Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 11 de 11
Filter
Add more filters










Publication year range
1.
Biosci Biotechnol Biochem ; 87(6): 653-662, 2023 May 19.
Article in English | MEDLINE | ID: mdl-36972615

ABSTRACT

Staphylococcus lugdunensis produces lugdulysin, a metalloprotease that may contribute to its virulence. This study aimed to evaluate the biochemical aspects of lugdulysin and investigate its effect on Staphylococcus aureus biofilms. The protease was isolated and characterized for its optimal pH and temperature, hydrolysis kinetics, and influence of metal cofactor supplementation. The protein structure was determined via homology modeling. The effect on S. aureus biofilms was assessed by the micromethod technique. The protease optimal pH and temperature were 7.0 and 37 °C, respectively. EDTA inhibited protease activity, confirming it as a metalloprotease. Lugdulysin activity was not recovered by divalent ion supplementation post-inhibition, and supplementation with divalent ions did not change enzymatic activity. The isolated enzyme was stable for up to 3 h. Lugdulysin significantly inhibited the formation and disrupted preestablished protein-matrix MRSA biofilm. This preliminary study indicates that lugdulysin has a potential role as a competition mechanism and/or modulation of staphylococcal biofilm.


Subject(s)
Methicillin-Resistant Staphylococcus aureus , Staphylococcal Infections , Staphylococcus lugdunensis , Humans , Staphylococcus aureus , Anti-Bacterial Agents/pharmacology , Biofilms , Metalloproteases/pharmacology , Peptide Hydrolases , Microbial Sensitivity Tests
2.
Sci Rep ; 9(1): 11736, 2019 08 13.
Article in English | MEDLINE | ID: mdl-31409863

ABSTRACT

Staphylococcus hominis is part of the normal human microbiome. Two subspecies, S. hominis hominis (Shh) and S. hominis novobiosepticus (Shn), have clinical significance. Forty-nine S. hominis isolates were analyzed by the MicroScan automated system, SDS-PAGE and MALDI-TOF methods, followed by partial sequencing of the 16S rDNA gene. The trehalose fermentation test, disk diffusion and broth microdilution tests were used to identify (novobiocin test) and access the susceptibility to oxacillin and vancomycin of isolates. The SCCmec elements and genomic diversity were evaluated by PCR and PFGE methods, respectively. Profiles of 28 (57%; 8 Shh and 20 Shn) isolates corroborated with the results found in all the applied methods of identification. The remaining 21 (43%) isolates were phenotypically identified as Shh by MicroScan; however, they were identified as Shn by SDS-PAGE and mass spectral, and confirmed by 16S rDNA sequencing. Among 41 isolates identified as Shn by the molecular and mass spectrometry methods, 19 (41%) were novobiocin-sensitive, and the trehalose test indicated 11 positive isolates, which are considered atypical phenotypic results for this subspecies. In addition, 92.7% of the isolates identified as Shn by these methods carried mecA gene, while only 12.5% of the Shh isolates were positive. Together, the results highlighted the SDS-PAGE and MALDI-TOF MS methods as promising tools for discriminating S. hominis subspecies.


Subject(s)
Bacterial Proteins/metabolism , Electrophoresis, Polyacrylamide Gel , Proteome , Proteomics , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Staphylococcus hominis/classification , Staphylococcus hominis/metabolism , Humans , Proteomics/methods
3.
Microb Drug Resist ; 22(8): 700-706, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27045297

