Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 4.190
Filtrar
1.
Mar Drugs ; 20(3)2022 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-35323468

RESUMO

Volatile compounds from the marine cyanolichen Lichina pygmaea, collected from the Moroccan Atlantic coast, were extracted by hydrodistillation and their putative chemical composition was investigated by gas chromatography coupled to mass spectrometry (GC/MS). Based on the obtained results, Lichina pygmaea volatile compounds (LPVCs) were mainly dominated by sesquiterpenes compounds, where γ-himachalene, ß-himachalene, (2E,4E)-2,4 decadienal and α-himachalene were assumed to be the most abundant constituents, with percentage of 37.51%, 11.71%, 8.59% and 7.62%, respectively. LPVCs depicted significant antimicrobial activity against all tested strains (Staphylococcus aureus CCMM B3, Pseudomonas aeruginosa DSM 50090, Escherichia coli ATCC 8739 and Candida albicans CCMM-L4) with minimum inhibitory concentration (MIC) values within the range of 1.69-13.5 mg/mL. Moreover, this LPVC showed interesting scavenging effects on the 2,2-diphenyl-1-picrylhydrazyl radical with an IC50 of 0.21 mg/mL. LPVCs could be an approving resource with moderate antimicrobial potential and interesting antioxidant activity for cosmetics and pharmaceutical applications.


Assuntos
Anti-Infecciosos , Antioxidantes , Ascomicetos/química , Sesquiterpenos , Compostos Orgânicos Voláteis , Anti-Infecciosos/química , Anti-Infecciosos/isolamento & purificação , Anti-Infecciosos/farmacologia , Antioxidantes/química , Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Compostos de Bifenilo/química , Candida albicans/efeitos dos fármacos , Candida albicans/crescimento & desenvolvimento , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Picratos/química , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Sesquiterpenos/análise , Sesquiterpenos/isolamento & purificação , Sesquiterpenos/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/isolamento & purificação , Compostos Orgânicos Voláteis/farmacologia
2.
Nat Commun ; 13(1): 721, 2022 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-35132084

RESUMO

Much of our understanding of bacterial behavior stems from studies in liquid culture. In nature, however, bacteria frequently live in densely packed spatially-structured communities. How does spatial structure affect bacterial cooperative behaviors? In this work, we examine rhamnolipid production-a cooperative and virulent behavior of Pseudomonas aeruginosa. Here we show that, in striking contrast to well-mixed liquid culture, rhamnolipid gene expression in spatially-structured colonies is strongly associated with colony specific growth rate, and is impacted by perturbation with diffusible quorum signals. To interpret these findings, we construct a data-driven statistical inference model which captures a length-scale of bacterial interaction that develops over time. Finally, we find that perturbation of P. aeruginosa swarms with quorum signals preserves the cooperating genotype in competition, rather than creating opportunities for cheaters. Overall, our data demonstrate that the complex response to spatial localization is key to preserving bacterial cooperative behaviors.


Assuntos
Interações Microbianas/fisiologia , Modelos Biológicos , Proteínas de Bactérias/genética , Biomassa , Contagem de Colônia Microbiana , Regulação Bacteriana da Expressão Gênica , Glicolipídeos/genética , Glicolipídeos/metabolismo , Locomoção , Interações Microbianas/genética , Mutação , Imagem Óptica , Regiões Promotoras Genéticas , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/metabolismo , Pseudomonas aeruginosa/fisiologia , Percepção de Quorum , Análise Espaço-Temporal
3.
Int J Mol Sci ; 23(3)2022 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-35163794

RESUMO

The search for new microbicide compounds is of an urgent need, especially against difficult-to-eradicate biofilm-forming bacteria. One attractive option is the application of cationic multivalent dendrimers as antibacterials and also as carriers of active molecules. These compounds require an adequate hydrophilic/hydrophobic structural balance to maximize the effect. Herein, we evaluated the antimicrobial activity of cationic carbosilane (CBS) dendrimers unmodified or modified with polyethylene glycol (PEG) units, against planktonic and biofilm-forming P. aeruginosa culture. Our study revealed that the presence of PEG destabilized the hydrophilic/hydrophobic balance but reduced the antibacterial activity measured by microbiological cultivation methods, laser interferometry and fluorescence microscopy. On the other hand, the activity can be improved by the combination of the CBS dendrimers with endolysin, a bacteriophage-encoded peptidoglycan hydrolase. This enzyme applied in the absence of the cationic CBS dendrimers is ineffective against Gram-negative bacteria because of the protective outer membrane shield. However, the endolysin-CBS dendrimer mixture enables the penetration through the membrane and then deterioration of the peptidoglycan layer, providing a synergic antimicrobial effect.


