Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 602
Filtrar
1.
PLoS Comput Biol ; 16(8): e1007898, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32797038

RESUMO

New treatments for diseases caused by antimicrobial-resistant microorganisms can be developed by identifying unexplored therapeutic targets and by designing efficient drug screening protocols. In this study, we have screened a library of compounds to find ligands for the flavin-adenine dinucleotide synthase (FADS) -a potential target for drug design against tuberculosis and pneumonia- by implementing a new and efficient virtual screening protocol. The protocol has been developed for the in silico search of ligands of unexplored therapeutic targets, for which limited information about ligands or ligand-receptor structures is available. It implements an integrative funnel-like strategy with filtering layers that increase in computational accuracy. The protocol starts with a pharmacophore-based virtual screening strategy that uses ligand-free receptor conformations from molecular dynamics (MD) simulations. Then, it performs a molecular docking stage using several docking programs and an exponential consensus ranking strategy. The last filter, samples the conformations of compounds bound to the target using MD simulations. The MD conformations are scored using several traditional scoring functions in combination with a newly-proposed score that takes into account the fluctuations of the molecule with a Morse-based potential. The protocol was optimized and validated using a compound library with known ligands of the Corynebacterium ammoniagenes FADS. Then, it was used to find new FADS ligands from a compound library of 14,000 molecules. A small set of 17 in silico filtered molecules were tested experimentally. We identified five inhibitors of the activity of the flavin adenylyl transferase module of the FADS, and some of them were able to inhibit growth of three bacterial species: C. ammoniagenes, Mycobacterium tuberculosis, and Streptococcus pneumoniae, where the last two are human pathogens. Overall, the results show that the integrative VS protocol is a cost-effective solution for the discovery of ligands of unexplored therapeutic targets.


Assuntos
Antibacterianos , Proteínas de Bactérias , Nucleotidiltransferases , Antibacterianos/química , Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Corynebacterium/efeitos dos fármacos , Corynebacterium/enzimologia , Desenho de Fármacos , Farmacorresistência Bacteriana/efeitos dos fármacos , Ligantes , Simulação de Dinâmica Molecular , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/enzimologia , Nucleotidiltransferases/antagonistas & inibidores , Nucleotidiltransferases/química , Nucleotidiltransferases/metabolismo
2.
J Vet Sci ; 21(3): e40, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32476314

RESUMO

The purpose of this study was to investigate the high-level mupirocin resistance (HLMR) in Gram-positive bacteria isolated from companion animals. A total of 931 clinical specimens were collected from diseased pets. The detection of mupirocin-resistant bacteria and plasmid-mediated mupirocin resistance genes were evaluated by antimicrobial susceptibility tests, polymerase chain reactions, and sequencing analysis. Four-hundred and six (43.6%) bacteria were isolated and 17 (4.2%), including 14 staphylococci and 3 Corynebacterium were high-level mupirocin-resistant (MICs, ≥ 1,024 ug/mL) harboring mupA. Six staphylococci of HLMR strains had plasmid-mediated mupA-IS257 flanking regions. The results show that HLMR bacteria could spread in veterinary medicine in the near future.


Assuntos
Antibacterianos/farmacologia , Corynebacterium/efeitos dos fármacos , Farmacorresistência Bacteriana , Mupirocina/farmacologia , Staphylococcus/efeitos dos fármacos , Animais , Doenças do Gato/tratamento farmacológico , Gatos , Infecções por Corynebacterium/tratamento farmacológico , Doenças do Cão/tratamento farmacológico , Cães , Testes de Sensibilidade Microbiana/veterinária , Reação em Cadeia da Polimerase/veterinária , Análise de Sequência de DNA/veterinária , Infecções Estafilocócicas/tratamento farmacológico
3.
Antonie Van Leeuwenhoek ; 113(4): 589-592, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31736013

RESUMO

The resistance to fluoroquinolones in corynebacteria is due to mutations occurring in the quinolone-resistance-determining region (QRDR) of the gyrA gene encoding the enzyme gyrase A subunit. In recent years we can observe an increasing number of infections caused by multidrug-resistant Corynebacterium striatum, Corynebacterium jeikeium and Corynebacterium urealyticum, including wide range of disorders, such as invasive infections. In this study 14 Corynebacterium spp. isolated from intravenous sites were sequenced and new combinations of mutations in the QRDR of the gyrA gene were found in C. jeikeium and C. urealyticum. Nowadays, no study comparing mutations in this region and the susceptibility to fluoroquinolones in C. jeikeium and C. urealyticum has been described. All the isolates that showed double mutation (position 87 and 91) in the QRDR gyrA gene had high MIC to the fluoroquinolones tested.