ABSTRACT

Methicillin-resistant Staphylococcus aureus (MRSA) carrying SCCmec type IV has emerged in hospitals worldwide. The aim of this study was to evaluate phenotypic and molecular characteristics of antimicrobial resistance in MRSA SCCmec IV isolates, presenting different genetic backgrounds, isolated from hospitals in Rio de Janeiro. The antimicrobial resistance of 128 S. aureus type IV isolates from 11 hospitals was characterized by the disk diffusion test and minimum inhibitory concentration (MIC) test. Mutations in parC gene, which encodes ciprofloxacin resistance, and genes associated with macrolide-lincosamide-streptogramin B (MLSb) resistance were also investigated. MRSA isolates belonging to USA400/ST1 (60 isolates), USA800/ST5 (40), USA1100/ST30 (13), and other 11 (15) lineages were mainly resistant to erythromycin (68%), ciprofloxacin (56%), and clindamycin (50%). The highest antimicrobial resistance rates were found among USA400 isolates (p < 0.05). The majority of them (90%) carried only the erm(C) gene and mainly presented two mutation types in the parC gene. The msr(A) gene was most frequently found among USA800 isolates (p < 0.05). Among MRSA type IV isolates from Rio de Janeiro hospitals, multiresistance, including mutations in parC gene, was associated to the USA400/ST1, while the msr(A) gene was associated with USA800/ST5 isolates, highlighting that these lineages could have more potential to persist in a hospital environment.


Subject(s)
DNA Topoisomerase IV/genetics , Drug Resistance, Multiple, Bacterial/genetics , Gene Expression Regulation, Bacterial , Methicillin-Resistant Staphylococcus aureus/genetics , Methionine Sulfoxide Reductases/genetics , Methyltransferases/genetics , Anti-Bacterial Agents/pharmacology , Bacterial Typing Techniques , Brazil/epidemiology , DNA Topoisomerase IV/metabolism , Hospitals , Humans , Lincosamides/pharmacology , Macrolides/pharmacology , Methicillin-Resistant Staphylococcus aureus/drug effects , Methicillin-Resistant Staphylococcus aureus/growth & development , Methicillin-Resistant Staphylococcus aureus/isolation & purification , Methionine Sulfoxide Reductases/metabolism , Methyltransferases/metabolism , Microbial Sensitivity Tests , Molecular Epidemiology , Mutation , Quinolones/pharmacology , Staphylococcal Infections/drug therapy , Staphylococcal Infections/epidemiology , Staphylococcal Infections/microbiology , Streptogramin B/pharmacology
4.
Diagn Microbiol Infect Dis ; 75(3): 235-9, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23313084

ABSTRACT

Staphylococcus epidermidis in immunocompromised patients can cause bacteremia related to the use of catheter due to biofilm production. There are different phenotypic methods to detect biofilm formation. One method is based on culture in brain heart infusion agar (BHIA) containing sucrose and red Congo dye (original Congo red agar). Our group created a new CRA formula and we have confirmed its capacity to detect biofilm production in 210 S. epidermidis strains, including 76 (36.2%) icaAB gene-positive strains. Other parameters were also evaluated. The new CRA formula that gave the best results was BHIA with sucrose (5%), Congo red (0.08%), NaCl (1.5%), glucose (2%), and vancomycin (0.5 mg/mL) (vancomycin-modified CRA-CRAmod). The CRAmod plus vancomycin may be a promising tool and can help to determine the real participation of S. epidermidis in the infectious process.


Subject(s)
Bacteriological Techniques/methods , Biofilms , Congo Red/chemistry , Culture Media/chemistry , Staphylococcus epidermidis/isolation & purification , Genes, Bacterial , Glucose/chemistry , Humans , Multiplex Polymerase Chain Reaction , Phenotype , Reproducibility of Results , Sensitivity and Specificity , Sodium Chloride/chemistry , Staphylococcal Infections/blood , Staphylococcal Infections/microbiology , Staphylococcus epidermidis/chemistry , Staphylococcus epidermidis/drug effects , Staphylococcus epidermidis/genetics , Sucrose/chemistry , Vancomycin/pharmacology
5.
Mem Inst Oswaldo Cruz ; 106(3): 368-70, 2011 May.
Article in English | MEDLINE | ID: mdl-21655828

ABSTRACT

Carbapenemase production is an important mechanism of carbapenem resistance among nonfermentative Gram-negative isolates. This study aimed to report the detection of bla(OXA-58) gene in multiresistant clinical isolates of Acinetobacter baumannii recovered from inpatients in a public hospital. Polymerase chain reaction tests were performed to detect the bla(OXA-23-like), bla(OXA-24-like), bla(OXA-58-like) and bla(OXA-51-like) genes. The bla(OXA-58) and bla(OXA-23) genes were detected in one and three isolates, respectively. Sequencing of the bla(OXA-58-like) amplicon revealed 100% identity with the A. baumannii bla(OXA-58) gene listed in the GenBank database. This is the first report of an OXA-58-producing A. baumannii isolate in Rio de Janeiro, Brazil.


Subject(s)
Acinetobacter baumannii/genetics , beta-Lactamases/genetics , Acinetobacter Infections/microbiology , Acinetobacter baumannii/drug effects , Acinetobacter baumannii/enzymology , Anti-Bacterial Agents/pharmacology , Disk Diffusion Antimicrobial Tests , Drug Resistance, Multiple, Bacterial , Humans , Polymerase Chain Reaction
6.
Braz J Infect Dis ; 15(3): 293-5, 2011.
Article in English | MEDLINE | ID: mdl-21670934

ABSTRACT

Staphylococcus lugdunensis is a rare cause of severe infections and clinical manifestations are similar to those related to S. aureus infection. We describe a hospital-acquired bacteremia due to methicillin-resistant Staphylococcus lugdunensis, misidentified as methicillin-resistant S. aureus. The oxacillin MIC was 16 µg/mL and the mecA gene and SCCmec type V were determined by PCR. Although treatment had been appropriated, the patient died after rapid progressive respiratory failure and another nosocomial sepsis. It is important not only to identify S. lugdunensis in view of its clinical course, but also to determine its susceptibility to oxacillin by detecting the mecA gene or its product.


Subject(s)
Bacteremia/microbiology , Cross Infection/microbiology , Methicillin Resistance/genetics , Staphylococcal Infections/microbiology , Staphylococcus lugdunensis/genetics , Aged , Anti-Bacterial Agents/pharmacology , Bacteremia/diagnosis , Bacterial Proteins/genetics , Cross Infection/diagnosis , Female , Humans , Methicillin Resistance/drug effects , Methicillin-Resistant Staphylococcus aureus , Oxacillin/pharmacology , Staphylococcal Infections/diagnosis , Staphylococcus lugdunensis/drug effects
7.
Braz. j. infect. dis ; 15(3): 293-295, May-June 2011.
Article in English | LILACS | ID: lil-589965

ABSTRACT

Staphylococcus lugdunensis is a rare cause of severe infections and clinical manifestations are similar to those related to S. aureus infection. We describe a hospital-acquired bacteremia due to methicillin-resistant Staphylococcus lugdunensis, misidentified as methicillin-resistant S. aureus. The oxacillin MIC was 16 µg/mL and the mecA gene and SCCmec type V were determined by PCR. Although treatment had been appropriated, the patient died after rapid progressive respiratory failure and another nosocomial sepsis. It is important not only to identify S. lugdunensis in view of its clinical course, but also to determine its susceptibility to oxacillin by detecting the mecA gene or its product.


Subject(s)
Aged , Female , Humans , Bacteremia/microbiology , Cross Infection/microbiology , Methicillin Resistance/genetics , Staphylococcal Infections/microbiology , Staphylococcus lugdunensis/genetics , Anti-Bacterial Agents/pharmacology , Bacteremia/diagnosis , Bacterial Proteins/genetics , Cross Infection/diagnosis , Methicillin-Resistant Staphylococcus aureus , Methicillin Resistance/drug effects , Oxacillin/pharmacology , Staphylococcal Infections/diagnosis , Staphylococcus lugdunensis/drug effects
8.
Mem. Inst. Oswaldo Cruz ; 106(3): 368-370, May 2011. tab
Article in English | LILACS | ID: lil-589049

ABSTRACT

Carbapenemase production is an important mechanism of carbapenem resistance among nonfermentative Gram-negative isolates. This study aimed to report the detection of blaOXA-58 gene in multiresistant clinical isolates of Acinetobacter baumannii recovered from inpatients in a public hospital. Polymerase chain reaction tests were performed to detect the blaOXA-23-like, blaOXA-24-like, blaOXA-58-like and blaOXA-51-like genes. The blaOXA-58 and blaOXA-23 genes were detected in one and three isolates, respectively. Sequencing of the blaOXA-58-like amplicon revealed 100 percent identity with the A. baumannii blaOXA-58 gene listed in the GenBank database. This is the first report of an OXA-58-producing A. baumannii isolate in Rio de Janeiro, Brazil.


Subject(s)
Humans , Acinetobacter baumannii , beta-Lactamases , Acinetobacter Infections , Acinetobacter baumannii , Acinetobacter baumannii/enzymology , Anti-Bacterial Agents , Disk Diffusion Antimicrobial Tests , Drug Resistance, Multiple, Bacterial , Polymerase Chain Reaction
9.
Rev Soc Bras Med Trop ; 43(3): 298-303, 2010.
Article in Portuguese | MEDLINE | ID: mdl-20563500

ABSTRACT

INTRODUCTION: The genus Staphylococcus is of great importance because of its high prevalence in hospital infections and because it presents high rates of resistance to oxacillin and other antimicrobials. Thus, evaluation of the accuracy of the phenotypic methods that are used to determine the profile of antimicrobial resistance is essential to ensure that the most appropriate therapy is chosen. METHODS: One hundred and fourteen strains of Staphylococcus sp (53 S. aureus and 61 CNS) were used to evaluate the accuracy of the methods of disk diffusion, agar microdilution, oxacillin screening agar and automated systems, in comparison with PCR for investigating resistance to oxacillin. RESULTS: The mecA gene was detected in 48 strains (42.1%), and 27 strains (23.7%) showed discrepant results in at least one of the methods (74.1% of CNS, 25.9% of S. aureus). For S. aureus, with the exception of the Microscan Walkaway, all the methods showed 100% specificity and sensitivity. In relation to CNS, the automated system and cefoxitin disk had lower accuracy. CONCLUSIONS: Use of two methods should be the best option for improved accuracy, especially when the diagnostic laboratory only uses an automated system or oxacillin disk diffusion test. Combination of these methods with others presented almost 100% sensitivity and specificity in our study.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Cefoxitin/pharmacology , Microbial Sensitivity Tests/methods , Oxacillin/pharmacology , Staphylococcus/drug effects , Humans , Penicillin-Binding Proteins , Phenotype , Polymerase Chain Reaction , Sensitivity and Specificity , Staphylococcus/isolation & purification
10.
Rev. Soc. Bras. Med. Trop ; 43(3): 298-303, May-June 2010. tab
Article in Portuguese | LILACS | ID: lil-548527

ABSTRACT

INTRODUÇÃO: O gênero Staphylococcus é de grande importância devido a sua alta prevalência em infecções hospitalares e por apresentar taxas elevadas de resistência a oxacilina e a outros antimicrobianos. Assim, a avaliação da acurácia dos métodos fenotípicos usados para determinação do perfil de suscetibilidade a antimicrobianos é essencial para garantir a escolha da terapia mais adequada. MÉTODOS: Foram usadas 114 amostras de Staphylococcus sp (53 S. aureus e 61 SCN) na avaliação da acurácia dos métodos de difusão de disco, microdiluição em agar, ágar triagem oxacilina e sistema automatizado em comparação com a PCR para verificação da resistência a oxacilina. RESULTADOS: O gene mecA foi detectado em 48 (42,1 por cento) amostras e 27 (23,7 por cento) amostras apresentaram discrepância de resultados em pelo menos um dos métodos (74,1 por cento SCN, 25,9 por cento S. aureus). Para S. aureus, com exceção do Microscan Walkaway, todos os métodos apresentaram 100 por cento de especificidade e sensibilidade. Já para os SCN, o sistema automatizado e o disco de cefoxitina apresentaram menor acurácia. CONCLUSÕES: O uso de dois métodos deve ser a melhor opção para a melhora da acurácia, principalmente quando o laboratório de diagnóstico utiliza somente sistema automatizado ou teste de difusão do disco de oxacilina. A associação destes métodos com outros apresentaram praticamente 100 por cento de sensibilidade e especificidade em nosso estudo.


INTRODUCTION: The genus Staphylococcus is of great importance because of its high prevalence in hospital infections and because it presents high rates of resistance to oxacillin and other antimicrobials. Thus, evaluation of the accuracy of the phenotypic methods that are used to determine the profile of antimicrobial resistance is essential to ensure that the most appropriate therapy is chosen. METHODS: One hundred and fourteen strains of Staphylococcus sp (53 S. aureus and 61 CNS) were used to evaluate the accuracy of the methods of disk diffusion, agar microdilution, oxacillin screening agar and automated systems, in comparison with PCR for investigating resistance to oxacillin. RESULTS: The mecA gene was detected in 48 strains (42.1 percent), and 27 strains (23.7 percent) showed discrepant results in at least one of the methods (74.1 percent of CNS, 25.9 percent of S. aureus). For S. aureus, with the exception of the Microscan Walkaway, all the methods showed 100 percent specificity and sensitivity. In relation to CNS, the automated system and cefoxitin disk had lower accuracy. CONCLUSIONS: Use of two methods should be the best option for improved accuracy, especially when the diagnostic laboratory only uses an automated system or oxacillin disk diffusion test. Combination of these methods with others presented almost 100 percent sensitivity and specificity in our study.


Subject(s)
Humans , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Cefoxitin/pharmacology , Microbial Sensitivity Tests/methods , Oxacillin/pharmacology , Staphylococcus/drug effects , Phenotype , Polymerase Chain Reaction , Sensitivity and Specificity , Staphylococcus/isolation & purification
11.
Ann Clin Microbiol Antimicrob ; 5: 5, 2006 Mar 22.
Article in English | MEDLINE | ID: mdl-16553949

ABSTRACT

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococcus infections are a worldwide concern. Currently, these isolates have also shown resistance to vancomycin, the last therapy used in these cases. It has been observed that quinones and other related compounds exhibit antibacterial activity. This study evaluated the antibacterial activity, toxicity and in vivo dermal irritability of lapachol extracted from Tabebuia avellanedae and derivatives against methicillin-resistant staphylococcal isolates. In addition, its mechanism of action was also analyzed. METHODS: The compounds beta-lapachone, 3-hydroxy beta N lapachone and alpha-lapachone were tested to determine the MIC values against methicillin-resistant S. aureus, S. epidermidis and S. haemolyticus strains, being the two last ones hetero-resistant to vancomycin. Experiments of protein synthesis analysis to investigate the naphthoquinones action were assessed. In vitro toxicity to eukaryotic BSC-40 African Green Monkey Kidney cell cultures and in vivo primary dermal irritability in healthy rabbits were also performed. RESULTS: The compounds tested showed antibacterial activity (MICs of 8, 4/8 and 64/128 microg/mL to beta-lapachone, 3-hydroxy beta N lapachone and alpha-lapachone, respectively), but no bactericidal activity was observed (MBC > 512 microg/mL for all compounds). Although it has been observed toxic effect in eukaryotic cells, the compounds were shown to be atoxic when applied as topic preparations in healthy rabbits. No inhibition of proteins synthesis was observed. CONCLUSION: Our results suggest that quinones could be used in topic preparations against wound infections caused by staphylococci, after major investigation of the pharmacological properties of the compounds. Studies about the use of these compounds on tumoral cells could be carried on, due to their effect in eukaryotic cells metabolism.


Subject(s)
Irritants/toxicity , Naphthoquinones/pharmacology , Plant Extracts/pharmacology , Skin/pathology , Staphylococcus aureus/drug effects , Staphylococcus epidermidis/drug effects , Staphylococcus haemolyticus/drug effects , Tabebuia/chemistry , Animals , Cell Line , Chlorocebus aethiops , Methicillin Resistance , Naphthoquinones/isolation & purification , Naphthoquinones/toxicity , Plant Extracts/isolation & purification , Plant Extracts/toxicity , Rabbits , Skin/drug effects
SELECTION OF CITATIONS
SEARCH DETAIL
...