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1.
PLoS Pathog ; 16(8): e1008740, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32822429

RESUMO

Adenosine-to-inosine (A-to-I) RNA editing is an important posttranscriptional event in eukaryotes; however, many features remain largely unexplored in prokaryotes. This study focuses on a serine-to-proline recoding event (S128P) that originated in the mRNA of fliC, which encodes a flagellar filament protein; the editing event was observed in RNA-seq samples exposed to oxidative stress. Using Sanger sequencing, we show that the S128P editing event is induced by H2O2. To investigate the in vivo interaction between RNAs and TadA, which is the principal enzyme for A-to-I editing, genome-wide RNA immunoprecipitation-coupled high-throughput sequencing (iRIP-Seq) analysis was performed using HA-tagged TadA from Xanthomonas oryzae pv. oryzicola. We found that TadA can bind to the mRNA of fliC and the binding motif is identical to that previously reported by Bar-Yaacov and colleagues. This editing event increased motility and enhanced tolerance to oxidative stress due to changes in flagellar filament structure, which was modelled in 3D and measured by TEM. The change in filament structure due to the S128P mutant increased biofilm formation, which was measured by the 3D laser scanning confocal microscopy. RNA-seq revealed that a gene cluster that contributes to siderophore biosynthesis and Fe3+ uptake was upregulated in S128P compared with WT. Based on intracellular levels of reactive oxygen species and an oxidative stress survival assay, we found that this gene cluster can contribute to the reduction of the Fenton reaction and increases biofilm formation and bacterial virulence. This oxidative stress response was also confirmed in Pseudomonas putida. Overall, our work demonstrates that A-to-I RNA editing plays a role in bacterial pathogenicity and adaptation to oxidative stress.


Assuntos
Proteínas de Bactérias/genética , Edição de RNA , Xanthomonas/genética , Xanthomonas/metabolismo , Adenosina/genética , Adenosina/metabolismo , Proteínas de Bactérias/metabolismo , Peróxido de Hidrogênio/farmacologia , Inosina/genética , Inosina/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Doenças das Plantas/microbiologia , Virulência/efeitos dos fármacos , Xanthomonas/efeitos dos fármacos , Xanthomonas/patogenicidade
3.
J Med Microbiol ; 69(7): 932-943, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32530393

RESUMO

Introduction. Diarrhoeagenic Escherichia coli (DEC) are difficult to distinguish from non-pathogenic commensal E. coli using traditional culture methods. The implementation of PCR targeting specific virulence genes characteristic of the five DEC pathotypes, has improved the detection of DEC in faecal specimens from patients with symptoms of gastrointestinal disease.Aim. Antimicrobial resistance (AMR) profiles of 660 strains of DEC isolated between 2015 and 2017 from UK travellers reporting symptoms of gastrointestinal disease were reviewed to look for evidence of emerging AMR associated with travellers' diarrhoea.Methodology. All isolates of DEC were sequenced, and sequence type, serotype, pathotype markers and AMR profiles were derived from the genome data.Results. A travel history was provided for 54.1 % (357/660) of cases, of which 77.0 % (275/357) reported travel outside the UK within 7 days of onset of symptoms, and 23.0 % (82/357) reported no travel in that time frame. Of the 660 strains of DEC in this study, 265 (40.2 %) samples were identified as EAEC, 48 (7.3 %) as EIEC, 61 (9.2 %) were ETEC and 286 (43.3 %) were EPEC. EPEC caused the highest percentage of infections in children (40.6 %) whilst the highest proportion of cases reporting recent travel were infected with ETEC (86.1 %). There were 390/660 (59.0 %) isolates resistant to at least one antimicrobial on the panel tested (EIEC, 81.3 %; ETEC, n=65.6 %; EAEC, n=73.2 %; EPEC, 40.9 %) and 265/660 (40.2 %) were multidrug-resistant (EIEC, 33.3 %; ETEC, 32.8 %; EAEC, 56.2 %; EPEC, 28.0 %). Genes conferring resistance to the beta-lactams and fluroquinolones were highest in the EAEC pathotype, 56.6 and 60.7%, respectively.Conclusions. Increasing MDR, along with resistance to the fluroquinolones and the third-generation cephalosporins, in DEC causing travellers' diarrhoea provides further evidence for the need to restrict the use of antimicrobial agents and continuous monitoring.