Assuntos
Antibacterianos/farmacologia , Corynebacterium/efeitos dos fármacos , Corynebacterium/genética , DNA Girase/genética , Farmacorresistência Bacteriana Múltipla/genética , Bacteriemia/sangue , Bacteriemia/microbiologia , Infecções Relacionadas a Cateter/microbiologia , Infecções por Corynebacterium/microbiologia , DNA Girase/metabolismo , Humanos , Injeções Intravenosas , Mutação
4.
Environ Geochem Health ; 42(7): 2039-2057, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31776886

RESUMO

The common therapeutic indications of Portuguese Natural Mineral Waters (NMWs) are primarily for respiratory, rheumatic and musculoskeletal systems. However, these NMWs have been increasingly sought for dermatologic purposes. Opposing to what is observed in the major European Thermal Centres, there are few scientific evidences supporting the use of Portuguese NMWs for clinical applications. The aim of this study was to characterize the antimicrobial profile of individual NMWs from the central region of Portugal and correlate the results with their physicochemical characterization. An extensive multivariate analysis (principal component analysis) was also performed to further investigate this possible correlation. Six collection strains representing skin microbiota, namely Staphylococcus aureus, Escherichia coli, Corynebacterium amycolatum, Candida albicans, Staphylococcus epidermidis and Cutibacterium acnes, were analysed, and their antimicrobial profile was determined using Clinical and Laboratory Standards Institute M07-A10, M45-A2, M11-A6 and M27-A3 microdilution methods. Different NMWs presented different antimicrobial profiles against the strains used; the physicochemical composition of NMWs seemed to be correlated with the different susceptibility profiles. Cutibacterium acnes showed a particularly high susceptibility to all NMWs belonging sulphurous/bicarbonated/sodic ionic profile, exhibiting microbial reductions up to 65%. However, due to the complex physicochemical composition of each water an overall conclusion regarding the effect of a specific ion on the growth of different microorganisms is yet to be known.


Assuntos
Anti-Infecciosos/farmacologia , Águas Minerais/análise , Águas Minerais/uso terapêutico , Pele/microbiologia , Corynebacterium/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Microbiota , Portugal , Análise de Componente Principal , Propionibacterium acnes/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus epidermidis/efeitos dos fármacos
5.
Nat Rev Dis Primers ; 5(1): 81, 2019 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-31804499

RESUMO

Diphtheria is a potentially fatal infection mostly caused by toxigenic Corynebacterium diphtheriae strains and occasionally by toxigenic C. ulcerans and C. pseudotuberculosis strains. Diphtheria is generally an acute respiratory infection, characterized by the formation of a pseudomembrane in the throat, but cutaneous infections are possible. Systemic effects, such as myocarditis and neuropathy, which are associated with increased fatality risk, are due to diphtheria toxin, an exotoxin produced by the pathogen that inhibits protein synthesis and causes cell death. Clinical diagnosis is confirmed by the isolation and identification of the causative Corynebacterium spp., usually by bacterial culture followed by enzymatic and toxin detection tests. Diphtheria can be treated with the timely administration of diphtheria antitoxin and antimicrobial therapy. Although effective vaccines are available, this disease has the potential to re-emerge in countries where the recommended vaccination programmes are not sustained, and increasing proportions of adults are becoming susceptible to diphtheria. Thousands of diphtheria cases are still reported annually from several countries in Asia and Africa, along with many outbreaks. Changes in the epidemiology of diphtheria have been reported worldwide. The prevalence of toxigenic Corynebacterium spp. highlights the need for proper clinical and epidemiological investigations to quickly identify and treat affected individuals, along with public health measures to prevent and contain the spread of this disease.


