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1.
PLoS One ; 16(1): e0243976, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33493159

RESUMO

Due to the inefficient reproduction of microorganisms in oxygen-deprived environments of the reservoir, the applications of microbial enhanced oil recovery (MEOR) are restricted. To overcome this problem, a new type of air-assisted MEOR process was investigated. Three compounding oil degradation strains were screened using biochemical experiments. Their performances in bacterial suspensions with different amounts of dissolved oxygen were evaluated. Water flooding, microbial flooding and air-assisted microbial flooding core flow experiments were carried out. Carbon distribution curve of biodegraded oil with different oxygen concentration was determined by chromatographic analysis. The long-chain alkanes are degraded by microorganisms. A simulation model was established to take into account the change in oxygen concentration in the reservoir. The results showed that the optimal dissolved oxygen concentration for microbial growth was 4.5~5.5mg/L. The main oxygen consumption in the reservoir happened in the stationary and declining phases of the microbial growth systems. In order to reduce the oxygen concentration to a safe level, the minimum radius of oxygen consumption was found to be about 145m. These results demonstrate that the air-assisted MEOR process can overcome the shortcomings of traditional microbial flooding techniques. The findings of this study can help for better understanding of microbial enhanced oil recovery and improving the efficiency of microbial oil displacement.


Assuntos
Alcanos/metabolismo , Bactérias , Biodegradação Ambiental , Campos de Petróleo e Gás/microbiologia , Petróleo/microbiologia , Bacillus/crescimento & desenvolvimento , Bacillus/isolamento & purificação , Bacillus/metabolismo , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Bactérias/metabolismo , Enterobacter/crescimento & desenvolvimento , Enterobacter/isolamento & purificação , Enterobacter/metabolismo , Fermentação , Oxigênio/metabolismo , Pseudomonas/crescimento & desenvolvimento , Pseudomonas/isolamento & purificação , Pseudomonas/metabolismo
2.
J Basic Microbiol ; 60(5): 390-399, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32115726

RESUMO

Excessive use of pesticides in agricultural fields is a matter of great concern for living beings as well as the environment across the world, in particular, the third world countries. Therefore, there is an urgent need to find out an effective way to degrade these hazardous chemicals from the soil in an environment-friendly way. In the current project, a bacterial species were isolated through enrichment culture from carbofuran-supplemented rice-field soil and identified as a carbofuran degrader. The rate of carbofuran degradation by this bacterial species was evaluated using reverse-phase high-performance liquid chromatography (RP-HPLC), which confirmed the ability to utilize as a carbon source up to 4 µg/ml of 99% technical grade carbofuran. The morphological, physiological, biochemical characteristics and phylogenetic analysis of the 16S rRNA sequence showed that this strain belongs to the genus of Enterobacter sp. (sequence accession number LC368285 in DDBJ), and the optimum growth condition for the isolated strain was 37°C at pH 7.0. Moreover, an antibiotic sensitivity test showed that it was susceptible to azithromycin, penicillin, ceftazidime, ciprofloxacin, and gentamycin, and the minimal inhibitory concentration value of gentamycin was 400 µg/ml against the bacteria. It shows beyond doubt from the RP-HPLC quantification that the isolated bacterium has the ability to detoxify carbofuran (99% pure). Finally, the obtained results imply that the isolated strain of Enterobacter can be used as a potential and effective carbofuran degrader for bioremediation of contaminated sites through bioaugmentation.


Assuntos
Carbofurano/metabolismo , Enterobacter/metabolismo , Inseticidas/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Animais , Antibacterianos/farmacologia , Artemia/efeitos dos fármacos , Biodegradação Ambiental , Carbofurano/toxicidade , Cromatografia Líquida de Alta Pressão , Enterobacter/classificação , Enterobacter/efeitos dos fármacos , Enterobacter/crescimento & desenvolvimento , Inseticidas/toxicidade , Testes de Sensibilidade Microbiana , Filogenia , RNA Ribossômico 16S/genética , Solo/química , Poluentes do Solo/toxicidade
3.
J Sci Food Agric ; 100(4): 1532-1540, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31769023

RESUMO

BACKGROUND: Heavy metal resistant bacterium Enterobacter sp. C1D was evaluated for cadmium (Cd) mediated exopolysaccharide production, biofilm formation and legume root colonization ability under Cd stress to alleviate metal induced stress. RESULTS: The plant was sensitive to Cd (IC50 3-4 µg mL-1 ), whereas the bacterium showed high Cd tolerance (MIC99 120 µg mL-1 ). Confocal laser scanning microscopy of the Cajanus cajan roots showed heavy loads of green fluorescence protein labelled Enterobacter sp. C1D on the surface of plant root, specifically at the point of root hair/lateral root formation along with cortex, even under metal stress. The root colonizing ability of Enterobacter sp. C1D was not affected by the presence of Rhizobium and the bacteria could be observed after 30 days of incubation in soil. Various plant growth parameters, antioxidant metabolites and oxidative stress indicator were significantly influenced by bacterial treatment, which, overall, reduced the adverse effect of Cd. CONCLUSION: Heavy metal tolerant bacteria may be a good choice for the development of biofertilizers and may work well with the native soil microbes such as Rhizobium under the metal polluted soil. © 2019 Society of Chemical Industry.