Assuntos
Farmacorresistência Bacteriana/genética , Disenteria/genética , Escherichia coli/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/farmacologia , Criança , Pré-Escolar , Diarreia/patologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Disenteria/epidemiologia , Disenteria/microbiologia , Escherichia coli/isolamento & purificação , Escherichia coli/patogenicidade , Infecções por Escherichia coli/genética , Fezes/microbiologia , Feminino , Gastroenteropatias/epidemiologia , Gastroenteropatias/genética , Gastroenteropatias/microbiologia , Humanos , Lactente , Recém-Nascido , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase/métodos , Viagem , Reino Unido , Virulência/efeitos dos fármacos
5.
Medicine (Baltimore) ; 99(21): e20360, 2020 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-32481328

RESUMO

RATIONALE: Invasive community-acquired infections, including pyogenic liver abscesses, caused by hypervirulent Klebsiella pneumoniae (hvKp) strains have been well recognized worldwide. Among these, sporadic hvKp-related community-acquired pneumonia (CAP) is an acute-onset, rapidly progressing disease that can likely turn fatal, if left untreated. However, the clinical diagnosis of hvKp infection remains challenging due to its non-specific symptoms, lack of awareness regarding this disease, and no consensus definition of hvKp. PATIENT CONCERNS: A 39-year-old man presented with high-grade fever and sudden-onset chest pain. Laboratory testing revealed an elevated white blood cell count of 11,600 cells/µl and C-reactive protein level (>32 mg/dl). A chest X-ray and computed tomography revealed a focal consolidation in the left lower lung field. DIAGNOSIS: Diagnosis of fulminant CAP caused by a hvKp K2-ST86 strain was made based upon multilocus sequencing typing (MLST). INTERVENTIONS: The patient was treated with ampicillin/sulbactam. OUTCOMES: The pneumonia became fulminant. Despite intensive care and treatment, he eventually died 15.5 hours after admission. LESSONS: This is the first case of fatal fulminant CAP caused by a hvKp K2-ST86 strain reported in Japan. MLST was extremely useful for providing a definitive diagnosis for this infection. Thus, we propose that a biomarker-based approach should be considered even for an exploratory diagnosis of CAP related to hvKp infection.


Assuntos
Pneumonia Associada a Assistência à Saúde/diagnóstico , Klebsiella pneumoniae/efeitos dos fármacos , Virulência/imunologia , Adulto , Dor no Peito/etiologia , Infecções Comunitárias Adquiridas/complicações , Infecções Comunitárias Adquiridas/fisiopatologia , Febre/etiologia , Pneumonia Associada a Assistência à Saúde/complicações , Pneumonia Associada a Assistência à Saúde/fisiopatologia , Humanos , Japão , Infecções por Klebsiella/complicações , Infecções por Klebsiella/etiologia , Infecções por Klebsiella/terapia , Klebsiella pneumoniae/patogenicidade , Masculino , Tipagem de Sequências Multilocus/métodos , Virulência/efeitos dos fármacos
6.
PLoS One ; 15(5): e0233916, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32470037

RESUMO

The olive tree (Olea europaea L.) is the most important oil-producing crop of the Mediterranean basin. However, although plant protection measures are regularly applied, disease outbreaks represent an obstacle towards the further development of the sector. Therefore, there is an urge for the improvement of plant protection strategies based on information acquired by the implementation of advanced methodologies. Recently, heavy fungal infections of olive fruits have been recorded in major olive-producing areas of Greece causing devastating yield losses. Thus, initially, we have undertaken the task to identify their causal agent(s) and assess their pathogenicity and sensitivity to fungicides. The disease was identified as the olive anthracnose, and although Colletotrichum gloeosporioides and Colletotrichum acutatum species complexes are the two major causes, the obtained results confirmed that in Southern Greece the latter is the main causal agent. The obtained isolates were grouped into eight morphotypes based on their phenotypes, which differ in their sensitivities to fungicides and pathogenicity. The triazoles difenoconazole and tebuconazole were more toxic than the strobilurins being tested. Furthermore, a GC/EI/MS metabolomics model was developed for the robust chemotaxonomy of the isolates and the dissection of differences between their endo-metabolomes, which could explain the obtained phenotypes. The corresponding metabolites-biomarkers for the discrimination between morphotypes were discovered, with the most important ones being the amino acids L-tyrosine, L-phenylalanine, and L-proline, the disaccharide α,α-trehalose, and the phytotoxic pathogenesis-related metabolite hydroxyphenylacetate. These metabolites play important roles in fungal metabolism, pathogenesis, and stress responses. The study adds critical information that could be further exploited to combat olive anthracnose through its monitoring and the design of improved, customized plant protection strategies. Also, results suggest the necessity for the comprehensive mapping of the C. acutatum species complex morphotypes in order to avoid issues such as the development of fungicide-resistant genotypes.


