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1.
Environ Pollut ; 256: 113382, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31662252

RESUMO

The widespread use of zinc oxide nanoparticles (ZnO-NPs) has led to their release into the environment, and they thus represent a potential risk for both humans and ecosystems. However, the negative impact of ZnO-NPs on the immune system, especially in relation to host defense against pathogenic infection and its underlying regulatory mechanisms, remains largely unexplored. This study investigated the effects of early-life long-term ZnO-NPs exposure (from L1 larvae to adults) on innate immunity and its underlying mechanisms using a host-pathogen Caenorhabditis elegans model, and this was compared with the effect of ionic Zn. The results showed that the ZnO-NPs taken up by C. elegans primarily accumulated in the intestine and that early-life long-term ZnO-NPs exposure at environmentally relevant concentrations (50 and 500 µg/L) decreased the survival of wild-type C. elegans when faced with pathogenic Pseudomonas aeruginosa PA14 infection. Early-life long-term ZnO-NPs (500 µg/L) exposure significantly increased (by about 3-fold) the accumulation of live P. aeruginosa PA14 colonies in the intestine of C. elegans. In addition, ZnO-NPs (500 µg/L) inhibited the intestinal nuclear translocation of SKN-1 and also downregulated gcs-1 gene expression, which is an SKN-1 target gene. Further evidence revealed that early-life long-term exposure to ZnO-NPs (500 µg/L) did not increase susceptibility to mutation among the genes (pmk-1, sek-1, and nsy-1) encoding the p38 mitogen-activated protein kinase (MAPK) cascade in response to P. aeruginosa PA14 infection, though ZnO-NPs significantly decreased the mRNA levels of pmk-1, sek-1, and nsy-1. This study provides regulatory insight based on evidence that ZnO-NPs suppress the innate immunity of C. elegans and highlights the potential health risks of certain environmental nanomaterials, including ZnO-NPs, in terms of their immunotoxicity at environmentally relevant concentrations.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/efeitos dos fármacos , Proteínas de Ligação a DNA/metabolismo , Imunidade Inata/efeitos dos fármacos , Nanopartículas/toxicidade , Fatores de Transcrição/metabolismo , Óxido de Zinco/toxicidade , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Animais , Caenorhabditis elegans/imunologia , Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/microbiologia , Ecossistema , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento
2.
Chem Biodivers ; 17(1): e1900462, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31788939

RESUMO

A series of coumarin-tagged ß-lactam triazole hybrids (10a-10o) were synthesized and tested for their cytotoxic activity against MDA-MB-231 (triple negative breast cancer), MCF-7 (estrogen receptor positive breast cancer (ER+)) and A549 (human lung carcinoma) cancer cell lines including one normal cell line, HEK-293 (human embryonic kidney). Two compounds 10b and 10d exhibited substantial cytotoxic effect against MCF-7 cancer cell lines with IC50 values of 53.55 and 58.62 µm, respectively. More importantly, compounds 10b and 10d were non-cytotoxic against HEK-293 cell lines. Structure-activity relationship (SAR) studies suggested that the nitro and chloro group at the C-3 position of phenyl ring are favorable for anticancer activity, particularly against MCF-7 cell lines. Furthermore, antimicrobial evaluation of these compounds revealed modest inhibition of examined pathogenic strains with compounds 10c and 10i being the most promising antimicrobial agents against Pseudomonas aeruginosa and Candida albicans, respectively.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antineoplásicos/farmacologia , Cumarínicos/farmacologia , Triazóis/farmacologia , beta-Lactamas/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Antifúngicos/síntese química , Antifúngicos/química , Antineoplásicos/síntese química , Antineoplásicos/química , Candida albicans/efeitos dos fármacos , Candida albicans/crescimento & desenvolvimento , Proliferação de Células/efeitos dos fármacos , Cumarínicos/síntese química , Cumarínicos/química , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células HEK293 , Humanos , Células MCF-7 , Testes de Sensibilidade Microbiana , Estrutura Molecular , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Relação Estrutura-Atividade , Triazóis/química , beta-Lactamas/química
3.
J Med Microbiol ; 69(1): 139-145, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31859619

RESUMO

Laboratory research with Pseudomonas aeruginosa commonly involves the prototype strain PAO1. There is continued concern that PAO1 sublines maintained and propagated in the same laboratory or different laboratories exhibit genetic and phenotypic variability that may affect the reproducibility and validity of research. Whole-genome sequencing and other research identified the mexT locus as a mutational hotspot, but the explication of the diverse mutations present in the various sublines and consequences remained rather cursory. Here we present evidence that MexT sequence diversity is a predictor of PAO1 lineage integrity and define the protein's prototype sequence.


Assuntos
Proteínas de Bactérias/genética , Variação Genética , Mutação , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/genética , Inoculações Seriadas , Sequenciamento Completo do Genoma
4.
Chem Pharm Bull (Tokyo) ; 67(10): 1088-1098, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31582628

RESUMO

In this study, we synthesized four series of novel L-homoserine lactone analogs and evaluated their in vitro quorum sensing (QS) inhibitory activity against two biomonitor strains, Chromobacterium violaceum CV026 and Pseudomonas aeruginosa PAO1. Studies of the structure-activity relationships of the set of L-homoserine lactone analogs indicated that phenylurea-containing N-dithiocarbamated homoserine lactones are more potent than (Z)-4-bromo-5-(bromomethylene)-2(5H)-furanone (C30), a positive control for biofilm formation. In particular, compared with C30, QS inhibitor 11f significantly reduced the production of virulence factors (pyocyanin, elastase and rhamnolipid), swarming motility, the formation of biofilm and the mRNA level of QS-related genes regulated by the QS system of PAO1. These results reveal 11f as a potential lead compound for developing novel antibacterial quorum sensing inhibitors.


Assuntos
4-Butirolactona/análogos & derivados , Antibacterianos/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Percepção de Quorum/efeitos dos fármacos , 4-Butirolactona/síntese química , 4-Butirolactona/química , 4-Butirolactona/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Estrutura Molecular , Pseudomonas aeruginosa/crescimento & desenvolvimento , Percepção de Quorum/genética , Relação Estrutura-Atividade
5.
Life Sci ; 237: 116947, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31605708

RESUMO

AIMS: Pseudomonas aeruginosa is one of the leading causes of opportunistic and hospital-acquired infections worldwide, which is frequently linked with clinical treatment difficulties. Ibuprofen, a widely used non-steroidal anti-inflammatory drug, has been previously reported to exert antimicrobial activity with the specific mechanism. We hypothesized that inhibition of P. aeruginosa with ibuprofen is involved in the quorum sensing (QS) systems. MAIN METHODS: CFU was utilized to assessed the growth condition of P. aeruginosa. Crystal violent staining and acridine orange staining was used to evaluate the biofilm formation and adherence activity. The detection of QS virulence factors such as pyocyanin, elastase, protease, and rhamnolipids were applied to investigation the anti-QS activity of ibuprofen against P. aeruginosa. The production of 3-oxo-C12-HSL and C4-HSL was confirmed by liquid chromatography/mass spectrometry analysis. qRT-PCR was used to identify the QS-related gene expression. Furthermore, we explored the binding effects between ibuprofen and QS-associated proteins with molecular docking. KEY FINDINGS: Ibuprofen inhibits P. aeruginosa biofilm formation and adherence activity. And the inhibitory effects of ibuprofen on C4-HSL levels were concentration-dependent (p < 0.05), while it has no effect on 3-oxo-C12-HSL. Moreover, ibuprofen attenuates the production of virulence factors in P. aeruginosa (p < 0.05). In addition, the genes of QS system were decreased after the ibuprofen treatment (p < 0.05). Of note, ibuprofen was binding with LuxR, LasR, LasI, and RhlR at high binding scores. SIGNIFICANCE: The antibiofilm and anti-QS activity of ibuprofen suggest that it can be a candidate drug for the treatment of clinical infections with P. aeruginosa.


Assuntos
Proteínas de Bactérias/genética , Biofilmes/crescimento & desenvolvimento , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Ibuprofeno/farmacologia , Pseudomonas aeruginosa/genética , Percepção de Quorum/efeitos dos fármacos , Fatores de Virulência/genética , Anti-Inflamatórios não Esteroides/farmacologia , Biofilmes/efeitos dos fármacos , Humanos , Infecções por Pseudomonas/tratamento farmacológico , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento
6.
J Basic Microbiol ; 59(11): 1154-1162, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31553498

RESUMO

Nitric oxide (NO) reductase (NorCB) of Pseudomonas aeruginosa is an essential enzyme that metabolizes NO and alleviates anaerobic NO toxicity during denitrification processes under anaerobic conditions. However, the molecular functions of norCB in the presence of oxygen are poorly understood. This study utilized norCB knockout from P. aeruginosa ATCC 9027 to analyze the resulting phenotypic changes of ΔnorCB in comparison to the wild-type parental strain (WT) and the complementary strain (ΔnorCB-com). The results demonstrated an increase in planktonic growth and biofilm formation by ΔnorCB compared to WT and ΔnorCB-com in the presence of isothiazolones under aerobic conditions. Deletion of norCB led to increased swimming ability and decreased pyocyanin production. Inactivation of norCB also led to an increase of cellular H2 O2 concentration due to decreased activity of its catalases. In addition, the deletion of norCB also influenced the relative expressions of several other genes, including norD, nirS, hmgA, and hpd. These findings provide preliminary evidence that norCB in P. aeruginosa plays an essential role in bacterial life process under aerobic conditions and improves the application of denitrification in the next step.


