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1.
Dokl Biochem Biophys ; 486(1): 206-208, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31367822

RESUMO

The aim of this work was to study the fine structure of bacterial films grown on the inner tube surface of a flow reactor. Using the scanning electron microscopy (SEM) approaches, the detailed biofilm relief was visualized. The action of electrochemically reduced water (ERW) on the biofilm ultrastructure generated by the plankton form of E. coli and/or lacto bacteria was investigated. The treatment with an ERW solution destroyed the biofilm organic polymer matrix and bacterial cells embedded in the matrix.


Assuntos
Biofilmes/efeitos dos fármacos , Água/química , Água/farmacologia , Biofilmes/crescimento & desenvolvimento , Eletroquímica , Escherichia coli/efeitos dos fármacos , Escherichia coli/fisiologia
2.
J Insect Sci ; 19(4)2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31343690

RESUMO

Bombyx mori (Lepidoptera: Bombycidae) is an important economic insect and a classic Lepidopteran model system. Although immune-related genes have been identified at a genome-wide scale in the silkworm, proteins involved in immune defense of the silkworm have not been comprehensively characterized. In this study, two types of bacteria were injected into the silkworm larvae, Gram-negative Escherichia coli (Enterobacteriales: Enterobacteriaceae), or Gram-positive Staphylococcus aureus (Bacillales: Staphylococcaceae). After injection, proteomic analyses of hemolymph were performed by liquid chromatography-tandem mass spectrometry. In total, 514 proteins were identified in the uninduced control group, 540 were identified in the E. coli-induced group, and 537 were identified in the S. aureus-induced group. Based on Uniprot annotations, 32 immunological recognition proteins, 28 immunological signaling proteins, and 21 immunological effector proteins were identified. We found that 127 proteins showed significant upregulation, including 10 immunological recognition proteins, 4 immunological signaling proteins, 11 immunological effector proteins, and 102 other proteins. Using real-time quantitative polymerase chain reaction in the fat body, we verified that immunological recognition proteins, signaling proteins, and effector proteins also showed significant increases at the transcriptional level after infection with E. coli and S. aureus. Five newly identified proteins showed upregulation at both protein and transcription levels after infection, including 30K protein, yellow-d protein, chemosensory protein, and two uncharacterized proteins. This study identified many new immune-related proteins, deepening our understanding of the immune defense system in B. mori. The data have been deposited to the iProX with identifier IPX0001337000.


Assuntos
Bombyx/genética , Bombyx/imunologia , Escherichia coli/fisiologia , Proteínas de Insetos/imunologia , Proteoma/imunologia , Staphylococcus aureus/fisiologia , Animais , Bombyx/crescimento & desenvolvimento , Bombyx/microbiologia , Proteínas de Insetos/análise , Larva/crescimento & desenvolvimento , Larva/imunologia , Larva/microbiologia , Proteoma/análise , Proteômica
3.
Nat Commun ; 10(1): 2635, 2019 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-31201302

RESUMO

Multidrug efflux pumps actively expel a wide range of toxic substrates from the cell and play a major role in intrinsic and acquired drug resistance. In Gram-negative bacteria, these pumps form tripartite assemblies that span the cell envelope. However, the in situ structure and assembly mechanism of multidrug efflux pumps remain unknown. Here we report the in situ structure of the Escherichia coli AcrAB-TolC multidrug efflux pump obtained by electron cryo-tomography and subtomogram averaging. The fully assembled efflux pump is observed in a closed state under conditions of antibiotic challenge and in an open state in the presence of AcrB inhibitor. We also observe intermediate AcrAB complexes without TolC and discover that AcrA contacts the peptidoglycan layer of the periplasm. Our data point to a sequential assembly process in living bacteria, beginning with formation of the AcrAB subcomplex and suggest domains to target with efflux pump inhibitors.


