Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves [207]-216).

Thesis (doctoral)--Lund University, 1992. / Added t.p. with thesis statement inserted.

Thesis (doctoral)--Lund University, 1992. / Added t.p. with thesis statement inserted.

Thesis (Ph. D.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains xv, 205 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 163-190).

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains ix, 132 p.; also includes graphics (some col.). Includes bibliographical references (p. 112-132). Available online via OhioLINK's ETD Center

Orientador: Marcelo de Carvalho Ramos / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-10T01:23:41Z (GMT). No. of bitstreams: 1 Cacci_LucianaCamila_M.pdf: 1733904 bytes, checksum: 2616f843895d251e8e236cdd873fe436 (MD5) Previous issue date: 2007 / Resumo: Introdução: As metalo beta-lactamases, presentes em Pseudomonas aeruginosa assim como em diversos microrganismos Gram negativos, são grande ameaça ao tratamento dos pacientes portadores de infecções causadas por este microrganismo. Objetivos: A produção de MBLs e a relação genética foram investigadas em isolados de P. aeruginosa resistentes ao Imipenem, recuperados de infecções hospitalares. Descrição do estudo: Estudo restropectivo em uma amostra de microrganismos. O estudo foi conduzido em dois hospitais universitários, em Campinas. Todos os isolados de P. aeruginosa resistentes ao Imipenem foram coletados de pacientes hospitalizados no período de Março de 2000 a Dezembro de 2004. Métodos: O método da disco-difusão foi utilizado para confirmar a resistência ao Imipenem. O E-test MBL@ foi feito para verificar a produção de MBLs e a Concentração Inibitória Mínima (CIM) do Imipenem. Os ftagmentos das seqüências dos genes blaIMP-I, blaVIM-I, blaVIM-2 e blaSPM-I foram amplificados. Resultados: Cento e vinte e oito isolados resistentes ao Imipenem foram coletados durante o período do estudo. A maioria dos isolados exibiu CIM do Imipenem maior ou igual a 256 ug/mL. A análise por macrorestrição com a enzima SpeI através do Pulsed Field Gel Electrophoresis (PFGE) mostrou um polimorfismo significativo. Apenas 15 cepas puderam ser distribuídas em sete "clusters", seis com dois isolados e um com três isolados. Noventa e oito isolados resistentes ao Imipenem foram triados para a pesquisa da produção de MBL. Setenta isolados apresentaram produção de MBL e o fragmento do gene blaSPM-l pôde ser amplificado em 12 isolados. Nas cepas restantes nenhum outro tipo de MBL referente aos genes blaIMP-l, blaVIM-I, blaVIM-2 foi encontrado. Conclusão: A disseminação de cepas de P. aeruginosa produtoras de MEL genotipicamente heterogêneas foi documentada nos hospitais estudados. Apenas a metalo beta-lactamase SPM-1 foi encontrada entre essas cepas / Abstract: Objective: Genetic relatedness and Metallo-lactamase production was investigated in Imipenem resistant Pseudomonas aeruginosa recovered from hospital acquired infections. Design: Descriptive study in a convenient sample of organisms. Setting: Two 400-bed tertiary care teaching hospitals, in Campinas, Brazil. All Imipenem resistant P. aeruginosa, recovered from March, 2000 through December 2004 from hospitalized patients were collected Methods: Disk diffusion tests were used to confirm Imipenem resistance. E-test MBL@ was done to check for MBL production, ando Imipenem MIC's blasPM-l, .blaIMP-l, blaVIM-l and blaVIM-2 sequences were amplified. Results: A sample of 128 Imipenem resistant P. aeruginosa isolates was collected during the study period. Most isolates exhibited Imipenem MIC's > 256 ug/mL. Macrorestriction analysis (Spel) using pulsed field gel electrophoresis (PFGE) showed a substantial polymorphism. Only 15 strains could be allocated to seven clusters, six with two isolates and one with three isolates. Ninety-eight Imipenem resistant isolates were screened for MBL production. Seventy isolates showed MBL production, and blasPM-l sequence could be amplified from 12 isolates. In the remaining strains no other MBL-type from blaIMP-l, blaVIM-l and blaVIM-2 investigated in the study was demonstrated. Conclusion: Dissemination of MBL producing-genotypically heterogenous Pseudomonas aeruginosa strains was documented in the hospitals studied. Only SPM-l metallo-_-lactamase was found among these strains / Mestrado / Ciencias Basicas / Mestre em Clinica Medica

The major outer membrane protein OprF from Pseudomonas aeruginosa was compared with OprF from the fluorescent phytopathogen Pseudomonas syringae. The P. syringae oprF gene was subcloned and sequenced and found to code for a sequence of 344 amino acids containing a 24 amino acid leader sequence. The mature protein, with a deduced molecular weight of 34,225, contained four cysteine residues and an alanine-proline rich area. Comparison of the P. syringae OprF amino acid sequence with the P. aeruginosa OprF and the E. coli OmpA sequences showed that the sequences were most similar at the carboxy-terrninal ends. Restriction enzyme site heterogeneity near the oprF gene from nine different P. syringae pathovars was determined. All pathovars had a conserved SalI site within the gene and conserved PstI. and BamHI sites near the ends of the gene. The location of the PstI and the SalI sites outside the gene was variable, although similar. Immunological relatedness between P. syringae OprF from the different pathovars and P. aeruginosa OprF was confirmed. Protein OprF from all the pathovars was shown to be 2-mercaptoethanol modifiable and more easily heat modifiable than was OprF from P. aeruginosa. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

The human opportunistic pathogen, Pseudomonas aeruginosa PAO1, has been shown to kill the nematode Caenorhabditis elegans. C. elegans has been a valuable model for the study of bacterial pathogenesis, and has reinforced the notion that common virulence and host defense mechanisms exist. Recently, the pyrimidine pathway was shown to regulate virulence levels. Therefore, mutations in the pyrimidine pathway of PAO1 showed decrease virulence in the nematode. When starving the nematode, bacterial resistance was also shown to increase. It was hypothesized that starvation induced the DAF pathway, which regulates the transcription of genes involved with the antibacterial defense mechanism. Further research will be conducted to test this theory by performing RNAi experiments for the genes functioning in the antibacterial defense mechanism.

Cell-free extracts from Pseudomonas fluorescens NCIMB 11764 catalyzed the degradation of cyanide into products that included C02, formic acid, formamide and ammonia. Cyanide-degrading activity was localized to cytosolic cell fractions and was observed at substrate concentrations as high as 100 mM. Two cyanide degrading activities were identified by: (i) the determination of reaction products stoichiometries, (ii) requirements for NADH and oxygen, and (iii) kinetic analysis. The first activity produced CO2 and NH3 as reaction products, was dependent on oxygen and NADH for activity, and displayed an apparent Km for cyanide of 1.2 mM. The second activity generated formic acid (and NH3) pfus formamide as reaction products, was oxygen independent, and had an apparent Km of 12 mM for cyanide. The first enzymatic activity was identified as cyanide oxygenase whereas the second activity consists of two enzymes, a cyanide nitrilase (dihydratase) and putative cyanide hydratase. In addition to these enzymes, cyanide-grown cells were also induced for formate dehydrogenase (FDH), providing a means of recycling NADH utilized by cyanide oxygenase.

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