Assuntos
Colletotrichum/fisiologia , Olea/microbiologia , Doenças das Plantas/prevenção & controle , Colletotrichum/efeitos dos fármacos , Colletotrichum/crescimento & desenvolvimento , Colletotrichum/isolamento & purificação , Flores/microbiologia , Frutas/microbiologia , Fungicidas Industriais/farmacologia , Grécia , Metabolômica , Azeite de Oliva , Folhas de Planta/microbiologia , Especificidade da Espécie , Virulência/efeitos dos fármacos
7.
PLoS One ; 15(5): e0233291, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32437373

RESUMO

A study was conducted to assess the efficacy of ozone gas in inactivating spores of both Bacillus anthracis and Bacillus subtilis inoculated onto six building materials (glass, wood, carpet, laminate, galvanized metal, and wallboard paper). Testing conditions consisted of ozone gas concentrations ranging from 7,000-12,000 parts per million (ppm), contact times from 4 to 12 h, and two relative humidity (RH) levels of 75 and 85%. Results showed that increasing the ozone concentration, contact time, and RH generally increased decontamination efficacy. The materials in which the highest decontamination efficacy was achieved for B. anthracis spores were wallboard paper, carpet, and wood with ≥ 6 log10 reduction (LR) occurring with 9,800 ppm ozone, 85% RH, for 6 h. The laminate and galvanized metal materials were generally more difficult to decontaminate, requiring 12,000 ppm ozone, 85% RH, and 9-12 h contact time to achieve ≥6 LR of B. anthracis. Lastly, overall, there were no significant differences in decontamination efficacy between the two species.


Assuntos
Bacillus anthracis/efeitos dos fármacos , Bacillus subtilis/efeitos dos fármacos , Materiais de Construção/microbiologia , Ozônio/farmacologia , Bacillus anthracis/patogenicidade , Bacillus subtilis/patogenicidade , Descontaminação/métodos , Desinfetantes/farmacologia , Desinfecção/métodos , Fumigação/métodos , Humanos , Especificidade da Espécie , Esporos Bacterianos/efeitos dos fármacos , Esporos Bacterianos/patogenicidade , Virulência/efeitos dos fármacos
8.
PLoS One ; 15(4): e0232461, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32348373

RESUMO

AST-120 (Kremezin) is used to treat progressive chronic kidney disease (CKD) by adsorbing uremic toxin precursors produced by gut microbiota, such as indole and phenols. In this study, we propose that AST-120 reduces indole level, consequently suppresses indole effects on induction of drug tolerance and virulence in Escherichia coli including enterohaemorrhagic strains. In experiments, AST-120 adsorbed both indole and tryptophan, a precursor of indole production, and led to decreased expression of acrD and mdtEF which encode drug efflux pumps, and elevated glpT, which encodes a transporter for fosfomycin uptake and increases susceptibility to aztreonam, rhodamine 6G, and fosfomycin. AST-120 also decreased the production of EspB, which contributes to pathogenicity of enterohaemorrhagic E. coli (EHEC). Aztreonam, ciprofloxacin, minocycline, trimethoprim, and sulfamethoxazole were also adsorbed by AST-120. However, fosfomycin, in addition to rifampicin, colistin and amikacin were not adsorbed, thus AST-120 can be used together with these drugs for therapy to treat infections. These results suggest another benefit of AST-120, i.e., that it assists antibacterial chemotherapy.


Assuntos
Antibacterianos/farmacologia , Carbono/farmacologia , Infecções por Escherichia coli/tratamento farmacológico , Escherichia coli/efeitos dos fármacos , Indóis/metabolismo , Óxidos/farmacologia , Transdução de Sinais/efeitos dos fármacos , Farmacorresistência Bacteriana/efeitos dos fármacos , Escherichia coli Êntero-Hemorrágica/efeitos dos fármacos , Escherichia coli Êntero-Hemorrágica/metabolismo , Escherichia coli Êntero-Hemorrágica/patogenicidade , Escherichia coli/metabolismo , Escherichia coli/patogenicidade , Infecções por Escherichia coli/microbiologia , Humanos , Virulência/efeitos dos fármacos
9.
J Med Microbiol ; 69(5): 767-780, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32320374

