Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 14.599
Filtrar
1.
Klin Lab Diagn ; 64(8): 497-502, 2019.
Artigo em Russo | MEDLINE | ID: mdl-31479607

RESUMO

The growing prevalence of metallo-ß-lactamase (MBL)-producing Pseudomonas aeruginosa in nosocomial pathogen populations has been attributed to their clonal spread, and/or horizontal transfer of MBL determinants in mobile genetic elements, including integrons. To characterize the genetic background of the beta-lactamase VIM-2 encoding gene in the population of carbapenemresistant (Carba-R) P. aeruginosa clinical isolates.The detection of class 1 integrons was performed by PCR. Typing of the class 1 integrons containing the blaVIM gene cassette was performed by the PCR-restriction fragment length polymorphism (RFLP) approach followed by sequencing of variable regions of class 1 integrons. Five types of the blaVIM-2-carrying integrons were identified: ST654-isolates accounting for more than 50% of the Carba-R population harbored In56; ST235-isolates contained In559 (26% Carba-R isolates); ST111-isolates (19% Carba-R isolates) were characterized by carrying In59-like integron; two ST235-isolates harbored In59 and In249 each. Except In56, carrying the only blaVIM-2-gene cassette, all other identified integron types harbored the genes of resistance to trimethoprim and/or aminoglycosides. No new types of integrons were identified in the P. aeruginosa clinical isolates. The observed correlation of the integron type with specific STs indicates a clonal dissemination of significant resistance determinant producers - ST111, ST654 and ST235 epidemic lines. The features of the integron variable regions can be used for the epidemiological characterization of clinical P. aeruginosa isolates.


Assuntos
Carbapenêmicos/farmacologia , Farmacorresistência Bacteriana , Integrons , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/genética , beta-Lactamases/genética , Antibacterianos/farmacologia , Humanos , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/efeitos dos fármacos
2.
Rev Soc Bras Med Trop ; 52: e20190237, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31508785

RESUMO

INTRODUCTION: The increased use of colistin against infections caused by Acinetobacter baumannii and Pseudomonas aeruginosa has resulted in colistin resistance. The purpose of this study was to detect plasmid-mediated mcr-1 gene in colistin-resistant A. baumannii and P. aeruginosa isolates. METHODS: A total of 146 clinical isolates of A. baumannii (n = 62) and P. aeruginosa (n = 84) were collected from the four largest tertiary care hospitals in Peshawar, Pakistan. All bacterial isolates were phenotypically screened for multidrug resistance using the Kirby-Baur disc diffusion method. The minimum inhibitory concentration (MIC) of colistin in all isolates was phenotypically performed using dilution methods. mcr-1 gene was detected through polymerase chain reaction and the nucleotide sequence of amplicon was determined using Sanger sequencing. RESULTS: Approximately 96.7% A. baumannii and 83.3% P. aeruginosa isolates were resistant to multiple antibiotics. Colistin resistance was found in 9.6% (6/62) of A. baumannii and 11.9% (10/84) of P. aeruginosa isolates. Among 16 colistin resistant isolates, the mcr-1 gene was detected in one A. baumannii (1.61% of total isolates; 16.6% of colistin resistant isolates) and one P. aeruginosa strain (1.19% of total isolates; 10% of colistin resistant isolates). Nucleotide BLAST showed 98-99% sequence similarity to sequences of the mcr-1 gene in GenBank. CONCLUSIONS: Our study reports, for the first time, the emergence of plasmid-mediated mcr-1-encoded colistin resistance in multidrug resistant strains of A. baumannii and P. aeruginosa. Further large scales studies are recommended to investigate the prevalence of this mode of resistance in these highly pathogenic bacteria.


Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/genética , Proteínas de Bactérias/genética , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/genética , Acinetobacter baumannii/efeitos dos fármacos , Farmacorresistência Bacteriana , Humanos , Testes de Sensibilidade Microbiana , Paquistão , Plasmídeos/genética , Pseudomonas aeruginosa/efeitos dos fármacos
4.
Adv Exp Med Biol ; 1145: 1-8, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31364067

RESUMO

Antibiotic resistance has become the most significant threat to human health across the globe. Polymyxins are often used as the only available therapeutic option against Gram-negative 'superbugs', namely Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae. The limited pharmacological and clinical knowledge on the polymyxins in the old literature substantially limited optimizing their clinical use. The current chapter provides a general introduction to this first-ever polymyxin book which comprehensively reviews the significant progress over the last two decades in the chemistry, microbiology, pharmacology, clinical use and drug discovery of polymyxins. In particular, recent pharmacological results have led to the first scientifically-based dosing recommendations and facilitated the discovery of new-generation polymyxins. Future challenges in polymyxin research are highlighted, aiming at improving the clinical utility of this last-line defence.


