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1.
Nature ; 574(7779): 549-552, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31645729

RESUMO

About half of all bacteria carry genes for CRISPR-Cas adaptive immune systems1, which provide immunological memory by inserting short DNA sequences from phage and other parasitic DNA elements into CRISPR loci on the host genome2. Whereas CRISPR loci evolve rapidly in natural environments3,4, bacterial species typically evolve phage resistance by the mutation or loss of phage receptors under laboratory conditions5,6. Here we report how this discrepancy may in part be explained by differences in the biotic complexity of in vitro and natural environments7,8. Specifically, by using the opportunistic pathogen Pseudomonas aeruginosa and its phage DMS3vir, we show that coexistence with other human pathogens amplifies the fitness trade-offs associated with the mutation of phage receptors, and therefore tips the balance in favour of the evolution of CRISPR-based resistance. We also demonstrate that this has important knock-on effects for the virulence of P. aeruginosa, which became attenuated only if the bacteria evolved surface-based resistance. Our data reveal that the biotic complexity of microbial communities in natural environments is an important driver of the evolution of CRISPR-Cas adaptive immunity, with key implications for bacterial fitness and virulence.


Assuntos
Bacteriófagos/genética , Bacteriófagos/imunologia , Biodiversidade , Sistemas CRISPR-Cas/genética , Evolução Molecular , Pseudomonas aeruginosa/imunologia , Pseudomonas aeruginosa/virologia , Bacteriófagos/patogenicidade , Sistemas CRISPR-Cas/imunologia , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/patogenicidade , Receptores Virais/metabolismo
2.
Microbiol Res ; 226: 19-26, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31284940

RESUMO

Pseudomonas aeruginosa is one of the most common pathogens associated with nosocomial infections and a great concern to immunocompromised individuals especially in the cases of cystic fibrosis, AIDS and burn wounds. The pathogenicity of P. aeruginosa is largely directed by the quorum sensing (QS) system. Hence, QS may be considered an important therapeutic target to combat P. aeruginosa infections. The anti-quorum sensing and anti-biofilm efficacy of aromatic aldehyde, 5-hydroxymethylfurfural (5-HMF) against P. aeruginosa PAO1 were assessed. At the sub-inhibitory concentration, 5-HMF suppressed the production of QS-controlled virulence phenotypes and biofilm formation in P. aeruginosa. It was also able to significantly enhance the survival rate of C. elegans infected with P. aeruginosa. The in silico studies revealed that 5-HMF could serve as a competitive inhibitor for the auto-inducer molecules as it exhibited a strong affinity for the regulatory proteins of the QS-circuits i.e. LasR and RhlR. In addition, a significant down-regulation in the expression of QS-related genes was observed suggesting the ability of 5-HMF in mitigating the pathogenicity of P. aeruginosa.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Furaldeído/análogos & derivados , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/patogenicidade , Percepção de Quorum/efeitos dos fármacos , Animais , Proteínas de Bactérias , Caenorhabditis elegans , Simulação por Computador , Modelos Animais de Doenças , Furaldeído/farmacologia , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Percepção de Quorum/genética , Taxa de Sobrevida , Transativadores , Virulência/efeitos dos fármacos , Fatores de Virulência
3.
Rev Chilena Infectol ; 36(2): 180-189, 2019 Apr.
Artigo em Espanhol | MEDLINE | ID: mdl-31344154

RESUMO

Among the most frequent nosocomial infections associated with polyresistant bacteria and with a worse prognosis, are those produced by Pseudomonas aeruginosa. This bacterium has a high capacity to adapt to adverse conditions such as pH and osmolarity of urine. Pseudomonas aeruginosa is one of the main pathogens involved in nosocomial infections and immunosuppressed patients. This bacterium is considered an opportunistic infectious agent that has diverse mechanisms of pathogenicity, as well as resistance to antimicrobials, which contributes to the difficulty in the treatment of these infections. In the present bibliographic review, the taxonomy, pathogenicity mechanisms and resistance genes of P. aeruginosa are analyzed. Likewise, the micro-environmental factors of the urinary infection produced by this bacterium are approached, making an approach to the understanding of the pathophysiological bases of this infection.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Infecções por Pseudomonas/tratamento farmacológico , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/patogenicidade , Infecções Urinárias/microbiologia , Proteínas de Bactérias/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Humanos , Infecções Urinárias/tratamento farmacológico , Fatores de Virulência
4.
Nat Commun ; 10(1): 2931, 2019 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-31270321

RESUMO

The virulence of Pseudomonas aeruginosa, a Gram-negative opportunistic pathogen, is regulated by many transcriptional factors (TFs) that control the expression of quorum sensing and protein secretion systems. Here, we report a genome-wide, network-based approach to dissect the crosstalk between 20 key virulence-related TFs. Using chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-seq), as well as RNA-seq, we identify 1200 TF-bound genes and 4775 differentially expressed genes. We experimentally validate 347 of these genes as functional target genes, and describe the regulatory relationships of the 20 TFs with their targets in a network that we call 'Pseudomonas aeruginosa genomic regulatory network' (PAGnet). Analysis of the network led to the identification of novel functions for two TFs (ExsA and GacA) in quorum sensing and nitrogen metabolism. Furthermore, we present an online platform and R package based on PAGnet to facilitate updating and user-customised analyses.


