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1.
Rev. Soc. Bras. Med. Trop ; 46(1): 100-102, Jan.-Feb. 2013. tab
Artigo em Inglês | LILACS | ID: lil-666803

RESUMO

INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) can be difficult to detect at the clinical practice. METHODS: We analyzed 140 MRSA isolates from inpatients to correlate the antimicrobial susceptibility with the SCCmec types. RESULTS: Type III (n = 63) isolates were more resistant to ciprofloxacin, clindamycin, cloramphenicol, erythromycin, gentamicin, and rifampin than type IV (n = 65) ones (p < 0.05). Moreover, type IV isolates were susceptible to tetracycline (100%) and trimethoprim/sulfamethoxazole (98%), while type III isolates presented resistance to them. CONCLUSIONS: In regions where these SCCmec types are prevalent, the detection of specific resistant phenotypes could help to predict them, mainly when there are no technical conditions to SCCmec typing.


Assuntos
Humanos , Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Staphylococcus aureus Resistente à Meticilina/genética , Tetraciclina/farmacologia , Combinação Trimetoprima e Sulfametoxazol/farmacologia , Cromossomos Bacterianos/genética , DNA Bacteriano/genética , Genótipo , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Testes de Sensibilidade Microbiana/métodos , Fenótipo
2.
Braz. j. med. biol. res ; 41(4): 295-304, Apr. 2008. ilus, graf
Artigo em Inglês | LILACS | ID: lil-479685

RESUMO

The features of the nucleotide sequences in both replication and promoter regions have been investigated in many organisms. Intrinsically bent DNA sites associated with transcription have been described in several prokaryotic organisms. The aim of the present study was to investigate intrinsic bent DNA sites in the segment that holds the chromosomal replication origin, oriC, of Xylella fastidiosa 9a5c. Electrophoretic behavior analyses, as well as in silico analyses of both the 2-D projection and helical parameters, were performed. The chromosomal segment analyzed contains the initial sequence of the rpmH gene, an intergenic region, the dnaA gene, the oriC sequence, and the 5' partial sequence of the dnaN gene. The analysis revealed fragments with reduced electrophoretic mobility, which indicates the presence of curved DNA segments. The analysis of the helical parameter ENDS ratio revealed three bent DNA sites (b1, b2, and b3) located in the rpmH-dnaA intergenic region, the dnaA gene, and the oriC 5' end, respectively. The chromosomal segment of X. fastidiosa analyzed here is rich in phased AT tracts and in CAnT motifs. The 2-D projection indicated a segment whose structure was determined by the cumulative effect of all bent DNA sites. Further, the in silico analysis of the three different bacterial oriC sequences indicated similar negative roll and twist >34.00° values. The DnaA box sequences, and other motifs in them, may be associated with the intrinsic DNA curvature.


Assuntos
Cromossomos Bacterianos/genética , DNA Bacteriano/genética , Origem de Replicação/genética , Xylella/genética , Sequência de Bases , Replicação do DNA/genética , Eletroforese em Gel de Ágar , Análise de Sequência de DNA
3.
Mem. Inst. Oswaldo Cruz ; 102(7): 861-866, Nov. 2007. ilus, tab
Artigo em Inglês | LILACS | ID: lil-470358

RESUMO

This study analyzed the involvement of tetA and tetE genes in the tetracycline resistance of 16 strains of genus Aeromonas, isolated from clinical and food sources. Polymerase chain reactions revealed that 37.5 percent of the samples were positive for tetA, and also 37.5 percent were tetE positive. One isolate was positive for both genes. Only the isolate A. caviae 5.2 had its resistance associated to the presence of a plasmid, pSS2. The molecular characterization of pSS2 involved the construction of its restriction map and the determination of its size. The digestion of pSS2 with HindIII originated two fragments (A and B) that were cloned separately into the pUC18 vector. The tetA gene was shown to be located on the HindIII-A fragment by PCR. After transforming a tetracycline-sensitive strain with pSS2, the transformants expressed the resistance phenotype and harbored a plasmid whose size was identical to that of pSS2. The results confirmed the association between pSS2 and the tetracycline resistance phenotype, and suggest a feasible dissemination of tetA and tetE among strains of Aeromonas. This study suggests the spreading tetA and tetE genes in Aeromonas in Brazil and describes a resistance plasmid that probably contributes to the dissemination of the resistance.