Assuntos
Antibacterianos/farmacologia , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Polimixinas/farmacologia , Acinetobacter baumannii/efeitos dos fármacos , Humanos , Pseudomonas aeruginosa/efeitos dos fármacos
5.
Adv Exp Med Biol ; 1145: 9-13, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31364068

RESUMO

Antibiotic resistance has presented a major health challenge in the world and many isolates of Enterobacteriaceae, Acinetobacter baumannii and Pseudomonas aeruginosa become resistant to almost all current antibiotics. This chapter provides an overview on the mechanisms of antibiotic resistance in these Gram-negative pathogens and outlines the formidable problem of the genetics of bacterial resistance. Prevalent multidrug-resistance in Gram-negative bacteria underscores the need for optimizing the clinical use of the last-line polymyxins.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Polimixinas/farmacologia , Acinetobacter baumannii/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Humanos , Pseudomonas aeruginosa/efeitos dos fármacos
6.
Adv Exp Med Biol ; 1145: 105-116, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31364074

RESUMO

In the last decade, considerable advancements have been made to identify the pharmacokinetic/pharmacodynamic (PK/PD) index that defines the antimicrobial activity of polymyxins. Dose-fractionation studies performed in hollow-fiber models found that altering the dosing schedule had little impact on the killing or suppression of resistance emergence, alluding to AUC/MIC as the pharmacodynamic index that best describes polymyxin's activity. For in vivo efficacy, the PK/PD index that was the most predictive of the antibacterial effect of colistin against P. aeruginosa and A. baumannii was ƒAUC/MIC.


Assuntos
Antibacterianos/farmacologia , Antibacterianos/farmacocinética , Polimixinas/farmacologia , Polimixinas/farmacocinética , Acinetobacter baumannii/efeitos dos fármacos , Animais , Colistina/farmacocinética , Colistina/farmacologia , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/efeitos dos fármacos
7.
J Enzyme Inhib Med Chem ; 34(1): 1414-1425, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31401901

RESUMO

The emergence of drug-resistant pathogenic bacteria is occurring due to the global overuse and misuse of ß-lactam antibiotics. Infections caused by some bacteria which secrete metallo-ß-lactamases (enzymes that inactivate ß-lactam antibiotics) are increasingly prevalent and have become a major worldwide threat to human health. These bacteria are resistant to ß-lactam antibiotics and MBL-inhibitor/ß-lactam antibiotic combination therapy can be a strategy to overcome this problem. So far, no clinically available inhibitors of metallo-ß-lactamases (MBLs) have been reported. In this study, L-benzyl tyrosine thiol carboxylic acid analogues (2a-2k) were synthesized after the study of computational simulation by adding of methyl, chloro, bromo and nitro groups to the benzyl ring for investigation of SAR analysis. Although the synthesized molecules 2a-k shows the potent inhibitory effects against metallo-ß-lactamase (IMP-1) with the range of Kic values of 1.04-4.77 µM, they are not as potent as the candidate inhibitor.


Assuntos
Ácidos Carboxílicos/síntese química , Ácidos Carboxílicos/farmacologia , Compostos de Sulfidrila/química , Tirosina/química , Inibidores de beta-Lactamases/síntese química , Inibidores de beta-Lactamases/farmacologia , beta-Lactamases/efeitos dos fármacos , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/farmacologia , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Ácidos Carboxílicos/química , Espectrometria de Massas , Testes de Sensibilidade Microbiana , Espectroscopia de Prótons por Ressonância Magnética , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/enzimologia , Serratia marcescens/efeitos dos fármacos , Serratia marcescens/enzimologia , Relação Estrutura-Atividade , Inibidores de beta-Lactamases/química
8.
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
9.
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
10.
J Nanobiotechnology ; 17(1): 81, 2019 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-31286976