Assuntos
Proteínas da Membrana Bacteriana Externa/metabolismo , Proteínas de Transporte/fisiologia , Proteínas de Escherichia coli/metabolismo , Proteínas de Escherichia coli/fisiologia , Escherichia coli/fisiologia , Lipoproteínas/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Antibacterianos/farmacologia , Proteínas de Transporte/efeitos dos fármacos , Proteínas de Transporte/ultraestrutura , Microscopia Crioeletrônica/métodos , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Tomografia com Microscopia Eletrônica/métodos , Escherichia coli/efeitos dos fármacos , Escherichia coli/ultraestrutura , Proteínas de Escherichia coli/antagonistas & inibidores , Proteínas de Escherichia coli/efeitos dos fármacos , Proteínas de Escherichia coli/ultraestrutura , Microscopia Intravital/métodos , Proteínas Associadas à Resistência a Múltiplos Medicamentos/antagonistas & inibidores , Peptidoglicano/metabolismo , Periplasma/metabolismo , Ligação Proteica/efeitos dos fármacos , Estrutura Quaternária de Proteína/efeitos dos fármacos
4.
Water Sci Technol ; 79(8): 1550-1560, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31169513

RESUMO

Free water surface constructed wetlands (FWS CW) are efficient technologies to limit the transfer of antibiotic resistant bacteria (ARB) originating from urban effluents into the aquatic environment. However, the decrease in ARB from inflow to outflow through the FWS CW may be explained by their transfer from the water body to the sediment. To investigate the behavior of ARB in the sediment of a FWS CW, we inoculated three microcosms with two strains of extended-spectrum beta-lactamase producing Escherichia coli (ESBL E. coli) belonging to two genotypes. Microcosms were composed of two sediments collected at two locations of an FWS CW from which the strains were isolated. Phragmites were planted in one of the microcosms. The survival curves of the two strains were close regardless of the genotype and the type of sediment. After a rapid decline, both strains were able to survive at low level in the sediments for 50 days. Their fate was not affected by the presence of phragmites. Changes in the bla content and antibiotic resistance of the inoculated strains were observed after three weeks of incubation, indicating that FWS CW sediments are favorable environments for spread of antibiotic resistance genes and for the acquisition of new antibiotic resistance.


Assuntos
Resistência Microbiana a Medicamentos/genética , Escherichia coli/fisiologia , Áreas Alagadas , beta-Lactamases/metabolismo , Humanos , Microbiologia da Água
5.
Nat Commun ; 10(1): 2442, 2019 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-31164651

RESUMO

Motile cells often explore natural environments characterized by a high degree of structural complexity. Moreover cell motility is also intrinsically noisy due to spontaneous random reorientations and speed fluctuations. This interplay of internal and external noise sources gives rise to a complex dynamical behavior that can be strongly sensitive to details and hard to model quantitatively. In striking contrast to this general picture we show that the mean residence time of swimming bacteria inside artificial complex microstructures is quantitatively predicted by a generic invariance property of random walks. We find that while external shape and internal disorder have dramatic effects on the distributions of path lengths and residence times, the corresponding mean values are constrained by the sole free surface to perimeter ratio. As a counterintuitive consequence, bacteria escape faster from structures with higher density of obstacles due to the lower accessible surface.


Assuntos
Fenômenos Fisiológicos Bacterianos , Escherichia coli/fisiologia , Microscopia de Fluorescência
6.
J Med Microbiol ; 68(8): 1244-1252, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31184571

RESUMO

The high incidence of urinary tract infection (UTI) among women and children, in combination with a lack of antibiotic efficacy with regard to pathogen eradication and recurrence prevention, as well as the negative side effects associated with antibiotics, has led researchers to explore the role of non-steroidal anti-inflammatory drugs as a primary management strategy. The aim of this study was to determine whether ibuprofen (IBU) or one of its major metabolites, 2-carboxyibuprofen (CIBU), could affect the growth and adhesion of the two most common uropathogens, Escherichia coli and Enterococcus faecalis. The bacterial growth and adhesion to the urothelial cells of E. coli UTI89 and E. faecalis 1131 in the presence of physiologically relevant concentrations of IBU and CIBU were assessed. The effect of IBU on bacterial adhesion to urothelial cells was also assessed following exposure to trimethoprim/sulfamethoxazole (TMP/SMX) and nitrofurantoin. Bacterial growth was not affected by IBU. Further, only at high levels of IBU not regularly found in the bladder was there a significant increase in E. faecalis 1131 attachment at growth inhibitory concentrations of TMP/SMX. There was no effect on the attachment of E. faecalis or E. coli to urothelial cells in the presence of nitrofurantoin. These studies indicate that the beneficial effects of IBU for UTI management are likely mediated through its anti-inflammatory properties rather than direct interactions with uropathogens in the bladder.


Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Enterococcus faecalis/isolamento & purificação , Escherichia coli/isolamento & purificação , Ibuprofeno/farmacologia , Infecções Urinárias/microbiologia , Anti-Infecciosos Urinários/farmacologia , Bactérias/efeitos dos fármacos , Aderência Bacteriana/efeitos dos fármacos , Linhagem Celular , Enterococcus faecalis/efeitos dos fármacos , Enterococcus faecalis/crescimento & desenvolvimento , Enterococcus faecalis/fisiologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/fisiologia , Humanos , Ibuprofeno/análogos & derivados , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Nitrofurantoína/farmacologia , Combinação Trimetoprima e Sulfametoxazol/farmacologia , Urotélio
7.
Nat Commun ; 10(1): 2052, 2019 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-31053707

RESUMO

Many microbial functions happen within communities of interacting species. Explaining how species with disparate growth rates can coexist is important for applications such as manipulating host-associated microbiota or engineering industrial communities. Here, we ask how microbes interacting through their chemical environment can achieve coexistence in a continuous growth setup (similar to an industrial bioreactor or gut microbiota) where external resources are being supplied. We formulate and experimentally constrain a model in which mediators of interactions (e.g. metabolites or waste-products) are explicitly incorporated. Our model highlights facilitation and self-restraint as interactions that contribute to coexistence, consistent with our intuition. When interactions are strong, we observe that coexistence is determined primarily by the topology of facilitation and inhibition influences not their strengths. Importantly, we show that consumption or degradation of chemical mediators moderates interaction strengths and promotes coexistence. Our results offer insights into how to build or restructure microbial communities of interest.


Assuntos
Interações Microbianas/fisiologia , Microbiota/fisiologia , Modelos Biológicos , Brevibacillus/fisiologia , Escherichia coli/fisiologia , Staphylococcus/fisiologia
8.
BMC Infect Dis ; 19(1): 369, 2019 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-31046689

RESUMO

BACKGROUND: Urinary tract infections (UTIs) are one of the most common bacterial infections. High recurrence rates and the increasing antibiotic resistance among uropathogens constitute a large social and economic problem in current public health. We assumed that combination of treatment that includes the administration ceragenins (CSAs), will reinforce the effect of antimicrobial LL-37 peptide continuously produced by urinary tract epithelial cells. Such treatment might be an innovative approach to enhance innate antibacterial activity against multidrug-resistant E. coli. METHODS: Antibacterial activity measured using killing assays. Biofilm formation was assessed using crystal violet staining. Viability of bacteria and bladder epithelial cells subjected to incubation with tested agents was determined using MTT assays. We investigated the effects of chosen molecules, both alone and in combinations against four clinical strains of E. coli, obtained from patients diagnosed with recurrent UTI. RESULTS: We observed that the LL-37 peptide, whose concentration increases at sites of urinary infection, exerts increased bactericidal effect against E. coli when combined with ceragenins CSA-13 and CSA-131. CONCLUSION: We suggest that the employment of combination of natural peptide LL-37 with synthetic analogs might be a potential solution to treat urinary tract infections caused by drug-resistant bacteria.


Assuntos
Antibacterianos/uso terapêutico , Esteroides/uso terapêutico , Infecções Urinárias/tratamento farmacológico , Peptídeos Catiônicos Antimicrobianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/uso terapêutico , Biofilmes/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Escherichia coli/fisiologia , Humanos , Esteroides/farmacologia , Infecções Urinárias/microbiologia
9.
Vet Res ; 50(1): 31, 2019 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-31046828