Assuntos
Proteínas de Bactérias/genética , Pseudomonas aeruginosa/genética , Fatores de Transcrição/genética , Proteínas de Bactérias/metabolismo , Imunoprecipitação da Cromatina , Regulação Bacteriana da Expressão Gênica , Genoma Bacteriano , Genômica , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/metabolismo , Pseudomonas aeruginosa/patogenicidade , Fatores de Transcrição/metabolismo , Virulência , Fatores de Virulência/genética , Fatores de Virulência/metabolismo
5.
PLoS Pathog ; 15(6): e1007812, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31220187

RESUMO

While considered solely an extracellular pathogen, increasing evidence indicates that Pseudomonas aeruginosa encounters intracellular environment in diverse mammalian cell types, including macrophages. In the present study, we have deciphered the intramacrophage fate of wild-type P. aeruginosa PAO1 strain by live and electron microscopy. P. aeruginosa first resided in phagosomal vacuoles and subsequently could be detected in the cytoplasm, indicating phagosomal escape of the pathogen, a finding also supported by vacuolar rupture assay. The intracellular bacteria could eventually induce cell lysis, both in a macrophage cell line and primary human macrophages. Two bacterial factors, MgtC and OprF, recently identified to be important for survival of P. aeruginosa in macrophages, were found to be involved in bacterial escape from the phagosome as well as in cell lysis caused by intracellular bacteria. Strikingly, type III secretion system (T3SS) genes of P. aeruginosa were down-regulated within macrophages in both mgtC and oprF mutants. Concordantly, cyclic di-GMP (c-di-GMP) level was increased in both mutants, providing a clue for negative regulation of T3SS inside macrophages. Consistent with the phenotypes and gene expression pattern of mgtC and oprF mutants, a T3SS mutant (ΔpscN) exhibited defect in phagosomal escape and macrophage lysis driven by internalized bacteria. Importantly, these effects appeared to be largely dependent on the ExoS effector, in contrast with the known T3SS-dependent, but ExoS independent, cytotoxicity caused by extracellular P. aeruginosa towards macrophages. Moreover, this macrophage damage caused by intracellular P. aeruginosa was found to be dependent on GTPase Activating Protein (GAP) domain of ExoS. Hence, our work highlights T3SS and ExoS, whose expression is modulated by MgtC and OprF, as key players in the intramacrophage life of P. aeruginosa which allow internalized bacteria to lyse macrophages.


Assuntos
Proteínas de Bactérias/biossíntese , Regulação para Baixo , Regulação Bacteriana da Expressão Gênica , Macrófagos/microbiologia , Pseudomonas aeruginosa , Sistemas de Secreção Tipo III/metabolismo , ADP Ribose Transferases/genética , ADP Ribose Transferases/metabolismo , Animais , Proteínas de Bactérias/genética , Toxinas Bacterianas/genética , Toxinas Bacterianas/metabolismo , Linhagem Celular , Humanos , Macrófagos/metabolismo , Macrófagos/ultraestrutura , Camundongos , Mutação , Fagossomos/microbiologia , Fagossomos/ultraestrutura , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/metabolismo , Pseudomonas aeruginosa/patogenicidade , Sistemas de Secreção Tipo III/genética
6.
Prensa méd. argent ; 105(5): 302-308, jun 2019. fig, tab
Artigo em Inglês | LILACS, BINACIS | ID: biblio-1024638

RESUMO

Aim: The current venture, were made to evaluate the inhibitory effect of Trigonella foenum seed Extract and ZiO2 Nanoparticles on some selected species of Fungi and Bacteria. Materials and Methods: two bacterial species included Pseudomonas aeruginosa and Staphylococcus aureus and three fungal species which is Cryptococcus neoformans, Candidda albicans and Chaetomium were used to evaluate the antibacterial activity of Trigonella foenum Extract and ZiO2 Nanoparticles. Results: This study showed that the Zirconium Oxide (ZiO2) nanoparticles have antifungal and antibacterial activities on the isolates of Cryptococcus neoformans, Candida alicans and Staphylococcus aureus, respectively. While the antimicrobial activity of Zirconium Oxide nanoparticles on the Chaetomium and Pseudomonas aeruginosa was negative. All tested fungi and bacterial isolates were found to be sensitive to Trigonella foenum seed extract, the results of the compination of the ZiO2 Nanoparticle and the Trigonella foenum seed extract were poisitive for all tested fungi isolates and bacterial isolates. The XRD analysis was done for Zirconium Oxide nanoparticles and the result showed that the biocrystallization on the surface of the Zirconium Oxide manoparticles. The average partides size was about (29.8) nm. Conclusions: This investigation conclude that the use of Trigonella foenum seed Extract has the effect of killing all bacteria and fungi under study, result indicate the Trigonella foenun seed Extract best antibacterial efficacy than the ZiO2 together (AU)


