In order to gain a better understanding of this microorganismand its role in human pathogenesis, a physical map of Moraxella catarrhalis type strain ATCC25238 was constructed using pulsed field gel electrophoresis (PFGE) in combination with Southern hybridization techniques. Restriction endonucleases Not I, Rsr II, and Sma I were used to digest the chromosomal DNA. An overlapping circular map was generated by cross-hybridization of isolated radiolabeled fragments of Moraxella catarrhalis genomic DNA to dried PFGE gels. The number and location of the 16S and 23S ribosomal RNA genes were determined by digestion with l-Ceul enzyme and by Southern hybridization. Virulence-associated genes, the gene for β-lactamase, and housekeeping genes were also placed onto the physical map.

Thèse (M.Sc.)--Université Laval, 2000. / Bibliogr.: f. 64-79. Publié aussi en version électronique.

Bacterial aspartate transcarbamoylases (ATCase's) are divided into three classes that correspond to taxonomic relationships within the bacteria. The opportunistic pathogen Moraxeila catarrhalis has undergone several reclassifications based on traditional microbiological criteria. The previously uncharacterized ATCase from M. catarrhalis was purified to homogeneity and its chemical properties characterized. The ATCase from M. catarrhalis is a class C ATCase with an apparent molecular mass of 480-520 kDa. The M. catarrhalis ATCase is a dodecomer composed of six 35 kDa polypeptides and six 45 kDa polypeptides. The enzyme has an unusually high pH optimum of greater than pH 10. The enzyme exhibited hyperbolic kinetic with a Km for aspartate of 2 mM. A single, separate 78 kDa dihydroorotase from M. catarrhalis was identified and it was not associated with ATCase. These data support the reclassification of M. catarrhalis out of the Neisseriaceae family.

No description available.

Zugl.: Berlin, Freie Universiẗat, Diss., 2009.

Antimicrobial susceptibility profiles were assembled for isolates of Moraxella catarrhalis collected from the Mountain Home Veteran's Affairs Medical Center (VAMC) clinical laboratory in Johnson City, Tennessee. The goal of the study was to identify isolates for genetic characterization using comparisons of susceptibility profiles. Isolates of Moraxella catarrhalis collected from July 1984 through 1994 were analyzed for β-lactamase production using a Cefinase disk assay. A multi-drug profile consisting of 11 β-lactam antibiotics was performed on the 41 M. catarrhalis isolates. Kirby Bauer disk assays were performed for 7 cephalosporin and 4 non-cephalosporin antibiotics. In summary, 2 observations implicate more complex resistance determinants than the 2 known forms of the BRO β-lactamase. First, there was overlap in the ranges of inhibition zones. Second, several isolates had antibiotic-specific deviations from typical profiles. These data suggest either more variation in the M. catarrhalis BRO β-lactamase than described or contributions to resistance from undescribed determinants.

No description available.

No description available.