RESUMO

Avian pathogenic Escherichia coli (APEC) is a facultative intracellular pathogen, and intracellular persistence in macrophages is essential for APEC extraintestinal dissemination. Until now, there is still no systematic interpretation of APEC intracellular proliferation. Intracellular survival factors, especially involved in pathometabolism, need to be further revealed. Acetate plays critical roles in supporting energy homeostasis and acts as a metabolic signal in the inflammatory response of eukaryotes. In this study, we identified that APEC acs-yjcH-actP operon, encoding acetate assimilation system, presented the host-induced transcription during its proliferation in macrophages. Our result showed that this acetate assimilation system acted as a novel intracellular survival factor to promote APEC replication within macrophages. Furthermore, deletion of acs-yjcH-actP operon in APEC decreased its cytotoxic level to macrophages. qRT-PCR results showed that the production of pro-inflammatory cytokines (IL-1ß, IL-6, IL-8, IL-12ß, and TNF-α) and iNOS in FY26∆acs-yjcH-actP infected macrophages were obviously down-regulated compared to that in wild-type FY26 infected cells. Deletion of actP/yjcH/acs genes attenuated APEC virulence and colonization capability in avian lungs in vivo for colibacillosis infection models. And acetate assimilation system acted as a virulence factor and conferred a fitness advantage during APEC early colonization. Taken together, our research unravelled the metabolic requirement of APEC intracellular survival/replication within macrophages, and acetate metabolic requirement acted as an important strategy of APEC pathometabolism. The intracellular acetate consumption during facultative intracellular bacteria replication within macrophages promoted immunomodulatory disorders, resulting in excessively pro-inflammatory responses of host macrophages.


Assuntos
Acetatos/metabolismo , Doenças das Aves/microbiologia , Infecções por Escherichia coli/veterinária , Escherichia coli/metabolismo , Macrófagos/microbiologia , Animais , Linhagem Celular , Galinhas , Citocinas/metabolismo , Patos/microbiologia , Ensaio de Imunoadsorção Enzimática , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/fisiologia , Infecções por Escherichia coli/metabolismo , Infecções por Escherichia coli/microbiologia , Doenças das Aves Domésticas/microbiologia , Reação em Cadeia da Polimerase em Tempo Real
10.
Int J Food Microbiol ; 300: 53-63, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31048092

RESUMO

Microbial survival of heating and cross-contamination are the two transmission routes during food preparation in the consumers' kitchen that are relevant for QMRA (Quantitative Microbial Risk Assessment). The aim of the present study was to extend the limited amount of data on microbial survival during real-life preparation of meat and meat products and to obtain accessory temperature data that allow for a more general (product unspecific) approach. Therefore survival data were combined with extensive measurements of time- and location dependent temperature using an infrared camera for the surface and buttons for the inside of the product, supplemented with interpolation modelling. We investigated the survival of heating of Escherichia coli O111:H2 in beefsteak, hamburgers (beef and 50% beef 50% pork (HH)), meatballs (beef and HH) and crumbs (HH). For beefsteak, survival as a whole is dominated by the sides, giving a log reduction of 1-2 (rare), 3-4 (medium) and 6-7 (done). Limited measurements indicated that done preparation gave 5-6 log reduction for crumbs and at least 8-9 log for the other products. Medium preparation gave a higher reduction in hamburgers (2-4 log) than in meatballs (1-2 log) and in beef (3-4) than in HH (2-3) hamburgers. In general, our 'done' results give larger inactivation than found in literature, whereas 'rare' and 'medium' results are similar. The experiments resulted in two types of curves of D70/z-values, dependent on product, doneness and for beefsteaks sides vs. top/bottom. One type of curve agrees reasonably with literature D70/z estimates from isothermal temperature experiments, which supports using these estimates for home style cooking QMRA calculations. In case of the other type of curve, which is mainly found for (near) surface contamination in close contact with the pan, these literature estimates cannot be applied. We also applied a simplified approach, assuming thermal inactivation is dominated by the highest temperatures reached. The time duration of this highest temperature gives accessory D-values which prove to fit with isothermal temperature literature data, thus suggesting application of such data for QMRA is possible by this approach also, which is less labor intensive both in terms of measurements and modelling. In real life, variability in product properties and preparation styles is large. Further studies are needed to analyze the effect on survival, preferably focusing on determining the essential variables. More variation in heating time will allow for estimating D70/z point estimates rather than curves representing possible sets of D70/z-values.


