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1.
Ecotoxicol Environ Saf ; 211: 111919, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33476853

RESUMO

The aim of this study was to elucidate the effect of pH on bacterial resistance mechanisms to copper (Cu) stress by genomic and transcriptomic analysis. Klebsiella michiganensis cells were exposed to 0.5 mM CuCl2 at pH 4 and 5. Lower pH (pH < 4) strongly inhibited K. michiganensis growth, while Cu stress and higher pH (pH > 5) induced Cu precipitation in the medium. Transcriptomic analyses indicated that two groups of genes related to quorum sensing (QS) systems (lsrABCDFGKR) and type II secretion systems (T2SS) (gspCDEFGHIJKLM) were significantly up-regulated at pH 4 only. These results suggest that T2SS may be induced and controlled by QS, thereby contributing to the formation of extracellular polymeric substances (EPS) and the secretion of proteins to prevent Cu ions from entering cells. Six Cu resistance genes (cusABF, copA, cueO, and gene05308) were more significantly up-regulated at pH 4 than at pH 5. In addition, the relative expression (log2|FC=) of the sulfur assimilation genes cysHJIK was relatively higher at pH 4 than at pH 5, while the gene encoding organic sulfur metabolism, tauB, was also significantly up-regulated at only pH 4. These results indicate that the Cu efflux system can remove intracellular Cu ions from cells, and that the sulfur assimilation system is related to the detoxification of Cu ions. Furthermore, increased free Cu ions at lower pH (4) could induce communication signals among cells, thereby stimulating the response of T2SS-related genes in K. michiganensis to tolerate Cu stress. Consequently, the resistance of K. michiganensis to Cu stress is a multisystem collaborative process composed of intracellular and extracellular components.


Assuntos
Cobre/toxicidade , Poluentes Ambientais/toxicidade , Klebsiella/fisiologia , Transcriptoma/fisiologia , Cobre/metabolismo , Perfilação da Expressão Gênica , Íons , Klebsiella/genética
2.
Ecotoxicol Environ Saf ; 207: 111514, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33254394

RESUMO

The present study investigated the stability and efficacy of a biosurfactant produced by Klebsiella sp. KOD36 under extreme conditions and its potential for enhancing the solubilization and degradation of phenanthrene in various environmental matrices. Klebsiella sp. KOD36 produced a mono-rhamnolipids biosurfactant with a low critical micelle concentration (CMC) value. The biosurfactant was stable under extreme conditions (60 °C, pH 10 and 10% salinity) and could lower surface tension by 30% and maintained an emulsification index of > 40%. The emulsion index was also higher (17-43%) in the presence of petroleum hydrocarbons compared to synthetic surfactant Triton X-100. Investigation on phenanthrene degradation in three different environmental matrices (aqueous, soil-slurry and soil) confirmed that the biosurfactant enhanced the solubilization and biodegradation of phenanthrene in all matrices. The high functional stability and performance of the biosurfactant under extreme conditions on phenanthrene degradation show the great potential of the biosurfactant for remediation applications under harsh environmental conditions.


Assuntos
Biodegradação Ambiental , Klebsiella/fisiologia , Fenantrenos/metabolismo , Tensoativos/metabolismo , Meios de Cultura , Emulsões , Glicolipídeos , Hidrocarbonetos/metabolismo , Klebsiella/metabolismo , Micelas , Petróleo/metabolismo , Solo , Poluentes do Solo/metabolismo
3.
PLoS One ; 15(12): e0243739, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33351813

RESUMO

Lignin is a recalcitrant macromolecule formed by three alcohols (monolignols) predominantly connected by ß-aryl ether linkages and is one of the most abundant organic macromolecules in the biosphere. However, the role played by environmental bacteria in lignin degradation is still not entirely understood. In this study, we identified an environmental Klebsiella strain isolated from sediment collected from an altitudinal region in a unique Brazilian biome called Caatinga. This organism can also grow in the presence of kraft lignin as a sole source of carbon and aromatic compounds. We performed whole-genome sequencing and conducted an extensive genome-based metabolic reconstruction to reveal the potential mechanisms used by the bacterium Klebsiella variicola P1CD1 for lignin utilization as a carbon source. We identified 262 genes associated with lignin-modifying enzymes (LMEs) and lignin-degrading auxiliary enzymes (LDAs) required for lignin and aromatic compound degradation. The presence of one DyP (Dye-decolorizing Peroxidase) gene suggests the ability of P1CD1 strain to access phenolic and nonphenolic structures of lignin molecules, resulting in the production of catechol and protocatechuate (via vanillin or syringate) along the peripheral pathways of lignin degradation. K. variicola P1CD1 uses aldehyde-alcohol dehydrogenase to perform direct conversion of vanillin to protocatechol. The upper funneling pathways are linked to the central pathways of the protocatechuate/catechol catabolic branches via ß-ketoadipate pathways, connecting the more abundant catabolized aromatic compounds with essential cellular functions, such as energy cellular and biomass production (i.e., via acetyl-CoA formation). The combination of phenotypic and genomic approaches revealed the potential dissimilatory and assimilatory ability of K. variicola P1CD1 to perform base-catalyzed lignin degradation, acting on high- and low-molecular-weight lignin fragments. These findings will be relevant for developing metabolic models to predict the ligninolytic mechanism used by environmental bacteria and shedding light on the flux of carbon in the soil.