Assuntos
Cádmio/metabolismo , Cajanus/microbiologia , Enterobacter/metabolismo , Raízes de Plantas/microbiologia , Cajanus/metabolismo , Enterobacter/crescimento & desenvolvimento , Estresse Oxidativo , Raízes de Plantas/metabolismo , Rhizobium/crescimento & desenvolvimento , Microbiologia do Solo , Poluentes do Solo/metabolismo
4.
J Hazard Mater ; 389: 121834, 2020 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-31843407

RESUMO

Environmental problems caused by the large-scale use of chemical pesticides are becoming more and more serious, and the removal of chemical pesticides from the ecological environment by microbial degradation has attracted wide attention. In this study, using enrichment screening with seven chemical pesticides as the sole carbon source, a mixed microbial culture (PCS-1) was obtained from the continuous cropping of strawberry fields. The microbial community composition, degradation ability, and detoxification effect of PCS-1 was determined for the seven pesticides. Inoculation with PCS-1 showed significant degradation of and tolerance to the seven pesticides. Microbial community composition analysis indicated that Pseudomonas, Enterobacter, Aspergillus, and Rhodotorula were the dominant genera for the degradation of the seven pesticides by PCS-1. The concentration of the seven pesticides was 10 mg L-1 in hydroponic and soil culture experiments. The fresh weight, plant height, and root length of PCS-1-inoculated alfalfa (Medicago sativa) significantly increased compared with those of non-PCS-1-inoculated M. sativa. PCS-1 not only effectively degraded the residual content of the seven pesticides in water and soil but also reduced the pesticide residues in the roots, stems, and leaves of M. sativa. This study shows that PCS-1 may be important in environmental remediation involving the seven pesticides.


Assuntos
Poluentes Ambientais/análise , Medicago sativa/efeitos dos fármacos , Microbiota/efeitos dos fármacos , Praguicidas/análise , Microbiologia do Solo , Poluentes do Solo/análise , Aspergillus/efeitos dos fármacos , Aspergillus/crescimento & desenvolvimento , Biodegradação Ambiental , Enterobacter/efeitos dos fármacos , Enterobacter/crescimento & desenvolvimento , Poluentes Ambientais/toxicidade , Medicago sativa/crescimento & desenvolvimento , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/toxicidade , Praguicidas/toxicidade , Pseudomonas/efeitos dos fármacos , Pseudomonas/crescimento & desenvolvimento , Rhodotorula/efeitos dos fármacos , Rhodotorula/crescimento & desenvolvimento , Poluentes do Solo/toxicidade
5.
Molecules ; 24(24)2019 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-31842291

RESUMO

The newly-isolated strain Enterobacter sp. LU1, which has previously been shown to be an effective producer of succinic acid on glycerol with the addition of lactose, was used for further intensive works aimed at improving the production parameters of the said process. The introduction of an initial stage of gentle culture aeration allowed almost 47 g/L of succinic acid to be obtained after 168 h of incubation, which is almost two times faster than the time previously taken to obtain this amount. Furthermore, the replacement of glycerol with crude glycerin and the replacement of lactose with whey permeate allowed the final concentration of succinic acid to be increased to 54 g/L. Considering the high content of yeast extract (YE) in the culture medium, tests were also performed with a reduced YE content via its partial substitution with urea. Although this substitution led to a deterioration of the kinetic parameters of the production process, using the fed-batch strategy, it allowed a succinic acid concentration of 69 g/L to be obtained in the culture medium, the highest concentration ever achieved using this process. Furthermore, the use of microaerophilic conditions meant that the addition of lactose to the medium was not required, with 37 g/L of succinic acid being produced on crude glycerol alone.


Assuntos
Enterobacter/crescimento & desenvolvimento , Glicerol/farmacologia , Ácido Succínico/metabolismo , Proteínas do Soro do Leite/farmacologia
6.
BMC Biotechnol ; 19(Suppl 2): 90, 2019 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-31847833

RESUMO

BACKGROUND: Enterobacter sp. AA26 was recently isolated from the midgut of Ceratitis capitata (Wiedemann) and it was shown to have positive effects in rearing efficiency when used as larval probiotics. In this study, biomass production was carried out in bench-scale bioreactors to elucidate the biokinetic properties of Enterobacter sp. AA26 and its nutritional value. RESULTS: Strain AA26 is a psychrotolerant, halotolerant, facultatively anaerobic bacterium with broad pH range for growth (pH 4 to 10.2), which possessed the typical biochemical profile of Enterobacter spp. The specific oxygen uptake rate (SOUR) was calculated as 63.2 ± 1.26 and 121 ± 1.73 mg O2 g- 1 VSS h- 1, with the yield coefficients in acetate and glucose being equal to 0.62 ± 0.03 and 0.67 ± 0.003 g biomass produced/g substrate consumed, respectively. The maximum specific growth rate (µmax) of strain AA26 grown in fill-and-draw bioreactors at 20 °C and 35 °C was 0.035 and 0.069 h- 1, respectively. Strain AA26 grew effectively in agro-industrial wastewaters, i.e. cheese whey wastewater (CWW), as alternative substrate for replacing yeast-based media. Biomass of strain AA26 could provide all the essential amino acids and vitamins for the artificial rearing of C. capitata. Greater intracellular α- and ß-glucosidase activities were observed during growth of strain AA26 in CWW than in yeast-based substrate, although the opposite pattern was observed for the respective extracellular activities (p < 0.01). Low protease activity was exhibited in cells grown in yeast-based medium, while no lipase activities were detected. CONCLUSIONS: The ability of strain AA26 to grow in agro-industrial wastes and to provide all the essential nutrients can minimize the cost of commercial media used for mass rearing and large scale sterile insect technique applications.


Assuntos
Aminoácidos Essenciais/metabolismo , Reatores Biológicos/microbiologia , Ceratitis capitata/microbiologia , Enterobacter/crescimento & desenvolvimento , Vitaminas/metabolismo , Acetatos/metabolismo , Animais , Técnicas de Cultura Celular por Lotes , Biomassa , Ceratitis capitata/fisiologia , Enterobacter/metabolismo , Enterobacter/fisiologia , Glucose/metabolismo , Resíduos Industriais , Probióticos/administração & dosagem , Águas Residuárias/microbiologia
7.
Appl Biochem Biotechnol ; 189(4): 1183-1194, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31218530

RESUMO

The dye decolorization potential of the white-rot fungus Phlebia brevispora TMIC33929 when grown alone or in coculture with its growth-promoting bacterium Enterobacter sp. TN3W-14 was evaluated in low nitrogen liquid medium at different pHs. Axenic fungus removed a similar amount of Congo red and crystal violet at pH 4.5 and 7.0, respectively. The bacterium alone achieved only slightly better decolorization of crystal violet than the fungus at pH 9.0. Compared with axenic fungus, cocultures provided no increased crystal violet removal but achieved higher removal of crystal violet in mixed dye at all pHs, and the best-mixed dye decolorization at pH 9.0. Unlike bacterial growth on dyes, growth of fungal mycelia was not inhibited by the dyes at all pH but the cocultures gave comparably higher mycelial growth.


Assuntos
Vermelho Congo/metabolismo , Enterobacter/crescimento & desenvolvimento , Violeta Genciana/metabolismo , Polyporales/crescimento & desenvolvimento , Águas Residuárias/microbiologia , Purificação da Água , Concentração de Íons de Hidrogênio , Poluição da Água
8.
Microbiologyopen ; 8(9): e00843, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31066221

RESUMO

A novel oligotrophic bacterium, designated strain CCA6, was isolated from leaf soil collected in Japan. Cells of the strain were found to be a Gram-negative, non-sporulating, motile, rod-shaped bacterium. Strain CCA6 grew at 10-45°C (optimum 20°C) and pH 4.5-10.0 (optimum pH 5.0). The strain was capable of growth in poor-nutrient (oligotrophic) medium, and growth was unaffected by high-nutrient medium. The major fatty acid and predominant quinone system were C16:0 and ubiquinone-8. Phylogenetic analysis based on 16S rRNA gene sequences indicated strain CCA6 presented as a member of the family Enterobacteriaceae. Multilocus sequence analysis (MLSA) based on fragments of the atpD, gyrB, infB, and rpoB gene sequences was performed to further identify strain CCA6. The MLSA showed clear branching of strain CCA6 with respect to Enterobacter type strains. The complete genome of strain CCA6 consisted of 4,476,585 bp with a G+C content of 54.3% and comprising 4,372 predicted coding sequences. The genome average nucleotide identity values between strain CCA6 and the closest related Enterobacter type strain were <88.02%. Based on its phenotypic, chemotaxonomic and phylogenetic features, strain CCA6 (=HUT 8142T =KCTC 62525T ) can be considered as a novel species within the genus Enterobacter with the proposed name Enterobacter oligotrophica.