Assuntos
Antitoxina Diftérica/uso terapêutico , Difteria/diagnóstico , Difteria/tratamento farmacológico , Antibacterianos/uso terapêutico , Corynebacterium/efeitos dos fármacos , Corynebacterium/patogenicidade , Difteria/epidemiologia , Humanos , Vacinação/métodos
9.
J Med Microbiol ; 68(10): 1517-1525, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31418673

RESUMO

In Western Europe, the incidence of both respiratory and cutaneous diphtheria, caused by toxin-producing Corynebacterium diphtheriae, Corynebacterium ulcerans or Corynebacterium pseudotuberculosis, has been low over the past few decades thanks to the use of an effective vaccine and a high level of vaccination coverage. However, the disease has still not been eradicated and continues to occur in all of Europe. In order to prevent sequelae or a fatal outcome, diphtheria antitoxin (DAT) should be administered to suspected diphtheria patients as soon as possible, but economic factors and issues concerning regulations have led to poor availability of DAT in many countries. The European Centre for Disease Prevention and Control and World Health Organization have called for European Union-wide solutions to this DAT-shortage. In order to illustrate the importance of these efforts and underline the need for continued diphtheria surveillance, we present data on all registered cases of toxigenic and non-toxigenic C. diphtheriae, C. ulcerans and C. pseudotuberculosis in Belgium during the past decade, up to and including 2017.


Assuntos
Corynebacterium/isolamento & purificação , Difteria/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/farmacologia , Bélgica/epidemiologia , Pré-Escolar , Corynebacterium/classificação , Corynebacterium/efeitos dos fármacos , Corynebacterium/genética , Difteria/microbiologia , Toxina Diftérica/genética , Toxina Diftérica/metabolismo , Farmacorresistência Bacteriana , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
10.
BMC Infect Dis ; 19(1): 672, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31357945

RESUMO

BACKGROUND: Corynebacterium striatum is an emerging multidrug-resistant (MDR) pathogen associated with immunocompromised and chronically ill patients, as well as nosocomial outbreaks. In this study, we characterized 23 MDR C. striatum isolated of bloodstream and catheter-related infections from a hospital of Rio de Janeiro. METHODS: C. striatum isolates were identified by 16S rRNA and rpoB genes sequencing. The dissemination of these isolates was accomplished by pulsed-field gel electrophoresis (PFGE). All isolates were submitted to antimicrobial susceptibility testing by disk diffusion and by minimum inhibitory concentration using E-test strips methods. Antimicrobial resistance genes were detected by polymerase chain reaction. Quantitative tests were performed on four different abiotic surfaces and the ability to produce biofilm on the surface of polyurethane and silicone catheter was also demonstrated by scanning electron microscopy. RESULTS: Eleven PFGE profiles were found. The PFGE profile I was the most frequently observed among isolates. Five different MDR profiles were found and all PFGE profile I isolates presented susceptibility only to tetracycline, vancomycin, linezolid and daptomycin. Only the multidrug-susceptible isolate did not show mutations in the quinolone-resistance determinant region (QRDR) of the gyrA gene and was negative in the search of genes encoding antibiotic resistance. The other 22 isolates were positive to resistance genes to aminoglycoside, macrolides/lincosamides and chloramphenicol and showed mutations in the QRDR of the gyrA gene. Scanning electron microscopy illustrated the ability of MDR blood isolate partaker of the epidemic clone (PFGE profile I) to produce mature biofilm on the surface of polyurethane and silicone catheter. CONCLUSIONS: Genotyping analysis by PFGE revealed the permanence of the MDR PFGE profile I in the nosocomial environment. Other new PFGE profiles emerged as etiologic agents of invasive infections. However, the MDR PFGE profile I was also found predominant among patients with hematogenic infections. The high level of multidrug resistance associated with biofilm formation capacity observed in MDR C. striatum is a case of concern.


Assuntos
Bacteriemia/microbiologia , Biofilmes/crescimento & desenvolvimento , Infecções Relacionadas a Cateter/microbiologia , Infecções por Corynebacterium/microbiologia , Corynebacterium/fisiologia , Surtos de Doenças , Antibacterianos/farmacologia , Bacteriemia/epidemiologia , Proteínas de Bactérias/genética , Infecções Relacionadas a Cateter/epidemiologia , Corynebacterium/efeitos dos fármacos , Corynebacterium/genética , Infecções por Corynebacterium/epidemiologia , Infecção Hospitalar , Farmacorresistência Bacteriana Múltipla , Eletroforese em Gel de Campo Pulsado , Feminino , Técnicas de Genotipagem , Humanos , Masculino , Testes de Sensibilidade Microbiana , RNA Bacteriano/genética , RNA Ribossômico 16S/genética
11.
J Clin Microbiol ; 57(9)2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31315959