Assuntos
Proteínas de Bactérias/genética , Biodegradação Ambiental , Klebsiella/metabolismo , Lignina/metabolismo , Oxirredutases/genética , Proteínas de Bactérias/metabolismo , Ciclo do Carbono , Genoma Bacteriano/genética , Klebsiella/genética , Oxirredutases/metabolismo , Solo/química , Microbiologia do Solo , Sequenciamento Completo do Genoma
4.
BMJ Case Rep ; 13(12)2020 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-33370932

RESUMO

A 58-year-old woman presented with a 1-week history of lower limb bruising. She had a medical history of recurrent metastatic colon cancer with a sigmoid colectomy and complete pelvic exenteration leading to colostomy and urostomy formation. She had malignant sacral mass encroaching on the spinal cord. This caused a left-sided foot drop for which she used an ankle-foot orthosis. She was on cetuximab and had received radiotherapy to the sacral mass 1 month ago. On examination, there were macular ecchymoses with petechiae on the lower limbs. There was sparing of areas that had been compressed by the ankle-foot orthosis. Bloods showed mild thrombocytopaenia and anaemia with markedly raised inflammatory markers. Coagulation studies consistent with inflammation rather than disseminated intravascular coagulation. She was found to have Klebsiella bacteraemia secondary to urinary source. Skin biopsy showed dermal haemorrhage without vessel inflammation. Vitamin C levels were low confirming the diagnosis of scurvy.


Assuntos
Ácido Ascórbico , Colectomia/efeitos adversos , Neoplasias Colorretais , Equimose , Desnutrição , Apoio Nutricional/métodos , Escorbuto , Antineoplásicos Imunológicos/uso terapêutico , Ácido Ascórbico/administração & dosagem , Ácido Ascórbico/sangue , Bacteriemia/diagnóstico , Bacteriemia/microbiologia , Colectomia/métodos , Neoplasias Colorretais/patologia , Neoplasias Colorretais/fisiopatologia , Neoplasias Colorretais/secundário , Neoplasias Colorretais/terapia , Diagnóstico Diferencial , Equimose/sangue , Equimose/diagnóstico , Equimose/etiologia , Feminino , Humanos , Klebsiella/isolamento & purificação , Extremidade Inferior , Desnutrição/etiologia , Desnutrição/terapia , Pessoa de Meia-Idade , Metástase Neoplásica , Estadiamento de Neoplasias , Exenteração Pélvica/efeitos adversos , Exenteração Pélvica/métodos , Escorbuto/sangue , Escorbuto/etiologia , Escorbuto/fisiopatologia , Escorbuto/terapia , Pele/patologia , Resultado do Tratamento , Vitaminas/administração & dosagem
5.
Mymensingh Med J ; 29(4): 895-900, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33116093

RESUMO

This cross-sectional study was conducted to determine the prevalence of AmpC beta-lactamase enzyme producing Escherichia coli and Klebsiella species in a tertiary care hospital of Bangladesh, as well as to observe the patterns of antibiotic resistance and AmpC beta-lactamase resistance genes among them. This study was conducted in the Department of Microbiology of Dhaka Medical College, Dhaka, Bangladesh from January 2015 to December 2015. Total 166 Escherichia coli, Klebsiella pneumoniae and Klebsiella oxytoca were isolated from urine, wound swab, pus, sputum and blood samples of patients of Dhaka Medical College Hospital. Antibiotic susceptibility test was performed by disk-diffusion technique. AmpC beta-lactamase producers were detected phenotypically by Modified three-dimensional test (MTDT). AmpC beta-lactamase genes (DHA, ACC, EBC, CIT, MOX, FOX) among the cefoxitin resistant Escherichia coli and Klebsiella species were detected by polymerase chain reaction (PCR). Sixty seven cefoxitin resistant Escherichia coli, Klebsiella pneumoniae and Klebsiella oxytoca were isolated during disk-diffusion technique. Among the 67 cefoxitin resistant strains, 30(44.78%) AmpC beta-lactamase producers were detected by MTDT and 59(88.06%) were detected by PCR. The dominant genotype found was CIT (62.69%) followed by DHA (53.73%). The results of this study showed high proportion of AmpC beta- lactamase enzyme producing Escherichia coli and Klebsiella species in Bangladesh. Regular surveillance of antibiotic resistance should be done in every tertiary care hospital to prevent spread of these strains.