RESUMO

BACKGROUND: Magnetic nanoparticles (MNPs) are characterized by unique physicochemical and biological properties that allow their employment as highly biocompatible drug carriers. Gelsolin (GSN) is a multifunctional actin-binding protein involved in cytoskeleton remodeling and free circulating actin sequestering. It was reported that a gelsolin derived phosphoinositide binding domain GSN 160-169, (PBP10 peptide) coupled with rhodamine B, exerts strong bactericidal activity. RESULTS: In this study, we synthesized a new antibacterial and antifungal nanosystem composed of MNPs and a PBP10 peptide attached to the surface. The physicochemical properties of these nanosystems were analyzed by spectroscopy, calorimetry, electron microscopy, and X-ray studies. Using luminescence based techniques and a standard killing assay against representative strains of Gram-positive (Staphylococcus aureus MRSA Xen 30) and Gram-negative (Pseudomonas aeruginosa Xen 5) bacteria and against fungal cells (Candida spp.) we demonstrated that magnetic nanoparticles significantly enhance the effect of PBP10 peptides through a membrane-based mode of action, involving attachment and interaction with cell wall components, disruption of microbial membrane and increased uptake of peptide. Our results also indicate that treatment of both planktonic and biofilm forms of pathogens by PBP10-based nanosystems is more effective than therapy with either of these agents alone. CONCLUSIONS: The results show that magnetic nanoparticles enhance the antimicrobial activity of the phosphoinositide-binding domain of gelsolin, modulate its mode of action and strengthen the idea of its employment for developing the new treatment methods of infections.


Assuntos
Antibacterianos/química , Antifúngicos/química , Gelsolina/química , Nanopartículas de Magnetita/química , Fragmentos de Peptídeos/química , Biofilmes , Candida/efeitos dos fármacos , Membrana Celular/metabolismo , Ouro/química , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Nanoconchas/química , Plâncton , Pseudomonas aeruginosa/efeitos dos fármacos , Rodaminas/química
11.
Chemotherapy ; 64(1): 22-27, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31167192

RESUMO

BACKGROUND: Pantothenate, the fundamental precursor to coenzyme A, is required for optimal growth and virulence of microbial pathogens. It is synthesized by the enzyme-catalyzed condensation of ß-alanine and pantoate, which has shown susceptibility to inhibition by analogs of its molecular constituents. Accordingly, analogs of ß-alanine are gaining inquiry as potential antimicrobial chemotherapeutics. METHODS: We synthesized and evaluated 35 derivatives of ß-alanine, substituted at the α, ß, amine, and carboxyl sites, derived from in silico, dynamic molecular modeling to be potential competitive inhibitors of pantothenate synthetase. Employing the Clinical Laboratory Standards M7-A6 broth microdilution method, we tested these for inhibition of growth in Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. RESULTS: All compounds proved entirely ineffective in all species tested, with no inhibition of growth being observed up to 200 µM/mL. CONCLUSIONS: Upon revision of the literature, we conclude that high enzyme selectivity or external salvage mechanisms may render this strategy futile against most bacteria.


Assuntos
Proteínas de Bactérias/metabolismo , Peptídeo Sintases/metabolismo , beta-Alanina/metabolismo , Proteínas de Bactérias/antagonistas & inibidores , Sítios de Ligação , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Escherichia coli/crescimento & desenvolvimento , Simulação de Acoplamento Molecular , Peptídeo Sintases/antagonistas & inibidores , Estrutura Terciária de Proteína , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , beta-Alanina/análogos & derivados , beta-Alanina/farmacologia
12.
Int J Nanomedicine ; 14: 3861-3874, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31213806