Assuntos
Humanos , Pseudomonas aeruginosa/patogenicidade , Staphylococcus aureus/patogenicidade , Candida albicans/patogenicidade , Chaetomium/patogenicidade , Cryptococcus neoformans/patogenicidade , Trigonella/microbiologia , Nanopartículas/efeitos adversos , Fabaceae/efeitos adversos , Anti-Infecciosos/uso terapêutico , Antibacterianos/uso terapêutico , Antifúngicos/uso terapêutico
7.
World J Microbiol Biotechnol ; 35(6): 94, 2019 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-31187291

RESUMO

Pseudomonas aeruginosa is the major infectious agent of concern for cystic fibrosis (CF) patients. Therefore, it is necessary to develop appropriate strategies for preventing colonization by this bacterium and/or neutralizing virulence factors. In this study, we formulated the encapsulation of exotoxin A into PLGA nanoparticles. The biological activities of the nanovaccine candidate were also characterized. Based on the results, ETA-PLGA can act as a suitable immunogen to stimulate the humoral and cellular immune response. The antibodies raised against ETA-PLGA significantly decreased bacterial titer in the spleens of the immunized mice after challenge with PAO1 strain, compared to the control groups. The encapsulation of PLGA into ETA led to a significantly higher production of INF-γ, TNF-α, IL-4, and IL-17A cytokine responses compared to the ETA group. ETA-PLGA enhanced IgG responses in immunized mice compared to ETA antigen. We concluded that encapsulation of Pseudomonas aeruginosa ETA to PLGA nanoparticles can increase its functional activity by decreasing the bacterial dissemination.


Assuntos
ADP Ribose Transferases/imunologia , Toxinas Bacterianas/imunologia , Exotoxinas/imunologia , Imunização , Nanoconjugados , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/imunologia , Infecções por Pseudomonas/prevenção & controle , Pseudomonas aeruginosa/patogenicidade , Vacinas Conjugadas , Fatores de Virulência/imunologia , ADP Ribose Transferases/uso terapêutico , Animais , Toxinas Bacterianas/uso terapêutico , Citocinas/metabolismo , Modelos Animais de Doenças , Exotoxinas/uso terapêutico , Feminino , Imunidade Celular , Imunidade Humoral , Imunoglobulina G/sangue , Interferon gama/metabolismo , Interleucina-17/metabolismo , Interleucina-4/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Nanopartículas , Tamanho da Partícula , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/uso terapêutico , Infecções por Pseudomonas/imunologia , Baço/imunologia , Baço/microbiologia , Fatores de Virulência/uso terapêutico
8.
J Microbiol ; 57(8): 704-710, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31187416

RESUMO

KatA is the major catalase required for hydrogen peroxide (H2O2) resistance and acute virulence in Pseudomonas aeruginosa PA14, whose transcription is governed by its dual promoters (katAp1 and katAp2). Here, we observed that KatA was not required for acute virulence in another wild type P. aeruginosa strain, PAO1, but that PAO1 exhibited higher KatA expression than PA14 did. This was in a good agreement with the observation that PAO1 was more resistant than PA14 to H2O2 as well as to the antibiotic peptide, polymyxin B (PMB), supposed to involve reactive oxygen species (ROS) for its antibacterial activity. The higher KatA expression in PAO1 than in PA14 was attributed to both katAp1 and katAp2 transcripts, as assessed by S1 nuclease mapping. In addition, it was confirmed that the PMB resistance is attributed to both katAp1 and katAp2 in a complementary manner in PA14 and PAO1, by exploiting the promoter mutants for each -10 box (p1m, p2m, and p1p2m). These results provide an evidence that the two widely used P. aeruginosa strains display different virulence mechanisms associated with OxyR and Anr, which need to be further characterized for better understanding of the critical virulence pathways that may differ in various P. aeruginosa strains.