Assuntos
Culinária , Microbiologia de Alimentos , Produtos da Carne/microbiologia , Carne/microbiologia , Temperatura Ambiente , Animais , Bovinos , Culinária/normas , Escherichia coli/fisiologia , Modelos Teóricos , Suínos
11.
Nat Commun ; 10(1): 2075, 2019 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-31061418

RESUMO

Diverse processes-e.g. bioremediation, biofertilization, and microbial drug delivery-rely on bacterial migration in disordered, three-dimensional (3D) porous media. However, how pore-scale confinement alters bacterial motility is unknown due to the opacity of typical 3D media. As a result, models of migration are limited and often employ ad hoc assumptions. Here we reveal that the paradigm of run-and-tumble motility is dramatically altered in a porous medium. By directly visualizing individual Escherichia coli, we find that the cells are intermittently and transiently trapped as they navigate the pore space, exhibiting diffusive behavior at long time scales. The trapping durations and the lengths of "hops" between traps are broadly distributed, reminiscent of transport in diverse other disordered systems; nevertheless, we show that these quantities can together predict the long-time bacterial translational diffusivity. Our work thus provides a revised picture of bacterial motility in complex media and yields principles for predicting cellular migration.


Assuntos
Escherichia coli/fisiologia , Microscopia Intravital/métodos , Modelos Biológicos , Análise de Célula Única/métodos , Hidrogéis/química , Microscopia de Fluorescência/métodos , Movimento/fisiologia , Porosidade
12.
Malawi Med J ; 31(1): 12-18, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-31143391

RESUMO

Introduction: In Malawi, EcoSan sludge from ecological sanitation (EcoSan) latrines has been found to contain helminths, Salmonella and E. coli above WHO recommended levels making sludge unsuitable for direct handling and use on food crops. This research investigated survival of pathogens in EcoSan sludge with time after sealing the pit. Method: An observational longitudinal follow-up study was conducted where EcoSan latrines were followed from August 2015 to July 2016 in Blantyre and Chikwawa in Southern Malawi. The study enrolled 51 latrines in total with 35 latrines [13 fossa alterna (FAs) and 22 urine diverting dry latrines (UDDLs)] remaining at the end of study. Samples were collected five times from each latrine and examined for helminths, Salmonella and E. coli in the laboratory. Poisson regression was employed to assess factors that significantly contribute to pathogen die off at p<0.05. Results: Average concentrations of all pathogens investigated reduced over 12-month follow-up period except for Salmonella which increased. A. lumbricoides, increased to 2.3 viable eggs during the second sampling and decreased to 0.4 viable eggs per gram after 12 months of follow-up. Time was the only consistent predictor for concentration of helminths. Type of latrine and location were not significant predictors of helminths concentration (p>0.05). However, Salmonella and E. coli colonies were significantly higher in UDDLs (Blantyre) than FAs (Chikwawa) (p<0.05). Conclusion: Pathogen concentration was highest after recommended six months of storage posing a public health risk to those handling and using it for agriculture purposes. It is therefore recommended that the current guidelines be reviewed to suit Malawi context. A storage period of one year or more is recommended.


Assuntos
Infecções por Escherichia coli/epidemiologia , Helmintíase/epidemiologia , Saúde Pública , Saneamento/métodos , Esgotos/análise , Toaletes/estatística & dados numéricos , Animais , Escherichia coli/fisiologia , Infecções por Escherichia coli/microbiologia , Seguimentos , Helmintíase/parasitologia , Helmintos/fisiologia , Humanos , Estudos Longitudinais , Malaui/epidemiologia
13.
Biomed Res Int ; 2019: 2487921, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31093495

RESUMO

Sepsis is a critical, complex medical condition, and the major causative pathogens of sepsis are both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Genome-wide studies identify differentially expressed genes for sepsis. However, the results for the identification of DEGs are inconsistent or discrepant among different studies because of heterogeneity of specimen sources, various data processing methods, or different backgrounds of the samples. To identify potential transcriptional biomarkers that are differently expressed in S. aureus- and E. coli-induced sepsis, we have analyzed four microarray datasets from GEO database and integrated results with bioinformatics tools. 42 and 54 DEGs were identified in both S. aureus and E. coli samples from any three different arrays, respectively. Hierarchical clustering revealed dramatic differences between control and sepsis samples. GO functional annotations suggested that DEGs in the S. aureus group were mainly involved in the responses of both defense and immune regulation, but DEGs in the E. coli group were mainly related to the regulation of endopeptidase activity involved in the apoptotic signaling pathway. Although KEGG showed inflammatory bowel disease in the E. coli group, the KEGG pathway analysis showed that these DEGs were mainly involved in the tumor necrosis factor signaling pathway, fructose metabolism, and mannose metabolism in both S. aureus- and E. coli-induced sepsis. Eight common genes were identified between sepsis patients with either S. aureus or E. coli infection and controls in this study. All the candidate genes were further validated to be differentially expressed by an ex-vivo human blood model, and the relative expression of these genes was performed by qPCR. The qPCR results suggest that GK and PFKFB3 might contribute to the progression of S. aureus-induced sepsis, and CEACAM1, TNFAIP6, PSTPIP2, SOCS3, and IL18RAP might be closely linked with E. coli-induced sepsis. These results provide new viewpoints for the pathogenesis of both sepsis and pathogen identification.


Assuntos
Biomarcadores/metabolismo , Escherichia coli/fisiologia , Sepse/genética , Sepse/microbiologia , Staphylococcus aureus/fisiologia , Transcrição Genética , Análise por Conglomerados , Bases de Dados Genéticas , Perfilação da Expressão Gênica , Ontologia Genética , Humanos , Anotação de Sequência Molecular , Reprodutibilidade dos Testes , Transcriptoma/genética , Regulação para Cima/genética
14.
Environ Sci Pollut Res Int ; 26(21): 21304-21311, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31124069

RESUMO

Several strains of Escherichia coli harbor virulence traits, resulting in E. coli-related intestinal and extra-intestinal infections. Various studies have reported that extra-intestinal pathogenic E. coli (ExPEC) strains were prevalent in nonhuman reservoirs, including environmental waterways. It is therefore important to identify the pathogenic potential and/or ExPEC status of E. coli strains inhabiting the aquatic environments associated with anthropogenic activities. Besides virulence-associated genes, biofilm production also helps in the survival of E. coli in environmental waterbodies. Thus, the aim of the current study was to assess the virulence potential, ExPEC status, and biofilm-producing capability of E. coli isolated from the River Yamuna, a major river traversing the National Capital Region of Delhi, India. We also tried to discern a co-relation, if any, between virulence, biofilm formation, and antimicrobial resistance in these strains. Our results indicated that virulence-associated genes were scarce and none of the strain qualified the molecular criteria essential for ExPEC. This suggested that E. coli strains which can presumably cause human extra-intestinal infections were not prominent in the River Yamuna. However, the fact that more than 80% of the aquatic E. coli isolates were moderate and strong biofilm producers suggests that E. coli in these environments might serve as opportunistic pathogens. Also, no unequivocal association was observed between biofilm production, virulence, and ß-lactamase genes in E. coli strains. As per the best of our knowledge, this is the first study where the relationship between virulence, biofilms, and antimicrobials has been examined in E. coli, isolated from an Indian urban aquatic waterbody.


Assuntos
Monitoramento Ambiental , Escherichia coli/fisiologia , Rios/microbiologia , Biofilmes , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Proteínas de Escherichia coli/genética , Humanos , Índia , Fenótipo , Filogenia , Virulência/genética , Fatores de Virulência/genética , beta-Lactamases/genética
15.
Anal Bioanal Chem ; 411(16): 3653-3663, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31049617

RESUMO

A rapid and easy method that takes advantage of an inexpensive and portable fibre-based spectroscopic system (optrode) to determine the ratio of live to dead bacteria is proposed. Mixtures of live and dead Escherichia coli with proportions of live:dead cells varying from 0 to 100% were stained using SYTO 9 and propidium iodide (PI) and measured using the optrode. We demonstrated several approaches to obtaining the proportions of live:dead E. coli in a mixture of both live and dead, from analyses of the fluorescence spectra collected by the optrode. To find a suitable technique for predicting the percentage of live bacteria in a sample, four analysis methods were assessed and compared: SYTO 9:PI fluorescence intensity ratio, an adjusted fluorescence intensity ratio, single-spectrum support vector regression (SVR) and multi-spectra SVR. Of the four analysis methods, multi-spectra SVR obtained the most reliable results and was able to predict the percentage of live bacteria in 108 bacteria/mL samples between c. 7 and 100% live, and in 107 bacteria/mL samples between c. 7 and 73% live. By demonstrating the use of multi-spectra SVR and the optrode to monitor E. coli viability, we raise points of consideration for spectroscopic analysis of SYTO 9 and PI and aim to lay the foundation for future work that uses similar methods for different bacterial species.