Assuntos
Enterobacter/classificação , Enterobacter/isolamento & purificação , Filogenia , Microbiologia do Solo , Proteínas de Bactérias/genética , Técnicas de Tipagem Bacteriana , Composição de Bases , Análise por Conglomerados , Citosol/química , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Enterobacter/genética , Enterobacter/crescimento & desenvolvimento , Ácidos Graxos/análise , Concentração de Íons de Hidrogênio , Japão , Locomoção , Tipagem de Sequências Multilocus , Quinonas/análise , RNA Ribossômico 16S/genética , Temperatura
9.
FEMS Microbiol Ecol ; 95(3)2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30863859

RESUMO

Understanding the ecology of phosphate solubilizing bacteria (PSBs) is critical for developing better strategies to increase crop productivity. In this study, the diversity of PSBs and of the total bacteria in the rhizosphere of eggplant (Solanum melongena L.) cultivated in organic, integrated and conventional farming systems was compared at four developmental stages of its lifecycle. Both selective culture and high-throughput sequencing analysis of 16S rRNA amplicons indicated that Enterobacter with strong or very strong in vivo phosphate solubilization activities was enriched in the rhizosphere during the fruiting stage. The high-throughput sequencing analysis results demonstrated that farming systems explained 23% of total bacterial community variation. Plant development and farming systems synergistically shaped the rhizospheric bacterial community, in which the degree of variation influenced by farming systems decreased over the plant development phase from 56% to 26.3% to 16.3%, and finally to no significant effect as the plant reached at fruiting stage. Pangenome analysis indicated that two-component and transporter systems varied between the rhizosphere and soil PSBs. This study elucidated the complex interactions among farming systems, plant development and rhizosphere microbiomes.


Assuntos
Agricultura/métodos , Bactérias/metabolismo , Fosfatos/metabolismo , Solanum melongena/crescimento & desenvolvimento , Solanum melongena/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Enterobacter/crescimento & desenvolvimento , Enterobacter/metabolismo , Microbiota/genética , RNA Ribossômico 16S/genética , Rizosfera , Microbiologia do Solo
10.
Appl Environ Microbiol ; 85(8)2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30796063

RESUMO

Isogenic bacterial populations are known to exhibit phenotypic heterogeneity at the single-cell level. Because of difficulties in assessing the phenotypic heterogeneity of a single taxon in a mixed community, the importance of this deeper level of organization remains relatively unknown for natural communities. In this study, we have used membrane-based microcosms that allow the probing of the phenotypic heterogeneity of a single taxon while interacting with a synthetic or natural community. Individual taxa were studied under axenic conditions, as members of a coculture with physical separation, and as a mixed culture. Phenotypic heterogeneity was assessed through both flow cytometry and Raman spectroscopy. Using this setup, we investigated the effect of microbial interactions on the individual phenotypic heterogeneities of two interacting drinking water isolates. Through flow cytometry we have demonstrated that interactions between these bacteria lead to a reduction of their individual phenotypic diversities and that this adjustment is conditional on the bacterial taxon. Single-cell Raman spectroscopy confirmed a taxon-dependent phenotypic shift due to the interaction. In conclusion, our data suggest that bacterial interactions may be a general driver of phenotypic heterogeneity in mixed microbial populations.IMPORTANCE Laboratory studies have shown the impact of phenotypic heterogeneity on the survival and functionality of isogenic populations. Because phenotypic heterogeneity plays an important role in pathogenicity and virulence, antibiotic resistance, biotechnological applications, and ecosystem properties, it is crucial to understand its influencing factors. An unanswered question is whether bacteria in mixed communities influence the phenotypic heterogeneity of their community partners. We found that coculturing bacteria leads to a reduction in their individual phenotypic heterogeneities, which led us to the hypothesis that the individual phenotypic diversity of a taxon is dependent on the community composition.


Assuntos
Cultura Axênica , Bactérias/crescimento & desenvolvimento , Fenômenos Fisiológicos Bacterianos , Técnicas de Cocultura , Interações Microbianas/fisiologia , Bactérias/genética , Biodiversidade , DNA Bacteriano , Ecossistema , Enterobacter/genética , Enterobacter/crescimento & desenvolvimento , Enterobacter/fisiologia , Meio Ambiente , Microbiologia Ambiental , Citometria de Fluxo , Heterogeneidade Genética , Fenótipo , Pseudomonas/genética , Pseudomonas/crescimento & desenvolvimento , Pseudomonas/fisiologia , Virulência
11.
Ecotoxicol Environ Saf ; 172: 159-166, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30708227