Die COPD (chronic obstructive pulmonary disease) ist eine weltweit vorkommende, chronisch obstruktive Erkrankung der Lunge. Sie gilt als vierthäufigste Todesursache weltweit, wobei ein Viertel der akuten bakteriellen Exazerbationen auf eine Infektion mit Moraxella catharralis zurückzuführen sind. Sowohl das akute, als auch das chronische Entzündungsbild der COPD wird überwiegend durch neutrophile Granulozyten in den Atemwegen bestimmt, die neben antimikrobiellen Effektorfunktionen durch Freisetzung von Zytokinen auch die Entzündungsreaktion bzw. Immunantwort regulieren können. In dieser Arbeit wurde untersucht inwiefern die Interaktion von M.catarrhalis mit dem humanen Granuloyzten-spezifischen Rezeptor carcinoembryonic antigen-related cell adhesion molecule (CEACAM)3 zu einer Aktivierung der neutrophilen Granuloyzten sowie zu einer NF-kappaB-abhängigen Chemokinproduktion führt. Primäre Granulozyten gesunder Spender sowie NB4 Zellen wurden mit M.catarrhalis in Anwesenheit verschiedener Inhibitoren, siRNA oder CEACAM-blockender Antikörper infiziert und anschließend die Chemokinsekretion mittels ELISA bestimmt. Mit Hilfe eines Luziferase Reportergenassays und Chromatinimmunpräzipitation wurde die Aktivierung des Transkriptionsfaktors NF-kappaB untersucht. Im Rahmen dieser Arbeit konnte nachgewiesen werden, dass die spezifische Interaktion von CEACAM3 mit M. catarrhalis UspA1 in einer Aktivierung neutrophiler Granulozyten resultiert. Desweiteren kommt es zu einer CEACAM3-UspA1 abhängigen Aktivierung des Transkriptionsfaktors NF-kappaB und verstärkter Sekretion proinflammatorischer Chemokine. Die NF-kappaB-Aktivierung ist abhängig von der Phosphorylierung des CEACAM3 ITAM-like Motivs und erfolgt über den Syk und Card9 Signalweg. Die Ergebnisse lassen den Schluss zu, dass neutrophile Granulozyten in der Lage sind, die durch M. catarrhalis induzierte Atemwegsentzündung in der COPD über den Oberflächenrezeptor CEACAM3 spezifisch zu modulieren. / The chronic obstructive pulmonary disease (COPD) is the fourth most common cause of death worldwide. 25 % of the acute bacterial exacerbations are caused by infection with the human restricted pathogen Moraxella catharralis. Both the acute and the chronic inflammatory stage of COPD are predominantly determined by neutrophil granulocytes in the respiratory tract, which in addition to antimicrobial effector functions can also regulate the inflammation or immune response by releasing cytokines. This work investigated if the interaction of M. catarrhalis with the human granulocyte-specific receptor carcinoembryonic antigen-related cell adhesion molecule (CEACAM) 3 leads to an activation of the neutrophil granulocytes and to a NF-kappaB-dependent chemokine production. Primary granulocytes from healthy donors as well as NB4 cells were infected with M. catarrhalis in the presence of various inhibitors, siRNA or CEACAM-blocking antibodies, and then chemokine secretion was determined by ELISA. Using a luciferase reporter gene assay and chromatin immunoprecipitation, activation of the transcription factor NF-kappaB was investigated. In this work it could be shown that the specific interaction of CEACAM3 with M. catarrhalis UspA1 results in the activation of neutrophil granulocytes. Furthermore, there is a CEACAM3-UspA1-dependent activation of the transcription factor NF-kappaB and increased secretion of proinflammatory chemokines. NF-kappaB activation is dependent on the phosphorylation of the CEACAM3 ITAM-like motif and occurs via the Syk and Card9 signaling pathways. The results suggest that neutrophil granulocytes are able to specifically modulate M. catarrhalis induced airway inflammation in COPD via the surface receptor CEACAM3.

<p>Försämrat immunförsvar och ökad risk att drabbas av bakterie- och virusinfektioner förekommer hos patienter med blodsjukdomarna multipelt myelom, Waldenströms makroglobulinemi samt hos vissa patienter med blodsjukdomen monoklonal gammopati av oklar signifikans. Infektionerna kräver ofta antibiotikabehandling och behandling med antivirala medel. I dagsläget är det svårt att förutsäga vilka av patienterna som kommer att drabbas av svåra och ibland livshotande infektioner. Därför ges många av patienterna förebyggande antibiotikabehandling.</p><p>I studiens början sattes en enzyme-linked immunosorbent assay (ELISA) för detektion av antikroppar mot <em>Moraxella catarrhalis </em>upp. I studien undersöktes om antikroppstitrar i serum mot bakterien <em>Moraxella catarrhalis</em> var lägre hos patientgrupperna än hos friska kontrollpersoner i samma ålder och om variationer förekom mellan patientgrupperna samt hur kontrollgrupper i olika åldrar skiljde sig från varandra. Kontrollgrupperna som undersöktes var mellan 20-40 år, 40-60 år samt 60 år och äldre.</p><p>Resultatet var att patienterna med multipelt myelom hade lägst antikroppstitrar, patienter med monoklonal gammopati av oklar signifikans hade något högre och patienter med Waldenströms makroglobulinemi hade ännu högre antikroppstitrar. Kontrollgruppen äldre än 60 år hade högre antikroppstitrar än både kontrollgruppen 20-40 år och 40-60 år. Lägst antikroppstitrar hade kontrollgrupp 40-60 år men ingen signifikant skillnad påvisades mellan kontrollgrupp 20-40 år och 40-60 år.</p>