Assuntos
Análise Custo-Benefício , Escherichia coli/fisiologia , Viabilidade Microbiana , Espectrometria de Fluorescência/métodos , Escherichia coli/isolamento & purificação , Citometria de Fluxo , Corantes Fluorescentes/química , Compostos Orgânicos/química , Reprodutibilidade dos Testes
16.
Phys Rev E ; 99(4-1): 042409, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31108688

RESUMO

Bacteria communicate with each other to coordinate macroscale behaviors including pathogenesis, biofilm formation, and antibiotic production. Empirical evidence suggests that bacteria are capable of communicating at length scales far exceeding the size of individual cells. Several mechanisms of signal interference have been observed in nature, and how interference influences macroscale activity within microbial populations is unclear. Here we examined the exchange of quorum sensing signals to coordinate microbial activity over long distances in the presence of a variable amount of interference through a neighboring signal-degrading strain. As the level of interference increased, communication over large distances was disrupted and at a critical amount of interference, large-scale communication was suppressed. We explored this transition in experiments and reaction-diffusion models, and confirmed that this transition is a two-dimensional percolation transition. These results demonstrate the utility of applying physical models to emergence in complex biological networks to probe robustness and universal quantitative features.


Assuntos
Escherichia coli/citologia , Modelos Biológicos , Percepção de Quorum , Biofilmes , Difusão , Escherichia coli/genética , Escherichia coli/fisiologia
17.
Schweiz Arch Tierheilkd ; 161(6): 387-394, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31145681

RESUMO

INTRODUCTION: Fluoroquinolones (FQ) undergo minimal metabolization in animals and are excreted via faeces and urine, where they enter the environment almost unchanged. In this study we investigated the presence of quinolone-resistant Escherichia coli (E. coli) in the environment of 65 farms of a sow pool system in Switzerland. Two hundred and seventy-nine samples from liquid manure and wipes of dust and pen walls were collected and the use of FQ on the farms was investigated. From 45% of dust samples, 52% of pen wall samples and 69% of liquid manure samples quinolone-resistant E. coli (QRE) were cultivated. Significant higher counts of quinolone-resistant colonies were found in liquid manure samples than in dust (p < 0.01) or pen wall samples (p < 0.05). Samples from breeding farms were significantly more often positive than samples from fattening farms (p < 0.01). Samples taken from farms using FQ were significantly more frequently positive for QRE than samples from farms without FQ usage (p < 0.01). On 97% of the farms with FQ use and 85% (23/27) of the farms without FQ use QRE could be found in at least one sample (no significant difference). Overall, QRE were widespread in the environment of the investigated pig farms.


Assuntos
Farmacorresistência Bacteriana , Microbiologia Ambiental , Escherichia coli/fisiologia , Animais , Escherichia coli/efeitos dos fármacos , Quinolonas/farmacologia , Suínos , Suíça
18.
Int J Food Microbiol ; 299: 33-38, 2019 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-30952015

RESUMO

In order to determine the microbial safety of produce, conventional fecal indicator bacteria (CFIB) such as Escherichia coli and Enterococcus are quantified as a standard practice. Bacteroidales are also fecal indicators mostly used for water samples; however, their use and persistence in foods has been rarely studied. In this study, persistence of both CFIB and genetic markers of host-specific Bacteroidales was determined in artificially contaminated materials and vegetables with different textured surfaces under different storage conditions. Sterile feces were contaminated with E. coli, E. faecalis, Bacteroidesthetaiotaomicron (human origin), and Bacteroidales from porcine and bovine origin. Feces were applied to filters of mixed cellulose esters and tomatoes (smooth surface) and flat cork coupons and melons (rough surface) and stored at 10 °C/95% relative humidity (RH) and 25 °C/65%RH for up to 25 days. Bacteroidales markers were analyzed by real-time polymerase chain reaction (qPCR), whereas CFIB were plated onto selective agars. CFIB detection on filters and cork surfaces declined over time. E. coli decreased 2.9 log CFU and 1.2 log CFU per filter and cork, respectively, at 10 °C/95%RH and 5.8 log CFU and 1.8 log CFU per filter and cork, respectively, at 25 °C/65%RH. E. faecalis decreased 1.9 log CFU on filters and 1.3 log CFU on cork at 10 °C/95%RH and 2.6 log CFU/filter and cork under both storage conditions. Although E. coli levels in tomatoes slightly increased during storage, the levels decreased by the end of the assays. However, CFIB levels in melons stored at 10 °C/95%RH increased after 20 days; when stored at 25 °C/65%RH, these levels increased after five days. Bacteroidales levels (universal and host-specific markers) in inanimated material and produce did not show significant differences (P ≤ 0.01) over time. Stability and persistence of Bacteroidales genetic markers make them superior to CFIB as markers and are alternatives for determining the risk of exposure to feces-contaminated produce.


Assuntos
Bacteroidetes/fisiologia , Enterococcus/fisiologia , Escherichia coli/fisiologia , Microbiologia de Alimentos/métodos , Frutas/microbiologia , Animais , Bacteroidetes/genética , Bovinos , Cucurbitaceae/microbiologia , Enterococcus/genética , Escherichia coli/genética , Marcadores Genéticos/genética , Humanos , Lycopersicon esculentum/microbiologia , Reação em Cadeia da Polimerase em Tempo Real , Suínos
19.
Dokl Biochem Biophys ; 484(1): 85-87, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31012022

RESUMO

The biofilm formation by bacteria E. coli is a magnetosensitive process. The combined effects of a magnetic magnesium isotope 25Mg and a static magnetic field in the range of 20-35 mT stimulate biofilm formation by E. coli compared to nonmagnetic magnesium isotopes 24.26Mg. Magnetic field effects in the range of 2-10 mT, recorded for all bacteria regardless of the magnesium-isotope enrichment of the nutrient medium, indicate the sensitivity of intracellular processes to weak magnetic fields.


Assuntos
Biofilmes/crescimento & desenvolvimento , Escherichia coli/fisiologia , Magnésio/farmacologia , Campos Magnéticos , Isótopos/farmacologia
20.
Int J Nanomedicine ; 14: 1907-1918, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30936693

RESUMO

Purpose: Alumina substrates are one of the commonly used scaffolds applied in cell culture, but in order to prevent formation of biofilm on the alumina substrate, these substrates are modified with carbon nanotube. Methods: The alumina substrate was made by a two-step anodization method and was then modified with carbon nanotubes by simple chemical reaction. The substrates were characterized with FTIR, SEM, EDX, 3D laser scanning digital microscope, contact angle (CA) and surface free energy (SFE). To determine how this modification influences the reduction of biofilm, biofilm of two various bacteria, Escherichia coli (E.coli) and Staphylococcus aureus (S. aureus), were investigated. Results: The biofilm on the modified substrate decreased due to the presence of carbon nanotubes and increased antibacterial properties. Dental pulp stem cells (DPSCs) were cultured onto flat alumina (FA) and nanoporous alumina-multiwalled carbon nanotubes (NAMC) substrates to examine how the chemical modification and surface topography affects growth of DPSCs. Conclusion: Cell attachment and proliferation were investigated with SEM and Presto Blue assay, and the findings show that the NAMC substrates are suitable for cell culture.


Assuntos
Técnicas de Cultura de Células/instrumentação , Técnicas de Cultura de Células/métodos , Polpa Dentária/citologia , Nanotubos de Carbono , Células-Tronco/citologia , Óxido de Alumínio , Aderência Bacteriana , Biofilmes , Proliferação de Células , Células Cultivadas , Escherichia coli/fisiologia , Humanos , Microscopia Confocal , Microscopia Eletrônica de Varredura , Nanoporos , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/fisiologia
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