RESUMO

The interaction between pure culture microorganisms has been evaluated allowing for the enhanced biodegradation of various kinds of pollutants. Arthrobacter sp. DNS10 previously enriched in an atrazine-containing soil was capable of utilizing atrazine as the sole nitrogen source for growth, and Enterobacter sp. P1 is a phosphorus-solubilizing bacterium that releases various kinds of organic acids but lacks the ability to degrade atrazine. Whether strain P1 could enhance atrazine biodegradation by the degrader strain DNS10 was investigated in this experiment. Gas chromatography and high-performance liquid chromatography results showed that co-culture of both strains degraded 99.18 ±â€¯1.00% of the atrazine (initial concentration was 100 mg L-1), while the single strain DNS10 only degraded 38.57 ±â€¯7.39% after a 48 h culture, and the resulting concentration of the atrazine final metabolite cyanuric acid were 63.91 ±â€¯3.34 mg L-1 and 26.60 ±â€¯3.87 mg L-1, respectively. In addition, the expression of the atrazine degradation-related genes trzN, atzB and atzC in co-culture treatments was 6.61, 1.81 and 3.09 times that of the single strain DNS10 culture treatment. A substrates utilization test showed that the atrazine-degrading metabolites ethylamine and isopropylamine could serve as the nitrogen source to support strain P1 growth, although strain P1 cannot degrade atrazine or utilize atrazine for growth. Furthermore, the pH of the medium was significantly decreased when strain P1 utilized ethylamine and isopropylamine as the nitrogen source for growth. The results suggest that nondegrader strain P1 could promote the atrazine biodegradation when co-cultured with strain DNS10. This phenomenon is due to metabolite exchange between the two strains. Culturing these two strains together is a new biostimulation strategy to enhance the biodegradation of atrazine by culturing these two strains together.


Assuntos
Arthrobacter/metabolismo , Atrazina/metabolismo , Enterobacter/metabolismo , Fósforo/metabolismo , Poluentes do Solo/metabolismo , Atrazina/análise , Biodegradação Ambiental , Técnicas de Cocultura , Enterobacter/crescimento & desenvolvimento , Herbicidas/análise , Nitrogênio/metabolismo , Solo/química , Microbiologia do Solo , Poluentes do Solo/análise , Triazinas
12.
FEMS Microbiol Lett ; 366(1)2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30476146

RESUMO

2,3-Butanediol (BDO) is an important platform chemical with a wide range of applications in various industries. In the present study, a newly isolated wild Enterobacter sp. strain (FMCC-208) was evaluated towards its ability to produce BDO on media composed of sugars derived from sucrose refinery plant. Optimum values of temperature and pH as well as substrate inhibition were determined through batch experiments. The ability of the strain to convert various monosaccharides was also investigated. Maximum BDO concentrations of 90.3 and 10 g l-1 of acetoin were obtained during a fed-batch bioreactor experiment with cane molasses and sucrose employed as substrates. A high volumetric productivity was noted in a fed-batch experiment using molasses and sucrose as carbon sources at T = 37°C, in which 73.0 g l-1 of BDO together with 12.4 g l-1 of acetoin was produced where 1.15 g l-1 h-1 of diol/acetoin was produced. In previously pasteurized media, 70.0 g l-1 of BDO and 5.0 g l-1 of acetoin were produced (yield = 0.39 g g-1). Finally, besides BDO production, growth on molasses was accompanied by non-negligible decolorization (25-35%) of the residue. Therefore, the strain is a promising candidate for the conversion of sucrose-based materials into BDO.


Assuntos
Butileno Glicóis/metabolismo , Metabolismo dos Carboidratos , Meios de Cultura/química , Enterobacter/metabolismo , Reatores Biológicos , Carboidratos/química , Meios de Cultura/economia , Enterobacter/crescimento & desenvolvimento , Concentração de Íons de Hidrogênio , Temperatura
13.
Int J Antimicrob Agents ; 52(4): 474-484, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30012439

RESUMO

We report contemporary (2014-2016) Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) global data on activity of tigecycline and comparators against WHO 'priority pathogens', and global trends (2004-2016) in antimicrobial resistance. MICs were determined using CLSI broth microdilution methodology. Antimicrobial resistance was determined using CLSI breakpoints (FDA breakpoints for tigecycline). Data are reported for Africa, Asia, Europe, North America and South America. From 2014-2016, Africa, Asia and South America reported highest resistance rates among Acinetobacter baumannii; North America lowest (all antimicrobials tested). The tigecycline MIC90 against A. baumannii was 2 mg/L in all regions except South America (1 mg/L). Among Enterobacteriaceae, meropenem resistance was low and tigecycline resistance was ≤1.3% in all regions (Escherichia coli, 0.0-0.3%; Klebsiella pneumoniae 0.0-1.3%; Enterobacter spp. 0.5-1.1%; Serratia marcescens 0.0-1.3%). Ceftriaxone resistance among E. coli ranged from 14.5% (North America) to 54.7% (Asia), and among K. pneumoniae from 9.1% (North America) to 54.0% (South America). North America reported highest rates of vancomycin-resistant Enterococcus faecium (64.6%); Europe lowest (17.7%). The tigecycline MIC90 against methicillin-resistant Staphylococcus aureus (MRSA) ranged from 0.12 mg/L (Africa and North America) to 0.5 mg/L (Asia). From 2004-2016, carbapenem resistance increased among A. baumannii (all regions), reaching 92.3% in Africa and 85.7% in South America (2016). Rates of ceftriaxone-resistant E. coli increased in all regions except Asia. Ceftriaxone resistance in K. pneumoniae increased in Europe. Rates of vancomycin-resistant E. faecium and MRSA were highest in North America and South America (and Asia for MRSA); lowest in Europe.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla , Monitoramento Epidemiológico , Infecções por Bactérias Gram-Negativas/epidemiologia , Infecções por Bactérias Gram-Positivas/epidemiologia , Tigeciclina/farmacologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/crescimento & desenvolvimento , África/epidemiologia , Ásia/epidemiologia , Carbapenêmicos/farmacologia , Ceftriaxona/farmacologia , Enterobacter/efeitos dos fármacos , Enterobacter/crescimento & desenvolvimento , Enterococcus faecium/efeitos dos fármacos , Enterococcus faecium/crescimento & desenvolvimento , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Europa (Continente)/epidemiologia , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Infecções por Bactérias Gram-Positivas/microbiologia , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/crescimento & desenvolvimento , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , América do Norte/epidemiologia , Serratia marcescens/efeitos dos fármacos , Serratia marcescens/crescimento & desenvolvimento , América do Sul/epidemiologia
14.
Artigo em Inglês | MEDLINE | ID: mdl-29866876