Assuntos
Proteínas de Bactérias/genética , Catalase/genética , Regulação Bacteriana da Expressão Gênica , Peróxido de Hidrogênio/metabolismo , Polimixina B/metabolismo , Pseudomonas aeruginosa/enzimologia , Antibacterianos/metabolismo , Regiões Promotoras Genéticas , Pseudomonas aeruginosa/patogenicidade , Virulência
9.
Microbiol Res ; 223-225: 137-143, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31178047

RESUMO

Pseudomonas aeruginosa is an opportunistic pathogen with high clinical relevance for hospital infections of patients. Accumulating DNA sequencing results of clinical P. aeruginosa isolates have revealed frequent mutations in lasR gene, which encodes the highest arches component of quorum-sensing system (QS). We analyzed the sequencing data of lasR gene from a large collection of cystic fibrosis (CF) P. aeruginosa isolates. Our systematical analyses revealed that single nucleotide polymorphisms (SNPs) selection in lasR gene were largely constrained by codon-usage frequency. As a whole, SNP-substituted codons encoding unconserved amino acid resulted in unfavored codons with relatively low codon-usage frequency, while those associating with conserved amino acid were not strictly regulated in such way. These SNPs substitutions gives rise to diverse functional LasR isoforms and contributes to the relative growth fitness of recombinant lasR variant strains. Our survey reveals a novel pattern of SNPs selections in lasR gene of CF isolates. Our findings could be served as a powerful resource for understanding adaptive mechanism of clinical isolates under environmental constrains and developing anti-bacteria drugs for CF patients.


Assuntos
Proteínas de Bactérias/genética , Códon/genética , Fibrose Cística/microbiologia , Polimorfismo de Nucleotídeo Único/genética , Pseudomonas aeruginosa/genética , Transativadores/genética , Sequência de Aminoácidos , Regulação Bacteriana da Expressão Gênica , Isoformas de Proteínas , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/patogenicidade , Percepção de Quorum/genética , Alinhamento de Sequência , Análise de Sequência de DNA
10.
Int J Mol Sci ; 20(9)2019 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-31052156

RESUMO

Cystic fibrosis (CF) is a genetic disorder affecting several organs including airways. Bacterial infection, inflammation and iron dysbalance play a major role in the chronicity and severity of the lung pathology. The aim of this study was to investigate the effect of lactoferrin (Lf), a multifunctional iron-chelating glycoprotein of innate immunity, in a CF murine model of Pseudomonas aeruginosa chronic lung infection. To induce chronic lung infection, C57BL/6 mice, either cystic fibrosis transmembrane conductance regulator (CFTR)-deficient (Cftrtm1UNCTgN(FABPCFTR)#Jaw) or wild-type (WT), were intra-tracheally inoculated with multidrug-resistant MDR-RP73 P. aeruginosa embedded in agar beads. Treatments with aerosolized bovine Lf (bLf) or saline were started five minutes after infection and repeated daily for six days. Our results demonstrated that aerosolized bLf was effective in significantly reducing both pulmonary bacterial load and infiltrated leukocytes in infected CF mice. Furthermore, for the first time, we showed that bLf reduced pulmonary iron overload, in both WT and CF mice. In particular, at molecular level, a significant decrease of both the iron exporter ferroportin and iron storage ferritin, as well as luminal iron content was observed. Overall, bLf acts as a potent multi-targeting agent able to break the vicious cycle induced by P. aeruginosa, inflammation and iron dysbalance, thus mitigating the severity of CF-related pathology and sequelae.


Assuntos
Anti-Infecciosos/uso terapêutico , Fibrose Cística/terapia , Lactoferrina/uso terapêutico , Pneumonia/terapia , Administração por Inalação , Animais , Anti-Infecciosos/administração & dosagem , Proteínas de Transporte de Cátions/metabolismo , Bovinos , Fibrose Cística/complicações , Fibrose Cística/genética , Ferritinas/metabolismo , Lactoferrina/administração & dosagem , Camundongos , Camundongos Endogâmicos C57BL , Pneumonia/etiologia , Pneumonia/microbiologia , Pseudomonas aeruginosa/patogenicidade
11.
Biomed Res Int ; 2019: 4834396, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31119172

RESUMO

Lower respiratory tract infections (LRTIs) remain a challenge in African healthcare settings and only few data are available on their aetiology in Cameroon. The purpose of this study was to access the bacterial cause of LRTIs in patients in Cameroon by two methods. Methods. Participants with LRTIs were enrolled in the referral centre for respiratory diseases in Yaoundé city and its surroundings. To detect bacteria, specimens were tested by conventional bacterial culture and a commercial reverse-transcriptase real-time polymerase chain reaction (RT-PCR) assay. One hundred forty-one adult patients with LRTIs were enrolled in the study. Among the participants, 46.8% were positive for at least one bacterium. Streptococcus pneumoniae and Haemophilus influenzae were the most detected bacteria with 14.2% (20/141) followed by Klebsiella pneumoniae, 9.2% (13/141), Staphylococcus aureus, 7.1% (10/141), and Moraxella catarrhalis, 4.3% (6/141). Bacterial coinfection accounted for 23% (14/61) with Haemophilus influenzae being implicated in 19.7% (12/61). The diagnostic performance of RT-PCR for bacteria detection (43.3%) was significantly different from that of culture (17.7%) (p< 0.001). Only Streptococcus pneumoniae detection was associated with empyema by RT-PCR (p<0.001). These findings enhance understanding of bacterial aetiologies in order to improve respiratory infection management and treatment. It also highlights the need to implement molecular tools as part of the diagnosis of LRTIs.


Assuntos
Antibacterianos/uso terapêutico , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/microbiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Camarões/epidemiologia , Feminino , Haemophilus influenzae/isolamento & purificação , Haemophilus influenzae/patogenicidade , Humanos , Klebsiella pneumoniae/isolamento & purificação , Klebsiella pneumoniae/patogenicidade , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Mycobacterium tuberculosis/isolamento & purificação , Mycobacterium tuberculosis/patogenicidade , Pseudomonas aeruginosa/isolamento & purificação , Pseudomonas aeruginosa/patogenicidade , Infecções Respiratórias/tratamento farmacológico , Infecções Respiratórias/patologia , Staphylococcus aureus/isolamento & purificação , Staphylococcus aureus/patogenicidade , Streptococcus pneumoniae/isolamento & purificação , Streptococcus pneumoniae/patogenicidade , Adulto Jovem
12.
Microb Pathog ; 132: 230-242, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31082528

RESUMO

Virulence pathways in gram-negative pathogenic bacteria are regulated by quorum sensing mechanisms, through the production and sensing of N-acylhomoserine lactone (AHL) signal molecules. Enzymatic degradation to disrupt quorum-sensing in these bacteria could pave the way for the new development in decreasing resistance strains and are of significant interest for clinical, agricultural, and industrial applications. Isolated endophytic Bacillus thuringiensis strain KMCL07 showing quorum quenching activity on Pseudomonas aeruginosa PAO1 has been studied. AiiA lactonase KMMI17 identified belongs to metallo- ß-lactamase superfamily preserving conserved regions of 106HXDH-59 amino acids-H169-21 amino acids-D191 motif, significantly inhibits the biofilm formation and attenuates virulence factor pyocyanin production of PAO1. Insilico molecular docking analysis of lactonase KMMI17 using alternative catalytic site (PDB entry: 3DHA) with the AHL-based QS system regulators of PAO-1, C4 AHL, C6 AHL and 3-oxo-C12 AHL molecules showed good binding affinity between the protein and ligands, Phe111 and Tyr198 residues plays an important role in binding them. Crude enzyme extract was found to have Km value for C6-HSL: 134.2702 ±â€¯34.83 µM-1, C4-HSL: 308.217 ±â€¯139.9 µM-1 and 3-oxo-C12-HSL: 760.463 ±â€¯251.3 µM-1. LCMS analysis confirms the degradation activity of lactonase KMMI17 on AHL molecules and its hydrolytic process, which indicates the potential application of lactonase KMMI17 as a biocontrol agent or an anti-pathogenic drug.


Assuntos
Bacillus thuringiensis/metabolismo , Proteínas de Bactérias/antagonistas & inibidores , Lactonas/metabolismo , Metaloendopeptidases/antagonistas & inibidores , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/metabolismo , Percepção de Quorum/fisiologia , Proteínas de Bactérias/metabolismo , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Hidrolases de Éster Carboxílico/metabolismo , Índia , Madhuca/microbiologia , Metaloendopeptidases/metabolismo , Simulação de Acoplamento Molecular , Fenótipo , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/patogenicidade , Piocianina/metabolismo , Fatores de Virulência
13.
Microbiol Immunol ; 63(6): 229-237, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31041998

RESUMO

Pseudomonas aeruginosa is a major cause of nosocomial infections and contributes to higher mortality in hospitalized individuals. Infection by P. aeruginosa triggers host immune response through activation of pathogen recognition receptors, which are present in innate cells. Several studies have reported the mechanism of P. aeruginosa induced innate immunity in multiple cell types. But so far there is no reports on response of megakaryocytes to P. aeruginosa infection. Hence, our aim was to investigate the precise role and signaling mechanism of megakaryocytes during P. aeruginosa infection. In this study, we used Mo7e cells as representatives of human megakaryocyte and found that P. aeruginosa infection induces cytotoxicity in these cells. We further demonstrated that P. aeruginosa infection modulates p38 and extracellular signal regulated kinase pathways in Mo7e cells. Protein expression profiling in P. aeruginosa lipopolysaccharide-treated Mo7e cells revealed upregulation of importin subunit ß and downregulation of metabolic enzymes. Our results suggest that P. aeruginosa infection regulates mitogen-activated protein kinases signaling pathway and importin in Mo7e cells and that this is a potential mechanism for nuclear translocation of nuclear factor binding near the κ light-chain gene in B cells and c-Jun N-terminal kinases to induce cell cytotoxicity.