RESUMO

Introduction. An important factor for delayed healing of chronic wounds is the presence of bacteria. Quorum sensing (QS), a cell density-dependent signalling system, controls the production of many virulence factors and biofilm formation in Pseudomonas aeruginosa.Aim. Inhibition by sodium salicylate (NaSa) of QS-regulated virulence expression was evaluated in QS-characterized clinical wound isolates of P. aeruginosa, cultured in serum-containing medium.Methodology. Fourteen clinical P. aeruginosa strains from chronic wounds were evaluated for the production of QS signals and virulence factors. Inhibition of QS by NaSa in P. aeruginosa clinical strains, wild-type PAO1 and QS reporter strains was evaluated using in vitro assays for the production of biofilm, pyocyanin, siderophores, alkaline protease, elastase and stapholytic protease.Results. Six clinical strains secreted several QS-associated virulence factors and signal molecules and two were negative for all factors. Sub-inhibitory concentrations of NaSa downregulated the expression of the QS-related genes lasB, rhlA and pqsA and reduced the secretion of several virulence factors in PAO1 and clinical strains cultured in serum. Compared to serum-free media, the presence of serum increased the expression of QS genes and production of siderophores and pyocyanin but decreased biofilm formation.Conclusions. Pseudomonas aeruginosa from chronic wound infections showed different virulence properties. While very few strains showed no QS activity, approximately half were highly virulent and produced QS signals, suggesting that the targeting of QS is a viable and relevant strategy for infection control. NaSa showed activity as a QS-inhibitor by lowering the virulence phenotypes and QS signals at both transcriptional and extracellular levels.


Assuntos
Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/fisiologia , Percepção de Quorum/efeitos dos fármacos , Salicilato de Sódio/farmacologia , Doença Crônica , Humanos , Pseudomonas aeruginosa/isolamento & purificação , Virulência/efeitos dos fármacos , Fatores de Virulência/genética
10.
PLoS One ; 15(4): e0231625, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32298346

RESUMO

BACKGROUND: Serratia marcescens is an emerging pathogen that causes a variety of health care associated infections. S. marcescens is equipped with an arsenal of virulence factors such as biofilm formation, swimming and swarming motilities, prodigiosin, protease and others which enable it to initiate and cause the infection. These virulence factors are orchestrated under the umbrella of an intercellular communication system named Quorum sensing (QS). QS allows bacterial population to synchronize the expression of virulence genes upon detection of a chemical signaling molecule. Targeting bacterial virulence is a promising approach to attenuate bacteria and enhances the ability of immune system to eradicate the bacterial infection. Drug repurposing is an advantageous strategy that confers new applications for drugs outside the scope of their original medical use. This promising strategy offers the use of safe approved compounds, which potentially lowers the costs and shortens the time than that needed for development of new drugs. Sitagliptin is dipeptidyl peptidase-4 (DPP-4) inhibitor, is used to treat diabetes mellitus type II as it increases the production of insulin and decreasing the production of glucagon by the pancreas. We aimed in this study to repurpose sitagliptin, investigating the anti-virulence activities of sitagliptin on S. marcescens. METHODS: The effect of sub-inhibitory concentrations of sitagliptin on virulence factors; protease, prodigiosin, biofilm formation, swimming and swarming motilities was estimated phenotypically. The qRT-PCR was used to show the effect of sitagliptin on the expression of QS-regulated virulence genes. The in-vivo protective activity of sitagliptin on S. marcescens pathogenesis was evaluated on mice. RESULTS: Sitagliptin (1 mg/ml) significantly reduced the biofilm formation, swimming and swarming motilities, prodigiosin and protease. The qRT-PCR confirmed the effect on virulence as shown by down regulating the expression of fimA, fimC, flhC, flhD, bsmB, rssB, rsmA, pigP, and shlA genes. Moreover, the in-vivo findings showed the efficient ability of sitagliptin to weaken S. marcescens pathogenesis. CONCLUSION: Sitagliptin is a promising anti-virulence agent against S. marcescens that may be beneficial in the control of healthcare associated infections caused by S. marcescens.