Assuntos
Escherichia coli , Klebsiella , Antibacterianos/farmacologia , Proteínas de Bactérias , Bangladesh/epidemiologia , Estudos Transversais , Escherichia coli/genética , Humanos , Klebsiella/genética , Testes de Sensibilidade Microbiana , Centros de Atenção Terciária , beta-Lactamases/genética
6.
Bull Environ Contam Toxicol ; 105(3): 481-489, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32914331

RESUMO

The purpose of this study is to enhance the biodegradability of atrazine with FH-1 and NJ-1 alone by selecting the mixing ratio, optimizing the culture medium and conditions. The results showed that FH-1 and NJ-1 have the best biodegradation effect on atrazine being mixed in a volume ratio of 3:2. In a single factor experiment, sucrose and NH4Cl provided carbon and nitrogen sources for the mixed bacteria. Subsequently, composition of fermentation medium was further optimized using Box-Behnken design of response surface methodology. Based on the results, growth of mixed bacteria and biodegradation of atrazine performed best effects with a biodegradation rate of 85.6% when sucrose and NH4Cl amounts were 35.30 g/L and 10.28 g/L. The optimal medium condition was 10% inoculum of mixed bacteria, with initial atrazine concentration of 50 mg/L, neutral or weakly alkaline pH value, 30°C. The biodegradation rate reached 97.4%, 11.8% higher than the unoptimized condition.


Assuntos
Atrazina/metabolismo , Biodegradação Ambiental , Herbicidas/metabolismo , Klebsiella/metabolismo , Arthrobacter/metabolismo , Atrazina/análise , Carbono/metabolismo , Herbicidas/análise , Nitrogênio/metabolismo , Microbiologia do Solo
7.
Sci Total Environ ; 738: 140138, 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-32806344

RESUMO

An understanding of the inter-species relationships, especially their metabolic network in a mixed-culture system, is crucial to design an effective inoculum for enhancing the power generation of wastewater fed microbial fuel cell (MFC). In the present study, the influence of microbial mutualistic interactions on the power generation of palm oil mill effluent fed MFCs has been widely investigated by designing several co-culture and mixed culture inoculums. Among the different inoculum compositions, the highest power density of 14.8 W/m3 was achieved by Pseudomonas aeruginosa and Klebsiella variicola co-culture inoculum due to their synergistic relationships which were inter-linked via fermentation-based metabolites. Besides, the interaction of K. variicola and Bacillus cereus positively influenced the power generation resulting in a maximum power density of 11.8 W/m3 whereas the antagonistic relationship between B. cereus and P. aeruginosa resulted in a lower power generation of 1.9 W/m3. The microbial mutualistic interactions were investigated with polarization, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), as well as by using metabolite and biofilm analysis. It was observed that the synergism between bacteria enhanced power generation through the production of higher electron shuttling mediators and efficient biofilm formation as evidenced by polarization, CV and EIS analysis. In contrast, the antagonistic relationship resulted in production of cell inhibiting metabolites leading to the formation of ineffective biofilm. These findings demonstrate that the synergistic interaction between or within microorganisms is emergent in designing co-culture or mixed-culture inoculum for achieving maximum power generation in MFCs.


Assuntos
Fontes de Energia Bioelétrica , Técnicas de Cocultura , Klebsiella , Interações Microbianas , Águas Residuárias
8.
Arq. bras. med. vet. zootec. (Online) ; 72(4): 1277-1285, July-Aug. 2020. tab, ilus
Artigo em Português | LILACS, VETINDEX | ID: biblio-1131473

RESUMO

Foram padronizados os graus de lesões dos sacos aéreos em perus com aerossaculite, associadas com a presença de isolados de enterobactérias nesses órgãos. Um total de 110 amostras de sacos aéreos de perus machos com aerossaculite foi coletado para o estudo. Durante o processo de abate, as amostras foram coletadas por meio de swabs e submetidas a três métodos de armazenamento (imediato, congelado ou pré-incubado após congelamento) para posterior comparação das suas eficiências de isolamento. Os gêneros da família Enterobacteriaceae foram identificados pelas séries bioquímicas EPM, MILi e citrato de Simmons. O crescimento bacteriano ocorreu em 43,64% das amostras. Neste estudo, quatro padrões de lesões de aerossaculite foram identificados de acordo com as características patológicas dos sacos aéreos. Os principais gêneros de enterobactérias identificadas foram: Escherichia coli, Citrobacter, Proteus, Edwardsiella, Morganella, Kluyvera, Salmonella e Klebsiella. Foi observado que os graus padronizados como 3 e 4 apresentaram maior variedade de gêneros bacterianos. O armazenamento imediato apresentou maior porcentagem de positividade, 41,82%, no entanto o pré-incubado após congelamento se apresentou mais eficaz em relação à quantidade de colônias.(AU)


The degrees of air sac lesions in turkeys with airsacculitis were standardized, associated with the presence of Enterobacteriaceae isolated from these organs. A total of 110 samples of air sacs from male turkeys with airsacculitis were collected and analyzed. During the slaughtering process, the sample collection was done using swabs and submitted to three storage methods (immediate, frozen, or pre incubated after freezing) for further comparison of their isolated efficiency. The bacterial genera of the family Enterobacteriaceae were identified biochemical series EPM, MILi and Simmons citrate. Bacterial growth occurred in 43.64% of samples. In this study, four patterns of aerossaculitis lesions were identified according to the pathological characteristics of air sacs. The frequencies of the Enterobacteriaceae isolated identified in the samples were: Escherichia coli, Citrobacter, Proteus, Edwardsiella, Morganell, Kluyvera, Salmonella and Klebsiella. Otherwise, it was observed that the levels already standardized as level three and four showed higher variety of genus. The immediate storage showed higher percentage of positivity at 41.82%, however, the pre incubated after freezing showed more efficiency in relation to the quantity of colonies.(AU)


Assuntos
Animais , Perus , Sacos Aéreos/microbiologia , Enterobacteriaceae/isolamento & purificação , Infecções por Enterobacteriaceae/veterinária , Proteus , Salmonella , Citrobacter , Edwardsiella , Morganella , Kluyvera , Escherichia coli , Klebsiella
9.
PLoS One ; 15(6): e0235391, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32603368

RESUMO

BACKGROUND: Neonatal septicemia is a life threatening medical emergency that requires timely detection of pathogens with urgent rational antibiotics therapy. METHODS: A cross-sectional study was conducted between March 2017 to September 2018 among 317 septicemia suspected neonates at neonatal intensive care unit, Ayder Comprehensive Specialized Hospital, Mekelle, Tigray, North Ethiopia. A 3 mL of blood was collected from each participant. Identification of bacterial species was done using the standard microbiological techniques. Antibiotic sensitivity test was done using disk diffusion method. Data were entered and analyzed using computer software SPSS version 22. Bivariate and multivariate regression analysis was applied to determine the association between variables. RESULTS: Of the 317 (190 male and 127 female) neonates, 116 (36.6%) were found to be with culture proven septicemia. Klebsiella species were the predominant etiologic agents. Length of hospital stay (AOR (adjusted odds ratio) = 3.65 (2.17-6.13), p < 0.001) and low birth weight (AOR = 1.64 (1.13-2.78), p = 0.04) were the factors associated with neonatalsepticemia. Most isolates showeda frightening drug resistance rate to the commonly used antimicrobial drugs. K. pneumoniae, E. coli, Enterobacter and Citrobacter species were 57% to100% resistant to ceftazidime, ceftriaxone, gentamycin, amoxacillin-clavulunic acid and ampicillin. All, 9 (100%) isolates of S. aureus were resistant to oxacilline, ampicillin,erythromycin and gentamycin. Furthermore, 55.6% S. aureus isolates were Methicillin Resistant Staphylococcus aureus. CONCLUSION: Neonaltal septicemia is found to be significantly high in the present study. As most of the isolates are potentially related to hospital acquired infections, prevention and control policy should have to be more strengthening in the neonatal intensive care unit.


Assuntos
Antibacterianos/uso terapêutico , Bactérias , Sepse Neonatal , Ampicilina/uso terapêutico , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/isolamento & purificação , Citrobacter/efeitos dos fármacos , Citrobacter/isolamento & purificação , Estudos Transversais , Farmacorresistência Bacteriana , Enterobacter/efeitos dos fármacos , Enterobacter/isolamento & purificação , Escherichia coli/efeitos dos fármacos , Escherichia coli/isolamento & purificação , Etiópia , Feminino , Humanos , Recém-Nascido , Unidades de Terapia Intensiva Neonatal , Klebsiella/efeitos dos fármacos , Klebsiella/isolamento & purificação , Masculino , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Testes de Sensibilidade Microbiana , Sepse Neonatal/tratamento farmacológico , Sepse Neonatal/microbiologia , Oxacilina/uso terapêutico , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/isolamento & purificação
10.
Rev Assoc Med Bras (1992) ; 66(6): 824-829, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32696865

RESUMO

OBJECTIVE To describe the concentration of total and specific IgG antibodies anti-Streptococcus B, anti-lipopolysaccharide of Klebsiella spp, and anti-lipopolysaccharide of Pseudomonas spp in the umbilical cord of newborn(NB) twins and to analyze the association between neonatal infection and antibody concentration in the umbilical cord blood. METHODS A prospective cross-sectional study of a cohort of NB twins admitted during the period of 20 months. Patients with malformations and mothers with infection were excluded. Variables analyzed: gestational age(GA); birth weight(BW); antibody concentrations in umbilical cord blood; infection episodes. We used the paired Student t-test, Spearman correlation, and generalized estimation equation. RESULTS 57 pairs of twins were included, 4 excluded, making the sample of 110 newborns. GA=36±1.65weeks and BW=2304.8±460g(mean±SD). Antibody concentrations in twins(mean±SD): total IgG=835.71±190.73mg/dL, anti-StreptococcusB IgG=250.66±295.1 AU/mL, anti-lipopolysaccharide of Pseudomonas spp IgG=280.04±498.66 AU/mL and anti-lipopolysaccharide of Klebsiella spp IgG=504.75±933.93 AU/mL. There was a positive correlation between maternal antibody levels and those observed in newborns(p <0.005). The transplacental transfer of maternal total IgG and anti-LPS Pseudomonas IgG antibodies was significantly lower at NB GA <34 weeks(p <0.05). Five newborns were diagnosed with an infection. Infants with infection had significantly lower total IgG concentration(p <0.05). CONCLUSION This study showed a positive correlation between maternal and newborn antibodies levels. In infants younger than 34 weeks there is less transfer of total IgG and anti-LPS Pseudomonas IgG. The highest incidence of infection in the newborn group who had significantly lower total IgG serum antibodies reinforces the importance of anti-infectious protection afforded by passive immunity transferred from the mother.