RESUMO

Purpose: Infections associated with medical devices that are caused by biofilms remain a considerable challenge for health care systems owing to their multidrug resistance patterns. Biofilms of Pseudomonas aeruginosa and Staphylococcus aureus can result in life-threatening situations which are tough to eliminate by traditional methods. Antimicrobial photodynamic inactivation (aPDT) constitutes an alternative method of killing deadly pathogens and their biofilms using reactive oxygen species (ROS). This study investigated the efficacy of enhanced in vitro aPDT of P. aeruginosa and S. aureus using malachite green conjugated to carboxyl-functionalized multi-walled carbon nanotubes (MGCNT). Both the planktonic cells and biofilms of test bacteria were demonstrated to be susceptible to the MGCNT conjugate. These MGCNT conjugates may thus be employed as a facile strategy for designing antibacterial and anti-biofilm coatings to prevent the infections associated with medical devices. Methods: Conjugation of the cationic dye malachite green to carbon nanotube was studied by UV-visible spectroscopy, high-resolution transmission electron microscopy, and Fourier transform infrared spectrometry. P. aeruginosa and S. aureus photodestruction were studied using MGCNT conjugate irradiated for 3 mins with a red laser of wavelength 660 nm and radiant exposure of 58.49 J cm-2. Results: Upon MGCNT treatment, S. aureus and P. aeruginosa were reduced by 5.16 and 5.55 log10 , respectively. Compared to free dye, treatment with MGCNT afforded improved phototoxicity against test bacteria, concomitant with greater ROS production. The results revealed improved biofilm inhibition, exopolysaccharide inhibition, and reduced cell viability in test bacteria treated with MGCNT conjugate. P. aeruginosa and S. aureus biofilms were considerably reduced to 60.20±2.48% and 67.59±3.53%, respectively. Enhanced relative MGCNT phototoxicity in test bacteria was confirmed using confocal laser scanning microscopy. Conclusion: The findings indicated that MGCNT conjugate could be useful to eliminate the biofilms formed on medical devices by S. aureus and P. aeruginosa.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Nanotubos de Carbono/química , Fotoquimioterapia , Plâncton/citologia , Plâncton/efeitos dos fármacos , Pseudomonas aeruginosa/fisiologia , Corantes de Rosanilina/farmacologia , Staphylococcus aureus/fisiologia , Cinética , Peroxidação de Lipídeos/efeitos dos fármacos , Viabilidade Microbiana/efeitos dos fármacos , Nanotubos de Carbono/ultraestrutura , Pseudomonas aeruginosa/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Staphylococcus aureus/efeitos dos fármacos
13.
J Photochem Photobiol B ; 197: 111510, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31163288

RESUMO

Treatment of chronic lung infection becomes a great challenge due to the drug resistant bacteria. In this scenario, evolving a new drug based on lipid metal conjugation loaded with potential antibiotic provides better drug delivery. In this study, ciprofloxacin loaded selenium-lipid nanoparticle (CxLSENPs) is produced in a novel route and its antimicrobial properties were tested against clinically important Gram-negative P. aeruginosa. The synthesized CxLSENPs was characterized by biophysical techniques (UV, Fluorescence spectroscopy, Raman spectroscopy, FTIR, FESEM, HRTEM and Zeta potential). Raman spectra coupled with FTIR spectra confirmed the possible interaction of lipid components in the NPs. HRTEM analysis confirmed the spherical shape of NPs. CxLSENPs recorded greater antibacterial effects on P. aeruginosa. A drastic reduction in the count of P. aeruginosa was observed after treatment with CxLSENPs. In order to further confirm the antibacterial efficiency, the live/dead cell assay was carried out. Live/dead analysis helps us to investigate the viability of bacterial cells. The number of dead bacterial cells was significantly higher in CxLSENPs treated groups when compare to the control. Furthermore, CxLSENPs increased the antioxidant enzyme activities (SOD, GPx, CAT and LPO) in mouse and protected the liver damage from bacterial infection. This study concludes that the developed CxLSENPs might be employed as strong antimicrobial and antioxidant agents for treating lung infection or interstitial lung diseases.


Assuntos
Antibacterianos/química , Ciprofloxacino/química , Portadores de Fármacos/síntese química , Lipídeos/química , Nanopartículas/química , Selênio/química , Animais , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Antioxidantes/metabolismo , Infecções Bacterianas/microbiologia , Infecções Bacterianas/prevenção & controle , Catalase/metabolismo , Ciprofloxacino/farmacologia , Ciprofloxacino/uso terapêutico , Portadores de Fármacos/química , Peroxidação de Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Doenças Pulmonares Intersticiais/tratamento farmacológico , Doenças Pulmonares Intersticiais/microbiologia , Doenças Pulmonares Intersticiais/patologia , Masculino , Camundongos , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/isolamento & purificação , Superóxido Dismutase/metabolismo
14.
BMC Infect Dis ; 19(1): 530, 2019 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-31208366

RESUMO

BACKGROUND: Infective endocarditis (IE) caused by gram-negative bacilli is rare. However, the incidence of this severe infection is rising because of the increasing number of persons at risk, such as patients with immunosuppression or with cardiac implantable devices and prosthetic valves. The diagnosis of IE is often difficult, particularly when microorganisms such as Pseudomonas aeruginosa, which rarely cause this infection, are involved. One of the mainstays for the diagnosis of IE are persistently positive blood cultures with the same bacteria, while polymicrobial bacteremia usually points to another cause, e.g. an abscess. The antimicrobial resistance profile of some P. aeruginosa strains may change, falsely suggesting an infection with several strains, thus further increasing the diagnostic difficulties. CASE PRESENTATION: A 66-year old male patient who had a transcatheter aortic valve implantation (TAVI) one year previously developed fever seven days after an elective inguinal hernia repair. During the following four weeks, P. aeruginosa with different antibiotic resistance profiles was repeatedly isolated from blood cultures. Repeated trans-esophageal echocardiograms (TEE) were negative and an infection by different P. aeruginosa strains was suspected. Extensive diagnostic workup for an infectious focus was performed with no results. Finally, an oscillating mass on the aortic valve was detected by TEE five weeks after the initial positive blood cultures. P. aeruginosa endocarditis was confirmed by culture of the surgically removed valve. Whole genome sequencing of the last two P. aeruginosa isolates (valve and blood culture) revealed identical strains, with genome mutations for AmpR, AmpD and OprD. CONCLUSIONS: The diagnosis of prosthetic valve endocarditis is particularly difficult for several reasons. The modified Duke criteria have a lower sensitivity for patients with prosthetic valve endocarditis and the infection may be caused by "unusual" pathogens such as P. aeruginosa. Patients with repeatedly positive blood cultures should make clinicians suspicious for endocarditis even if imaging studies are negative and if isolated pathogens are "unusual". Repeatedly positive blood cultures for P. aeruginosa should be considered as "persistent bacteremia" (suspicious for IE) even in the presence of different antibiotic susceptibility patterns, since P. aeruginosa might rapidly activate or deactivate resistance mechanisms depending on antibiotic exposition.


Assuntos
Antibacterianos/uso terapêutico , Valva Aórtica/microbiologia , Endocardite Bacteriana/diagnóstico , Próteses Valvulares Cardíacas/efeitos adversos , Infecções por Pseudomonas/diagnóstico , Pseudomonas aeruginosa , Idoso , Farmacorresistência Bacteriana , Ecocardiografia Transesofagiana , Endocardite Bacteriana/tratamento farmacológico , Endocardite Bacteriana/etiologia , Endocardite Bacteriana/microbiologia , Feminino , Humanos , Masculino , Infecções por Pseudomonas/etiologia , Pseudomonas aeruginosa/efeitos dos fármacos
15.
Int J Infect Dis ; 84: 143-150, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31204002

RESUMO

OBJECTIVES: Carbapenem resistance in Pseudomonas aeruginosa is growing and results from variable mechanisms. The objectives of the current study were to investigate mechanisms of carbapenem resistance and genetic relatedness of P. aeruginosa isolates recovered in Dubai hospitals. METHODS: From June 2015 through June 2016, carbapenem-nonsusceptible P. aeruginosa were collected from 4 hospitals in Dubai, and subjected to antimicrobial susceptibility testing, molecular investigation of carbapenemases by PCR-sequencing, analysis of outer membrane porin OprD2 and multidrug efflux channel MexAB-OprM levels by qPCR, and fingerprinting by ERIC-PCR. RESULTS: Out of 1969 P. aeruginosa isolated during the study period, 471 (23.9%) showed reduced carbapenem susceptibility. Of these, 37 were analyzed and 32% of them produced VIM-type metallo-ß-lactamases, including VIM-2, VIM-30, VIM-31, and VIM-42, while GES-5 and GES-9 co-existed with VIM in 5.4% of isolates. Outer membrane impermeability was observed in 73% of isolates and 75.6% displayed overproduced MexAB-OprM. ERIC-PCR revealed one large clone including most carbapenemase-producing isolates indicating clonal dissemination. CONCLUSION: This is the first study on carbapenem-nonsusceptible P. aeruginosa from Dubai, incriminating VIM production as well as outer membrane permeability and efflux systems as resistance mechanisms. Further studies on carbapenem-nonsusceptible P. aeruginosa in Dubai are warranted for containment of such health hazard.


Assuntos
Proteínas de Bactérias/fisiologia , Carbapenêmicos/farmacologia , Porinas/fisiologia , Pseudomonas aeruginosa/efeitos dos fármacos , beta-Lactamases/fisiologia , Permeabilidade da Membrana Celular , Estudos Transversais , Farmacorresistência Bacteriana , Humanos , Pseudomonas aeruginosa/enzimologia
17.
Nat Commun ; 10(1): 1979, 2019 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-31040286

RESUMO

Hospital acquired infections (HAIs) and the emergence of antibiotic resistant strains are major threats to human health. Copper is well known for its high antimicrobial efficacy, including the ability to kill superbugs and the notorious ESKAPE group of pathogens. We sought a material that maintains the antimicrobial efficacy of copper while minimizing the downsides - cost, appearance and metallic properties - that limit application. Here we describe a copper-glass ceramic powder as an additive for antimicrobial surfaces; its mechanism is based on the controlled release of copper (I) ions (Cu1+) from cuprite nanocrystals that form in situ in the water labile phase of the biphasic glass ceramic. Latex paints containing copper-glass ceramic powder exhibit ≥99.9% reduction in S. aureus, P. aeruginosa, K. aerogenes and E. Coli colony counts when evaluated by the US EPA test method for efficacy of copper-alloy surfaces as sanitizer, approaching that of benchmark metallic copper.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Cerâmica/química , Cobre/química , Nanopartículas/química , Klebsiella pneumoniae/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos
18.
mSphere ; 4(3)2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-31043516

RESUMO

Periprosthetic joint infection (PJI) develops clinically, even with antibiotic treatment, and methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa are predominant causes of these infections. Due to biofilm formation, antibiotic treatment for patients with PJI can perpetuate resistance, further complicating the use of noninvasive treatments. This study evaluated cathodic-voltage-controlled electrical stimulation (CVCES) of titanium, in combination with a clinically relevant antibiotic, to synergistically prevent MRSA and P. aeruginosa PJIs by inhibiting bacterial adherence or as a treatment for eradicating established biofilms. CVCES of -1.0 V, -1.5 V, or -1.8 V (versus Ag/AgCl), with or without vancomycin for MRSA or gentamicin for P. aeruginosa, was applied to sterile titanium incubated with cultures to evaluate prevention of attachment or eradication of preestablished biofilms. Treatments were 24 h long and included open-circuit potential controls, antibiotic alone, CVCES, and CVCES plus antibiotic. Biofilm-associated and planktonic CFU were enumerated. In general, CVCES at -1.8 V alone or with antibiotic completely eradicated biofilm-associated CFU for both strains, and these parameters were also highly effective against planktonic bacteria, resulting in a >6-log reduction in MRSA and no detectable planktonic P. aeruginosa All CFU were reduced ∼3 to 5 logs from controls for prevention CVCES plus antibiotics at -1.0 V and -1.5 V against MRSA. Remarkably, there were no detectable P. aeruginosa CFU following prevention CVCES at -1.0 V or -1.5 V with gentamicin. Our results suggest that CVCES in combination with antibiotics may be an effective approach for prevention and treatment of PJI.IMPORTANCE Periprosthetic joint infections (PJIs) develop clinically in the presence of antibiotic therapies and are responsible for increased patient morbidity and rising health care costs. Many of these infections involve bacterial biofilm formation on orthopedic hardware, and it has been well established that these biofilms are refractory to most antibiotic treatments. Recent studies have focused on novel methods to prevent and eradicate infection. Cathodic-voltage-controlled electrical stimulation (CVCES) has previously been shown to be effective as a method for prevention and eradication of Gram-positive and Gram-negative infections. The present study revealed that the utility of CVCES for prevention and eradication of methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa is enhanced in the presence of clinically relevant antibiotics. The synergistic effects of CVCES and antibiotics are effective in a magnitude-dependent manner. The results of this study indicate a promising alternative method to current PJI mitigation techniques.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos dos fármacos , Titânio/química , Aderência Bacteriana/efeitos dos fármacos , Estimulação Elétrica , Eletrodos , Humanos , Infecções Relacionadas à Prótese/tratamento farmacológico , Infecções Relacionadas à Prótese/prevenção & controle , Infecções por Pseudomonas/tratamento farmacológico , Infecções por Pseudomonas/prevenção & controle , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/prevenção & controle , Células-Tronco , Titânio/uso terapêutico
19.
J Med Microbiol ; 68(6): 893-897, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31050629

RESUMO

PURPOSE: We assessed the synergistic potential of fosfomycin and parenteral antibiotics among carbapenem-resistant Pseudomonas aeruginosa (CRP). METHODOLOGY: Minimum inhibitory concentrations (MICs) were determined by broth microdilution for all antibiotics except fosfomycin, for which the gradient diffusion strip (GDS) method was used. The GDS cross method was performed to assess interactions between fosfomycin and: aztreonam, cefepime, ceftazidime, ceftazidime/avibactam, ceftolozane/tazobactam, meropenem, piperacillin/tazobactam and tobramycin. Only organisms that were nonsusceptible to the second drug were assessed. RESULTS: Among 153 clinical isolates, the fosfomycin MIC50/90 was 48/≥1024 mg l-1 . Synergy was detected in 131/604 (21.7 %) fosfomycin-antibiotic combinations among 76 (49.7 %) isolates. Ceftazidime (42/81, 51.9%) and ceftolozane/tazobactam (7/14, 50.0%) displayed synergy most frequently. Meropenem susceptibility was restored in 21 (13.7 %) isolates. Antagonism was not observed. CONCLUSION: Fosfomycin synergy was commonly observed in vitro among CRP. These data may guide the selection of combination antibiotic therapy. The susceptibility to other antibiotics was restored in combination with fosfomycin, warranting further in vivo evaluation.


Assuntos
Anti-Infecciosos/farmacologia , Fosfomicina/farmacologia , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa/efeitos dos fármacos , Antibacterianos/farmacologia , Compostos Azabicíclicos/farmacologia , Carbapenêmicos/farmacologia , Ceftazidima/farmacologia , Cefalosporinas/farmacologia , Combinação de Medicamentos , Farmacorresistência Bacteriana , Sinergismo Farmacológico , Humanos , Meropeném/farmacologia , Prevalência , Infecções por Pseudomonas/epidemiologia , Infecções por Pseudomonas/microbiologia , Tazobactam/farmacologia , Tobramicina/farmacologia , Estados Unidos/epidemiologia
20.
J Med Microbiol ; 68(6): 961-972, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31107198

RESUMO

PURPOSE: Antibiotic-loaded polymethylmethacrylate-based bone cement has been implemented in orthopaedics to cope with implant-related infections associated with the formation of bacterial biofilms. In the context of emerging bacterial resistance to current antibiotics, we examined the efficacy of short antimicrobial peptide-loaded bone cement in inhibiting bacterial adhesion and consequent biofilm formation on its surface. METHODOLOGY: The ability of α-helical antimicrobial peptides composed of 12 amino acid residues to prevent bacterial biofilm [methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Pseudomonas aeruginosa and Escherichia coli] formation on the surface of model implants made from polymethylmethacrylate-based bone cement was evaluated by colony-forming unit (c.f.u.) counting of bacteria released by sonication from the biofilms formed on their surfaces. The biofilms on model implant surfaces were also visualized by light microscopy after staining with tetrazolium dye (MTT) and by scanning electron microscopy. RESULTS: When incorporated in the implants, these peptides caused a mean reduction in the number of bacterial cells attached to implants' surfaces (by five orders of magnitude), and 88 % of these implants showed no bacterial adhesion after being exposed to growth media containing various bacteria. CONCLUSION: The results showed that the antibiofilm activity of these peptides was comparable to that of the antibiotics, but the peptides exhibited broader specificity than the antibiotics. Given the rapid development of antibiotic resistance, antimicrobial peptides show promise as a substitute for antibiotics for loading into bone cements.


Assuntos
Anti-Infecciosos/farmacologia , Biofilmes/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Peptídeos/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus epidermidis/efeitos dos fármacos , Antibacterianos/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Cimentos para Ossos , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Peptídeos/síntese química , Polimetil Metacrilato , Próteses e Implantes/microbiologia , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus epidermidis/crescimento & desenvolvimento
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA