absence of NaCl). It contained meso-2,6-diaminopimelic acid as the cell-wall diamino acid and MK-7 as isoprenoid quinone. The major cellular fatty acids were iso-C15:0, iso-C17:0 and C16:0. The polar were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and unidentified phospholipid. The genomic DNA G + C content was 38.0 mol %. The digital DNA-DNA hybridization and average nucleotide identity values between SYSU G01002T and closely related members of the genus Bacillus were below the cut-off level recommended for interspecies identity. Based on the above results, strain SYSU G01002T represents a novel species of the genus Bacillus, for which the name Bacillus tepidiphilus sp. nov. is proposed. The type strain, SYSU G01002T (= KCTC 43131T = CGMCC 1.17491T).


Assuntos
Bacillus/classificação , Água Doce/microbiologia , Bacillus/química , Bacillus/genética , Bacillus/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , Ácido Diaminopimélico/análise , Ácidos Graxos/análise , Hibridização de Ácido Nucleico , Fosfolipídeos/análise , Filogenia , RNA Ribossômico 16S/genética , Especificidade da Espécie
13.
PLoS One ; 15(4): e0232289, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32353007

RESUMO

Antibiotic-resistant bacteria represent an emerging global health problem and are frequently detected in riverine environments. Analyzing the occurrence of corresponding antibiotic-resistant genes in rivers is of public interest as it contributes towards understanding the origin and dissemination of these emerging microbial contaminants via surface water. This is critical for devising strategies to mitigate the spread of resistances in the environment. Concentrations of blaCTX-M antibiotic resistance genes were quantified weekly over a 12-month period in Lahn River surface water at two sampling sites using quantitative real-time PCR. Gene abundances were statistically assessed with regard to previously determined concentrations of fecal indicator organisms Escherichia coli, intestinal enterococci and somatic coliphages, as well as influential environmental factors. Similar seasonal patterns and strong positive correlations between fecal indicators and blaCTX-M genes indicated identical sources. Accordingly, linear regression analyses showed that blaCTX-M concentrations could largely be explained by fecal pollution. E. coli provided the best estimates (75% explained variance) at the upstream site, where proportions of blaCTX-M genes in relation to fecal indicator organisms were highest. At this site, rainfall proved to be more influential, hinting at surface runoff as an emission source. The level of agricultural impact increased from downstream to upstream, linking increasing blaCTX-M concentrations after rainfall events to the degree of agricultural land use. Exposure assessment revealed that even participants in non-swimming recreational activities were at risk of incidentally ingesting blaCTX-M genes and thus potentially antibiotic resistant bacteria. Considering that blaCTX-M genes are ubiquitous in Lahn River and participants in bathing and non-bathing water sports are at risk of exposure, results highlight the importance of microbial water quality monitoring with an emphasis on antibiotic resistance not only in designated bathing waters. Moreover, E. coli might serve as a suitable estimate for the presence of respective antibiotic resistant strains.


Assuntos
Proteínas de Bactérias/genética , Resistência Microbiana a Medicamentos/genética , Fezes/microbiologia , Rios/microbiologia , beta-Lactamases/genética , Antibacterianos/uso terapêutico , Colífagos/genética , Monitoramento Ambiental/métodos , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Água Doce/microbiologia , Alemanha , Humanos , Prevalência , Recreação , Estações do Ano , Microbiologia da Água , Qualidade da Água
14.
Lett Appl Microbiol ; 71(1): 3-25, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32304575

RESUMO

Surface water is prone to bacterial contamination as it receives wastes and pollutants from human and animal sources, and contaminated water may expose local populations to health risks. This review provides a brief overview on the prevalence and antimicrobial resistance (AR) phenotypes of Salmonella, Escherichia coli and Enterococcus, found in natural freshwaters. These bacteria are frequently detected in surface waters, sometimes as etiological agents of waterborne infections, and AR strains are not uncommonly identified in both developed and developing countries. Data relating to Salmonella, E. coli and Enterococcus present in environmental water are lacking, and in order to understand their development and dissemination using the One Health approach, understanding the prevalence, distribution and characteristics of the bacteria present in surface water as well as their potential sources is important. Furthermore, AR bacteria in natural watersheds are not well investigated and their impacts on human health and food safety are not well understood. As surface water is a receptacle for AR bacteria from human and animal sources and a vehicle for their dissemination, this is a crucial data gap in understanding AR and minimizing its spread. For this review, Salmonella, E. coli and Enterococcus were chosen to evaluate the presence of primary pathogens and opportunistic pathogens as well as to monitor AR trends in the environmental water. Studies around the world have demonstrated the widespread distribution of pathogenic and AR bacteria in surface waters of both developing and developed countries, confirming the importance of environmental waters as a reservoir for these bacteria and the need for more attention on the environmental bacteria for emerging AR.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana/genética , Enterococcus/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Salmonella/efeitos dos fármacos , Animais , Enterococcus/genética , Enterococcus/isolamento & purificação , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Água Doce/microbiologia , Humanos , Testes de Sensibilidade Microbiana , Fenótipo , Prevalência , Salmonella/genética , Salmonella/isolamento & purificação , Poluição da Água
15.
Ecotoxicol Environ Saf ; 196: 110535, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32224368

RESUMO

Acid rain containing SO42- and NO3- in China has been a public concern for decades. However, a decrease of SO2 has been recorded since the government enacted a series of policies to control its emission. To comprehensively evaluate the consequence of realistic and future acid deposition scenarios, this study explored the effects of mixed acid rain with different molar ratios of SO42- and NO3- (0:1, 1:0, 2:1, 1:1, and 1:2) on stream leaf breakdown through a microcosm experiment. A significant inhibition of leaf breakdown rate was observed when the ratio was 1:2 with reduced microcosm pH, fungal biomass, enzyme activities as well as the frequencies of hub general in the fungal community. In conclusion, the ratio of SO42- and NO3- in acid rain was an important factor that could have a profound impact on leaf breakdown, even on ecosystem structure and functioning of streams.


Assuntos
Chuva Ácida/efeitos adversos , Água Doce/química , Nitratos/toxicidade , Folhas de Planta/metabolismo , Sulfatos/toxicidade , Chuva Ácida/análise , Biodegradação Ambiental/efeitos dos fármacos , Biomassa , China , Ecossistema , Água Doce/microbiologia , Micobioma/efeitos dos fármacos , Nitratos/análise , Sulfatos/análise
16.
PLoS One ; 15(3): e0230006, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32163465

RESUMO

The Caulobacter genus, including the widely-studied model organism Caulobacter crescentus, has been thought to be non-pathogenic and thus proposed as a bioengineering vector for various environmental remediation and medical purposes. However, Caulobacter species have been implicated as the causative agents of several hospital-acquired infections, raising the question of whether these clinical isolates represent an emerging pathogenic species or whether Caulobacters on whole possess previously-unappreciated virulence capability. Given the proposed environmental and medical applications for C. crescentus, understanding the potential pathogenicity of this bacterium is crucial. Consequently, we sequenced a clinical Caulobacter isolate to determine if it has acquired novel virulence determinants. We found that the clinical isolate represents a new species, Caulobacter mirare that, unlike C. crescentus, grows well in standard clinical culture conditions. C. mirare phylogenetically resembles both C. crescentus and the related C. segnis, which was also thought to be non-pathogenic. The similarity to other Caulobacters and lack of obvious pathogenesis markers suggested that C. mirare is not unique amongst Caulobacters and that consequently other Caulobacters may also have the potential to be virulent. We tested this hypothesis by characterizing the ability of Caulobacters to infect the model animal host Galleria mellonella. In this context, two different lab strains of C. crescentus proved to be as pathogenic as C. mirare, while lab strains of E. coli were non-pathogenic. Further characterization showed that Caulobacter pathogenesis in the Galleria model is mediated by lipopolysaccharide (LPS), and that differences in LPS chemical composition across species could explain their differential toxicity. Taken together, our findings suggest that many Caulobacter species can be virulent in specific contexts and highlight the importance of broadening our methods for identifying and characterizing potential pathogens.


Assuntos
Caulobacter/patogenicidade , Mariposas/microbiologia , Animais , Caulobacter/classificação , Caulobacter/genética , Caulobacter/isolamento & purificação , Modelos Animais de Doenças , Água Doce/microbiologia , Genoma Bacteriano , Lipopolissacarídeos/toxicidade , Longevidade/efeitos dos fármacos , Mariposas/fisiologia , Filogenia , Microbiologia do Solo , Virulência
17.
PLoS One ; 15(3): e0230174, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32163471

RESUMO

The environmental DNA (eDNA) method is being increasingly applied in various environments. Although eDNA undergoes rapid degradation in aqueous environments, it has been detected in streams up to 10 km downstream from its source. As environmental bacteria can uptake free DNA, transfer their genetic traits, and amplify, there is a potential risk that they, rather than a target aquatic species, could become a source of measured eDNA. This study examined whether bacteria with incorporated fish DNA could be such a source by investigating the detectability of fish DNA generated by bacteria inhabiting river water and riverbed sediment. We attempted to detect common carp (Cyprinus carpio) eDNA in stream water and sediment samples and the DNA of common carp produced by bacterial colonies (Escherichia coli, total coliform, and heterotrophic bacteria) cultured from the samples. The eDNA was detected in the environmental samples but the carp DNA from the targeted bacteria was rarely detected in both water and riverbed sediment samples. Our results suggest that the risk of bacterium-induced false positive detection for fish eDNA is negligible.


Assuntos
Bactérias/genética , Carpas/microbiologia , DNA/genética , DNA Ambiental/genética , Animais , Ecossistema , Monitoramento Ambiental/métodos , Água Doce/microbiologia , Temperatura
18.
PLoS One ; 15(3): e0230071, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32210450

RESUMO

Microbialites are highly diverse microbial communities that represent modern examples of the oldest life forms, stromatolites (dated >3.7 Ga). Bacalar Lagoon, in Mexico, harbors the largest freshwater microbialite occurrences of the world; yet diverse anthropogenic activities are changing the oligotrophic conditions of the lagoon. The objective of this work was to perform a spatial exploration of the microbialites of Bacalar Lagoon, analyze their prokaryote diversity, following a high throughput sequencing approach of the V4 region of the 16S rDNA, and correlate to the environmental parameters that influence the structure of these communities. The results indicate the presence of microbialites throughout the periphery of the lagoon. The microbiome of the microbialites is composed primarily of Proteobacteria (40-80%), Cyanobacteria (1-11%), Bacteroidetes (7-8%), Chloroflexi (8-14%), Firmicutes (1-23%), Planctomycetes (1-8%), and Verrucomicrobia (1-4%). Phylogenetic distance analyses suggests two distinct groups of microbialites associated with regions in the lagoon that have differences in their environmental parameters, including soluble reactive silicate (in the north), bicarbonates and available forms of nitrogen (ammonium, nitrates and nitrites) (in the south). These microbialite groups had differences in their microbiome composition associated to strong anthropogenic pressure on water quality (agriculture, landfill leachate, lack of water treatment infrastructure and intensive tourism), which were related to a loss of microbial diversity.


Assuntos
Bacteroidetes/classificação , Biodiversidade , Cianobactérias/classificação , Água Doce/microbiologia , Sedimentos Geológicos/microbiologia , Microbiota , Proteobactérias/classificação , Bacteroidetes/genética , Bacteroidetes/crescimento & desenvolvimento , Cianobactérias/genética , Cianobactérias/crescimento & desenvolvimento , Sedimentos Geológicos/análise , Sequenciamento de Nucleotídeos em Larga Escala , México , Nutrientes , Filogenia , Proteobactérias/genética , Proteobactérias/crescimento & desenvolvimento , RNA Ribossômico 16S/genética
19.
PLoS One ; 15(3): e0229365, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32182252

RESUMO

Irrigation water contaminated with Salmonella enterica and Listeria monocytogenes may provide a route of contamination of raw or minimally processed fruits and vegetables. While previous work has surveyed specific and singular types of agricultural irrigation water for bacterial pathogens, few studies have simultaneously surveyed different water sources repeatedly over an extended period of time. This study quantified S. enterica and L. monocytogenes levels (MPN/L) at 6 sites, including river waters: tidal freshwater river (MA04, n = 34), non-tidal freshwater river, (MA05, n = 32), one reclaimed water holding pond (MA06, n = 25), two pond water sites (MA10, n = 35; MA11, n = 34), and one produce wash water site (MA12, n = 10) from September 2016-October 2018. Overall, 50% (84/168) and 31% (53/170) of sampling events recovered S. enterica and L. monocytogenes, respectively. Results showed that river waters supported significantly (p < 0.05) greater levels of S. enterica than pond or reclaimed waters. The non-tidal river water sites (MA05) with the lowest water temperature supported significantly greater level of L. monocytogenes compared to all other sites; L. monocytogenes levels were also lower in winter and spring compared to summer seasons. Filtering 10 L of water through a modified Moore swab (MMS) was 43.5 (Odds ratio, p < 0.001) and 25.5 (p < 0.001) times more likely to recover S. enterica than filtering 1 L and 0.1 L, respectively; filtering 10 L was 4.8 (p < 0.05) and 3.9 (p < 0.05) times more likely to recover L. monocytogenes than 1L and 0.1 L, respectively. Work presented here shows that S. enterica and L. monocytogenes levels are higher in river waters compared to pond or reclaimed waters in the Mid-Atlantic region of the U.S., and quantitatively shows that analyzing 10 L water is more likely recover pathogens than smaller samples of environmental waters.


Assuntos
Irrigação Agrícola/métodos , Água Doce/microbiologia , Listeria monocytogenes/isolamento & purificação , Salmonella enterica/isolamento & purificação , Estações do Ano , Microbiologia da Água , Mid-Atlantic Region , Prevalência , Estados Unidos
20.
J Biosci Bioeng ; 130(1): 76-81, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32147250

RESUMO

The quantification of pathogens is important for assessing water safety and preventing disease outbreaks. Culture-independent approaches, such as quantitative PCR (qPCR) and digital PCR (dPCR), are useful techniques for quantifying pathogens in water samples. However, since pathogens are usually present at low concentrations in water, it is necessary to concentrate microbial cells before extracting their DNA. Many existing microbial concentration methods are inefficient or take a long time to perform. In this study, we applied a coagulation and foam separation method to concentrate environmental water samples of between 1000 and 5000 mL to 100 µL of DNA (i.e., a 1-5 × 104-fold concentration). The concentration process took <1 h. The DNA samples were then used to quantify various target pathogens using dPCR. One gene, the Shiga toxin gene (stx2) of Shiga toxin-producing Escherichia coli, was detected at 32 copies/100 mL in a river water sample. The coagulation and foam concentration method followed by dPCR reported herein is a fast, sensitive, and reliable method to quantify pathogen genes in environmental water samples.


Assuntos
Água Doce/microbiologia , Reação em Cadeia da Polimerase/métodos , Água Doce/química , Reação em Cadeia da Polimerase/instrumentação , Sensibilidade e Especificidade , Toxina Shiga/genética , Toxina Shiga/metabolismo , Escherichia coli Shiga Toxigênica/genética , Escherichia coli Shiga Toxigênica/isolamento & purificação , Escherichia coli Shiga Toxigênica/metabolismo
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