Assuntos
Imunoglobulina G/sangue , Klebsiella , Infecções por Pseudomonas/sangue , Infecções Estreptocócicas/sangue , Estudos Transversais , Humanos , Imunidade Materno-Adquirida , Lactente , Recém-Nascido , Infecções , Estudos Prospectivos , Pseudomonas
11.
BMC Public Health ; 20(1): 894, 2020 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-32517771

RESUMO

BACKGROUND: Milk being a suitable medium for bacterial growth, it can serve as a source of bacterial contamination. Pathogenic bacteria in milk pose a serious health threat to humans and constitute about 90% of all dairy-related diseases. However, there are few studies that examined the health hazards of raw milk consumption in Ethiopia. Therefore, the objective of this study was to assess the prevalence of bacterial contamination and associated factors in milk produced for commercial purpose in Tigray region, northern Ethiopia. METHODS: This study used a cross-sectional study design, selected 315 persons (168 cafeterias, 96 dairy farms, and 51 milk vendors) for interview and collected the same number of bulk raw milk samples using systematic sampling procedure. Data were collected on socio-demographic, farm hygiene and milk handling practices by trained health professionals. Bacterial contamination was defined as total bacterial count (TBC) > 1 × 105, staphylococcus count (SC) > 105, or coliform count (CC) > 102 CFU/ml by culture and the species of bacteria were determined by standard biochemical tests. RESULTS: From the 315 milk samples tested, the prevalence of bacterial contamination was 52% (95% CI: 46.5-57.6). The mean counts of contaminated samples of TBC, SC, and CC were 8.94 ± 0.46 Standard Deviation (SD), 8.52 ± 0.6 SD, and 8.78 ± 0.49 SD log CFU/ml, respectively. The proportion of contamination was significantly lower in milk collected from dairy farms (32/96, 33.3, 95% CI: 24.5-43.2) compared to milk from vendors (33/51, 64.7, 95% CI: 51.4-66.2) and cafeterias (99/168, 58.9, 95% CI, 50.9-76.85). The milk samples were culture-positive for Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, K. oxytoca and Citrobacter freundii. CONCLUSIONS: Over half of the sampled raw milk exhibited bacterial contamination with increasing trend from farmers to points of sale. Thus, milk vendors and cafeteria owners should apply good hygienic and sanitation practices during handling of milk; use appropriate, clean containers, and cold chain during milk transportation; and refrigeration of milk during storage.


Assuntos
Bactérias/crescimento & desenvolvimento , Comércio , Inocuidade dos Alimentos , Abastecimento de Alimentos , Doenças Transmitidas por Alimentos/microbiologia , Leite/microbiologia , Animais , Citrobacter freundii/crescimento & desenvolvimento , Estudos Transversais , Indústria de Laticínios , Escherichia coli/crescimento & desenvolvimento , Etiópia , Fazendas , Microbiologia de Alimentos , Bactérias Gram-Negativas/crescimento & desenvolvimento , Humanos , Higiene , Klebsiella/crescimento & desenvolvimento , Pasteurização , População Rural , Staphylococcus aureus/crescimento & desenvolvimento
12.
Ecotoxicol Environ Saf ; 201: 110804, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32502907

RESUMO

Phenanthrene (PHE) is harmful to human health and is difficult to be eliminated from environment. In this study, an aerobic bacterium capable of use PHE as a sole carbon source and energy was isolated and classified as Klebsiella sp. PD3 according to 16S rDNA analysis. The degradation efficiency of PHE reached to about 78.6% after 12 days of incubation with strain PD3. Identification of metabolites formed during PHE degradation process by this strain was carried out by GC-MS. The first degradation step of PHE by PD3 was proposed to generate 1-hydroxy-2-naphthoic acid. Two subsequent different routes for the metabolism of 1-hydroxy-2-naphthoic acid were proposed. Strain PD3 also showed two plant growth promoting properties like phosphate solubilization and ACC deaminase activity. Inoculation with Klebsiella sp. PD3 significantly improved growth performance, biomass production, seed germination rate, photosynthetic capacity, antioxidant levels, relative water content and chlorophyll accumulation in rice (Oryza sativa L.) plants under PHE stress conditions in comparison with non-inoculation treatment. Moreover, PD3-inoculated rice showed lower ROS accumulation, ethylene production, ACC content, ACC oxidase activity and electrolyte leakage under PHE treatment compared to non-inoculated ones. The combination use of rice plants and strain PD3 was also shown to enhance the removal efficiency of PHE from the soil and decline the PHE accumulation in plants. Synergistic use of plants and bacteria with PHE degradation ability and PGPR attributes to remediate the PHE-contaminated soil will be an important and effective way in the phytoremediation of PHE-contaminated soils.


Assuntos
Adaptação Fisiológica , Klebsiella/metabolismo , Oryza/crescimento & desenvolvimento , Fenantrenos/análise , Microbiologia do Solo , Poluentes do Solo/análise , Biodegradação Ambiental , Clorofila/metabolismo , Etilenos/metabolismo , Klebsiella/isolamento & purificação , Oryza/metabolismo , Oryza/microbiologia , Estresse Oxidativo/efeitos dos fármacos , Fenantrenos/metabolismo , Solo/química , Poluentes do Solo/metabolismo
13.
Environ Res ; 188: 109777, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32599390

RESUMO

Treating and reusing greywater for agricultural irrigation is becoming increasingly prevalent in water-scarce regions such as the Middle East. However, the potential for antibiotic-resistant bacteria to be introduced into food systems or the environment via greywater reuse is a potential area of concern. It is known that off-grid treated greywater often has elevated levels of bacteria, however, little is known regarding the prevalence of antibiotic-resistant bacteria in this water source. To address this knowledge gap, samples (n = 61) of off-grid, household greywater (influent), treated greywater effluent, and irrigation pond water were collected between October 2017 and June 2018 from four farms in the West Bank, Palestinian Territories. Samples were tested for pH, turbidity, dissolved oxygen, electrical conductivity, and oxidation reduction potential. Standard membrane filtration was used to enumerate presumptive Escherichia coli, and isolates (n = 88) were purified, confirmed using 16S rRNA sequencing, and subjected to antimicrobial susceptibility testing using microbroth dilution. The majority of influent (76.5%) and effluent (70.6%) samples had detectable presumptive E. coli. Interestingly, the majority of the isolates were confirmed as Klebsiella sp. (n = 37), followed by E. coli (n = 32), and the remainder were classified as other Enterobacteriaceae (n = 19). A higher percentage of effluent isolates were fully susceptible to all tested antibiotics when compared to influent isolates (28.6% vs 18.6%). Resistance was most commonly observed against ampicillin (69.3% of all isolates), trimethoprim-sulfamethoxazole (11.4%), tetracycline (9.1%), and cefazolin (7.9%), and 7.9% of isolates were observed to be multidrug-resistant. While most water quality parameters were within Israeli and Palestinian wastewater reuse requirements, E. coli levels in effluent violated available standards. These findings suggest that, despite observed decreases in bacteria and an overall decrease in isolates expressing antibiotic resistance from influent to effluent, off-grid greywater treatment systems are still a potential source of both susceptible and antibiotic-resistant bacteria in the agricultural environment.


Assuntos
Escherichia coli , Klebsiella , Irrigação Agrícola , Antibacterianos/farmacologia , Árabes , Escherichia coli/genética , Humanos , Oriente Médio , Tanques , RNA Ribossômico 16S , Águas Residuárias
14.
PLoS One ; 15(6): e0234558, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32584852

RESUMO

Recently, our understanding of the elusive bacterial communities in the lower respiratory tract and their role in chronic lung disease has increased significantly. However, little is known about the respiratory microorganisms in patients with endobronchial tuberculosis (EBTB), which is a chronic inflammatory disease characterized by destruction of the tracheobronchial tree due to Mycobacterium tuberculosis (MTB) infection. We retrospectively reviewed data for histopathologically and microbiologically confirmed EBTB patients diagnosed at a tertiary referral hospital in South Korea between January 2013 and January 2019. Bacterial cultures were performed on bronchial washing from these patients at the time of EBTB diagnosis. A total of 216 patients with EBTB were included in the study. The median age was 73 years and 142 (65.7%) patients were female. Bacteria were detected in 42 (19.4%) patients. Additionally, bacterial co-infection was present in 6 (2.8%) patients. Apart from MTB, the most common microorganisms identified were Staphylococcus aureus (n = 14, 33.3%) followed by Klebsiella species (n = 12, 28.6%; 10 Klebsiella pneumoniae, 2 Klebsiella oxytoca), Streptococcus species (n = 5, 11.9%), Enterobacter species (n = 4, 9.5%), and Pseudomonas aeruginosa (n = 3, 7.1%). A variety of microorganisms were isolated from the bronchial washing indicating that changes in microorganism composition occur in the airways of patients with EBTB. Further studies are needed to investigate the clinical significance of this finding.


Assuntos
Sistema Respiratório/microbiologia , Tuberculose Pulmonar/microbiologia , Idoso , Broncoscopia , Enterobacter/isolamento & purificação , Feminino , Humanos , Klebsiella/isolamento & purificação , Masculino , Pessoa de Meia-Idade , Mycobacterium tuberculosis/isolamento & purificação , Pseudomonas aeruginosa/isolamento & purificação , República da Coreia , Estudos Retrospectivos , Staphylococcus/isolamento & purificação
15.
Appl Environ Microbiol ; 86(16)2020 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-32503911

RESUMO

Traditional fermentations have been widely studied from the microbiological point of view, but little is known from the functional perspective. In this work, nitrogen fixation by free-living nitrogen-fixing bacteria was conclusively demonstrated in pozol, a traditional Mayan beverage prepared with nixtamalized and fermented maize dough. Three aspects of nitrogen fixation were investigated to ensure that fixation actually happens in the dough: (i) the detection of acetylene reduction activity directly in the substrate, (ii) the presence of potential diazotrophs, and (iii) an in situ increase in acetylene reduction by inoculation with one of the microorganisms isolated from the dough. Three genera were identified by sequencing the 16S rRNA and nifH genes as Kosakonia, Klebsiella, and Enterobacter, and their ability to fix nitrogen was confirmed.IMPORTANCE Nitrogen-fixing bacteria are found in different niches, as symbionts in plants, in the intestinal microbiome of several insects, and as free-living microorganisms. Their use in agriculture for plant growth promotion via biological nitrogen fixation has been extensively reported. This work demonstrates the ecological and functional importance that these bacteria can have in food fermentations, reevaluating the presence of these genera as an element that enriches the nutritional value of the dough.


Assuntos
Acetileno/metabolismo , Bactérias/metabolismo , Enterobacteriaceae/metabolismo , Alimentos e Bebidas Fermentados/microbiologia , Fixação de Nitrogênio , Enterobacter/isolamento & purificação , Enterobacter/metabolismo , Enterobacteriaceae/isolamento & purificação , Klebsiella/isolamento & purificação , Klebsiella/metabolismo , México , Oxirredução , Oxirredutases/análise , RNA Bacteriano/análise , RNA Ribossômico 16S/análise
16.
Artigo em Inglês | MEDLINE | ID: mdl-32365834

RESUMO

Microbial immobilization is considered as a novel and environmentally friendly technology that uses microbes to reduce heavy metals accumulation in plants. To explore microbial resources which are useful in these applications, three water spinach rhizosphere soils polluted by different levels of heavy metals (heavy pollution (CQ), medium pollution (JZ), and relative clean (NF)) were collected. The community composition of heavy metal-immobilizing bacteria in rhizosphere soils and its effects on reducing the Cd2+ and Pb2+ concentrations in water spinach were evaluated. Four hundred strains were isolated from the CQ (belonging to 3 phyla and 14 genera), JZ (belonging to 4 phyla and 25 genera) and NF (belonged to 6 phyla and 34 genera) samples, respectively. In the CQ sample, 137 strains showed a strong ability to immobilize Cd2+ and Pb2+, giving Cd2+ and Pb2+ removal rates of greater than 80% in solution; Brevundimonas, Serratia, and Pseudoarthrobacter were the main genera. In total, 62 strains showed a strong ability to immobilize Cd2+ and Pb2+ in the JZ sample and Bacillus and Serratia were the main genera. A total of 22 strains showed a strong ability to immobilize Cd2+ and Pb2+ in the NF sample, and Bacillus was the main genus. Compared to the control, Enterobacter bugandensis CQ-7, Bacillus thuringensis CQ-33, and Klebsiella michiganensis CQ-169 significantly increased the dry weight (17.16-148%) of water spinach and reduced the contents of Cd2+ (59.78-72.41%) and Pb2+ (43.36-74.21%) in water spinach. Moreover, the soluble protein and Vc contents in the shoots of water spinach were also significantly increased (72.1-193%) in the presence of strains CQ-7, CQ-33 and CQ-169 compared to the control. In addition, the contents of Cd and Pb in the shoots of water spinach meet the standard for limit of Cd2+ and Pb2+ in vegetables in the presence of strains CQ-7, CQ-33 and CQ-169. Thus, the results provide strains as resources and a theoretical basis for the remediation of Cd- and Pb-contaminated farmlands for the safe production of vegetables.


Assuntos
Ipomoea , Metais Pesados , Poluentes do Solo , Bacillus thuringiensis , Bactérias , Cádmio , Enterobacter , Ipomoea/química , Klebsiella , Chumbo , Metais Pesados/metabolismo , Solo , Água
17.
J Med Microbiol ; 69(6): 792-796, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32459618

RESUMO

Introduction. Klebsiella rods, belonging to the family Enterobacteriaceae, are generally opportunistic pathogens commonly associated with nosocomial infections, especially in intensive care units. Interestingly, strains of this genus also show multi-drug resistance. In recent years, multiple studies have indicated that the prevalence of carbapenem resistance has increased rapidly among Klebsiella representatives.Aim. The aim of this study was to assess the usefulness of selected phenotypic and genotypic methods for the detection of the most important carbapenemases in Klebsiella strains.Methodology. The study involved 51 Klebsiella strains. The ability to produce carbapenemases was determined by phenotypic methods (double disc synergy test, test with four discs and three inhibitors, CarbaNP test, culture on chromogenic medium, panels of automatic method - Phoenix, CIM test and modified Hodge test). The potential for carbapenemase synthesis was also evaluated using real-time PCR, detecting bla VIM/IMP, bla KPC, bla NDM and bla OXA-48 genes.Results. Using the phenotypic methods, positive results were obtained for all of the analysed strains. Using PCR, carbapenemase synthesis potential was confirmed on the molecular level; the bla VIM gene was detected in 23 strains, the bla NDM gene in 26 strains and the bla OXA-48 gene in two strains.Conclusion. There was complete agreement between the carbapenemases detected by the genetic method and the results obtained with phenotypic methods.


Assuntos
Proteínas de Bactérias/análise , Klebsiella/enzimologia , beta-Lactamases/análise , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/genética , Farmacorresistência Bacteriana , Genótipo , Fenótipo , beta-Lactamases/biossíntese , beta-Lactamases/genética
18.
Sci Total Environ ; 729: 139075, 2020 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-32388135

RESUMO

Microbial degradation is one of the most efficient and reliable ways to remove the residues of Chlorimuron-ethyl in the environments such as soil and water. In this study, a glutathione-s-transferase (GST) gene Kj-gst was cloned from the Chlorimuron-ethyl degrading bacterial strain Klebsiella jilinsis 2N3. Results showed that Kj-gst played a key role in the degradation of Chlorimuron-ethyl by strain 2N3. The mutant with gene Kj-gst knocked out showed reduced relative activity up to 70% compared with the wild type in 8 h in culture. After the knockout gene was complemented, the degradation ability of the complement mutant was essentially comparable to that of the wild type. The protein Kj-GST (50 µg) obtained from the gene Kj-gst expressed and purified in E. coli strain BL21(DE3) was capable of degrading Chlorimuron-ethyl with an initial concentration of 50 mg/mL by 42.91% under the optimal conditions (15 °C and pH = 7). Point mutation experiments on a glycine located at position 101 (Glu101) confirmed that the H site of glutathione (GSH) is the key component in Kj-GST for degrading Chlorimuron-ethyl. We conclude that Kj-GST is demonstrated for the first time to degrade Chlorimuron-ethyl with its main functional site identified at the H site of GSH, shedding insight to revealing the molecular mechanisms of degrading Chlorimuron-ethyl by Klebsiella jilinsis 2N3.


Assuntos
Klebsiella , Escherichia coli , Glutationa , Glutationa Transferase , Herbicidas , Pirimidinas , Poluentes do Solo , Compostos de Sulfonilureia
19.
Int J Syst Evol Microbiol ; 70(5): 3278-3286, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32375936

RESUMO

A novel bacterial strain, designated TOUT106T, was isolated from the surface of a tomato. The cells were rod-shaped, Gram-negative, encapsulated and non-motile. Strain TOUT106T grows best at 28 °C and pH 7.0 and can tolerate up to 2 % (w/v) NaCl. Based on 16S rRNA gene phylogeny, strain TOUT106T was placed close to the Salmonella clade, with close similarity to Salmonella enterica subsp. arizonae strain NCTC 8297T (98.42 %). Results of genome-based phylogenetic analysis revealed that strain TOUT106T is placed well in the Klebsiella-Raoultella clade, by forming a distinct branch with Klebsiella michiganensis DSM25444T, Klebsiella oxytoca NCTC132727T, Klebsiella grimontii 06D021T and Klebsiella pasteurii SB6412T. The genomic DNA G+C content of strain TOUT106T is 53.53 mol%. The average nucleotide identity values of TOUT106T were less than 86.5 % with closely related members of the family Enterobacteriaceae. The major fatty acids of strain TOUT106T were C16 : 0, C17:0 cyclo, C14:0 3OH/C16:1 iso, C14 : 0, C19:0 cyclo ω8c, C18:1 ω6c/C18:1 ω7c, C12 : 0 and C16:1 ω7c/C16:1 ω6c. Strain TOUT106T showed differences in physiological, phenotypic and protein profiles by MALDI-TOF MS compared to its closest relatives. Based on the results of phenotypic, chemotaxonomic and phylogenetic analyses, strain TOUT106T could be distinguished from the recognized species of the genus Klebsiella. It is suggested to represent a novel species of this genus, for which the name Klebsiella indica sp. nov. is proposed. The type strain is TOUT106T (=MCC 2901T=KACC 21384T=JCM 33718T).


Assuntos
Frutas/microbiologia , Klebsiella/classificação , Lycopersicon esculentum/microbiologia , Filogenia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Índia , Klebsiella/isolamento & purificação , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
20.
Chemosphere ; 253: 126729, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32289610

RESUMO

Microorganisms with high tetracycline (TC) degradation efficiencies are required for biological processes for TC-containing wastewater treatment. With multiple enrichment cultures, a TC-degrading strain TR5 was isolated from chicken manure mixture in a large broiler farm, which was identified as Klebsiella pneumoniae by 16S rRNA gene sequencing and biochemical properties. Strain TR5 could degrade TC quickly (∼90% within 36 h) with the initial TC concentration of 200 mg/L under optimized conditions via single-factor experiment coupled with RSM. Strain TR5 could detoxify TC and generate much less toxic products as long as cultured more than one day. Three TC-degrading pathways were proposed based on 8 possible products. A transformant containing a plasmid from TR5 acquired TC-degrading ability, indicating that TC-degrading genes were located on this plasmid. Complete sequencing of pYK5 showed that isomerase-, oxidoreductase-, and transferases-encoding genes were found and were inferred to be involved in TC degradation. TR5 may not degrade TC completely and it can utilize some carbon-containing compounds derived from TC via the effect of formylglutathione hydrolase-encoding gene. Our findings showed that strain TR5 could be a promising agent for wastewater treatment, and genes involved in TC degradation are worthy of further investigations for enzyme preparations development.


Assuntos
Antibacterianos/análise , Genes Bacterianos , Klebsiella/metabolismo , Redes e Vias Metabólicas/efeitos dos fármacos , Tetraciclina/análise , Águas Residuárias/química , Animais , Biodegradação Ambiental , Galinhas/metabolismo , Klebsiella/genética , Esterco/análise , Redes e Vias Metabólicas/genética , Plasmídeos , RNA Ribossômico 16S/genética
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