Assuntos
Antibacterianos/farmacologia , Endopeptidases/farmacologia , Polietilenoglicóis/química , Pseudomonas aeruginosa/crescimento & desenvolvimento , Silanos/farmacologia , Antibacterianos/química , Bacteriófagos/metabolismo , Biofilmes/efeitos dos fármacos , Dendrímeros , Composição de Medicamentos , Sinergismo Farmacológico , Interferometria , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Microscopia de Fluorescência , Plâncton/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos dos fármacos , Silanos/química
4.
Cell Rep ; 38(7): 110372, 2022 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-35172131

RESUMO

The Pseudomonas quinolone signal (PQS) is a multifunctional quorum sensing molecule of key importance to P. aeruginosa. Here, we report that the lytic Pseudomonas bacterial virus LUZ19 targets this population density-dependent signaling system by expressing quorum sensing targeting protein (Qst) early during infection. We demonstrate that Qst interacts with PqsD, a key host quinolone signal biosynthesis pathway enzyme, resulting in decreased levels of PQS and its precursor 2-heptyl-4(1H)-quinolone. The lack of a functional PqsD enzyme impairs LUZ19 infection but is restored by external supplementation of 2-heptyl-4(1H)-quinolone, suggesting that LUZ19 exploits the PQS system for successful infection. We establish a broad functional interaction network of Qst, which includes enzymes of cofactor biosynthesis pathways (CoaC/ThiD) and a non-ribosomal peptide synthetase pathway (PA1217). Qst therefore represents an exquisite example of intricate reprogramming of the bacterium by a phage, which may be further exploited as tool to combat antibiotic resistant bacterial pathogens.


Assuntos
Bacteriófagos/metabolismo , Pseudomonas aeruginosa/metabolismo , Percepção de Quorum , Acetiltransferases/metabolismo , Antibacterianos/metabolismo , Proteínas de Bactérias/metabolismo , Carbono/metabolismo , Redes e Vias Metabólicas , Metaboloma , Metabolômica , Modelos Biológicos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/virologia , Quinolonas/metabolismo , Metabolismo Secundário , Proteínas Virais/metabolismo
5.
Int J Mol Sci ; 23(3)2022 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-35163819

RESUMO

While blue LED (b-LED) light is increasingly being studied for its cytotoxic activity towards bacteria in therapy of skin-related infections, its effects on eukaryotic cells plasticity are less well characterized. Moreover, since different protocols are often used, comparing the effect of b-LED towards both microorganisms and epithelial surfaces may be difficult. The aim of this study was to analyze, in the same experimental setting, both the bactericidal activity and the effects on human keratinocytes. Exposure to b-LED induced an intense cytocidal activity against Gram-positive (i.e, Staphylococcus aureus) and Gram-negative (i.e., Pseudomonas aeruginosa) bacteria associated with catheter-related infections. Treatment with b-LED of a human keratinocyte cell line induced a transient cell cycle arrest. At the molecular level, exposure to b-LED induced a transient downregulation of Cyclin D1 and an upregulation of p21, but not signs of apoptosis. Interestingly, a transient induction of phosphor-histone γ-H2Ax, which is associated with genotoxic damages, was observed. At the same time, keratinocytes underwent a transient epithelial to mesenchymal transition (EMT)-like phenotype, characterized by E-cadherin downregulation and SNAIL/SLUG induction. As a functional readout of EMT induction, a scratch assay was performed. Surprisingly, b-LED treatment provoked a delay in the scratch closure. In conclusion, we demonstrated that b-LED microbicidal activity is associated with complex responses in keratinocytes that certainly deserve further analysis.


Assuntos
Pontos de Checagem do Ciclo Celular/efeitos da radiação , Queratinócitos/citologia , Luz/efeitos adversos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/crescimento & desenvolvimento , Antígenos CD/metabolismo , Caderinas/metabolismo , Proliferação de Células , Ciclina D1/metabolismo , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Síndrome de Down , Transição Epitelial-Mesenquimal/efeitos da radiação , Regulação da Expressão Gênica/efeitos dos fármacos , Células HaCaT , Humanos , Queratinócitos/metabolismo , Queratinócitos/efeitos da radiação , Viabilidade Microbiana/efeitos da radiação , Pseudomonas aeruginosa/efeitos da radiação , Fatores de Transcrição da Família Snail/metabolismo , Staphylococcus aureus/efeitos da radiação
6.
Molecules ; 27(4)2022 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-35208949