Assuntos
Antibacterianos/farmacologia , Reposicionamento de Medicamentos , Hipoglicemiantes/farmacologia , Serratia marcescens/efeitos dos fármacos , Fosfato de Sitagliptina/farmacologia , Virulência/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Infecção Hospitalar/tratamento farmacológico , Infecção Hospitalar/microbiologia , Humanos , Percepção de Quorum/efeitos dos fármacos , Infecções por Serratia/tratamento farmacológico , Infecções por Serratia/microbiologia , Serratia marcescens/patogenicidade , Serratia marcescens/fisiologia
12.
Arch Microbiol ; 202(6): 1327-1340, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32146497

RESUMO

Staphylococcus epidermidis is well recognized nosocomial pathogen in clinical settings for their implants associated infections. Biofilm and virulence production executes a S. epidermidis pathogenesis against host. Hence, interfering of biofilm formation has become an auspicious to control the pathogenesis of S. epidermidis. The present study evaluates antibiofilm potential of Rhizophora mucronata against S. epidermidis biofilms. Rhizophora mucronata leaves extract significantly inhibited the biofilm formation and quebrachitol was identified as an active compound responsible for the biofilm inhibition. Quebrachitol significantly inhibited biofilm formation at concentration dependent manner without exhibit non-bactericidal property. And, quebrachitol reduced the biofilm building components such as exopolysaccharides, lipase and proteins production. Confocal laser scanning microscopic studies obtained quebrachitol surface independent biofilm efficacy against S. epidermidis. Notably, quebrachitol significantly reduced S. epidermidis adherence on biotic (coated with type I collagen and fibrinogen) and abiotic (hydrophobic and hydrophilic) surfaces. Addition of quebrachitol inhibits autolysis mediated initial attachment and accumulation associated aggregation process. Moreover, quebrachitol significantly reduced the hydrolases virulence production which supports S. epidermidis invasion into the host. Furthermore, gene expression analysis revealed the ability of quebrachitol to downregulate the virulence genes expression which are mainly involved in biofilm formation and virulence production. The results obtained from the present study suggest that quebrachitol as an ideal candidate for the therapeutic action against S. epidermidis pathogenesis.


Assuntos
Aderência Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Inositol/análogos & derivados , Extratos Vegetais/farmacologia , Staphylococcus epidermidis/efeitos dos fármacos , Inositol/farmacologia , Microscopia Eletrônica de Varredura , Rhizophoraceae/química , Staphylococcus epidermidis/metabolismo , Staphylococcus epidermidis/fisiologia , Staphylococcus epidermidis/ultraestrutura , Virulência/efeitos dos fármacos
13.
Appl Environ Microbiol ; 86(10)2020 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-32169940

RESUMO

A longstanding awareness in generating resistance to common antimicrobial therapies by Gram-negative bacteria has made them a major threat to global health. The application of antimicrobial peptides as a therapeutic agent would be a great opportunity to combat bacterial diseases. Here, we introduce a new antimicrobial peptide (∼8.3 kDa) from probiotic strain Lactobacillus acidophilus ATCC 4356, designated acidocin 4356 (ACD). This multifunctional peptide exerts its anti-infective ability against Pseudomonas aeruginosa through an inhibitory action on virulence factors, bacterial killing, and biofilm degradation. Reliable performance over tough physiological conditions and low hemolytic activity confirmed a new hope for the therapeutic setting. Antibacterial kinetic studies using flow cytometry technique showed that the ACD activity is related to the change in permeability of the membrane. The results obtained from molecular dynamic (MD) simulation were perfectly suited to the experimental data of ACD behavior. The structure-function relationship of this natural compound, along with the results of transmission electron microscopy analysis and MD simulation, confirmed the ability of the ACD aimed at enhancing bacterial membrane perturbation. The peptide was effective in the treatment of P. aeruginosa infection in mouse model. The results support the therapeutic potential of ACD for the treatment of Pseudomonas infections.IMPORTANCE Multidrug-resistant bacteria are a major threat to global health, and the Pseudomonas bacterium with the ability to form biofilms is considered one of the main causative agents of nosocomial infections. Traditional antibiotics have failed because of increased resistance. Thus, finding new biocompatible antibacterial drugs is essential. Antimicrobial peptides are produced by various organisms as a natural defense mechanism against pathogens, inspiring the possible design of the next generation of antibiotics. In this study, a new antimicrobial peptide was isolated from Lactobacillus acidophilus ATCC 4356, counteracting both biofilm and planktonic cells of Pseudomonas aeruginosa A detailed investigation was then conducted concerning the functional mechanism of this peptide by using fluorescence techniques, electron microscopy, and in silico methods. The antibacterial and antibiofilm properties of this peptide may be important in the treatment of Pseudomonas infections.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Proteínas de Bactérias/farmacologia , Lactobacillus acidophilus/química , Pseudomonas aeruginosa/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Cinética , Simulação de Dinâmica Molecular , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa/patogenicidade , Pseudomonas aeruginosa/fisiologia , Virulência/efeitos dos fármacos
14.
J Med Microbiol ; 69(4): 631-639, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32216868

RESUMO

Introduction. Clostridioides difficile is an enteric pathogen that causes a serious toxin-mediated colitis in humans. Bacterial exotoxins and sporulation are critical virulence components that contribute to pathogenesis, and disease transmission and relapse, respectively. Therefore, reducing toxin production and sporulation could significantly minimize C. difficile pathogenicity and disease outcome in affected individuals.Aim. This study investigated the efficacy of a natural flavone glycoside, baicalin, in reducing toxin synthesis, sporulation and spore germination in C. difficile in vitro.Methodology. Hypervirulent C. difficile isolates BAA 1870 or 1803 were cultured in brain heart infusion broth with or without the subinhibitory concentration (SIC) of baicalin, and incubated at 37 °C for 24 h under strictly anaerobic conditions. The supernatant was harvested after 24 h for determining C. difficile toxin production by ELISA. In addition, a similar experiment was performed wherein samples were harvested for assessing total viable counts, and heat-resistant spore counts at 72 h of incubation. Furthermore, C. difficile spore germination and spore outgrowth kinetics, with or without baicalin treatment, was measured in a plate reader by recording optical density at 600 nm. Finally, the effect of baicalin on C. difficile toxin, sporulation and virulence-associated genes was investigated using real-time quantitative PCR.Results. The SIC of baicalin significantly reduced toxin synthesis, sporulation and spore outgrowth when compared to control. In addition, C. difficile genes critical for pathogenesis were significantly down-regulated in the presence of baicalin.Conclusion. Our results suggest that baicalin could potentially be used to control C. difficile, and warrant future studies in vivo.


Assuntos
Antibacterianos/farmacologia , Clostridium difficile/efeitos dos fármacos , Clostridium difficile/patogenicidade , Flavonoides/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Infecções por Clostridium/microbiologia , Clostridium difficile/metabolismo , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Humanos , Virulência/efeitos dos fármacos
15.
Biofouling ; 36(2): 126-137, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32093497

RESUMO

Microbial biofilms are associated with persistent infections because of their high tolerance to antimicrobial agents and host defenses. The effects of centipede oil from Scolopendra subspinipes mutilans and its main components were investigated to identify non-toxic biofilm inhibitors. Centipede oil and linoleic acid at 20 µg ml-1 markedly inhibited biofilm formation by two fluconazole-resistant Candida albicans strains and three Staphylococcus aureus strains without affecting their planktonic cell growth. Also, both centipede oil and linoleic acid inhibited hyphal growth and cell aggregation by C. albicans. In addition, centipede oil and linoleic acid showed anti-biofilm activities against mixed C. albicans and S. aureus biofilms. Transcriptomic analysis showed that centipede oil and linoleic acid downregulated the expressions of several hypha/biofilm-related genes in C. albicans and α-hemolysin in S. aureus. Furthermore, both compounds effectively reduced C. albicans virulence in a nematode infection model with minimal toxicity.


Assuntos
Anti-Infecciosos/farmacologia , Biofilmes/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Ácido Linoleico/farmacologia , Óleos Voláteis/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Animais , Anti-Infecciosos/toxicidade , Artrópodes/química , Biofilmes/crescimento & desenvolvimento , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/microbiologia , Candida albicans/crescimento & desenvolvimento , Candida albicans/patogenicidade , Hifas/crescimento & desenvolvimento , Ácido Linoleico/toxicidade , Testes de Sensibilidade Microbiana , Óleos Voláteis/toxicidade , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus aureus/patogenicidade , Virulência/efeitos dos fármacos
16.
J Med Chem ; 63(6): 3104-3119, 2020 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-32031798

RESUMO

Caseinolytic protease P (ClpP) is considered as a promising target for the treatment of Staphylococcus aureus infections. In an unbiased screen of 2632 molecules, a peptidomimetic boronate, MLN9708, was found to be a potent suppressor of SaClpP function. A time-saving and cost-efficient strategy integrating in silico position scanning, multistep miniaturized synthesis, and bioactivity testing was deployed for optimization of this hit compound and led to fast exploration of structure-activity relationships. Five of 150 compounds from the miniaturized synthesis exhibited improved inhibitory activity. Compound 43Hf was the most active inhibitor and showed reversible covalent binding to SaClpP while did not destabilize the tetradecameric structure of SaClpP. The crystal structure of 43Hf-SaClpP complex provided mechanistic insight into the covalent binding mode of peptidomimetic boronate and SaClpP. Furthermore, 43Hf could bind endogenous ClpP in S. aureus cells and exhibited significant efficacy in attenuating S. aureus virulence in vitro and in vivo.


Assuntos
Antibacterianos/uso terapêutico , Ácidos Borônicos/uso terapêutico , Endopeptidase Clp/antagonistas & inibidores , Peptidomiméticos/uso terapêutico , Inibidores de Serino Proteinase/uso terapêutico , Infecções Cutâneas Estafilocócicas/tratamento farmacológico , Animais , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/metabolismo , Compostos de Boro/farmacologia , Ácidos Borônicos/metabolismo , Ácidos Borônicos/farmacologia , Endopeptidase Clp/metabolismo , Feminino , Glicina/análogos & derivados , Glicina/farmacologia , Humanos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/enzimologia , Camundongos Endogâmicos BALB C , Simulação de Acoplamento Molecular , Estrutura Molecular , Peptidomiméticos/metabolismo , Peptidomiméticos/farmacologia , Ligação Proteica , Inibidores de Serino Proteinase/metabolismo , Inibidores de Serino Proteinase/farmacologia , Pele/patologia , Bibliotecas de Moléculas Pequenas/farmacologia , Relação Estrutura-Atividade , Virulência/efeitos dos fármacos
17.
J Med Microbiol ; 69(4): 617-624, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32100708

RESUMO

Introduction. Growing concern about the increasing frequency of resistance of Helicobacter pylori to the available antimicrobial agents worldwide has encouraged the search for new strategies in treating and eradicating H. pylori infections. Endoscopic blue-light therapy has been used in patients with H. pylori gastritis with limited success due to subsequent repopulation with H. pylori. Clinical trials using Curcumin could not eradicate infection either.Aim. We studied the effect of blue light emitting diodes (LEDs) in conjunction with Curcumin on H. pylori, since this has not been previously reported.Methodology. We examined the effect of Curcumin with and without irradiation with blue LEDs on the viability of H. pylori and four key factors important for colonization and establishment of H. pylori infection, namely urease production, motility, adhesion and biofilm formation.Results. We found that a combination of Curcumin and blue LEDs caused significant reductions in viability, urease production, motility, haemagglutination activity, as well as increased disruption of mature preformed biofilms of H. pylori, in comparison to Curcumin alone (P<0.0001), at sublethal concentrations of Curcumin.Conclusion. Targeting the virulence factors of H. pylori with blue LED photoactivated Curcumin would theoretically cripple this pathogen from colonizing and causing tissue damage and perhaps overcome the problem of repopulation with H. pylori that often occurs following endoscopic blue-light therapy.


Assuntos
Antibacterianos/farmacologia , Curcumina/farmacologia , Infecções por Helicobacter/microbiologia , Helicobacter pylori/efeitos dos fármacos , Helicobacter pylori/efeitos da radiação , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Feminino , Helicobacter pylori/crescimento & desenvolvimento , Helicobacter pylori/patogenicidade , Humanos , Luz , Viabilidade Microbiana/efeitos dos fármacos , Viabilidade Microbiana/efeitos da radiação , Virulência/efeitos dos fármacos , Virulência/efeitos da radiação , Fatores de Virulência/genética , Fatores de Virulência/metabolismo
18.
Infect Immun ; 88(4)2020 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-31988178

RESUMO

Human studies have shown associations between cryptococcal meningitis and reduced IgM memory B cell levels, and studies in IgM- and/or B cell-deficient mice have demonstrated increased Cryptococcus neoformans dissemination from lungs to brain. Since immunoglobulins are part of the immune milieu that C. neoformans confronts in a human host, and its ability to form titan cells is an important virulence mechanism, we determined the effect of human immunoglobulins on C. neoformans titan cell formation in vitro (i) Fluorescence microscopy showed normal human IgG and IgM bind C. neoformans (ii) C. neoformans grown in titan cell-inducing medium with IgM, not IgG, inhibited titan-like cell formation. (iii) Absorption of IgM with laminarin or curdlan (branched and linear 1-3-beta-d-glucans, respectively) decreased this effect. (iv) Transmission electron microscopy revealed that cells grown with IgM had small capsules and unique features not seen with cells grown with IgG. (v) Comparative transcriptional analysis of cell wall, capsule, and stress response genes showed that C. neoformans grown with IgM, not IgG or phosphate-buffered saline (PBS), had decreased expression of chitin synthetase, CHS1, CHS2, and CHS8, and genes encoding cell wall carbohydrate synthetases α-1-3-glucan (AGS1) and ß-1,3-glucan (FKS1). IgM also decreased expression of RIM101 and HOG1, genes encoding central regulators of C. neoformans stress response pathways and cell morphogenesis. Our data show human IgM affects C. neoformans morphology in vitro and suggest that the hypothesis that human immunoglobulins may affect C. neoformans virulence in vivo warrants further investigation.


Assuntos
Cryptococcus neoformans/efeitos dos fármacos , Cryptococcus neoformans/crescimento & desenvolvimento , Interações Hospedeiro-Patógeno , Imunoglobulina M/metabolismo , Fatores Imunológicos/metabolismo , Cryptococcus neoformans/citologia , Humanos , Imunoglobulina G/metabolismo , Virulência/efeitos dos fármacos
19.
J Microbiol ; 58(1): 61-66, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31898254

RESUMO

Drug repositioning, the approach to explore existing drugs for use in new therapeutic indications, has emerged as an alternative drug development strategy. In this study, we found that a mucolytic drug, N-acetylcysteine (NAC) showed antibacterial activity against Vibrio cholerae. NAC can provide acid stress that selectively inhibited the growth of V. cholerae among other bacterial pathogens. To address the antibacterial mechanism of NAC against V. cholerae, six acr (acetylcys-teine-resistant) mutants were isolated from 3,118 random transposon insertion clones. The transposon insertion sites of the six mutants were mapped at the five genes. All these mutants did not display NAC resistance under acidic conditions, despite their resistance to NAC under alkaline conditions, indicating that the NAC resistance directed by the acr mutations was independent of the unusual pH-sensitivity of V. cholerae. Furthermore, all these mutants displayed attenuated virulence and reduced biofilm formation, suggesting that the acr genes are required for pathogenesis of V. cholerae. This study validates the relevance of drug repositioning for antibacterials with new modes of action and will provide an insight into a novel antibacterial therapy for V. cholerae infections to minimize side effects and resistance emergence.


Assuntos
Acetilcisteína/farmacologia , Antibacterianos/farmacologia , Cólera , Reposicionamento de Medicamentos , Vibrio cholerae , Virulência/efeitos dos fármacos , Cólera/tratamento farmacológico , Cólera/microbiologia , Vibrio cholerae/efeitos dos fármacos , Vibrio cholerae/patogenicidade
20.
Biofouling ; 36(1): 101-112, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31997643

RESUMO

Although disinfection procedures are widely implemented in food environments, bacteria can survive and present increased virulence/resistance. Since little is known about these phenomena regarding biofilms, this study aimed to investigate the effect of chemical disinfection on biofilm-derived cells of Salmonella Enteritidis. Using a reference strain (NCTC 13349) and a food isolate (350), biofilm susceptibility to benzalkonium chloride (BAC), sodium hypochlorite (SH) and hydrogen peroxide (HP) was evaluated and biofilms were exposed to sub-lethal concentrations of each disinfectant. Biofilm-derived cells were characterized for their biofilm forming ability, antibiotic resistance and expression of virulence-associated genes. Except for a few instances, disinfectant exposure did not alter antibiotic susceptibility. However, SH and HP exposure enhanced the biofilm forming ability of Salmonella Enteritidis NCTC 13349. After BAC and HP exposure, biofilm-derived cells presented a down-regulation of rpoS. Exposure to BAC also revealed an up-regulation of invA, avrA and csgD on Salmonella Enteritidis NCTC 13349. The results obtained suggest that biofilm-derived cells that survive disinfection may represent an increased health risk.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Desinfetantes/farmacologia , Desinfecção/métodos , Farmacorresistência Bacteriana/efeitos dos fármacos , Salmonella enteritidis/efeitos dos fármacos , Virulência , Compostos de Benzalcônio/farmacologia , Biofilmes/crescimento & desenvolvimento , Farmacorresistência Bacteriana/genética , Expressão Gênica/efeitos dos fármacos , Genes Bacterianos/efeitos dos fármacos , Salmonella enteritidis/genética , Salmonella enteritidis/crescimento & desenvolvimento , Salmonella enteritidis/patogenicidade , Hipoclorito de Sódio/farmacologia , Virulência/efeitos dos fármacos , Virulência/genética
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