Assuntos
Proteínas de Bactérias/metabolismo , Oxirredutases/metabolismo , Pseudomonas aeruginosa/metabolismo , Aerobiose , Proteínas de Bactérias/genética , Biofilmes/crescimento & desenvolvimento , Regulação Bacteriana da Expressão Gênica , Técnicas de Inativação de Genes , Peróxido de Hidrogênio/metabolismo , Locomoção/genética , Oxirredutases/genética , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/crescimento & desenvolvimento , Piocianina/biossíntese
7.
Mater Sci Eng C Mater Biol Appl ; 105: 110036, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546358

RESUMO

Rapid vascularization and long-term antibacterial property are desirable characteristics of the next-generation implants in orbital reconstruction. In this study, the new diopside-based orbital implants were developed by direct ink writing of diopside (CaMgSi2O6; DIO) and low-melt bioactive glass (BG)-assisted sintering approaches. The mechanical tests showed that the addition 5% or 10% BG could readily enhance the compressive strength of the DIO porous bioceramics after sintering at 1150 °C. The Tris buffer immersion test in vitro indicated that the porous bioceramics exhibited appreciable mechanical stability and very limited mass loss (<3.5%) after 8 weeks. The DIO/10BG porous bioceramic sintered at 1150 °C or 1250 °C could promote appreciable angiogenesis response at the early stage (2-6 weeks) of implantation in the rabbit panniculus carnosus muscle models in vivo. It is interesting that the steam autoclaved bioceramics exhibited outstanding contact-active inhibition against Staphylococcus aureus and Pseudomonas aeruginosa, but as-sintered bioceramics showed no antibacterial effect. It is reasonable to consider that our strategy paves the way toward a simple and effective approach to fabricate the multifunctional tailormade implants for orbital implantation, thus accelerating the clinical translation of biomaterials research.


Assuntos
Antibacterianos/farmacologia , Cerâmica/farmacologia , Neovascularização Fisiológica/efeitos dos fármacos , Implantes Orbitários , Ácido Silícico/farmacologia , Animais , Cerâmica/química , Masculino , Testes de Sensibilidade Microbiana , Porosidade , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Coelhos , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento
8.
Mater Sci Eng C Mater Biol Appl ; 105: 110063, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546412

RESUMO

Artificial dermal scaffolds, which are made of natural or synthetic materials, can improve new blood vessel formation, cell migration and cell proliferation after being implanted into wounds, and they degrade slowly, playing an important role in dermal reconstruction and scar inhibition, finally achieving the goal of wound healing and functional reconstruction. Although these scaffolds have been widely used in clinical applications, biomaterial-associated infection is a deficiency or even a life-threatening problem that must be addressed, as it greatly affects the survival of the scaffolds. The gallium ion (Ga3+) is a novel metallic antimicrobial whose broad-spectrum antimicrobial properties against most bacteria encountered in burn wound infections have been confirmed, and it has been proposed as a promising candidate to prevent implant-associated infections. In this study, a gallium-loaded antimicrobial artificial dermal scaffold was successfully prepared by gallium ions and a collagen solution. The characterization results showed a porous structure with pore sizes ranging from 50 to 150 µm and a large porosity value of 97.4%. The enzymatic degradation rate in vitro was 19 and 28% after 12 and 24 h, respectively. In vitro antimicrobial testing revealed that the 1 h antibacterial rate against Staphylococcus aureus and Pseudomonas aeruginosa was close to 90%, which indicated its great antimicrobial activity. The results of the cytological evaluation showed slight effect on cell proliferation, with a relative growth rate (RGR) value of 80% and great cytocompatibility with cultured cells according to laser scanning confocal microscopy (LSCM) and scanning electron microscope (SEM). Furthermore, the successful prevention of wound infections in SD rats was confirmed with an in vivo antimicrobial evaluation, and the artificial dermal scaffolds also demonstrated great biocompatibility. This gallium-loaded antimicrobial artificial dermal scaffold exerted excellent antimicrobial activity and great biosafety, warranting further research for future clinical applications.


Assuntos
Anti-Infecciosos/química , Derme , Gálio/química , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/crescimento & desenvolvimento , Tecidos Suporte/química , Animais , Linhagem Celular , Derme/química , Derme/metabolismo , Derme/microbiologia , Camundongos , Porosidade
9.
Mater Sci Eng C Mater Biol Appl ; 105: 110059, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546421

RESUMO

Post-surgery infection is one of the main causes of orthopedic implant failure. This paper presents a powder-feed 3D printing strategy for fabrication of silver (Ag) incorporated titanium (Ti) alloys as an antimicrobial solution for orthopedic implants. Alloys with various Ag concentration, ranging from 0.5% to 2% by weight, were fabricated through laser engineered net shaping (LENS) process. The composition and surface of the fabricated alloys were characterized through X-ray diffraction, energy-dispersive X-ray spectroscopy, and 3D surface profiling. The mechanical properties, antimicrobial performance, and biocompatibility of the alloys were also investigated. Results showed that LENS fabricated TiAg alloys had a marginally higher microhardness and a lower ductility compared to pure Ti. Within only 3 h, TiAg alloys significantly reduced the bacterial attachment of both gram-positive and gram-negative strains by one to four orders of magnitudes. These alloys also demonstrated excellent in-vitro biocompatibility to human osteosarcoma cells. For the first time, laser engineered net shaping (LENS) of TiAg alloy has been explored as an antimicrobial solution for orthopedic applications and showed great potential for biomedical instrumentation.


Assuntos
Anti-Infecciosos , Materiais Biocompatíveis , Lasers , Pseudomonas aeruginosa/crescimento & desenvolvimento , Prata , Staphylococcus aureus/crescimento & desenvolvimento , Titânio , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Linhagem Celular Tumoral , Humanos , Prata/química , Prata/farmacologia , Titânio/química , Titânio/farmacologia
10.
Drug Resist Updat ; 44: 100640, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31492517

RESUMO

Antibiotics are powerful drugs used in the treatment of bacterial infections. The inappropriate use of these medicines has driven the dissemination of antibiotic resistance (AR) in most bacteria. Pseudomonas aeruginosa is an opportunistic pathogen commonly involved in environmental- and difficult-to-treat hospital-acquired infections. This species is frequently resistant to several antibiotics, being in the "critical" category of the WHO's priority pathogens list for research and development of new antibiotics. In addition to a remarkable intrinsic resistance to several antibiotics, P. aeruginosa can acquire resistance through chromosomal mutations and acquisition of AR genes. P. aeruginosa has one of the largest bacterial genomes and possesses a significant assortment of genes acquired by horizontal gene transfer (HGT), which are frequently localized within integrons and mobile genetic elements (MGEs), such as transposons, insertion sequences, genomic islands, phages, plasmids and integrative and conjugative elements (ICEs). This genomic diversity results in a non-clonal population structure, punctuated by specific clones that are associated with significant morbidity and mortality worldwide, the so-called high-risk clones. Acquisition of MGEs produces a fitness cost in the host, that can be eased over time by compensatory mutations during MGE-host coevolution. Even though plasmids and ICEs are important drivers of AR, the underlying evolutionary traits that promote this dissemination are poorly understood. In this review, we provide a comprehensive description of the main strategies involved in AR in P. aeruginosa and the leading drivers of HGT in this species. The most recently developed genomic tools that allowed a better understanding of the features contributing for the success of P. aeruginosa are discussed.


Assuntos
Antibacterianos/uso terapêutico , Farmacorresistência Bacteriana Múltipla/genética , Genoma Bacteriano , Infecções Oportunistas/tratamento farmacológico , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa/genética , Células Clonais , Transferência Genética Horizontal , Aptidão Genética , Ilhas Genômicas , Interações Hospedeiro-Patógeno/genética , Humanos , Sequências Repetitivas Dispersas , Epidemiologia Molecular , Infecções Oportunistas/epidemiologia , Infecções Oportunistas/microbiologia , Plasmídeos/química , Plasmídeos/metabolismo , Infecções por Pseudomonas/epidemiologia , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/patogenicidade , beta-Lactamases/genética , beta-Lactamases/metabolismo
11.
BMC Complement Altern Med ; 19(1): 247, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31488126

RESUMO

BACKGROUND: With the current concern caused by drug resistant microorganisms, alternatives to traditional antimicrobials are increasingly necessary. Historical holistic treatments involving natural approaches are now of interest as a potential alternative. Many essential oils have antimicrobial properties with the ability to modify bacterial and fungal population dynamics in low concentrations. METHODS: In this study, bacterial and fungal growth in response to varying concentrations of arborvitae oil was assessed using spectrophotometric methods to obtain estimates of population growth parameters including carrying capacity (K) and intrinsic rate of growth (r). Estimates of these parameters were compared among doses within strains using general linear modeling. RESULTS: Results suggest the active component of the essential oil arborvitae is likely of hydrophilic nature and demonstrates the ability to influence both K and r during bacterial and fungal growth in a dose-dependent manner. Highly concentrated doses of arborvitae completely kill Escherichia coli and significantly inhibit Staphylococcus aureus, however these same doses have no effect on Pseudomonas aeruginosa. Accordingly, microdoses of arborvitae demonstrated the ability to inhibit population growth parameters in both prokaryotic and eukaryotic microorganisms. Specifically, K of E. coli, r of Candida auris, and both K and r of Candida albicans were significantly reduced in the presence of microdoses of arborvitae. CONCLUSIONS: Microdoses of essential oils have the ability to inhibit one or both population parameters in both prokaryotic and eukaryotic microorganisms. Some microorganisms appear to be more susceptible to this essential oil arborvitae than other microorganisms. The use of essential oils, such as arborvitae, as novel antimicrobials may prove useful when contending with the current epidemic of multidrug resistant pathogens.


Assuntos
Óleos Voláteis/farmacologia , Thuja/química , Candida albicans/efeitos dos fármacos , Candida albicans/crescimento & desenvolvimento , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Óleos Vegetais/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento
12.
ACS Appl Mater Interfaces ; 11(41): 37491-37501, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31532610

RESUMO

Microbial keratitis is a serious sight threatening infection affecting approximately two million individuals worldwide annually. While antibiotic eye drops remain the gold standard treatment for these infections, the significant problems associated with eye drop drug delivery and the alarming rise in antimicrobial resistance has meant that there is an urgent need to develop alternative treatments. In this work, a nitric oxide releasing contact lens gel displaying broad spectrum antimicrobial activity against two of the most common causative pathogens of microbial keratitis is described. The contact lens gel is composed of poly-ε-lysine (pεK) functionalized with nitric oxide (NO) releasing diazeniumdiolate moieties which enables the controlled and sustained release of bactericidal concentrations of NO at physiological pH over a period of 15 h. Diazeniumdiolate functionalization was confirmed by Fourier transform infrared (FTIR), and the concentration of NO released from the gels was determined by chemiluminescence. The bactericidal efficacy of the gels against Pseudomonas aeruginosa and Staphylococcus aureus was ascertained, and between 1 and 4 log reductions in bacterial populations were observed over 24 h. Additional cell cytotoxicity studies with human corneal epithelial cells (hCE-T) also demonstrated that the contact lens gels were not cytotoxic, suggesting that the developed technology could be a viable alternative treatment for microbial  keratitis.


Assuntos
Anti-Infecciosos , Lentes de Contato , Ceratite/tratamento farmacológico , Óxido Nítrico , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa/crescimento & desenvolvimento , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/crescimento & desenvolvimento , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacologia , Epitélio Anterior/metabolismo , Epitélio Anterior/microbiologia , Epitélio Anterior/patologia , Humanos , Teste de Materiais , Óxido Nítrico/química , Óxido Nítrico/farmacologia
13.
Biosens Bioelectron ; 142: 111538, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31376710

RESUMO

The opportunistic human pathogen Pseudomonas aeruginosa (Pa) causes several infections acquired in a healthcare setting. During initial stages of infection, Pa produces redox-active phenazine metabolites, including pyocyanin (PYO), 5-methylphenazine-1-carboxylic acid (5-MCA), and 1-hydroxyphenazine (OHPHZ), which have toxic effects on surrounding host cells and/or other microbes. Rapid and sensitive detection of these metabolites provides important evidence about the onset of Pa infections. Herein, we investigate differences in Pa phenazine production and dynamics in polymicrobial communities. Specifically, Pa was co-cultured with two pathogens of clinical relevance, Staphylococcus aureus (Sa) and Escherichia coli (Ec), which typically populate infection sites with Pa. Phenazine production rates and biosynthesis dynamics were electrochemically monitored during a 48-h period using recently developed transparent carbon ultramicroelectrode arrays (T-CUAs). Moreover, the effect on phenazine production rates and dynamics was explored in two growth media, lysogeny broth (LB) and tryptic soy broth (TSB). The concentrations of PYO and highly reactive 5-MCA were determined in different polymicrobial culture samples in both media. The results demonstrate that other bacterial pathogens noticeably influence Pa phenazine production and dynamics. In particular, Sa caused a decrease in phenazine production in TSB. However, the presence of Ec in polymicrobial samples drastically inhibited phenazine production rates in both LB and TSB. Conclusively, the media type significantly influences phenazine product distribution, especially in polymicrobial co-cultures, signifying the need for analytical standardization of simulation media in the study of polymicrobial communities.


Assuntos
Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/crescimento & desenvolvimento , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Técnicas de Cocultura , Coinfecção/microbiologia , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Desenho de Equipamento , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/metabolismo , Infecções por Escherichia coli/microbiologia , Humanos , Microeletrodos , Fenazinas/análise , Fenazinas/metabolismo , Pseudomonas aeruginosa/metabolismo , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus aureus/metabolismo
14.
World J Microbiol Biotechnol ; 35(9): 137, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31432268

RESUMO

The presence of very high concentrations of organic pollutants, phenols, tannins and heavy metals mainly chromium in wastewater discharged from leather industries, tags it as one of the most polluting industries. The phenolic syntans discharged from tanning units have an adverse effect on living organisms and cause serious environmental pollution, thereby making it very imperative to remove it. Among various treatment methods available for removal of phenols, biodegradation is environment friendly. The present study aims at the remediation of phenolic syntan used in the leather industry employing individual as well as co-culture of Bacillus cereus and Pseudomonas aeruginosa at varying syntan concentration in the medium. Parameters such as chemical oxygen demand (COD), total organic carbon (TOC), total phenol content (TPC) and Fourier Transform Infrared Spectroscopy (FTIR) indicating biodegradation were analyzed. Promising results were observed with P. aeruginosa, which exhibited a reduction in TPC by 62-72% in all the concentrations of syntan tested just within 12 h of inoculation, whereas about 67 and 83% reduction in COD and TOC respectively was observed for 2000 ppm concentration at the end of 5 days. B. cereus also demonstrated very good reduction in the above parameters however; percentage was less as compared to P. aeruginosa. In the case of co-culture, the TPC reduction was higher than B. cereus but lesser than P. aeruginosa. The percentage reduction in TOC and COD was highest for 500 ppm which eventually decreased for subsequent concentrations.


Assuntos
Bacillus cereus/metabolismo , Resíduos Industriais , Fenóis/metabolismo , Pseudomonas aeruginosa/metabolismo , Poluentes Químicos da Água/metabolismo , Bacillus cereus/crescimento & desenvolvimento , Análise da Demanda Biológica de Oxigênio , Biotransformação , Carbono/análise , Técnicas de Cocultura , Fenóis/análise , Pseudomonas aeruginosa/crescimento & desenvolvimento , Espectroscopia de Infravermelho com Transformada de Fourier , Água/química
15.
Nanoscale ; 11(35): 16455-16462, 2019 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-31451827

RESUMO

Nanostructured mechano-bactericidal surfaces represent a promising technology to prevent the incidence of microbial contamination on a variety of surfaces and to avoid bacterial infection, particularly with antibiotic resistant strains. In this work, a regular array of silicon nanopillars of 380 nm height and 35 nm diameter was used to study the release of bacterial cell debris off the surface, following inactivation of the cell due to nanostructure-induced rupture. It was confirmed that substantial bactericidal activity was achieved against Gram-negative Pseudomonas aeruginosa (85% non-viable cells) and only modest antibacterial activity towards Staphylococcus aureus (8% non-viable cells), as estimated by measuring the proportions of viable and non-viable cells via fluorescence imaging. In situ time-lapse AFM scans of the bacteria-nanopillar interface confirmed the removal rate of the dead P. aeruginosa cells from the surface to be approximately 19 minutes per cell, and approximately 11 minutes per cell for dead S. aureus cells. These results highlight that the killing and dead cell detachment cycle for bacteria on these substrata are dependant on the bacterial species and the surface architecture studied and will vary when these two parameters are altered. The outcomes of this work will enhance the current understanding of antibacterial nanostructures, and impact upon the development and implementation of next-generation implants and medical devices.


Assuntos
Antibacterianos/química , Farmacorresistência Bacteriana , Nanoestruturas/química , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/crescimento & desenvolvimento , Microscopia de Força Atômica , Nanoestruturas/ultraestrutura , Próteses e Implantes , Pseudomonas aeruginosa/ultraestrutura , Staphylococcus aureus/ultraestrutura , Propriedades de Superfície
16.
J Coll Physicians Surg Pak ; 29(9): 828-832, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31455476

RESUMO

OBJECTIVE: To determine the growth of microorganisms in propofol when combined with fentanyl and lidocaine in different temperatures and times in order to find out whether there is any improvement in antimicrobial effect to lengthen the safe duration of time for application of propofol. STUDY DESIGN: Cross-sectional study. PLACE AND DURATION OF STUDY: Istanbul Aydin University Laboratory, Istanbul, Turkey, from June to September 2018. METHODOLOGY: The studied drugs and thier combination was used to determine their effect on bacterial growth of Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans and Acinetobacter baumanni. Bacterial solutions were prepared at 0.5 MacFarland in sterile 0.9% physiological saline and diluted at 1:100 concentration. Colony numbers were measured as colony forming units mL-1 at 0, 8, and 24 hours and at 4oC, 22oC and 37oC. RESULTS: In general, propofol supported the growth of microorganisms. Fentanyl with propofol also promoted the growth, especially in room and body temperature at 8th and 24th hours but when combined with lidocaine, the number of CFUs was reduced significantly compared with propofol + fentanyl group. Lidocaine inhibited the growth of microorganisms in all the solutions except for candida albicans. CONCLUSION: Lidocaine was shown to have antibacterial effect which carries advantage for inhibiting infections due to propofol; but aseptic technique is essential during preparation of propofol infusions. Fentanyl like propofol also promoted the growth at room and body temperatures.


Assuntos
Acinetobacter baumannii/crescimento & desenvolvimento , Candida albicans/crescimento & desenvolvimento , Fentanila , Lidocaína , Propofol , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/crescimento & desenvolvimento , Anestésicos , Contagem de Colônia Microbiana , Armazenamento de Medicamentos , Temperatura Ambiente , Fatores de Tempo , Turquia
17.
J Med Microbiol ; 68(10): 1560-1572, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31460863

RESUMO

Introduction. Severely burned patients are susceptible to bacterial infection within their burn wounds, which frequently leads to sepsis, multiple organ failure and death. The opportunistic pathogen Pseudomonas aeruginosa, an organism inherently resistant to multiple antibiotics, is a common cause of sepsis in these patients.Aim. Development of a topical treatment unrelated to conventional antibiotics is essential for prevention of P. aeruginosa infection and sepsis, leading to a role for the direct application of probiotics or their by-products.Methodology. We examined the effectiveness of 20× concentrated supernatant from Lactobacillus gasseri strain 63 AM (LgCS) grown in de Man, Rogosa and Sharpe broth in inhibiting P. aeruginosa biofilms in vitro, as well as in reducing wound bioburden and P. aeruginosa sepsis in vivo.Results. LgCS inhibited the growth of P. aeruginosa strain PAO1, prevented its biofilm development and eliminated partially developed PAO1 biofilms. In the murine model of thermal injury, a single injection of LgCS following injury and PAO1 infection reduced mortality to 0 % and prevented systemic spread (sepsis). Furthermore, a second injection of LgCS 24 h after the first eliminated PAO1 from the wound. In the murine dorsal excision infection model, either LgCS or ceftazidime treatment of the PAO1-infected wound significantly reduced the mortality rate among infected mice, while combining LgCS with ceftazidime eliminated mortality.Conclusion. These results suggest the potential of LgCS in preventing sepsis from P. aeruginosa infection in severely burned and other immunocompromised patients.


Assuntos
Queimaduras/complicações , Lactobacillus gasseri/fisiologia , Infecções por Pseudomonas/terapia , Pseudomonas aeruginosa/crescimento & desenvolvimento , Sepse/terapia , Músculos Superficiais do Dorso/lesões , Animais , Antibiose , Biofilmes , Terapia Biológica , Modelos Animais de Doenças , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Infecções por Pseudomonas/etiologia , Infecções por Pseudomonas/microbiologia , Infecções por Pseudomonas/mortalidade , Pseudomonas aeruginosa/fisiologia , Sepse/etiologia , Sepse/microbiologia , Sepse/mortalidade , Músculos Superficiais do Dorso/microbiologia , Músculos Superficiais do Dorso/cirurgia , Infecção dos Ferimentos
18.
J Agric Food Chem ; 67(35): 9749-9756, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31415718

RESUMO

Bovine lactoferrin N-lobe plays an important key in the nonimmunological defense system. In this work, the most suitable promoter Pveg was selected and the fragment coding bovine lactoferrin N-lobe was optimized according to codon bias of Bacillus. The recombinant plasmid pMA0911-Pveg-mBLF-N was introduced into Baicillus subtilis 168 to create B. subtilis/pMA0911-Pveg-mBLF-N. The bovine lactoferrin N-lobe was highly expressed at 28 °C for 15 h. Its purified protein was obtained with 16.5 mg/L and a purity of 93.6% using ammonium sulfate precipitation, Ni-NTA, and molecular exclusion. About 200 ng/mL purified bovine lactoferrin N-lobe completely inhibited cell-growth of Escherichia coli JM109 (DE3), 70.3% of Pseudomonas aeruginosa CGMCC 1.6740, and 41.5% of Staphylococcus aureus CGMCC 1.282. To our knowledge, this is the first report about active expression, purification, and characterization of bovine lactoferrin N-lobe in safe bacterium B. subtilis, which opens an available application way in the biomedical and food industries.


Assuntos
Antibacterianos/farmacologia , Bacillus subtilis/genética , Códon/genética , Lactoferrina/genética , Regiões Promotoras Genéticas , Animais , Antibacterianos/metabolismo , Bacillus subtilis/metabolismo , Clonagem Molecular , Códon/metabolismo , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Expressão Gênica , Engenharia Genética , Lactoferrina/metabolismo , Lactoferrina/farmacologia , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento
19.
J Med Microbiol ; 68(10): 1552-1559, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31419210

RESUMO

Introductio n. Pseudomonas aeruginosa is an important Gram-negative pathogen that is intrinsically multidrug-resistant (MDR) and frequently associated with healthcare-associated outbreaks. With increasing resistance to antibiotics and with very few novel drugs under development, clinicians often use combinations to treat critically ill patients.Aim. The aim of this study was to evaluate the ability of epigallocatechin (EGCG) to restore the activity of aztreonam against clinical MDR strains of P. aeruginosa.Methodology. Checkerboard and time-kill kinetic assays were performed to assess synergy in vitro and the Galleria mellonella model of infection was used to test the efficacy of the combination in vivo. Accumulation assays were performed to gain insight into the mechanism of action.Results. The results demonstrate that synergy between aztreonam and EGCG exists [fractional inhibitory concentration indices (FICIs) 0.02-0.5], with the combination affording significantly (P=<0.05) enhanced bacterial killing, with a >3 log10 reduction in colony-forming units ml-1 at 24 h. EGCG was able to restore susceptibility to aztreonam to a level equal to or below the breakpoint set by the European Committee for Antimicrobial Susceptibility Testing. In G. mellonella, the combination was superior to monotherapy, with increased larval survival observed (94 % vs ≤63 %). We also demonstrated the relatively low toxicity of EGCG to human keratinocytes and G. mellonella larvae. Accumulation assay data suggest that the mechanism of synergy may be due to EGCG increasing the uptake of aztreonam.Conclusion. EGCG was able to restore the activity of aztreonam against MDR P. aeruginosa. The data presented support further evaluation of the aztreonam-EGCG combination and highlight its potential for use in clinical medicine.


Assuntos
Antibacterianos/farmacologia , Aztreonam/farmacologia , Catequina/análogos & derivados , Polifenóis/farmacologia , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/efeitos dos fármacos , Animais , Catequina/farmacologia , Farmacorresistência Bacteriana Múltipla , Sinergismo Farmacológico , Humanos , Larva/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Mariposas/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento
20.
Int J Pharm ; 567: 118502, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31295525

RESUMO

Montmorillonite (MMT) is a highly promising material for use in drug delivery due to its high drug loading capacity and controlled drug release properties. MMT protects drug molecules between layered structure; however, drug release from MMT is sustained less than 6 h, which is insufficient for the release of antibiotics. This study sought to synthesize an antibiotic delivery material with more sustained release properties. A ciprofloxacin (CIP)-MMT composite was fabricated using carboxymethylated nanocellulose (CMCNF). A simple adsorption reaction intercalated 31.1% of CIP molecules present into the MMT under optimized conditions (pH 5, CIP = 1000 mg/L, Reaction time = 3 h). The synthesized CIP-MMT composite was fabricated using 1.5, 2, or 3 wt% CMCNF. Increasing the CMCNF content delayed the erosion of the CMCNF matrix and prevented rapid dissolution of the CIP-MMT composite. In vitro release experiments revealed that the CIP-MMT composite material provided the sustained release of CIP over 6 h. Erosion of the 3 wt% CMCNF-CIP-MMT composite occurred slowly and provided 48 h of sustained CIP release. An anti-bacterial test revealed that the 3 wt% CMCNF-CIP-MMT composite displayed the most constant antibacterial activity over 12 days. These results demonstrated that the CMCNF prepared with CIP intercalation in MMT was highly effective in prolonging the antibiotic release.


Assuntos
Antibacterianos , Bentonita , Carboximetilcelulose Sódica , Ciprofloxacino , Nanopartículas , Antibacterianos/administração & dosagem , Antibacterianos/química , Bentonita/administração & dosagem , Bentonita/química , Carboximetilcelulose Sódica/administração & dosagem , Carboximetilcelulose Sódica/química , Ciprofloxacino/administração & dosagem , Ciprofloxacino/química , Preparações de Ação Retardada/administração & dosagem , Preparações de Ação Retardada/química , Liberação Controlada de Fármacos , Nanopartículas/administração & dosagem , Nanopartículas/química , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento
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