RESUMO

Nanotechnology has become a dire need of the current era and the green synthesis of nanoparticles offers several advantages over other methods. Nanobiotechnology is an emerging field that contributes to many domains of human life, such as the formulation of nanoscale drug systems or nanomedicine for the diagnosis and treatment of diseases. Medicinal plants are the main sources of lead compounds, drug candidates and drugs. This work reports the green synthesis of Ag nanoparticles (AgNPs) using the aqueous bark extract of Zanthozylum armatum, which was confirmed by a UV absorption at 457 nm. XRD analysis revealed an average size of 18.27 nm and SEM showed the particles' spherical shape, with few irregularly shaped particles due to the aggregation of the AgNPs. FT-IR revealed the critical functional groups of phytochemicals which acted as reducing and stabilizing agents. The bark extract showed rich flavonoids (333 mg RE/g) and phenolic contents (82 mg GAE/g), which were plausibly responsible for its high antioxidant potency (IC50 = 14.61 µg/mL). Extract-loaded AgNPs exhibited the highest but equal inhibition against E. coli and P. aeruginosa (Z.I. 11.0 mm), whereas methanolic bark extract inhibited to a lesser extent, but equally to both pathogens (Z.I. 6.0 mm). The aqueous bark extract inhibited P. aeruginosa (Z.I. 9.0 mm) and (Z.I. 6.0 mm) E. coli. These findings-especially the biosynthesis of spherical AgNPs of 18.27 nm-provide promise for further investigation and for the development of commercializable biomedical products.


Assuntos
Antibacterianos , Escherichia coli/crescimento & desenvolvimento , Nanopartículas Metálicas/química , Extratos Vegetais/química , Pseudomonas aeruginosa/crescimento & desenvolvimento , Prata , Zanthoxylum/química , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/farmacologia , Prata/química , Prata/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier
7.
Molecules ; 27(3)2022 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-35164333

RESUMO

BACKGROUND: Infectious diseases represent a significant global strain on public health security and impact on socio-economic stability all over the world. The increasing resistance to the current antimicrobial treatment has resulted in the crucial need for the discovery and development of novel entities for the infectious treatment with different modes of action that could target both sensitive and resistant strains. METHODS: Compounds were synthesized using the classical organic chemistry methods. Prediction of biological activity spectra was carried out using PASS and PASS-based web applications. Pharmacophore modeling in LigandScout software was used for quantitative modeling of the antibacterial activity. Antimicrobial activity was evaluated using the microdilution method. AutoDock 4.2® software was used to elucidate probable bacterial and fungal molecular targets of the studied compounds. RESULTS: All compounds exhibited better antibacterial potency than ampicillin against all bacteria tested. Three compounds were tested against resistant strains MRSA, P. aeruginosa and E. coli and were found to be more potent than MRSA than reference drugs. All compounds demonstrated a higher degree of antifungal activity than the reference drugs bifonazole (6-17-fold) and ketoconazole (13-52-fold). Three of the most active compounds could be considered for further development of the new, more potent antimicrobial agents. CONCLUSION: Compounds 5b (Z)-3-(3-hydroxyphenyl)-5-((1-methyl-1H-indol-3-yl)methylene)-2-thioxothiazolidin-4-one and 5g (Z)-3-[5-(1H-Indol-3-ylmethylene)-4-oxo-2-thioxo-thiazolidin-3-yl]-benzoic acid as well as 5h (Z)-3-(5-((5-methoxy-1H-indol-3-yl)methylene)-4-oxo-2-thioxothiazolidin-3-yl)benzoic acid can be considered as lead compounds for further development of more potent and safe antibacterial and antifungal agents.


Assuntos
Antibacterianos/síntese química , Antifúngicos/síntese química , Fungos/crescimento & desenvolvimento , Tiazolidinas/síntese química , Ampicilina/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Antifúngicos/química , Antifúngicos/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Fungos/efeitos dos fármacos , Imidazóis/farmacologia , Cetoconazol/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Simulação de Acoplamento Molecular , Estrutura Molecular , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Relação Estrutura-Atividade , Tiazolidinas/química , Tiazolidinas/farmacologia
8.
Microbiol Spectr ; 10(1): e0086021, 2022 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-35019682

RESUMO

Human neutrophil peptide-1 (HNP-1) is a promising antibiotic candidate, but its clinical applications have been hampered by challenges during mass production and an inadequate understanding of its bactericidal mechanisms. In this study, we demonstrated that Escherichia coli expressing full-length preproHNP-1 secretes a soluble form of HNP-1, which can be recovered from the total cell lysate after isopropyl thio-ß-d-galactoside (IPTG) induction and ultrafiltration. Label-free quantitative proteomics and co-immunoprecipitation experiments revealed that HNP-1 induces cell apoptosis in bacteria by causing DNA and membrane damage. Notably, we found that HNP-1 disrupts the DNA damage response pathway by interfering with the binding of RecA to single-stranded DNA (ssDNA). Further experiments demonstrated that HNP-1 encapsulated in liposomes inhibits the growth of methicillin-resistant Staphylococcus aureus (MRSA) and meropenem-resistant Pseudomonas aeruginosa (MRPA). These results indicated that recombinant protein expression may be a simple and cost-effective solution to produce HNP-1 and that RecA inhibition via HNP-1 may serve as an alternative strategy to counteract antibiotic resistance. IMPORTANCE Human neutrophil peptide-1 (HNP-1) is a promising antibiotic candidate, but its clinical application has been hampered by the difficulty of mass production and an inadequate understanding of its bactericidal mechanisms. In this study, we demonstrated that recombinant protein expression combined with ultrafiltration may be a simple and cost-effective solution to HNP-1 production. We further found that HNP-1 induces bacterial apoptosis and prevents its SOS repair pathway from binding to the RecA protein, which may be a new antibacterial mechanism. In addition, we showed that HNP-1 encapsulated in liposomes inhibits the growth of methicillin-resistant Staphylococcus aureus (MRSA) and meropenem-resistant Pseudomonas aeruginosa (MRPA). These results provide new insights into the production and antibacterial mechanism of HNP-1, both of which may promote its clinical application.


Assuntos
Antibacterianos/farmacologia , Escherichia coli/metabolismo , alfa-Defensinas/genética , alfa-Defensinas/farmacologia , Antibacterianos/metabolismo , Farmacorresistência Bacteriana , Escherichia coli/genética , Humanos , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , alfa-Defensinas/metabolismo
9.
Viruses ; 14(1)2022 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-35062325

RESUMO

Outer membrane vesicles (OMVs) released from gram-negative bacteria are key elements in bacterial physiology, pathogenesis, and defence. In this study, we investigated the role of Pseudomonas aeruginosa OMVs in the anti-phage defence as well as in the potential sensitization to LPS-specific phages. Using transmission electron microscopy, virion infectivity, and neutralization assays, we have shown that both phages efficiently absorb on free vesicles and are unable to infect P. aeruginosa host. Nevertheless, the accompanying decrease in PFU titre (neutralization) was only observed for myovirus KT28 but not podovirus LUZ7. Next, we verified whether OMVs derived from wild-type PAO1 strain can sensitize the LPS-deficient mutant (Δwbpl PAO1) resistant to tested phages. The flow cytometry experiments proved a quite effective and comparable association of OMVs to Δwbpl PAO1 and wild-type PAO1; however, the growth kinetic curves and one-step growth assay revealed no sensitization event of the OMV-associated phage-resistant P. aeruginosa deletant to LPS-specific phages. Our findings for the first time identify naturally formed OMVs as important players in passive resistance (protection) of P. aeruginosa population to phages, but we disproved the hypothesis of transferring phage receptors to make resistant strains susceptible to LPS-dependent phages.


Assuntos
Vesículas Citoplasmáticas/virologia , Lipopolissacarídeos , Fagos de Pseudomonas , Pseudomonas aeruginosa/virologia , Membrana Externa Bacteriana , Bacteriófagos , Bactérias Gram-Negativas , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/crescimento & desenvolvimento
10.
Sci Rep ; 12(1): 180, 2022 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-34996996

RESUMO

Pseudomonas aeruginosa is an opportunistic bacterium causing several health problems and having many virulence factors like biofilm formation on different surfaces. There is a significant need to develop new antimicrobials due to the spreading resistance to the commonly used antibiotics, partly attributed to biofilm formation. Consequently, this study aimed to investigate the anti-biofilm and anti-quorum sensing activities of Dioon spinulosum, Dyer Ex Eichler extract (DSE), against Pseudomonas aeruginosa clinical isolates. DSE exhibited a reduction in the biofilm formation by P. aeruginosa isolates both in vitro and in vivo rat models. It also resulted in a decrease in cell surface hydrophobicity and exopolysaccharide quantity of P. aeruginosa isolates. Both bright field and scanning electron microscopes provided evidence for the inhibiting ability of DSE on biofilm formation. Moreover, it reduced violacein production by Chromobacterium violaceum (ATCC 12,472). It decreased the relative expression of 4 quorum sensing genes (lasI, lasR, rhlI, rhlR) and the biofilm gene (ndvB) using qRT-PCR. Furthermore, DSE presented a cytotoxic activity with IC50 of 4.36 ± 0.52 µg/ml against human skin fibroblast cell lines. For the first time, this study reports that DSE is a promising resource of anti-biofilm and anti-quorum sensing agents.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Chromobacterium/efeitos dos fármacos , Extratos Vegetais/farmacologia , Infecções por Pseudomonas/prevenção & controle , Pseudomonas aeruginosa/efeitos dos fármacos , Percepção de Quorum/efeitos dos fármacos , Dermatopatias Bacterianas/prevenção & controle , Zamiaceae , Animais , Antibacterianos/isolamento & purificação , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biofilmes/crescimento & desenvolvimento , Chromobacterium/crescimento & desenvolvimento , Chromobacterium/metabolismo , Modelos Animais de Doenças , Feminino , Regulação Bacteriana da Expressão Gênica , Indóis/metabolismo , Testes de Sensibilidade Microbiana , Extratos Vegetais/isolamento & purificação , Infecções por Pseudomonas/microbiologia , Infecções por Pseudomonas/patologia , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/metabolismo , Ratos , Dermatopatias Bacterianas/microbiologia , Dermatopatias Bacterianas/patologia , Zamiaceae/química
11.
J Thorac Cardiovasc Surg ; 163(3): 841-849.e1, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33478833

RESUMO

INTRODUCTION: High-dose nitric oxide (NO) has been shown effective against a variety of micro-organisms in vitro, including common bacteria found in donor organs. However, clinical obstacles related to its implementation in vivo are the formation of methemoglobin and the accumulation of toxic nitrogen compounds. Ex vivo lung perfusion (EVLP) is a platform that allows for organ maintenance with an acellular perfusion solution, thus overcoming these limitations. The present study explores the safety of continuous high-dose inhaled (iNO) during EVLP for an extended period of 12 hours. METHODS: Lungs procured from Yorkshire pigs were randomized into control (standard ventilation) and treatment (standard ventilation + 200 ppm iNO) groups, then perfused with an acellular solution for 12 hours (n = 4/group). Lung physiology and biological markers were evaluated. RESULTS: After 12 hours of either standard EVLP or EVLP + 200 ppm iNO, we did not notice any significant physiologic difference between the groups: pulmonary oxygenation (P = .586), peak airway pressures (P = .998), and dynamic (P = .997) and static (P = .908) lung compliances. In addition, no significant differences were seen among proinflammatory cytokines measured in perfusate and lung tissue. Importantly, most common toxic compounds were kept at safe levels throughout the treatment course. CONCLUSIONS: High-dose inhaled NO delivered continuously over 12 hours appears to be safe without inducing any significant pulmonary inflammation or deterioration in lung function. These findings support further efficacy studies to explore the use of iNO for the treatment of infections in donor lungs during EVLP.


Assuntos
Anti-Infecciosos/administração & dosagem , Infecções Bacterianas/prevenção & controle , Circulação Extracorpórea , Pulmão/irrigação sanguínea , Pulmão/efeitos dos fármacos , Óxido Nítrico/administração & dosagem , Preservação de Órgãos , Perfusão , Administração por Inalação , Animais , Anti-Infecciosos/toxicidade , Infecções Bacterianas/microbiologia , Burkholderia cepacia/efeitos dos fármacos , Burkholderia cepacia/crescimento & desenvolvimento , Circulação Extracorpórea/efeitos adversos , Estudos de Viabilidade , Pulmão/microbiologia , Pulmão/cirurgia , Masculino , Metemoglobina/metabolismo , Modelos Animais , Óxido Nítrico/toxicidade , Preservação de Órgãos/efeitos adversos , Perfusão/efeitos adversos , Pneumonectomia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Sus scrofa
12.
Cell Host Microbe ; 30(1): 31-40.e5, 2022 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-34932986

RESUMO

Phages impose strong selection on bacteria to evolve resistance against viral predation. Bacteria can rapidly evolve phage resistance via receptor mutation or using their CRISPR-Cas adaptive immune systems. Acquisition of CRISPR immunity relies on the insertion of a phage-derived sequence into CRISPR arrays in the bacterial genome. Using Pseudomonas aeruginosa and its phage DMS3vir as a model, we demonstrate that conditions that reduce bacterial growth rates, such as exposure to bacteriostatic antibiotics (which inhibit cell growth without killing), promote the evolution of CRISPR immunity. We demonstrate that this is due to slower phage development under these conditions, which provides more time for cells to acquire phage-derived sequences and mount an immune response. Our data reveal that the speed of phage development is a key determinant of the evolution of CRISPR immunity and suggest that use of bacteriostatic antibiotics can trigger elevated levels of CRISPR immunity in human-associated and natural environments.


Assuntos
Imunidade Adaptativa/genética , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/genética , Sistemas CRISPR-Cas/imunologia , Bactérias/crescimento & desenvolvimento , Bactérias/imunologia , Bacteriófagos/genética , Genoma Bacteriano , Humanos , Mutação , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/imunologia
13.
Angew Chem Int Ed Engl ; 61(7): e202112456, 2022 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-34913238

RESUMO

Using artificial hemes for the reconstruction of natural heme proteins represents a fascinating approach to enhance the bioactivity of the latter. We report the synthesis of various metal 5-oxaporphyrinium cations as cofactors, and a cobalt 5-oxaporphyrinium cation was successfully incorporated into the heme-acquisition protein (HasA) secreted by Pseudomonas aeruginosa. We hypothesize that the oxaporphyrinium cation strongly binds to the HasA-specific outer membrane receptor (HasR) due to its cationic charge, which prevents the subsequent acquisition of heme. In fact, the reconstructed HasA inhibited the growth of Pseudomonas aeruginosa and even of multidrug-resistant P. aeruginosa.


Assuntos
Antibacterianos/farmacologia , Cobalto/farmacologia , Hemeproteínas/química , Porfirinas/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Antibacterianos/síntese química , Antibacterianos/química , Cátions/química , Cátions/farmacologia , Cobalto/química , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Porfirinas/química , Pseudomonas aeruginosa/crescimento & desenvolvimento
14.
J Microbiol ; 59(12): 1067-1074, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34865196

RESUMO

Transposon insertion site sequencing (TIS) is a technique that determines the insertion profile of a transposon mutant library by massive parallel sequencing of transposon-genomic DNA junctions. Because the transposon insertion profile reflects the abundance of each mutant in the library, it provides information to assess the fitness contribution of each genetic locus of a bacterial genome in a specific growth condition or strain background. Although introduced only about a dozen years ago, TIS has become an important tool in bacterial genetics that provides clues to study biological functions and regulatory mechanisms. Here, I describe a protocol for generating high density transposon insertion mutant libraries and preparing Illumina sequencing samples for mapping the transposon junctions of the transposon mutant libraries using Pseudomonas aeruginosa as an example.


Assuntos
Elementos de DNA Transponíveis , DNA Bacteriano/genética , Sequenciamento de Nucleotídeos em Larga Escala , Pseudomonas aeruginosa/genética , Análise de Sequência de DNA/métodos , Sequência de Bases , Biblioteca Gênica , Aptidão Genética , Genoma Bacteriano , Mutagênese Insercional , Mutação , Pseudomonas aeruginosa/crescimento & desenvolvimento
15.
Microbiol Spectr ; 9(3): e0090121, 2021 12 22.
Artigo em Inglês | MEDLINE | ID: mdl-34878335

RESUMO

Early initiated adequate antibiotic treatment is essential in intensive care. Shortening the length of antibiotic susceptibility testing (AST) can accelerate clinical decision-making. Our objective was to develop a simple flow cytometry (FC)-based AST that produces reliable results within a few hours. We developed a FC-based AST protocol (MICy) and tested it on six different bacteria strains (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pyogenes, Enterococcus faecalis) in Mueller-Hinton and Luria-Bertani broth. We monitored the bacterial growth by FC to define the optimal time of AST. All bacteria were tested against 12 antibiotics and the MIC values were compared to microdilution used as reference method. McNemar and Fleiss' kappa inter-observer tests were performed to analyze the bias between the two methods. Susceptibility profiles of the two methods were also compared. We found that FC is able to detect the bacterial growth after 4-h incubation. The point-by-point comparison of MICy and microdilution resulted in exact match above 87% (2642/3024) of all measurements. The MIC values obtained by MICy and microdilution agreed over 80% (173/216) within ±1 dilution range that gives a substantial inter-observer agreement with weighted Fleiss' kappa. By using the EUCAST clinical breakpoints, we defined susceptibility profiles of MICy that were identical to microdilution in more than 92% (197/213) of the decisions. MICy resulted 8.7% major and 3.2% very major discrepancies. MICy is a new, simple FC-based AST method that produces susceptibility profile with low failure rate a workday earlier than the microdilution method. IMPORTANCE MICy is a new, simple and rapid flow cytometry based antibiotic susceptibility testing (AST) method that produces susceptibility profile a workday earlier than the microdilution method or other classical phenotypic AST methods. Shortening the length of AST can accelerate clinical decision-making as targeted antibiotic treatment improves clinical outcomes and reduces mortality, duration of artificial ventilation, and length of stay in intensive care unit. It can also reduce nursing time and costs and the spreading of antibiotic resistance. In this study, we present the workflow and methodology of MICy and compare the results produced by MICy to microdilution step by step.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Citometria de Fluxo/métodos , Bactérias/crescimento & desenvolvimento , Enterococcus faecalis/efeitos dos fármacos , Enterococcus faecalis/crescimento & desenvolvimento , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana/métodos , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Streptococcus pyogenes/efeitos dos fármacos , Streptococcus pyogenes/crescimento & desenvolvimento
16.
Biomolecules ; 11(12)2021 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-34944534

RESUMO

There is a need for new antimicrobial systems due to increased global resistance to current antimicrobials. Pomegranate rind extract (PRE) and Zn (II) ions both possess a level of antimicrobial activity and work has previously shown that PRE/Zn (II) in combination possesses synergistic activity against Herpes simplex virus and Micrococcus luteus. Here, we determined whether such synergistic activity extended to other, more pathogenic, bacteria. Reference strains of methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Escherichia coli, and Pseudomonas aeruginosa were cultured and subjected to challenge by PRE, Zn (II), or PRE + Zn (II), in time-kill assays. Data were obtained independently by two researchers using different PRE preparations. Statistically significant synergistic activity for PRE + Zn (II) was shown for all four bacterial strains tested compared to untreated controls, although the extent of efficacy and timescales varied. Zn (II) exerted activity and at 1 h, it was not possible to distinguish with PRE + Zn (II) combination treatment in all cases. PRE alone showed low activity against all four bacteria. Reproducible synergistic bactericidal activity involving PRE and Zn (II) has been confirmed. Potential mechanisms are discussed. The development of a therapeutic system that possesses demonstrable antimicrobial activity is supported which lends itself particularly to topical delivery applications, for example MRSA infections.


Assuntos
Escherichia coli/crescimento & desenvolvimento , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Extratos Vegetais/farmacologia , Romã (Fruta)/química , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus epidermidis/crescimento & desenvolvimento , Zinco/farmacologia , Sinergismo Farmacológico , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Extratos Vegetais/química , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus epidermidis/efeitos dos fármacos
17.
Biomolecules ; 11(12)2021 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-34944398

RESUMO

Urinary tract infections (UTIs) are a serious health problem in the human population due to their chronic and recurrent nature. Bacteria causing UTIs form multispecies biofilms being resistant to the activity of the conventionally used antibiotics. Therefore, compounds of plant origin are currently being searched for, which could constitute an alternative strategy to antibiotic therapy. Our study aimed to determine the activity of asiatic acid (AA) against biofilms formed by uropathogenic Escherichia coli, Enterobacter cloacae, and Pseudomonas aeruginosa. The influence of AA on the survival, biofilm mass formation by bacteria living in mono-, dual-, and triple-species consortia as well as the metabolic activity and bacterial cell morphology were determined. The spectrophotometric methods were used for biofilm mass synthesis and metabolic activity determination. The survival of bacteria was established using the serial dilution assay. The decrease in survival and a weakening of the ability to create biofilms, both single and multi-species, as well as changes in the morphology of bacterial cells were noticed. As AA works best against young biofilms, the use of AA-containing formulations, especially during the initial stages of infection, seems to be reasonable. However, there is a need for further research concerning AA especially regarding its antibacterial mechanisms of action.


Assuntos
Biofilmes/efeitos dos fármacos , Enterobacter cloacae/crescimento & desenvolvimento , Triterpenos Pentacíclicos/farmacologia , Pseudomonas aeruginosa/crescimento & desenvolvimento , Escherichia coli Uropatogênica/crescimento & desenvolvimento , Aderência Bacteriana/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Enterobacter cloacae/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Estrutura Molecular , Triterpenos Pentacíclicos/química , Pseudomonas aeruginosa/efeitos dos fármacos , Infecções Urinárias/tratamento farmacológico , Infecções Urinárias/microbiologia , Escherichia coli Uropatogênica/efeitos dos fármacos
18.
Molecules ; 26(24)2021 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-34946717

RESUMO

Antimicrobial resistance is one of the current public health challenges to be solved. The World Health Organization (WHO) has urgently called for the development of strategies to expand the increasingly limited antimicrobial arsenal. The development of anti-virulence therapies is a viable option to counteract bacterial infections with the possibility of reducing the generation of resistance. Here we report on the chemical structures of pyrrolidones DEXT 1-4 (previously identified as furan derivatives) and their anti-virulence activity on Pseudomonas aeruginosa strains. DEXT 1-4 were shown to inhibit biofilm formation, swarming motility, and secretion of ExoU and ExoT effector proteins. Also, the anti-pathogenic property of DEXT-3 alone or in combination with furanone C-30 (quorum sensing inhibitor) or MBX-1641 (type III secretion system inhibitor) was analyzed in a model of necrosis induced by P. aeruginosa PA14. All treatments reduced necrosis; however, only the combination of C-30 50 µM with DEXT-3 100 µM showed significant inhibition of bacterial growth in the inoculation area and systemic dispersion. In conclusion, pyrrolidones DEXT 1-4 are chemical structures capable of reducing the pathogenicity of P. aeruginosa and with the potential for the development of anti-virulence combination therapies.


Assuntos
Antibacterianos , Furanos , Hidrocarbonetos Halogenados , Infecções por Pseudomonas , Pseudomonas aeruginosa , Pirrolidinonas , Sistemas de Secreção Tipo III/antagonistas & inibidores , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Furanos/química , Furanos/farmacologia , Humanos , Hidrocarbonetos Halogenados/química , Hidrocarbonetos Halogenados/farmacologia , Camundongos , Necrose , Infecções por Pseudomonas/tratamento farmacológico , Infecções por Pseudomonas/metabolismo , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/patogenicidade , Pirrolidinonas/química , Pirrolidinonas/farmacologia , Percepção de Quorum/efeitos dos fármacos , Sistemas de Secreção Tipo III/metabolismo , Fatores de Virulência/metabolismo
19.
mBio ; 12(6): e0314821, 2021 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-34903059

RESUMO

Drugs called CFTR modulators improve the physiologic defect underlying cystic fibrosis (CF) and alleviate many disease manifestations. However, studies to date indicate that chronic lung infections that are responsible for most disease-related mortality generally persist. Here, we investigated whether combining the CFTR modulator ivacaftor with an intensive 3.5-month antibiotic course could clear chronic Pseudomonas aeruginosa or Staphylococcus aureus lung infections in subjects with R117H-CFTR, who are highly ivacaftor-responsive. Ivacaftor alone improved CFTR activity, and lung function and inflammation within 48 h, and reduced P. aeruginosa and S. aureus pathogen density by ∼10-fold within a week. Antibiotics produced an additional ∼10-fold reduction in pathogen density, but this reduction was transient in subjects who remained infected. Only 1/5 P. aeruginosa-infected and 1/7 S. aureus-infected subjects became persistently culture-negative after the combined treatment. Subjects appearing to clear infection did not have particularly favorable baseline lung function or inflammation, pathogen density or antibiotic susceptibility, or bronchiectasis scores on CT scans, but they did have remarkably low sweat chloride values before and after ivacaftor. All persistently P. aeruginosa-positive subjects remained infected by their pretreatment strain, whereas subjects persistently S. aureus-positive frequently lost and gained strains. This work suggests chronic CF infections may resist eradication despite marked and rapid modulator-induced improvements in lung infection and inflammation parameters and aggressive antibiotic treatment. IMPORTANCE Recent work shows that people with CF and chronic lung infections generally remain persistently infected after treatment with drugs that target the CF physiological defect (called CFTR modulators). However, changes produced by modulators could increase antibiotic efficacy. We tested the approach of combining modulators and intensive antibiotics in rapid succession and found that while few subjects cleared their infections, combined treatment appeared most effective in subjects with the highest CFTR activity. These findings highlight challenges that remain to improve the health of people with CF.


Assuntos
Aminofenóis/administração & dosagem , Antibacterianos/administração & dosagem , Fibrose Cística/tratamento farmacológico , Quimioterapia Combinada , Quinolonas/administração & dosagem , Adulto , Estudos de Coortes , Fibrose Cística/genética , Fibrose Cística/metabolismo , Fibrose Cística/microbiologia , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Feminino , Humanos , Pulmão/microbiologia , Masculino , Mutação , Infecções por Pseudomonas/tratamento farmacológico , Infecções por Pseudomonas/genética , Infecções por Pseudomonas/metabolismo , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/genética , Infecções Estafilocócicas/metabolismo , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento
20.
Microbiol Spectr ; 9(3): e0104721, 2021 12 22.
Artigo em Inglês | MEDLINE | ID: mdl-34787464

RESUMO

Peritoneal catheter-associated biofilm infection is reported to be the main cause of refractory peritonitis in peritoneal dialysis patients. The application of antimicrobial lock therapy, based on results on central venous catheters, may be a promising option for treatment of biofilm-harboring peritoneal catheters. This study investigated the effects of two lock solutions, EDTA and taurolidine, on an in vitro model of Pseudomonas aeruginosa biofilm-related peritoneal catheter infection. Silicone peritoneal catheters were incubated for 24 h with a bioluminescent strain of P. aeruginosa. Then, serial dilutions of taurolidine and/or EDTA were applied (for 24 h) once or twice onto the contaminated catheters, and P. aeruginosa viability/persistence were evaluated in real time up to 120 h using a Fluoroskan reader. On selected supernatants, high-performance liquid chromatography mass spectrometry (HPLC-MS) analysis was performed to measure the production of autoinducers (AI), phenazines, and pyocyianines. Taurolidine alone or in combination with EDTA caused a significant decrease of bacterial load and biofilm persistence on the contaminated catheters. The treatment did not lead to the sterilization of the devices, yet it resulted in a substantial destructuration of the catheter-associated P. aeruginosa biofilm. HPLC-MS analysis showed that the treatment of biofilm-harboring catheters with taurolidine and EDTA also affected the secretory activity of the pathogen. EDTA and taurolidine affect P. aeruginosa biofilm produced on peritoneal catheters and profoundly compromise the microbial secretory profile. Future studies are needed to establish whether such lock solutions can be used to render peritoneal catheter-related infections more susceptible to antibiotic treatment. IMPORTANCE An in vitro model allows studies on the mechanisms by which the lock solutions exert their antimicrobial effects on catheter-associated biofilm, thus providing a better understanding of the management of devise-associated infections.


Assuntos
Antibacterianos/farmacologia , Infecções Relacionadas a Cateter/tratamento farmacológico , Ácido Edético/farmacologia , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa/efeitos dos fármacos , Taurina/análogos & derivados , Tiadiazinas/farmacologia , Carga Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Infecções Relacionadas a Cateter/microbiologia , Infecções Relacionadas a Cateter/prevenção & controle , Cateteres de Demora/microbiologia , Quimioterapia Combinada , Humanos , Diálise Peritoneal/efeitos adversos , Peritonite/tratamento farmacológico , Peritonite/microbiologia , Infecções por Pseudomonas/prevenção & controle , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/patogenicidade , Taurina/farmacologia , Virulência/efeitos dos fármacos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...