Assuntos
Aeromonas/efeitos dos fármacos , Antibacterianos/farmacologia , Antiporters/genética , Proteínas de Bactérias/genética , Alface/microbiologia , Resistência a Tetraciclina/genética , Tetraciclina/farmacologia , Aeromonas/genética , Aeromonas/isolamento & purificação , Cromossomos Bacterianos/genética , Testes de Sensibilidade Microbiana , Fenótipo , Reação em Cadeia da Polimerase
4.
Genet. mol. res. (Online) ; 5(4): 653-663, 2006. tab, ilus, graf
Artigo em Inglês | LILACS | ID: lil-482089

RESUMO

Corynebacterium pseudotuberculosis is a gram-positive bacterium that causes caseous lymphadenitis in sheep and goats. However, despite the economic losses caused by caseous lymphadenitis, there is little information about the molecular mechanisms of pathogenesis of this bacterium. Genomic libraries constructed in bacterial artificial chromosome (BAC) vectors have become the method of choice for clone development in high-throughput genomic-sequencing projects. Large-insert DNA libraries are useful for isolation and characterization of important genomic regions and genes. In order to identify targets that might be useful for genome sequencing, we constructed a C. pseudotuberculosis BAC library in the vector pBeloBAC11. This library contains about 18,000 BAC clones, with inserts ranging in size from 25 to 120 kb, theoretically representing a 390-fold coverage of the C. pseudotuberculosis genome (estimated to be 2.5-3.1 Mb). Many genomic survey sequences (GSSs) with homology to C. diphtheriae, C. glutamicum, C. efficiens, and C. jeikeium proteins were observed within a sample of 215 sequenced clones, confirming their close phylogenetic relationship. Computer analyses of GSSs did not detect chimeric, deleted, or rearranged BAC clones, showing that this library has low redundancy. This GSSs collection is now available for further genetic and physical analysis of the C. pseudotuberculosis genome. The GSS strategy that we used to develop our library proved to be efficient for the identification of genes and will be an important tool for mapping, assembly, comparative, and functional genomic studies in a C. pseudotuberculosis genome sequencing project that will begin this year.


Assuntos
Corynebacterium pseudotuberculosis/genética , Cromossomos Artificiais Bacterianos/genética , Cromossomos Bacterianos/genética , Biblioteca Gênica , Genoma Bacteriano/genética , Clonagem Molecular , Análise de Sequência de DNA
5.
Rev. Inst. Nac. Hig ; 35(2): 20-31, 2004. tab, graf
Artigo em Espanhol | LILACS | ID: lil-431595

RESUMO

Las islas patogénicas (PAIs) son segmentos de ADN bacteriano que portan uno o más genes de virulencia, los cuales han sido adquiridos en bloque de una fuente externa. El genoma de un patógeno usualmente representa un mosaico entre estas islas recién adquiridas y un ADN relativamente antiguo. Las PAIs son identificadas por su diferencia en el porcentaje de contenido de G+C en relación a la media del cromosoma y por otras características, que sugieren su adquisición a través de elementos genéticos móviles. Genes para una amplia gama de determinantes de virulencia están asociados con PAIs, incluyendo los que codifican para ciertos mecanismos que le permiten resistir las defensas del hospedador, factores de colonización, adquisición de nutrientes y toxinas. El estudio y conocimiento de las PAIs provee evidencias importantes de la biología de las bacterias patógenas. Los productos de las PAIs podrán representar, en un futuro, blancos para la terapia antimicrobiana, vacunas y herramientas diagnósticas


Assuntos
Bactérias , Cromossomos Bacterianos , Genoma Bacteriano , Virulência , Bacteriologia , Venezuela
6.
Rev. Fac. Farm. (Merida) ; 45(1): 49-53, ene.-jun. 2003. tab, graf
Artigo em Espanhol | LILACS | ID: lil-396382

RESUMO

Los antibióticos antraciclínicos (ATC) se utilizan en la terapéutica como antineoplásicos ya que actúan intercalándose entre las bases apareadas del ADN, modificando su estructura y conformación y afectando a las polimerasas y topoisomerasas. En el presente trabajo se intenta demostrar que la resistencia a antibióticos, cuando ésta se encuentra modificada por un plásmido, puede ser alterada por la presencia de ATC. La cepa bacteriana DH5 alfa/pUC19 se cultivo en medio tripticasa soya y luego se colocó en ausencia y presencia de ampicilina (como presión selectiva) y de una ATC (Doxorubicina a 4'epi Doxorubicina). El efecto se puso en evidencia por cuantificación del crecimiento y por evaluación del color en placas con X-gal. Los resultados sugieren que la Doxorubicina tiene un efecto negativo sobre la replicación del plásmido pero afecta positivamente la expresión del mismo. Mientras que 4'-epi Doxorubicina afecta negativamente ambos procesos. Se propone la 4'-epi Doxorubicina como antibiótico para curar plásmidos y así resistencias codificadas en plásmidos, haciéndose la bacteria sensible al antibiótico


Assuntos
Antibióticos Antineoplásicos/análise , Antibióticos Antineoplásicos/uso terapêutico , Cromossomos Bacterianos , Plasmídeos/análise , Plasmídeos/farmacologia , Farmacologia , Venezuela
7.
Braz. j. infect. dis ; 7(1): 32-43, Feb. 2003.
Artigo em Inglês | LILACS | ID: lil-351151

RESUMO

Staphylococcus aureus has long been recognised as an important pathogen in human disease. Serious staphylococcal infections can frequently occur in inpatients and may lead to dire consequences, especially as to therapy with antimicrobial agents. The increase in the frequency of Methicillin-Resistant Staphylococcus aureus (MRSA) as the causal agent of nosocomial infection and the possibility of emergence of resistance to vancomycin demands a quick and trustworthy characterization of isolates and identification of clonal spread within hospitals. Enough information must be generated to permit the implementation of appropriate measures for control of infection, so that outbreaks can be contained. Molecular typing techniques reviewed in this manuscript include: plasmid profile analysis, analysis of chromosomal DNA after enzymatic restriction, Southern blotting, pulsed field gel electrophoresis (PFGE), techniques involving polymerase chain reaction and multilocus sequence typing (MLST). Repetitive DNA Sequence PCR (rep-PCR) may be used for screening due to its practicality, low cost and reproducibility. Because of its high discriminatory power Pulsed-Field Gel Electrophoresis (PFGE) still remains the gold standard for MRSA typing. New techniques with higher reproducibility and discriminatory power, such as Multi-Locus Sequence Typing (MLST), are appearing. These are mostly useful for global epidemiology studies. Molecular typing techniques are invaluable tools for the assessment of putative MRSA outbreaks and so should be extensively used for this purpose


Assuntos
Humanos , Técnicas de Tipagem Bacteriana , Infecção Hospitalar/microbiologia , DNA Bacteriano/análise , Resistência a Meticilina/genética , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/classificação , Técnicas de Tipagem Bacteriana/métodos , Técnicas de Tipagem Bacteriana/normas , Brasil/epidemiologia , Cromossomos Bacterianos/química , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/prevenção & controle , Eletroforese em Gel de Campo Pulsado , Genótipo , Reação em Cadeia da Polimerase , Plasmídeos/análise , Sequências Repetitivas de Ácido Nucleico , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genética
8.
Biocell ; 20(3): 235-241, Dec. 1996.
Artigo em Inglês | LILACS | ID: lil-335995

RESUMO

The purpose of this study was to investigate the protective power of a cellular extract (CE) from Y. enterocolitica 0:8 grown in condition of expression of chromosomal antigens. Mice were immunized by s.c. route and challenged with: 0 LD50 (1 x 10(4) CFU/ml). Immunoblotting showed that CE-specific serum reacted with several CE antigens. Prominent bands, of molecular weights 60 and 35.5, were present in cytoplasmic and membrane fraction, respectively. The lipopolysaccharide (LPS) was detected in CE. These findings suggest that chromosomally-encoded antigens present in CE may induce protection against Y. enterocolitica infection. Both humoral and cellular immune response contribute to protection in mice.


Assuntos
Animais , Masculino , Feminino , Camundongos , Antígenos de Bactérias/imunologia , Yersinia enterocolitica , Transferência Adotiva , Anticorpos Antibacterianos/biossíntese , Anticorpos Antibacterianos/imunologia , Antígenos de Bactérias/administração & dosagem , Antígenos de Bactérias/genética , Cromossomos Bacterianos , Imunidade Celular , Imunização , Injeções Intraperitoneais , Injeções Subcutâneas , Lipopolissacarídeos/imunologia , Organismos Livres de Patógenos Específicos , Yersinia enterocolitica , Yersiniose
9.
Acta cient. venez ; 47(2): 121-6, 1996. ilus, tab
Artigo em Espanhol | LILACS | ID: lil-216822

RESUMO

Plasmid pT153, a stable recombinant between pBR322 plasmid and M13 bacteriophage, and Tn10 transposon were employed for in vivo cloning of a chromosomal segment of Escherichia coli including the nar locus. The strategy consisted in creating an homology between pT153 and the E. coli chromosome, incorporating a Tn10 transposon close to the nar locus of a polA12 temperature-sensitive strain. The selection of clones carrying the plasmid into the chromosome was realized at 42 degrees C, with ampiciline, taken advantage that the replicon of pT153 requires the ADN Polymerase I for its functioning. The plasmid integrated in the polA12 strain has the opportunity of excising and carrying part of bacterial genome and autonomically replicating after a thermal change from 42 degrees C to 30 degrees C. The stable recombinant plasmids could be efficiently transduced with the M13 bacteriophage to a E. coli strain (delta narGHJI), obtaining Nit+ Apr transductant clones. The versatility of this method of E. coli gene cloning is the facility to create the homologue region anywhere in the bacterial genome and the efficient transduction of pT153 plasmid by M13 bacteriophage


Assuntos
Cromossomos Bacterianos/genética , Clonagem Molecular , Clonagem de Organismos , Escherichia coli/genética , Recombinação Genética , Plasmídeos/genética
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