RESUMO

The next-generation aminoglycoside plazomicin, in development for infections due to multidrug-resistant (MDR) Enterobacteriaceae, was evaluated alongside comparators for bactericidal activity in minimum bactericidal concentration (MBC) and time-kill (TK) assays against MDR Enterobacteriaceae isolates with characterized aminoglycoside and ß-lactam resistance mechanisms. Overall, plazomicin and colistin were the most potent, with plazomicin demonstrating an MBC50/90 of 0.5/4 µg/ml and sustained 3-log10 kill against MDR Escherichia coli, Klebsiella pneumoniae, and Enterobacter spp.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Enterobacter/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Klebsiella pneumoniae/efeitos dos fármacos , Sisomicina/análogos & derivados , Aminoglicosídeos/farmacologia , Carbapenêmicos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Enterobacter/genética , Enterobacter/crescimento & desenvolvimento , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Fluoroquinolonas/farmacologia , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Polimixinas/farmacologia , Sisomicina/farmacologia , Tetraciclinas/farmacologia
15.
J Microbiol Biotechnol ; 28(6): 968-975, 2018 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-29642290

RESUMO

In the course of screening for microbes with nematicidal activity, we found that Enterobacter asburiae HK169 displayed promising nematicidal activity against the root-knot nematode Meloidogyne incognita, along with plant growth-promoting properties. Soil drenching of a culture of HK169 reduced gall formation by 66% while also increasing root and shoot weights by 251% and 160%, respectively, compared with an untreated control. The cell-free culture filtrate of the HK169 culture killed all juveniles of M. incognita within 48 h. In addition, the nematicidal activity of the culture filtrate was dramatically reduced by a protease inhibitor, suggesting that proteolytic enzymes contribute to the nematicidal activity of HK169. In order to obtain genomic information about the HK169 isolate related to its nematicidal and plant growth-promoting activities, we sequenced and analyzed the whole genome of the HK169 isolate, and the resulting information provided evidence that the HK169 isolate has nematicidal and plant growth-promoting activities. Taken together, these observations enable the future application of E. asburiae HK169 as a biocontrol agent for nematode control and promote our understanding of the beneficial interactions between E. asburiae HK169 and plants.


Assuntos
Anti-Helmínticos/metabolismo , Antibiose , Enterobacter/fisiologia , Lycopersicon esculentum/crescimento & desenvolvimento , Reguladores de Crescimento de Plantas/metabolismo , Tylenchoidea/fisiologia , Animais , Enterobacter/crescimento & desenvolvimento , Enterobacter/metabolismo , Genoma Bacteriano , Raízes de Plantas/crescimento & desenvolvimento , Brotos de Planta/crescimento & desenvolvimento , Análise de Sequência de DNA , Tylenchoidea/crescimento & desenvolvimento , Tylenchoidea/microbiologia , Sequenciamento Completo do Genoma
16.
Chemosphere ; 202: 280-288, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29573613

RESUMO

This study examined the potential of a cadmium-resistant Enterobacter sp. FM-1 to promote plant growth and assist in cadmium accumulation in both mine-type C. asiatica L. and non-mine type C. asiatica L. tissues in highly cadmium-polluted soils. The results indicated that Enterobacter sp. FM-1 significantly promoted growth and alleviated metal toxicity in both types of C. asiatica L. Meanwhile, inoculation with Enterobacter sp. FM-1 in contaminated soil can increased cadmium bioavailability in soil. Furthermore, it will increase plant uptake and the accumulation of cadmium in C. asiatica L. leaves, stems and roots compared to that in an uninoculated plant. However, mine-type C. asiatica L. had better cadmium tolerance than the non mine-type C. asiatica L. Because of its native metal-tolerant ability, which could easily grow and proliferate, and had a better performance under cadmium-contamination conditions. Additionally, inoculation with Enterobacter sp. FM-1 significantly enhanced the bioaccumulation factor (BAF) and the translocation factor (TF) values in both types of C. asiatica L. even under high cadmium concentration soil condition. Hence, based on higher BAF and TF values and strong cadmium accumulation in the leaves and stems, we concluded that inoculation with Enterobacter sp. FM-1 is potentially useful for the phytoremediation of cadmium-contaminated sites by Centella asiatica L.


Assuntos
Biodegradação Ambiental , Cádmio/metabolismo , Centella/química , Enterobacter/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Cádmio/análise , Cádmio/toxicidade , Enterobacter/efeitos dos fármacos , Enterobacter/crescimento & desenvolvimento , Infecções por Enterobacteriaceae/microbiologia , Desenvolvimento Vegetal/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Poluentes do Solo/análise
17.
Environ Sci Pollut Res Int ; 25(7): 7021-7032, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29273991

RESUMO

The contamination of soil with heavy metals is a major environmental problem worldwide. The combined use of plants and their associated microbes has gained popularity in recent years for their potential to remediate heavy metal-contaminated soil. In the current study, the effect that augmentation of soil with plant growth-promoting endophytes has on the phytostabilization of chromium (Cr)-contaminated soil was investigated. Three potential endophytic bacterial strains (Enterobacter sp. HU38, Microbacterium arborescens HU33, and Pantoea stewartii ASI11) were inoculated individually as well as in combination to Leptochloa fusca and Brachiaria mutica vegetated in Cr-contaminated soil. The accumulation of Cr in the root and shoot of the plants was determined. Moreover, bacterial persistence in the rhizosphere and endosphere was determined. Augmentation with potential endophytes significantly increased root length (24-45%), shoot height (39-64%), chlorophyll content (20-55%), and the overall biomass (32-61%) of the plants. Although L. fusca and B. mutica showed potential to accumulate Cr in their root and shoot, endophytic augmentation increased uptake, translocation, and accumulation of Cr in the roots and shoots of both plant species. However, L. fusca showed more potential to phytostabilize Cr as compared to B. mutica. Furthermore, the potential endophytes showed more survival and persistence within the roots than in the rhizosphere and shoot interior. This study provides useful evidence of endophyte-assisted phytoremediation to be the most sustainable and affordable approach for in situ remediation of Cr-contaminated soil.


Assuntos
Cromo/análise , Endófitos/crescimento & desenvolvimento , Poaceae/microbiologia , Microbiologia do Solo , Poluentes do Solo/análise , Biodegradação Ambiental , Biomassa , Enterobacter/crescimento & desenvolvimento , Pantoea/crescimento & desenvolvimento , Rizosfera
18.
J Appl Microbiol ; 124(2): 408-422, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29178633

RESUMO

AIMS: To enhance the antimicrobial and antibiofilm activity of norfloxacin against the planktonic and biofilm mode of growth in ESKAPE pathogens using chemically modified norfloxacin salts. METHODS AND RESULTS: Antimicrobial testing, synergy testing and time-kill curve analysis were performed to evaluate antibacterial effect of norfloxacin carboxylic acid salts against ESKAPE pathogens. In vivo efficacy to reduce bacterial bioburden was evaluated in zebrafish infection model. Crystal violet assay and live-dead staining were performed to discern antibiofilm effect. Membrane permeability, integrity and molecular docking studies were carried out to ascertain the mechanism of action. The carboxylic acid salts, relative to parent molecule norfloxacin, displayed two- to fourfold reduction in minimum inhibitory concentration against Staphylococcus aureus and Pseudomonas aeruginosa, in addition to displaying potent bacteriostatic effect against certain members of ESKAPE pathogens. In vivo treatments revealed that norfloxacin tartrate (SRIN2) reduced MRSA bioburden by greater than 1 log fold relative to parent molecule in the muscle tissue. In silico docking with gyrA of S. aureus showed increased affinity of SRIN2 towards DNA gyrase. The enhanced antibacterial effect of norfloxacin salts could be partially accounted by altered membrane permeability in S. aureus and perturbed membrane integrity in P. aeruginosa. Antibiofilm studies revealed that SRIN2 (norfloxacin tartrate) and SRIN3 (norfloxacin benzoate) exerted potent antibiofilm effect particularly against Gram-negative ESKAPE pathogens. The impaired colonization of both S. aureus and P. aeruginosa due to improved norfloxacin salts was further supported by live-dead imaging. CONCLUSION: Norfloxacin carboxylic acid salts can act as potential alternatives in terms of drug resensitization and reuse. SIGNIFICANCE AND IMPACT OF THE STUDY: Our study shows that carboxylic acid salts of norfloxacin could be effectively employed to treat both planktonic- and biofilm-based infections caused by select members of ESKAPE pathogens.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Bactérias Aeróbias Gram-Negativas/efeitos dos fármacos , Infecções por Bactérias Gram-Negativas/microbiologia , Norfloxacino/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/crescimento & desenvolvimento , Acinetobacter baumannii/fisiologia , Animais , Antibacterianos/química , Ácidos Carboxílicos/química , Ácidos Carboxílicos/farmacologia , Enterobacter/efeitos dos fármacos , Enterobacter/crescimento & desenvolvimento , Enterobacter/fisiologia , Enterococcus faecium/efeitos dos fármacos , Enterococcus faecium/crescimento & desenvolvimento , Enterococcus faecium/fisiologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/fisiologia , Bactérias Aeróbias Gram-Negativas/crescimento & desenvolvimento , Bactérias Aeróbias Gram-Negativas/fisiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/crescimento & desenvolvimento , Klebsiella pneumoniae/fisiologia , Testes de Sensibilidade Microbiana , Norfloxacino/química , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/fisiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus aureus/fisiologia
19.
PLoS One ; 12(10): e0186440, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29049419

RESUMO

The production of lignocellulosic-derived biofuels is a highly promising source of alternative energy, but it has been constrained by the lack of a microbial platform capable to efficiently degrade this recalcitrant material and cope with by-products that can be toxic to cells. Species that naturally grow in environments where carbon is mainly available as lignin are promising for finding new ways of removing the lignin that protects cellulose for improved conversion of lignin to fuel precursors. Enterobacter lignolyticus SCF1 is a facultative anaerobic Gammaproteobacteria isolated from tropical rain forest soil collected in El Yunque forest, Puerto Rico under anoxic growth conditions with lignin as sole carbon source. Whole transcriptome analysis of SCF1 during E.lignolyticus SCF1 lignin degradation was conducted on cells grown in the presence (0.1%, w/w) and the absence of lignin, where samples were taken at three different times during growth, beginning of exponential phase, mid-exponential phase and beginning of stationary phase. Lignin-amended cultures achieved twice the cell biomass as unamended cultures over three days, and in this time degraded 60% of lignin. Transcripts in early exponential phase reflected this accelerated growth. A complement of laccases, aryl-alcohol dehydrogenases, and peroxidases were most up-regulated in lignin amended conditions in mid-exponential and early stationary phases compared to unamended growth. The association of hydrogen production by way of the formate hydrogenlyase complex with lignin degradation suggests a possible value added to lignin degradation in the future.


Assuntos
Enterobacter/genética , Lignina/metabolismo , RNA Bacteriano/genética , Análise de Sequência de RNA/métodos , Meios de Cultura , Enterobacter/crescimento & desenvolvimento , Enterobacter/metabolismo
20.
Microb Pathog ; 112: 63-69, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28943150

RESUMO

Lignin, a common natural polymers, is abundant and complex, and termites can break down and utilize the lignin in their food. In this study an attempt was made to isolate and characterize the lignolytic bacteria from termite (Reticulitermes chinensis Snyder) gut. Two strains (PY12 and MX5) with high lignin peroxidase (LiP) activity were screened using the azure B method. By analyzing their 16S rRNA, the strain PY12 was classified as Enterobacter hormaechei; MX5, as Bacillus licheniformis. We then optimized the different conditions of liquid fermentation medium, and obtained LiP activities of 278 U/L and 256 U/L for PY12 and MX5, respectively. Subsequently, we confirmed the LiP activities of the strains by evaluating their decolorizing effects on various dyes. Finally, we cloned the LiP gene of strain PY12 and successfully transferred it to Lactococcus lactis. We believe that our results provide the theoretical and practical basis for the production of genetically engineered bacteria that produce LiP, thus allowing for the utilization of naturally available lignin as an energy resource.


Assuntos
Bactérias/isolamento & purificação , Bactérias/metabolismo , Trato Gastrointestinal/microbiologia , Isópteros/microbiologia , Lactococcus lactis/genética , Lignina/metabolismo , Peroxidases/genética , Peroxidases/metabolismo , Animais , Bacillus licheniformis/classificação , Bacillus licheniformis/enzimologia , Bacillus licheniformis/crescimento & desenvolvimento , Bacillus licheniformis/isolamento & purificação , Bactérias/classificação , Bactérias/enzimologia , Enterobacter/classificação , Enterobacter/enzimologia , Enterobacter/crescimento & desenvolvimento , Enterobacter/isolamento & purificação , Fermentação , Regulação Bacteriana da Expressão Gênica/genética , Genes Bacterianos/genética , Vetores Genéticos , Filogenia , RNA Ribossômico 16S/genética , Recombinação Genética , Transformação Bacteriana
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