Assuntos
Megacariócitos/imunologia , Megacariócitos/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Infecções por Pseudomonas/imunologia , Pseudomonas aeruginosa/patogenicidade , Transdução de Sinais , Linhagem Celular , Testes Imunológicos de Citotoxicidade , Regulação para Baixo , Perfilação da Expressão Gênica , Humanos , Imunidade Inata , Proteínas Quinases JNK Ativadas por Mitógeno , Lipopolissacarídeos , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Proteínas Quinases Ativadas por Mitógeno/genética , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
14.
Vet Microbiol ; 231: 169-176, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30955805

RESUMO

Purulent disease is the main factor that prevents the population increase of forest musk deer in artificial breeding, and especially the intracorporal suppurative lesions in late-stage with complex bacterial communities normally bring more difficulties for veterinary treatment. Although it is well-recognized that Pseudomonas aeruginosa and Escherichia coli are the two main bacterial pathogens which can be frequently co-isolated from the lung pus of forest musk deer, few studies have explored the interspecific relationship and coexistent mechanism of the two species. In this study, we identified a P. aeruginosa strain MYL-2, which harbored a loss-of-function mutation in the central regulator (LasR) of quorum-sensing (QS) system, from the lung pus of a dying forest musk deer with co-infecting E. coli strain MYL-58. Interestingly, P. aeruginosa MYL-2 could coexist with E. coli MYL-58 compared to the dominant role of lasR-intact P. aeruginosa strain MYL-1 in the competitive experiments. The results of in vitro coevolution assay further revealed that the QS-mediated competitive advantage of P. aeruginosa MYL-1 would be decreased along with the enrichment of lasR mutants in the communities, and P. aeruginosa could finally coexist with E. coli by forming a relatively stable equilibrium. Therefore, these findings provide an evolutionary explanation for the coexistence of P. aeruginosa and E. coli in the suppurative lesions of forest musk deer, and may also contribute to further understanding the pathology of animal purulent disease and the development of novel veterinary therapy.


Assuntos
Cervos/microbiologia , Infecções por Escherichia coli/veterinária , Pulmão/microbiologia , Infecções por Pseudomonas/veterinária , Infecções Respiratórias/veterinária , Animais , Evolução Molecular Direcionada , Escherichia coli/genética , Escherichia coli/patogenicidade , Pulmão/patologia , Microbiota , Mutação , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/patogenicidade , Percepção de Quorum , Infecções Respiratórias/microbiologia , Supuração/microbiologia , Virulência
15.
Artigo em Inglês | MEDLINE | ID: mdl-30970111

RESUMO

Multidrug resistance (MDR), virulence and transferable elements potentiate Pseudomonas aeruginosa's role as an opportunistic pathogen creating a high risk for public health. In this study, we evaluated the possible association of multidrug resistance, virulence factors and integrons with intrahospital P. aeruginosa strains isolated from patients at Cumana hospital, Venezuela. Relevant clinical-epidemiological data were collected to study 176 strains (2009-2016) isolated from different hospital units. Bacterial resistance was classified as susceptible, low-level resistant (LDR), multidrug resistant (MDR) and extensively drug-resistant (XDR). Most strains produced pyoverdine, DNase, gelatinase and hemolysin. Around 73% of the strains showed some type of movement. MDR and XDR strains increased from 2009 (24.2% and 4.8%, respectively) to 2016 (53.1% and 18.8%); while LDR decreased from 64.5% to 6.3%. The exoU and exoS genes were found in a significant number of strains (38.1 and 7.4%, respectively). Class I integrons were detected in 35.8% of the strains and the frequency was associated with resistance (42.9, 22.4, 41.4 and 61.9%, for susceptible, LDR, MDR and XDR, respectively). The MDR/XDR strains were positively associated with hemolysins and exoU, but negatively associated with bacterial twitching. MDR/XDR phenotypes were also associated with the Intensive Care Unit (ICU), septicemia, bronchial infection and diabetic foot ulcers, as well as long hospital stay (≥10 days) and previous antimicrobial treatment. High frequency of MDR/XDR strains and their association with class I integrons and virulence factors can increase the infection potential, as well as morbidity and mortality of patients attending this hospital and could spread infection to the community, creating a health risk for the region.


Assuntos
Antibacterianos/farmacologia , Integrons/genética , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/patogenicidade , Fatores de Virulência/genética , Biofilmes/crescimento & desenvolvimento , Farmacorresistência Bacteriana Múltipla , Hospitais Universitários , Humanos , Unidades de Terapia Intensiva , Testes de Sensibilidade Microbiana , Fenótipo , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/enzimologia , Venezuela , Virulência
16.
Sensors (Basel) ; 19(8)2019 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-31003541

RESUMO

One concern to the patients is the off-line detection of pneumonia infection status after using the ventilator in the intensive care unit. Hence, machine learning methods for ventilator-associated pneumonia (VAP) rapid diagnose are proposed. A popular device, Cyranose 320 e-nose, is usually used in research on lung disease, which is a highly integrated system and sensor comprising 32 array using polymer and carbon black materials. In this study, a total of 24 subjects were involved, including 12 subjects who are infected with pneumonia, and the rest are non-infected. Three layers of back propagation artificial neural network and support vector machine (SVM) methods were applied to patients' data to predict whether they are infected with VAP with Pseudomonas aeruginosa infection. Furthermore, in order to improve the accuracy and the generalization of the prediction models, the ensemble neural networks (ENN) method was applied. In this study, ENN and SVM prediction models were trained and tested. In order to evaluate the models' performance, a fivefold cross-validation method was applied. The results showed that both ENN and SVM models have high recognition rates of VAP with Pseudomonas aeruginosa infection, with 0.9479 ± 0.0135 and 0.8686 ± 0.0422 accuracies, 0.9714 ± 0.0131, 0.9250 ± 0.0423 sensitivities, and 0.9288 ± 0.0306, 0.8639 ± 0.0276 positive predictive values, respectively. The ENN model showed better performance compared to SVM in the recognition of VAP with Pseudomonas aeruginosa infection. The areas under the receiver operating characteristic curve of the two models were 0.9842 ± 0.0058 and 0.9410 ± 0.0301, respectively, showing that both models are very stable and accurate classifiers. This study aims to assist the physician in providing a scientific and effective reference for performing early detection in Pseudomonas aeruginosa infection or other diseases.


Assuntos
Nariz Eletrônico , Pneumonia Associada à Ventilação Mecânica/diagnóstico , Infecções por Pseudomonas/diagnóstico , Adulto , Feminino , Humanos , Unidades de Terapia Intensiva , Aprendizado de Máquina , Masculino , Pneumonia Associada à Ventilação Mecânica/complicações , Pneumonia Associada à Ventilação Mecânica/microbiologia , Pneumonia Associada à Ventilação Mecânica/fisiopatologia , Infecções por Pseudomonas/complicações , Infecções por Pseudomonas/microbiologia , Infecções por Pseudomonas/fisiopatologia , Pseudomonas aeruginosa/isolamento & purificação , Pseudomonas aeruginosa/patogenicidade
17.
Molecules ; 24(8)2019 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-31027179

RESUMO

Wound healing can be delayed following colonization and infection with the common bacterium Pseudomonas aeruginosa. While multiple therapies are used for their treatment, these are ineffective, expensive, and labour-intensive. Thus, there is an enormous unmet need for the treatment of infected wounds. Cinnamaldehyde, the major component of cinnamon oil, is well known for its antimicrobial properties. Herein, we investigated the effects of sub-inhibitory concentrations of cinnamaldehyde in the virulence of P. aeruginosa. We also assessed its healing potential in P. aeruginosa-infected mouse skin wounds and the mechanisms involved in this response. Sub-inhibitory concentrations of cinnamaldehyde reduced P. aeruginosa metabolic rate and its ability to form biofilm and to cause haemolysis. Daily topical application of cinnamaldehyde on P. aeruginosa-infected skin wounds reduced tissue bacterial load and promoted faster healing. Lower interleukin-17 (IL-17), vascular endothelial growth factor (VEGF) and nitric oxide levels were detected in cinnamaldehyde-treated wound samples. Blockage of transient receptor potential ankyrin 1, the pharmacological target of cinnamaldehyde, abrogated its healing activity and partially reversed the inhibitory actions of this compound on VEGF and IL-17 generation. We suggest that topical application of sub-inhibitory concentrations of cinnamaldehyde may represent an interesting approach to improve the healing of P. aeruginosa-infected skin wounds.


Assuntos
Acroleína/análogos & derivados , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/patogenicidade , Pele/microbiologia , Cicatrização/efeitos dos fármacos , Acroleína/uso terapêutico , Animais , Anti-Infecciosos/uso terapêutico , Biofilmes/efeitos dos fármacos , Modelos Animais de Doenças , Feminino , Interleucina-17/metabolismo , Camundongos , Infecções por Pseudomonas/tratamento farmacológico , Canal de Cátion TRPA1/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo
18.
Can J Microbiol ; 65(8): 563-574, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31009577

RESUMO

Pseudomonas aeruginosa is a virulent bacterium that secretes a variety of virulence factors that aid in establishing infections in individuals. Allicin, derived from garlic, has been shown to inhibit virulence factor production and biofilm formation in P. aeruginosa. However, the mechanisms underlying the allicin-mediated regulation of P. aeruginosa virulence remain unclear. In this study, we investigated the possible mechanisms underlying allicin-mediated virulence regulation in P. aeruginosa. The results showed that allicin attenuates the production of P. aeruginosa virulence-associated factors, such as elastase, pyocyanin, pyoverdine, and rhamnolipids, by inhibiting the rhl and pqs quorum-sensing systems. Further analysis revealed that the rhl and pqs systems play different roles during the allicin-mediated regulation process. Taken together, these results support the potential use of allicin as a therapeutic agent in controlling P. aeruginosa infection and associated mechanisms.


Assuntos
Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/patogenicidade , Percepção de Quorum/efeitos dos fármacos , Ácidos Sulfínicos/farmacologia , Fatores de Virulência/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Glicolipídeos/metabolismo , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/metabolismo , Piocianina/metabolismo , Virulência/efeitos dos fármacos , Fatores de Virulência/genética
19.
Molecules ; 24(7)2019 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-30979056

RESUMO

1,4-Naphthoquinones have antibacterial activity and are a promising new class of compound that can be used to treat bacterial infections. The goal was to improve effective antibacterial agents; therefore, we synthesized a new class of naphthoquinone hybrids, which contain phenylamino-phenylthio moieties as significant counterparts. Compound 4 was modified as a substituted aryl amide moiety, which enhanced the antibacterial activity of earlier compounds 3 and 4. In this study, five bacterial strains Staphylococcus aureus (S. aureus), Listeria monocytogenes (L. monocytogenes), Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) and Klebsiella pneumoniae (K. pneumoniae) were used to evaluate the antibacterial potency of synthesized naphthoquinones using the minimal inhibitory concentration (MIC) method. Most of the studied naphthoquinones demonstrated major antibacterial activity with a MIC of 15.6 µg/mL-500 µg/mL. Selected compounds (5a, 5f and 5x) were studied for the mode of action, using intracellular ROS generation, determination of apoptosis by the Annexin V-FITC/PI assay, a bactericidal kinetic study and in silico molecular modelling. Additionally, the redox potentials of the specified compounds were confirmed by cyclic voltammetry (CV).


Assuntos
Antibacterianos/farmacologia , Infecções Bacterianas/tratamento farmacológico , Naftoquinonas/farmacologia , Antibacterianos/química , Infecções Bacterianas/microbiologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/patogenicidade , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/patogenicidade , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/patogenicidade , Testes de Sensibilidade Microbiana , Naftoquinonas/química , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/patogenicidade , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/patogenicidade
20.
Microb Pathog ; 131: 181-185, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30978430

RESUMO

Pseudomonas aeruginosa is a notorious pathogen with increasing multi-drug resistance. This situation makes it urgent to develop a prophylactic vaccine against this pathogen. Different virulence factors play a crucial role in P. aeruginosa infection. This study focused on evaluation of the iron acquisition protein HitA as a potential vaccine candidate against P. aeruginosa in a murine infection model. The recombinant ferric iron-binding periplasmic protein HitA was overexpressed in Escherichia coli and was purified using metal affinity chromatography. The purified antigen was administered to mice in combination with Bacillus Calmette-Guérin (BCG) as an adjuvant using different vaccination regimens. Serum samples were tested for IgG1, IgG2a and total IgG antibody responses which were extremely significant. Following challenge of mice with P. aeruginosa, there was a significant reduction in bacterial load in lungs of immunized mice compared to negative control mice. Opsonophagocytic assay supported the previous results. In addition, histopathological examination of livers of challenged mice showed a significant improvement difference between immunized mice and negative control mice in various histopathological parameters. Up to our knowledge, this is the first report that investigates HitA as a potential vaccine antigen. Overall, the results of this study demonstrate the protective effect of HitA recombinant protein and highlight its importance as a promising vaccine candidate against P. aeruginosa infection.


Assuntos
Vacinas Bacterianas/imunologia , Imunização , Ferro/química , Proteínas Periplásmicas/farmacologia , Infecções por Pseudomonas/imunologia , Infecções por Pseudomonas/prevenção & controle , Pseudomonas aeruginosa/imunologia , Adjuvantes Imunológicos , Animais , Anticorpos Antibacterianos/sangue , Carga Bacteriana , Modelos Animais de Doenças , Escherichia coli/genética , Feminino , Imunoglobulina G/sangue , Pulmão/microbiologia , Pulmão/patologia , Camundongos , Necrose , Periplasma , Proteínas Periplásmicas/genética , Infecções por Pseudomonas/patologia , Pseudomonas aeruginosa/patogenicidade , Proteínas Recombinantes , Vacinação , Vacinas Sintéticas
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