RESUMO

Corynebacterium striatum is an emerging multidrug-resistant (MDR) pathogen that occurs primarily among immunocompromised and chronically ill patients. However, little is known about the genomic diversity of C. striatum, which contributes to its long-term persistence and transmission in hospitals. In this study, a total of 192 C. striatum isolates obtained from 14 September 2017 to 29 March 2018 in a hospital in Beijing, China, were analyzed by antimicrobial susceptibility testing and pulsed-field gel electrophoresis (PFGE). Whole-genome sequencing was conducted on 91 isolates. Nearly all isolates (96.3%, 183/190) were MDR. The highest resistance rate was observed for ciprofloxacin (99.0%, 190/192), followed by cefotaxime (90.6%, 174/192) and erythromycin (89.1%, 171/192). PFGE separated the 192 isolates into 79 pulsotypes, and differences in core genome single-nucleotide polymorphisms (SNPs) partitioned the 91 isolates sequenced into four clades. Isolates of the same pulsotype were identical or nearly identical at the genome level, with some exceptions. Two dominant subclones, clade 3a, and clade 4a, were responsible for the hospital-wide dissemination. Genomic analysis further revealed nine resistance genes mobilized by eight unique cassettes. PFGE and whole-genome sequencing revealed that the C. striatum isolates studied were the result mainly of predominant clones spreading in the hospital. C. striatum isolates in the hospital progressively acquired resistance to antimicrobial agents, demonstrating that isolates of C. striatum may adapt rapidly through the acquisition and accumulation of resistance genes and thus evolve into dominant and persistent clones. These insights will be useful for the prevention of C. striatum infection in hospitals.


Assuntos
Infecções por Corynebacterium/transmissão , Corynebacterium/classificação , Infecção Hospitalar/transmissão , Transmissão de Doença Infecciosa , Genótipo , Epidemiologia Molecular/métodos , Sequenciamento Completo do Genoma/métodos , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/farmacologia , China/epidemiologia , Corynebacterium/efeitos dos fármacos , Corynebacterium/genética , Corynebacterium/isolamento & purificação , Infecções por Corynebacterium/epidemiologia , Infecção Hospitalar/epidemiologia , Farmacorresistência Bacteriana Múltipla , Eletroforese em Gel de Campo Pulsado , Feminino , Variação Genética , Hospitais , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Estudos Retrospectivos
12.
J Infect Chemother ; 25(11): 906-908, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31101531

RESUMO

Corynebacterium striatum, generally considered an opportunistic organism in humans, has recently been known to develop high-level daptomycin resistance (HLDR) shortly after drug exposure. To date, however, only several such clinical isolates have been described in the literature and clinical background of the resistant pathogen remains to be elucidated. Here, we report a case involving a C. striatum strain with HLDR harboring novel nucleotide mutations, together with a review of the relevant literature. To the best of our knowledge, this is the first well-investigated clinical report from Japan including a genetic investigation. Considering the rapid emergence of HLDR C. striatum in vitro experiment, there could be a number of underreporting cases. Scrupulous attention is required when administering daptomycin for the treatment of C. striatum infections, even if the organism has initially exhibited susceptibility.


Assuntos
Bacteriemia/diagnóstico , Bacteriemia/microbiologia , Infecções por Corynebacterium/microbiologia , Corynebacterium/genética , Farmacorresistência Bacteriana/genética , Idoso , Antibacterianos/uso terapêutico , Bacteriemia/tratamento farmacológico , Corynebacterium/efeitos dos fármacos , Infecções por Corynebacterium/tratamento farmacológico , Daptomicina/uso terapêutico , Humanos , Japão , Masculino
13.
Eur J Clin Microbiol Infect Dis ; 38(7): 1339-1342, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31030337

RESUMO

Corynebacterium coyleae is part of the commensal microflora of the skin, urethra, mucous membranes, and genital tract. Isolates from patients with urinary tract infection (UTI) were reported, but the pathogenic potential of this species has not been defined yet. The aim of the study is to determine whether C. coyleae could be the etiological agent of UTI and to analyze its antibiotic susceptibility. Urine samples were cultured quantitatively according to accepted laboratory procedures. The identification of bacterial isolates was carried out using the Vitek MS (bioMérieux) and antibiotic susceptibility was tested using disc diffusion according to EUCAST guidelines. Between 1 January 2017 and 30 October 2018, a total of 39 C. coyleae strains were isolated. This represented 0.32% of all urine samples cultured in the laboratory during the collection period. The strains were isolated from samples obtained from 35 women and 3 men (age median for all-64 years). One female patient presented with C. coyleae in her urine twice at an interval of 21 months. In six cases of UTI, C. coyleae was isolated in monoculture. The isolates had the same resistance pattern. A total of 11 strains were obtained from cases with a clinical diagnosis of UTI. In 13 cases, the strain was cultured in a monoculture and in 28 cases with accompanying species. All strains were susceptible to vancomycin. However, resistance to ciprofloxacin was observed for 58.4% of the strains. Urine isolates of C. coyleae must be considered as contamination or normal flora in most cases (28/39, 72%). In the remaining cases, it can be considered as potential etiologic agents, mostly in women and especially in the 6 UTI cases where C. coyleae was found as the single culture-positive species. Several of these isolates demonstrate resistance to antibiotics commonly used in empiric treatment of urinary tract infections.


Assuntos
Infecções por Corynebacterium/urina , Corynebacterium/patogenicidade , Infecções Urinárias/microbiologia , Sistema Urinário/microbiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/uso terapêutico , Ciprofloxacino/uso terapêutico , Corynebacterium/efeitos dos fármacos , Corynebacterium/isolamento & purificação , Infecções por Corynebacterium/tratamento farmacológico , Farmacorresistência Bacteriana Múltipla , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Estudos Retrospectivos , Infecções Urinárias/tratamento farmacológico , Adulto Jovem
14.
BMC Microbiol ; 19(1): 62, 2019 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-30890149

RESUMO

BACKGROUND: Nontuberculous mycobacteria (NTM) are ubiquitous in nature and recognized agents of opportunistic infection, which is often aggravated by their intrinsic resistance to antimicrobials, poorly defined therapeutic strategies and by the lack of new drugs. However, evaluation of their prevalence in anthropogenic environments and the associated antimicrobial resistance profiles have been neglected. In this work, we sought to determine minimal inhibitory concentrations of 25 antimicrobials against 5 NTM isolates recovered from a tertiary-care hospital surfaces. Antimicrobial susceptibilities of 5 other Corynebacterineae isolated from the same hospital were also determined for their potential clinical relevance. RESULTS: Our phylogenetic study with each of the NTM isolates confirm they belong to Mycobacterium obuense, Mycobacterium mucogenicum and Mycobacterium paragordonae species, the latter initially misidentified as strains of M. gordonae, a species frequently isolated from patients with NTM disease in Portugal. In contrast to other strains, the M. obuense and M. mucogenicum examined here were resistant to several of the CLSI-recommended drugs, suggestive of multidrug-resistant profiles. Surprisingly, M. obuense was susceptible to vancomycin. Their genomes were sequenced allowing detection of gene erm (erythromycin resistance methylase) in M. obuense, explaining its resistance to clarithromycin. Remarkably, and unlike other strains of the genus, the Corynebacterium isolates were highly resistant to penicillin, ciprofloxacin and linezolid. CONCLUSIONS: This study highlights the importance of implementing effective measures to screen, accurately identify and control viable NTM and closely related bacteria in hospital settings. Our report on the occurrence of rare NTM species with antibiotic susceptibility profiles that are distinct from those of the corresponding Type strains, along with unexpected resistance mechanisms detected seem to suggest that resistance may be more common than previously thought and also a potential threat to frail and otherwise vulnerable inpatients.


Assuntos
Antibacterianos/farmacologia , Infecção Hospitalar/microbiologia , Farmacorresistência Bacteriana Múltipla , Micobactérias não Tuberculosas/efeitos dos fármacos , Micobactérias não Tuberculosas/isolamento & purificação , Corynebacterium/efeitos dos fármacos , Equipamentos e Provisões Hospitalares/microbiologia , Humanos , Testes de Sensibilidade Microbiana , Infecções por Mycobacterium não Tuberculosas/microbiologia , Quartos de Pacientes , Filogenia , Portugal , Centros de Atenção Terciária/estatística & dados numéricos
15.
Eur J Clin Microbiol Infect Dis ; 38(7): 1269-1278, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30903537

RESUMO

Corynebacterium striatum is a ubiquitous colonizer of human skin and mucous membranes. It is increasingly involved in infections, especially with prosthetic devices or in immunocompromised individuals. Microbiological diagnosis is challenging and bacterial resistance is a major concern. We performed a retrospective study of monomicrobial bone and joint infections (BJI) due to C. striatum in two referral centers from April 2012 to July 2017. We collected the patients' clinical and microbiological characteristics and outcomes. We also performed a literature review of BJI due to C. striatum. We identified 12 cases (nine prosthetic joint infections, one osteosynthetic device infection, one non-union, and one arthritis) in 11 patients, five of which were immunocompromised. Microbiological diagnosis was performed with prolonged culture media. Ten out of 12 strains were susceptible to aminopenicillin, a drug class not recommended for testing by the EUCAST/CASFM guidelines, and 8/12 patients were treated with amoxicillin-rifampicin. The cure rate was 8/12, after a median follow-up period of 487.5 days (IQR 140.3-1348.5). Twelve cases of BJI due to C. striatum were previously reported. Among them, 5/12 patients were immunocompromised, 3/12 cases were acute BJI, and 2/12 were device-related infections. The diagnosis was performed by PCR in one case, and 10/12 patients were treated with glycolipopeptides, with a cure rate of 11/12. We report the largest cohort of monomicrobial BJI with C. striatum. Determination of aminopenicillin susceptibility is essential since it is frequently active in our experience, even in BJI. The cure rate of this infection seems high.


Assuntos
Amoxicilina/uso terapêutico , Antibacterianos/uso terapêutico , Artrite Infecciosa/tratamento farmacológico , Doenças Ósseas Infecciosas/tratamento farmacológico , Infecções por Corynebacterium/tratamento farmacológico , Infecções Relacionadas à Prótese/tratamento farmacológico , Rifampina/uso terapêutico , Idoso , Idoso de 80 Anos ou mais , Artrite Infecciosa/microbiologia , Doenças Ósseas Infecciosas/microbiologia , Corynebacterium/efeitos dos fármacos , Corynebacterium/isolamento & purificação , Infecções por Corynebacterium/diagnóstico , Farmacorresistência Bacteriana Múltipla , Feminino , Humanos , Hospedeiro Imunocomprometido , Articulações/microbiologia , Masculino , Pessoa de Meia-Idade , Infecções Relacionadas à Prótese/microbiologia , Estudos Retrospectivos
16.
Antonie Van Leeuwenhoek ; 112(7): 1055-1065, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30771116

RESUMO

Diphtheria by Corynebacterium ulcerans is increasingly occurring in children, adolescents and adults. In addition to diphtheria toxin (DT), phospholipase D (PLD) is considered a virulence factor of C. ulcerans. In the present study, a first case of concurrent diphtheria by a PLD-negative C. ulcerans and infectious mononucleosis (IM) was verified. Clinical and microbiological profiles and binding properties to human Fibrinogen (Fbg), Fibronectin (Fn) and type I collagen (col I) biotinylated proteins and virulence to Caenorhabditis elegans were investigated for C. ulcerans strain 2590 (clinical isolate) and two control strains, including PLD-positive BR-AD22 wild type and PLD-negative ELHA-1 PLD mutant strains. MALDI-TOF assays and a multiplex PCR of genes coding for potentially toxigenic corynebacteria identified strain 2590 as non-DT producing. Interestingly, strain 2590 did not express PLD activity in the CAMP test although the presence of the pld gene was verified. PLD-negative 2590 and a PLD-positive 210932 strains showed similar affinity to Fbg, Fn and type I collagen. C. elegans were able to escape from C. ulcerans strains, independent of PLD and DT production. Higher mortality of nematodes was verified for PLD-negative strains. Additional studies concerning multifactorial virulence potential of C. ulcerans, including environmental conditions remain necessary.


Assuntos
Infecções por Corynebacterium/microbiologia , Corynebacterium/isolamento & purificação , Difteria/microbiologia , Mononucleose Infecciosa/microbiologia , Adolescente , Animais , Antibacterianos/farmacologia , Caenorhabditis elegans , Corynebacterium/classificação , Corynebacterium/efeitos dos fármacos , Corynebacterium/genética , Humanos , Masculino , Fosfolipase D/análise , Fosfolipase D/metabolismo , Fatores de Virulência/análise , Fatores de Virulência/metabolismo
17.
J Food Sci ; 84(1): 174-182, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30557901

RESUMO

In this study, the phenolic components, as well as the antioxidant and antimicrobial activities, of the ripe and unripe fruit of pawpaw (Asimina triloba [L.] Dunal) extracted using five different solvents (distilled water, 95% methanol, 80% methanol, 95% ethanol, and 80% ethanol) were analyzed. The total phenolic content and total flavonoid content were the highest in the 95% ethanol (149.50 mg CAE/g) and 80% ethanol (5.62 mg RE/g) extracts of the unripe fruit, respectively. Analysis of 17 phenolic compounds in pawpaw extracts revealed that epigallocatechin, epicatechin, and p-coumaric acid were the as major compounds, and the amounts of all components significantly decreased with the ripening (P < 0.05). In all antioxidant assays, the 95% ethanol extract of the unripe fruit showed the highest antioxidant activity (EC50 0.22 to 0.93 mg/mL). The pawpaw extracts were more sensitive against Corynebacterium xerosis and Clostridium perfringens. In particular, the 95% ethanol extract of the ripe fruit notably inhibited C. xerosis growth, with minimum inhibitory concentration of 1.56 mg/mL. These results showed that the unripe fruit of pawpaw has abundant phenolic compounds and superior antioxidant activity, and that the 95% ethanol extract of the ripe fruit shows strong inhibitory activity against various microorganisms. Therefore, pawpaw fruit can be utilized as an attractive source of nutrients and therapeutic agents. PRACTICAL APPLICATION: In this study, we identified that the unripe fruit of pawpaw is rich in phenolic compounds and shows strong antioxidant activities. The 95% ethanol extract of the ripe fruit showed strong high inhibitory effect against various microorganisms. These results suggest that pawpaw fruit can serve as a source of antioxidants and delay the aging process. In addition, the fruit could also potentially be utilized as a potential antimicrobial agent.


Assuntos
Anti-Infecciosos/análise , Antioxidantes/análise , Asimina/química , Frutas/química , Fenóis/análise , Bactérias/efeitos dos fármacos , Clostridium perfringens/efeitos dos fármacos , Corynebacterium/efeitos dos fármacos , Flavonoides/análise , Fungos/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Extratos Vegetais/análise
18.
Pol J Microbiol ; 67(4): 431-440, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30550229

RESUMO

Non-diphtherial corynebacteria are Gram-positive rods that cause opportunistic infections, what is supported by their ability to produce biofilm on artificial surfaces. In this study, the characteristic of the biofilm produced on vascular and urological catheters was determined using a confocal microscopy for the most frequently involved in infections diphtheroid species. They were represented by the reference strains of Corynebacterium striatum ATCC 6940 and C. amycolatum ATCC 700207. The effect of ciprofloxacin on the biofilm produced by the antibiotic-susceptible C. striatum strain was evaluated using three concentrations of the antimicrobial agent (2 ×, 4 ×, and 6 × the MIC - the Minimum Inhibitory Concentration). The basis for the interpretation of results was the statistical analysis of maximum points readings from the surface comprising a total of 245 areas of the biofilm image under the confocal microscope. It was observed that ciprofloxacin at a concentration equal to 4 × MIC paradoxically caused an enlargement of areas with live bacteria within the biofilm. Biofilm destruction required the application of ciprofloxacin at a concentration higher than 6 × MIC. This suggests that the use of relatively low doses of antimicrobial agents may increase the number of live bacteria within the biofilm, and further facilitate their detachment from the biofilm's structure thus leading to the spread of bacteria into the bloodstream or to the neighboring tissues. The method of biofilm analysis presented here provides the original and novel approach to the investigation of the diphtheroid biofilms and their interaction with antimicrobial agents.Non-diphtherial corynebacteria are Gram-positive rods that cause opportunistic infections, what is supported by their ability to produce biofilm on artificial surfaces. In this study, the characteristic of the biofilm produced on vascular and urological catheters was determined using a confocal microscopy for the most frequently involved in infections diphtheroid species. They were represented by the reference strains of Corynebacterium striatum ATCC 6940 and C. amycolatum ATCC 700207. The effect of ciprofloxacin on the biofilm produced by the antibiotic-susceptible C. striatum strain was evaluated using three concentrations of the antimicrobial agent (2 ×, 4 ×, and 6 × the MIC ­ the Minimum Inhibitory Concentration). The basis for the interpretation of results was the statistical analysis of maximum points readings from the surface comprising a total of 245 areas of the biofilm image under the confocal microscope. It was observed that ciprofloxacin at a concentration equal to 4 × MIC paradoxically caused an enlargement of areas with live bacteria within the biofilm. Biofilm destruction required the application of ciprofloxacin at a concentration higher than 6 × MIC. This suggests that the use of relatively low doses of antimicrobial agents may increase the number of live bacteria within the biofilm, and further facilitate their detachment from the biofilm's structure thus leading to the spread of bacteria into the bloodstream or to the neighboring tissues. The method of biofilm analysis presented here provides the original and novel approach to the investigation of the diphtheroid biofilms and their interaction with antimicrobial agents.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Ciprofloxacino/farmacologia , Corynebacterium/efeitos dos fármacos , Microscopia Confocal , Testes de Sensibilidade Microbiana
19.
Am J Health Syst Pharm ; 75(22): 1775-1782, 2018 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-30404894

RESUMO

PURPOSE: The clinical and microbiological data for urinary tract infections (UTIs) for 6 organisms detected by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) at community health systems were examined. SUMMARY: The use of precision microbiological diagnostic testing such as MALDI-TOF and real-time quantitative polymerase chain reaction has increased the ability to detect a wider spectrum of organisms. This has raised questions of the clinical relevance of infrequently encountered organisms, especially when cultured from urine. This article reviews clinical and microbiological data for UTIs for 6 organisms detected by MALDI-TOF at community health systems (Actinotignum schaalii, Chryseobacterium indologenes, Aerococcus urinae, Aerococcus sanguinicola, Corynebacterium riegelii, and Corynebacterium urealyticum). Since little information currently exists, most of the data associating the aforementioned organisms with UTIs were derived from case reports. Although these organisms are more readily identified using precision microbiological diagnostic testing methods, infection should not be assumed based on culture results alone since asymptomatic bacteriuria has been reported. Similar to more common urinary pathogens, clinical correlation is essential. To facilitate treatment, we provide a table of empirical options likely to achieve clinical success based on in vivo and in vitro data. If available, pathogen-specific susceptibility data should be used to direct therapy. CONCLUSION: Clinical and microbiological data and potential treatment options were presented for 6 traditionally underrecognized organisms that are increasingly being found from urinary specimens. The treatment recommendations should be interpreted cautiously as they were devised through the use of very limited data.


Assuntos
Antibacterianos/uso terapêutico , Infecções Urinárias/dietoterapia , Actinomycetaceae/efeitos dos fármacos , Infecções por Actinomycetales/tratamento farmacológico , Aerococcus/efeitos dos fármacos , Chryseobacterium/efeitos dos fármacos , Corynebacterium/efeitos dos fármacos , Infecções por Corynebacterium/tratamento farmacológico , Infecções por Flavobacteriaceae/tratamento farmacológico , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Humanos , Testes de Sensibilidade Microbiana , Reação em Cadeia da Polimerase em Tempo Real , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Infecções Urinárias/diagnóstico , Infecções Urinárias/microbiologia
20.
J Clin Microbiol ; 56(12)2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30305384

RESUMO

Corynebacterium spp. are rarely considered pathogens, but data on Corynebacterium spp. as a cause of orthopedic infections are sparse. Therefore, we asked how often Corynebacterium spp. caused an infection in a defined cohort of orthopedic patients with a positive culture. In addition, we aimed to determine the species variety and the susceptibility of isolated strains to define potential treatment strategies. We retrospectively assessed all bone and joint samples that were collected between 2006 and 2015 from an orthopedic ward and that were positive for Corynebacterium spp. by culture. The isolates were considered relevant to an infection if the same Corynebacterium sp. was present in at least two samples. We found 97 orthopedic cases with isolation of Corynebacterium spp. (128 positive samples). These were mainly Corynebacterium tuberculostearicum (n = 26), Corynebacterium amycolatum (n = 17), Corynebacterium striatum (n = 13), and Corynebacterium afermentans (n = 11). Compared to the species found in a cohort of patients with positive blood cultures hospitalized in nonorthopedic wards, we found significantly more C. striatum- and C. tuberculostearicum-positive cases but no C. jeikeium-positive cases in our orthopedic cohort. Only 16 out of 66 cases (24.2%) with an available diagnostic set of at least two samples had an infection. Antibiotic susceptibility testing (AST) showed various susceptibility results for all antibiotics except vancomycin and linezolid, to which 100% of the isolates were susceptible. The rates of susceptibility of corynebacteria isolated from orthopedic samples and of isolates from blood cultures were comparable. In conclusion, our study results confirmed that a Corynebacterium sp. is most often isolated as a contaminant in a cohort of orthopedic patients. AST is necessary to define the optimal treatment in orthopedic infections.


Assuntos
Artrite Infecciosa/microbiologia , Doenças Ósseas Infecciosas/microbiologia , Infecções por Corynebacterium/microbiologia , Corynebacterium/isolamento & purificação , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/farmacologia , Bacteriemia/microbiologia , Corynebacterium/classificação , Corynebacterium/efeitos dos fármacos , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Estudos Retrospectivos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA