Journal articles on the topic 'M. catarrhalis'
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1
Aebi, Christoph, Leslie D. Cope, Jo L. Latimer, Sharon E. Thomas, Clive A. Slaughter, George H. McCracken, and Eric J. Hansen. "Mapping of a Protective Epitope of the CopB Outer Membrane Protein of Moraxella catarrhalis." Infection and Immunity 66, no. 2 (February 1, 1998): 540–48. http://dx.doi.org/10.1128/iai.66.2.540-548.1998.
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ABSTRACT A monoclonal antibody (MAb) (MAb 10F3) directed against the CopB outer membrane protein of Moraxella catarrhalis previously was found to enhance pulmonary clearance of M. catarrhalisin an animal model (M. Helminen, I. Maciver, J. L. Latimer, L. D. Cope, G. H. McCracken, Jr., and E. J. Hansen, Infect. Immun. 61:2003–2010, 1993). In the present study, this same MAb was shown to exert complement-dependent bactericidal activity against this pathogen in vitro. Nucleotide sequence analysis of thecopB gene from two MAb 10F3-reactive and two MAb 10F3-unreactive strains of M. catarrhalis revealed that the deduced amino acid sequences of these four CopB proteins were at least 90% identical. Comparison of the amino acid sequences of these proteins allowed localization of possible MAb 10F3 binding sites to five relatively small regions of the CopB protein from M. catarrhalis O35E. When five synthetic peptides representing these regions were tested for their ability to bind MAb 10F3 in a direct enzyme-linked immunosorbent assay system, an oligopeptide containing 26 amino acids was shown to bind this MAb. The actual binding region for MAb 10F3 was localized further through the use of overlapping decapeptides that spanned this 26-mer. A fusion protein containing the same 26-mer readily bound MAb 10F3 and was used to immunize mice. The resultant antiserum contained antibodies that reacted with the CopB protein of the homologous M. catarrhalis strain in Western blot analysis and bound to the surface of both homologous and heterologous strains of M. catarrhalis.
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Slevogt, Hortense, Bernd Schmeck, Carola Jonatat, Janine Zahlten, Wiebke Beermann, Vincent van Laak, Bastian Opitz, et al. "Moraxella catarrhalis induces inflammatory response of bronchial epithelial cells via MAPK and NF-κB activation and histone deacetylase activity reduction." American Journal of Physiology-Lung Cellular and Molecular Physiology 290, no. 5 (May 2006): L818—L826. http://dx.doi.org/10.1152/ajplung.00428.2005.
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Moraxella catarrhalis is a major cause of infectious exacerbations of chronic obstructive lung disease (COPD) and may also contribute to the pathogenesis of COPD. Little is known about M. catarrhalis-bronchial epithelium interaction. We investigated activation of M. catarrhalis infected bronchial epithelial cells and characterized the signal transduction pathways. Moreover, we tested the hypothesis that the M. catarrhalis-induced cytokine expression is regulated by acetylation of histone residues and controlled by histone deacetylase activity (HDAC). We demonstrated that M. catarrhalis induced a strong time- and dose-dependent inflammatory response in the bronchial epithelial cell line (BEAS-2B), characterized by the release of IL-8 and GM-CSF. For this cytokine liberation activation of the ERK and p38 mitogen-activated protein (MAP) kinases and transcription factor NF-κB was required. Furthermore, M. catarrhalis-infected bronchial epithelial cells showed an enhanced acetylation of histone H3 and H4 globally and at the promoter of the il8 gene. Preventing histone deacetylation by the histone deacetylase inhibitor trichostatin A augmented the M. catarrhalis-induced IL-8 response. After exposure to M. catarrhalis, we found a decrease in global histone deacetylase expression and activity. Our findings suggest that M. catarrhalis-induced activation of il8 gene transcription was caused by interference with epigenetic mechanisms regulating il8 gene accessibility. Our findings provide insight into important molecular and cellular mechanisms of M. catarrhalis-induced activation of human bronchial epithelium.
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Gutbier, Birgitt, Katja Fischer, Jan-Moritz Doehn, Carolin von Lachner, Christian Herr, Esther Klaile, Ursula Frischmann, et al. "Moraxella catarrhalisinduces an immune response in the murine lung that is independent of human CEACAM5 expression and long-term smoke exposure." American Journal of Physiology-Lung Cellular and Molecular Physiology 309, no. 3 (August 1, 2015): L250—L261. http://dx.doi.org/10.1152/ajplung.00265.2014.
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In patients with chronic obstructive pulmonary disease (COPD), Moraxella catarrhalis infection of the lower airways is associated with chronic colonization and inflammation during stable disease and acute exacerbations. Chronic smoke exposure induces chronic inflammation and impairs mucociliary clearance, thus contributing to bacterial colonization of the lower airways in COPD patients. The human-specific carcinoembryonic antigen-related cell adhesion molecule (CEACAM) 5, expressed in human airways, has been shown to contribute to epithelial colonization of CEACAM-binding pathogens. To investigate the impact of CEACAM5 expression on pulmonary M. catarrhalis colonization, we infected mice transgenic for human CEACAM5 (hCEACAM5) and wild type mice intratracheally with M. catarrhalis with or without preceding smoke exposure and analyzed bacterial colonization and local and systemic inflammation. Our results show that airway infection with M. catarrhalis accelerated acute local but not systemic inflammation, albeit independent of hCEACAM5 expression. Long-term smoke exposure alone or prior to M. catarrhalis infection did not contribute to increased local or systemic inflammation. No difference was found in pulmonary clearance of M. catarrhalis in hCEACAM5-transgenic mice compared with wild-type mice. Smoke exposure neither altered time nor extent of persistence of M. catarrhalis in the lungs of both genotypes. In conclusion, M. catarrhalis induced a local acute immune response in murine airways. Neither hCEACAM5 expression nor chronic smoke exposure nor a combination of both was sufficient as prerequisites for the establishment of chronic M. catarrhalis colonization. Our results demonstrate the difficulties in mirroring conditions of chronic airways colonization of M. catarrhalis in a murine model.
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Luke, Nicole R., Joseph A. Jurcisek, Lauren O. Bakaletz, and Anthony A. Campagnari. "Contribution of Moraxella catarrhalis Type IV Pili to Nasopharyngeal Colonization and Biofilm Formation." Infection and Immunity 75, no. 12 (October 1, 2007): 5559–64. http://dx.doi.org/10.1128/iai.00946-07.
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ABSTRACT Moraxella catarrhalis is a gram-negative mucosal pathogen of the human respiratory tract. Although little information is available regarding the initial steps of M. catarrhalis pathogenesis, this organism must be able to colonize the human mucosal surface in order to initiate an infection. Type IV pili (TFP), filamentous surface appendages primarily comprised of a single protein subunit termed pilin, play a crucial role in the initiation of disease by a wide range of bacteria. We previously identified the genes that encode the major proteins involved in the biosynthesis of M. catarrhalis TFP and determined that the TFP expressed by this organism are highly conserved and essential for natural transformation. We extended this initial study by investigating the contribution of TFP to the early stages of M. catarrhalis colonization. TFP-deficient M. catarrhalis bacteria exhibit diminished adherence to eukaryotic cells in vitro. Additionally, our studies demonstrate that M. catarrhalis cells form a mature biofilm in continuous-flow chambers and that biofilm formation is enhanced by TFP expression. The potential role of TFP in colonization by M. catarrhalis was further investigated using in vivo studies comparing the abilities of wild-type M. catarrhalis and an isogenic TFP mutant to colonize the nasopharynx of the chinchilla. These results suggest that the expression of TFP contributes to mucosal airway colonization. Furthermore, these data indicate that the chinchilla model of nasopharyngeal colonization provides an effective animal system for studying the early steps of M. catarrhalis pathogenesis.
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Attia, Ahmed S., Jennifer L. Sedillo, Wei Wang, Wei Liu, Chad A. Brautigam, Wade Winkler, and Eric J. Hansen. "Moraxella catarrhalis Expresses an Unusual Hfq Protein." Infection and Immunity 76, no. 6 (March 24, 2008): 2520–30. http://dx.doi.org/10.1128/iai.01652-07.
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ABSTRACT The Hfq protein is recognized as a global regulatory molecule that facilitates certain RNA-RNA interactions in bacteria. BLAST analysis identified a 630-nucleotide open reading frame in the genome of Moraxella catarrhalis ATCC 43617 that was highly conserved among M. catarrhalis strains and which encoded a predicted protein with significant homology to the Hfq protein of Escherichia coli. This protein, containing 210 amino acids, was more than twice as large as the Hfq proteins previously described for other bacteria. The C-terminal half of the M. catarrhalis Hfq protein was very hydrophilic and contained two different types of amino acid repeats. A mutation in the M. catarrhalis hfq gene affected both the growth rate of this organism and its sensitivity to at least two different types of stress in vitro. Provision of the wild-type M. catarrhalis hfq gene in trans eliminated these phenotypic differences in the hfq mutant. This M. catarrhalis hfq mutant exhibited altered expression of some cell envelope proteins relative to the wild-type parent strain and also had a growth advantage in a continuous flow biofilm system. The presence of the wild-type M. catarrhalis hfq gene in trans in an E. coli hfq mutant fully reversed the modest growth deficiency of this E. coli mutant and partially reversed the stress sensitivity of this E. coli mutant to methyl viologen. The use of an electrophoretic mobility shift assay showed that this M. catarrhalis Hfq protein could bind RNA derived from a gene whose expression was altered in the M. catarrhalis hfq mutant.
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Hoopman, Todd C., Wei Wang, Chad A. Brautigam, Jennifer L. Sedillo, Thomas J. Reilly, and Eric J. Hansen. "Moraxella catarrhalis Synthesizes an Autotransporter That Is an Acid Phosphatase." Journal of Bacteriology 190, no. 4 (December 7, 2007): 1459–72. http://dx.doi.org/10.1128/jb.01688-07.
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ABSTRACT Moraxella catarrhalis O35E was shown to synthesize a 105-kDa protein that has similarity to both acid phosphatases and autotransporters. The N-terminal portion of the M. catarrhalis acid phosphatase A (MapA) was most similar (the BLAST probability score was 10−10) to bacterial class A nonspecific acid phosphatases. The central region of the MapA protein had similarity to passenger domains of other autotransporter proteins, whereas the C-terminal portion of MapA resembled the translocation domain of conventional autotransporters. Cloning and expression of the M. catarrhalis mapA gene in Escherichia coli confirmed the presence of acid phosphatase activity in the MapA protein. The MapA protein was shown to be localized to the outer membrane of M. catarrhalis and was not detected either in the soluble cytoplasmic fraction from disrupted M. catarrhalis cells or in the spent culture supernatant fluid from M. catarrhalis. Use of the predicted MapA translocation domain in a fusion construct with the passenger domain from another predicted M. catarrhalis autotransporter confirmed the translocation ability of this MapA domain. Inactivation of the mapA gene in M. catarrhalis strain O35E reduced the acid phosphatase activity expressed by this organism, and this mutation could be complemented in trans with the wild-type mapA gene. Nucleotide sequence analysis of the mapA gene from six M. catarrhalis strains showed that this protein was highly conserved among strains of this pathogen. Site-directed mutagenesis of a critical histidine residue (H233A) in the predicted active site of the acid phosphatase domain in MapA eliminated acid phosphatase activity in the recombinant MapA protein. This is the first description of an autotransporter protein that expresses acid phosphatase activity.
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Sano, Naoto, Satoshi Matsunaga, Tomonori Akiyama, Yukari Nakashima, Koji Kusaba, Zenzo Nagasawa, Shunzo Koizumi, Masaaki Goto, and Hiroshi Miyamoto. "Moraxella catarrhalis bacteraemia associated with prosthetic vascular graft infection." Journal of Medical Microbiology 59, no. 2 (February 1, 2010): 245–50. http://dx.doi.org/10.1099/jmm.0.013789-0.
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Moraxella catarrhalis, formerly called Branhamella catarrhalis, ‘Neisseria catarrhalis’ or ‘Micrococcus catarrhalis’, is a Gram-negative, aerobic diplococcus frequently found as a colonizer of the upper respiratory tract. Over the last 20–30 years, this bacterium has emerged as a genuine pathogen, and is now considered an important cause of otitis media in children and an aetiological agent in pneumonia in adults with chronic obstructive pulmonary disease. However, bacteraemia due to M. catarrhalis has rarely been reported. Presented here is a case of M. catarrhalis bacteraemia associated with prosthetic vascular graft infection along with a review of the relevant literature.
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Verduin, Cees M., Cees Hol, André Fleer, Hans van Dijk, and Alex van Belkum. "Moraxella catarrhalis: from Emerging to Established Pathogen." Clinical Microbiology Reviews 15, no. 1 (January 2002): 125–44. http://dx.doi.org/10.1128/cmr.15.1.125-144.2002.
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SUMMARY Moraxella catarrhalis (formerly known as Branhamella catarrhalis) has emerged as a significant bacterial pathogen of humans over the past two decades. During this period, microbiological and molecular diagnostic techniques have been developed and improved for M. catarrhalis, allowing the adequate determination and taxonomic positioning of this pathogen. Over the same period, studies have revealed its involvement in respiratory (e.g., sinusitis, otitis media, bronchitis, and pneumonia) and ocular infections in children and in laryngitis, bronchitis, and pneumonia in adults. The development of (molecular) epidemiological tools has enabled the national and international distribution of M. catarrhalis strains to be established, and has allowed the monitoring of nosocomial infections and the dynamics of carriage. Indeed, such monitoring has revealed an increasing number of Β-lactamase-positive M. catarrhalis isolates (now well above 90%), underscoring the pathogenic potential of this organism. Although a number of putative M. catarrhalis virulence factors have been identified and described in detail, their relationship to actual bacterial adhesion, invasion, complement resistance, etc. (and ultimately their role in infection and immunity), has been established in a only few cases. In the past 10 years, various animal models for the study of M. catarrhalis pathogenicity have been described, although not all of these models are equally suitable for the study of human infection. Techniques involving the molecular manipulation of M. catarrhalis genes and antigens are also advancing our knowledge of the host response to and pathogenesis of this bacterial species in humans, as well as providing insights into possible vaccine candidates. This review aims to outline our current knowledge of M. catarrhalis, an organism that has evolved from an emerging to a well-established human pathogen.
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Verhaegh, Suzanne J. C., Martine L. Snippe, Foster Levy, Henri A. Verbrugh, Vincent W. V. Jaddoe, Albert Hofman, Henriëtte A. Moll, Alex van Belkum, and John P. Hays. "Colonization of healthy children by Moraxella catarrhalis is characterized by genotype heterogeneity, virulence gene diversity and co-colonization with Haemophilus influenzae." Microbiology 157, no. 1 (January 1, 2011): 169–78. http://dx.doi.org/10.1099/mic.0.042929-0.
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The colonization dynamics of Moraxella catarrhalis were studied in a population comprising 1079 healthy children living in Rotterdam, The Netherlands (the Generation R Focus cohort). A total of 2751 nasal swabs were obtained during four clinic visits timed to take place at 1.5, 6, 14 and 24 months of age, yielding a total of 709 M. catarrhalis and 621 Haemophilus influenzae isolates. Between January 2004 and December 2006, approximate but regular 6-monthly cycles of colonization were observed, with peak colonization incidences occurring in the autumn/winter for M. catarrhalis, and winter/spring for H. influenzae. Co-colonization was significantly more likely than single-species colonization with either M. catarrhalis or H. influenzae, with genotypic analysis revealing no clonality for co-colonizing or single colonizers of either bacterial species. This finding is especially relevant considering the recent discovery of the importance of H. influenzae–M. catarrhalis quorum sensing in biofilm formation and host clearance. Bacterial genotype heterogeneity was maintained over the 3-year period of the study, even within this relatively localized geographical region, and there was no association of genotypes with either season or year of isolation. Furthermore, chronological and genotypic diversity in three immunologically important M. catarrhalis virulence genes (uspA1, uspA2 and hag/mid) was also observed. This study indicates that genotypic variation is a key factor contributing to the success of M. catarrhalis colonization of healthy children in the first years of life. Furthermore, variation in immunologically relevant virulence genes within colonizing populations, and even within genotypically identical M. catarrhalis isolates, may be a result of immune evasion by this pathogen. Finally, the factors facilitating M. catarrhalis and H. influenzae co-colonization need to be further investigated.
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Furano, Kristin, and Anthony A. Campagnari. "Identification of a Hemin Utilization Protein of Moraxella catarrhalis (HumA)." Infection and Immunity 72, no. 11 (November 2004): 6426–32. http://dx.doi.org/10.1128/iai.72.11.6426-6432.2004.
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ABSTRACT Moraxella catarrhalis is a major cause of acute otitis media in young children and has also been implicated as an important cause of exacerbations in adults with underlying pulmonary disease. Due to the considerable level of antibiotic resistance and the high degree of carriage rates in young children, it is likely that the incidence of M. catarrhalis infections will continue to rise. M. catarrhalis is a strict human respiratory pathogen, and this bacterium uses both transferrin and lactoferrin receptors to fulfill the essential iron requirement for survival in vivo. However, these are the only described iron acquisition systems for this organism. In this report we have demonstrated that M. catarrhalis can also utilize hemin as a sole source of iron for growth. In addition, we have identified and characterized an outer membrane protein with homology (26 to 28% similarity) to other known hemin binding and uptake proteins in related gram-negative organisms (i.e., Bordetella and Yersinia spp.). This newly described M. catarrhalis protein, termed HumA, is capable of directly binding to hemin coupled to a solid-phase matrix. M. catarrhalis HumA expressed on the surface of an Escherichia coli hemA-deficient strain (K-12 EB53) is fully capable of complementing the defect and thus restoring the ability of this strain to grow in the presence of hemin. When M. catarrhalis is grown in the presence of hemin, HumA expression is clearly increased as shown by Western blotting with polyclonal antiserum developed against a HumA peptide. In addition, growth analyses revealed that a HumA-deficient mutant of M. catarrhalis (7169::humA) is restricted for growth in the presence of hemin as the sole iron source compared to the wild-type strain. We conclude that HumA is an essential component of a hemin uptake and utilization system previously undescribed for M. catarrhalis, thus providing another mechanism of iron acquisition that may facilitate persistent colonization of the mucosal surface.
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Zaleski, Anthony, N. Karoline Scheffler, Peter Densen, Frank K. N. Lee, Anthony A. Campagnari, Bradford W. Gibson, and Michael A. Apicella. "Lipooligosaccharide Pk(Galα1-4Galβ1-4Glc) Epitope of Moraxella catarrhalis Is a Factor in Resistance to Bactericidal Activity Mediated by Normal Human Serum." Infection and Immunity 68, no. 9 (September 1, 2000): 5261–68. http://dx.doi.org/10.1128/iai.68.9.5261-5268.2000.
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ABSTRACT Moraxella catarrhalis is a respiratory pathogen responsible for acute bacterial otitis media in children and exacerbation of chronic bronchitis in adults. M. catarrhalis strains are frequently resistant to the bactericidal activity of normal human serum. In order to determine if the lipooligosaccharide (LOS) of M. catarrhalis has a role in serum resistance, the UDP-glucose-4-epimerase (galE) gene was identified, cloned, and sequenced and a deletion/insertion mutation was introduced into M. catarrhalis strain 2951. GalE enzymatic activity, measured in whole-cell lysates, was ablated inM. catarrhalis 2951 galE. Mass spectrometric analysis of LOS isolated with hot phenol-water confirmed that strain 2951 produced a type A LOS. These studies showed that the LOS from 2951galE had lost two hexose residues due to thegalE mutation and that the resultant LOS structure lacked the (Galα1-4Galβ1-4Glc) Pk epitope found onM. catarrhalis 2951. Wild-type M. catarrhalis2951 is resistant to complement-mediated serum bactericidal activity. In contrast, a greater than 2-log10-unit reduction in CFU occurred after incubation of 2951 galE in either 50 or 25% pooled human serum (PNHS), and CFU in 10% PNHS decreased by about 1 log10 unit. These studies suggest that the Pkepitope of the LOS may be an important factor in the resistance of M. catarrhalis to the complement-mediated bactericidal effect of normal human serum.
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Bootsma, H. J., H. van Dijk, J. Verhoef, A. Fleer, and F. R. Mooi. "Molecular characterization of the BRO beta-lactamase of Moraxella (Branhamella) catarrhalis." Antimicrobial Agents and Chemotherapy 40, no. 4 (April 1996): 966–72. http://dx.doi.org/10.1128/aac.40.4.966.
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A rapid increase in the prevalence of beta-lactamase-producing Moraxella (Branhamella) catarrhalis strains has been noticed during the last decades. Today, more than 80% of strains isolated worldwide produce beta-lactamase. To investigate beta-lactamase(s) of M. catarrhalis at the molecular level, the BRO-1 beta-lactamase gene (bla) was isolated as part of a 4,223-bp HindIII fragment. Sequence analysis indicated that bla encodes a polypeptide of 314 amino acid residues. Insertional inactivation of bla in M. catarrhalis resulted in complete abrogation of beta-lactamase production and ampicillin resistance, demonstrating that bla is solely responsible for beta-lactam resistance. Comparison with other beta-lactamases suggested that M. catarrhalis beta-lactamase is a unique enzyme with conserved residues at the active sites. The presence of a signal sequence for lipoproteins suggested that it is lipid modified at its N terminus. In keeping with this assumption was the observation that 10% of beta-lactamase activity was found in the membrane compartment of M. catarrhalis. M. catarrhalis strains produce two types of beta-lactamase, BRO-1 and BRO-2, which differ in their isoelectric points. The BRO-1 and BRO-2 genes from two ATCC strains of M. catarrhalis were sequenced, and only one amino acid difference was found between the predicted products. However, there was a 21-bp deletion in the promoter region of the BRO-2 gene, possibly explaining the lower level of production of BRO-2. The G + C content of bla (31%) was significantly lower than those of the flanking genes (47 and 50%), and the overall G + C content of the M. catarrhalis genome (41%). These results indicate that bla was acquired by horizontal gene transfer from another, still unknown species.
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Luke, Nicole R., Amy J. Howlett, Jianqiang Shao, and Anthony A. Campagnari. "Expression of Type IV Pili by Moraxella catarrhalis Is Essential for Natural Competence and Is Affected by Iron Limitation." Infection and Immunity 72, no. 11 (November 2004): 6262–70. http://dx.doi.org/10.1128/iai.72.11.6262-6270.2004.
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ABSTRACT Type IV pili, filamentous surface appendages primarily composed of a single protein subunit termed pilin, play a crucial role in the initiation of disease by a wide range of pathogenic bacteria. Although previous electron microscopic studies suggested that pili might be present on the surface of Moraxella catarrhalis isolates, detailed molecular and phenotypic analyses of these structures have not been reported to date. We identified and cloned the M. catarrhalis genes encoding PilA, the major pilin subunit, PilQ, the outer membrane secretin through which the pilus filament is extruded, and PilT, the NTPase that mediates pilin disassembly and retraction. To initiate investigation of the role of this surface organelle in pathogenesis, isogenic pilA, pilT, and pilQ mutants were constructed in M. catarrhalis strain 7169. Comparative analyses of the wild-type 7169 strain and three isogenic pil mutants demonstrated that M. catarrhalis expresses type IV pili that are essential for natural genetic transformation. Our studies suggest type IV pilus production by M. catarrhalis is constitutive and ubiquitous, although pilin expression was demonstrated to be iron responsive and Fur regulated. These data indicate that additional studies aimed at elucidating the prevalence and role of type IV pili in the pathogenesis and host response to M. catarrhalis infections are warranted.
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de Vries, Stefan P. W., Hester J. Bootsma, John P. Hays, and Peter W. M. Hermans. "Molecular Aspects of Moraxella catarrhalis Pathogenesis." Microbiology and Molecular Biology Reviews 73, no. 3 (September 2009): 389–406. http://dx.doi.org/10.1128/mmbr.00007-09.
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SUMMARY In recent years, Moraxella catarrhalis has established its position as an important human mucosal pathogen, no longer being regarded as just a commensal bacterium. Further, current research in the field has led to a better understanding of the molecular mechanisms involved in M. catarrhalis pathogenesis, including mechanisms associated with cellular adherence, target cell invasion, modulation of the host's immune response, and metabolism. Additionally, in order to be successful in the host, M. catarrhalis has to be able to interact and compete with the commensal flora and overcome stressful environmental conditions, such as nutrient limitation. In this review, we provide a timely overview of the current understanding of the molecular mechanisms associated with M. catarrhalis virulence and pathogenesis.
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Aiswariya, Alex, Kundoly Velayudhan Suseela, and Das Subi. "Prevalence of Moraxella catarrhalis in patients of lower respiratory tract infection with underlying risk factors." International Journal of Advances in Medicine 4, no. 2 (March 23, 2017): 442. http://dx.doi.org/10.18203/2349-3933.ijam20171038.
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Background: Moraxella catarrhalis is a Gram-negative diplococcus, commonly found as a normal flora in the human upper respiratory tract. Recently, M. catarrhalis has emerged as an important and common human respiratory tract pathogen. This study was aimed to determine the rate of isolation of M. Catarrhalis in patients attending a tertiary care hospital with lower respiratory tract infection (LRTI), antibiotic susceptibility pattern and predisposing factors responsible for their infection.Methods: A prospective study was carried out in 1001 lower respiratory specimens from patients (above 20 years’ age) with suspected LRTI. The study investigated by microscopic examination, culture and antibiotic sensitivity test according to the standard guidelines. Assessment of clinical significance of M. Catarrhalis was ascertained on the basis of preformed criteria.Results: A total of 60 clinically significant M. Catarrhalis were isolated from the 930 culture positive samples. The isolates showed maximum sensitivity to second and third generation cephalosporins (95%), azithromycin (90%) followed by amoxicillin clavulanic acid (85%). Rate of isolation was more in males (70%) and elderly people above 60 years (63.33%) were found to be more affected. Patients (58.33%) with Chronic Obstructive Pulmonary Diseases (COPD) were found to be more prone to get infection by M. Catarrhalis.Conclusions: Moraxella catarrhalis should be considered as significant lower respiratory tract pathogen especially in elderly patients with underlying risk factors like COPD.
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Ruckdeschel, Elizabeth A., Charmaine Kirkham, Alan J. Lesse, Zihua Hu, and Timothy F. Murphy. "Mining the Moraxella catarrhalis Genome: Identification of Potential Vaccine Antigens Expressed during Human Infection." Infection and Immunity 76, no. 4 (January 28, 2008): 1599–607. http://dx.doi.org/10.1128/iai.01253-07.
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ABSTRACT Moraxella catarrhalis is an important cause of respiratory infections in adults and otitis media in children. Developing an effective vaccine would reduce the morbidity, mortality, and costs associated with such infections. An unfinished genome sequence of a strain of M. catarrhalis available in the GenBank database was analyzed, and open reading frames predicted to encode potential vaccine candidates were identified. Three genes encoding proteins having molecular masses of approximately 22, 75, and 78 kDa (designated Msp [Moraxella surface proteins]) (msp22, msp75, and msp78, respectively) were determined to be conserved by competitive hybridization using a microarray, PCR, and sequencing of the genes in clinical isolates of M. catarrhalis. The genes were transcribed when M. catarrhalis was grown in vitro. These genes were amplified by PCR and cloned into Escherichia coli expression vectors. Recombinant proteins were generated and then studied using enzyme-linked immunosorbent assays with preacquisition and postclearance serum and sputum samples from 31 adults with chronic obstructive pulmonary disease (COPD) who acquired and cleared M. catarrhalis. New antibody responses to the three proteins were observed for a small proportion of the patients with COPD, indicating that these proteins were expressed during human infection. These studies indicate that the Msp22, Msp75, and Msp78 proteins, whose genes were discovered using genome mining, are highly conserved among strains, are expressed during human infection with M. catarrhalis, and represent potential vaccine antigens.
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Furano, Kristin, and Anthony A. Campagnari. "Inactivation of the Moraxella catarrhalis 7169 Ferric Uptake Regulator Increases Susceptibility to the Bactericidal Activity of Normal Human Sera." Infection and Immunity 71, no. 4 (April 2003): 1843–48. http://dx.doi.org/10.1128/iai.71.4.1843-1848.2003.
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ABSTRACT Moraxella catarrhalis is a strict human pathogen and a significant cause of respiratory disease and otitis media. In direct response to these infections, research efforts have focused primarily on the identification of potential vaccine targets. The general biology of M. catarrhalis, however, including the mechanisms utilized to survive in the human host, remains poorly understood. Previous work has demonstrated that M. catarrhalis expresses iron-repressible proteins, suggesting the presence of iron acquisition systems under the control of a ferric uptake regulator (Fur). In this study M. catarrhalis fur has been cloned and sequenced from strain 7169. A deletion-insertion mutation of 7169 fur resulted in upregulation of iron-repressible outer membrane proteins in the absence and presence of iron. This mutant strain, 7169fur1, was significantly more sensitive to the bactericidal activity of normal human serum than the resistant wild-type strain. These data suggest that constitutive expression of iron-regulated proteins may provide multiple targets for human antibodies. In addition, the 7169 fur mutant provides an important tool for further investigation of the iron acquisition mechanisms utilized by M. catarrhalis.
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Luke, Nicole R., Simon Allen, Bradford W. Gibson, and Anthony A. Campagnari. "Identification of a 3-Deoxy-d-manno-Octulosonic Acid Biosynthetic Operon in Moraxella catarrhalis and Analysis of a KdsA-Deficient Isogenic Mutant." Infection and Immunity 71, no. 11 (November 2003): 6426–34. http://dx.doi.org/10.1128/iai.71.11.6426-6434.2003.
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ABSTRACT Lipooligosaccharide (LOS), a predominant surface-exposed component of the outer membrane, has been implicated as a virulence factor in the pathogenesis of Moraxella catarrhalis infections. However, the critical steps involved in the biosynthesis and assembly of M. catarrhalis LOS currently remain undefined. In this study, we used random transposon mutagenesis to identify a 3-deoxy-d-manno-octulosonic acid (KDO) biosynthetic operon in M. catarrhalis with the gene order pyrG-kdsA-eno. The lipid A-KDO molecule serves as the acceptor onto which a variety of glycosyl transferases sequentially add the core and branch oligosaccharide extensions for the LOS molecule. KdsA, the KDO-8-phosphate synthase, catalyzes the first step of KDO biosynthesis and is an essential enzyme in gram-negative enteric bacteria for maintenance of bacterial viability. We report the construction of an isogenic M. catarrhalis kdsA mutant in strain 7169 by allelic exchange. Our data indicate that an LOS molecule consisting only of lipid A and lacking KDO glycosylation is sufficient to sustain M. catarrhalis survival in vitro. In addition, comparative growth and susceptibility assays were performed to assess the sensitivity of 7169kdsA11 compared to that of the parental strain. The results of these studies demonstrate that the native LOS molecule is an important factor in maintaining the integrity of the outer membrane and suggest that LOS is a critical component involved in the ability of M. catarrhalis to resist the bactericidal activity of human sera.
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Forsgren, Arne, Marta Brant, Mirela Karamehmedovic, and Kristian Riesbeck. "The Immunoglobulin D-Binding Protein MID from Moraxella catarrhalis Is Also an Adhesin." Infection and Immunity 71, no. 6 (June 2003): 3302–9. http://dx.doi.org/10.1128/iai.71.6.3302-3309.2003.
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ABSTRACT The Moraxella catarrhalis immunoglobulin D (IgD)-binding protein (MID) is a 200-kDa outer membrane protein displaying a unique and specific affinity for human IgD. MID is found in the majority of M. catarrhalis strains. In the present paper, we show that MID-expressing M. catarrhalis strains agglutinate human erythrocytes and bind to type II alveolar epithelial cells. In contrast, M. catarrhalis isolates with low MID expression levels and two mutants deficient in MID, but with readily detectable UspA1 expression, do not agglutinate erythrocytes and have a 50% lower adhesive capacity. To examine the adhesive part of MID, the protein was dissected into nine fragments covering the entire molecule. The truncated MID proteins were expressed in Escherichia coli, purified, and used for raising polyclonal antibodies in rabbits. Interestingly, by using recombinant fragments, we show that the hemagglutinating and adhesive part of MID is localized within the 150-amino-acid fragment MID764-913. In addition, antibodies against full-length MID, MID764-913, or a 30-amino-acid consensus sequence (MID775-804) inhibited adhesion to alveolar epithelial cells. Antibodies against UspA1, an outer membrane protein expressed in essentially all M. catarrhalis strains, also inhibited adhesion, suggesting that both MID and UspA1 are needed for optimal attachment to epithelial cells. Taken together, in addition to MID-dependent IgD binding, we have demonstrated that the outer membrane protein MID is a novel adhesin that would be a suitable target for a future vaccine against M. catarrhalis.
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Balder, Rachel, Thomas M. Krunkosky, Chi Q. Nguyen, Lacey Feezel, and Eric R. Lafontaine. "Hag Mediates Adherence of Moraxella catarrhalis to Ciliated Human Airway Cells." Infection and Immunity 77, no. 10 (August 10, 2009): 4597–608. http://dx.doi.org/10.1128/iai.00212-09.
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ABSTRACT Moraxella catarrhalis is a human pathogen causing otitis media in infants and respiratory infections in adults, particularly patients with chronic obstructive pulmonary disease. The surface protein Hag (also designated MID) has previously been shown to be a key adherence factor for several epithelial cell lines relevant to pathogenesis by M. catarrhalis, including NCIH292 lung cells, middle ear cells, and A549 type II pneumocytes. In this study, we demonstrate that Hag mediates adherence to air-liquid interface cultures of normal human bronchial epithelium (NHBE) exhibiting mucociliary activity. Immunofluorescent staining and laser scanning confocal microscopy experiments demonstrated that the M. catarrhalis wild-type isolates O35E, O12E, TTA37, V1171, and McGHS1 bind principally to ciliated NHBE cells and that their corresponding hag mutant strains no longer associate with cilia. The hag gene product of M. catarrhalis isolate O35E was expressed in the heterologous genetic background of a nonadherent Haemophilus influenzae strain, and quantitative assays revealed that the adherence of these recombinant bacteria to NHBE cultures was increased 27-fold. These experiments conclusively demonstrate that the hag gene product is responsible for the previously unidentified tropism of M. catarrhalis for ciliated NHBE cells.
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Gao, Song, Dabin Ren, Daxin Peng, Wenhong Zhang, Artur Muszyński, Russell W. Carlson, and Xin-Xing Gu. "Late acyltransferase genes lpxX and lpxL jointly contribute to the biological activities of Moraxella catarrhalis." Journal of Medical Microbiology 62, no. 6 (June 1, 2013): 807–12. http://dx.doi.org/10.1099/jmm.0.056846-0.
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Lipo-oligosaccharide (LOS) is a major surface component and virulence factor of the human respiratory pathogen Moraxella catarrhalis. Two late acyltransferase genes, lpxX and lpxL, have been identified involved in the incorporation of acyloxyacyl-linked secondary acyl chains into lipid A during M. catarrhalis LOS biosynthesis. In this study, a double mutant with a deletion of both the lpxX and lpxL genes in M. catarrhalis strain O35E was constructed and named O35ElpxXL. Structural analysis of lipid A showed that the O35ElpxXL mutant lacked two decanoic acids (10 : 0) and one dodecanoic (lauric) acid (12 : 0). In comparison with the O35E parental strain and the single mutants O35ElpxX and O35ElpxL, the double mutant O35ElpxXL displayed prominently decreased endotoxin content, reduced resistance to normal human serum and accelerated bacterial clearance at 0, 3 and 6 h after an aerosol challenge in a mouse model of bacterial pulmonary clearance. These results indicate that these two genes encoding late acyltransferases responsible for lipid A biosynthesis jointly contribute to the biological activities and pathogenicity of M. catarrhalis. The double mutant O35ElpxXL with dramatically reduced toxicity is proposed as a potential vaccine candidate against M. catarrhalis infections for further investigation.
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Ndiaye, Aissatou Geuye, Cheikh Saadbou Boye, Edwige Hounkponou, Fatou Bintou Gueye, and Aida Badiane. "Antimicrobial susceptibility of select respiratory tract pathogens in Dakar, Senegal." Journal of Infection in Developing Countries 3, no. 09 (October 22, 2009): 660–66. http://dx.doi.org/10.3855/jidc.20.
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Background : Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pyogenes, and Streptococcus pneumoniae are the most common causative agents of respiratory tract infections (RTIs). The increase in resistance to current antibacterial agents highlights the need to monitor the resistance pattern of these bacterial pathogens. Methodology: In this study, we assessed the antibacterial susceptibility of these pathogens causing respiratory tract infections in Dakar, Senegal, during 2007-2008. A total of 290 bacterial isolates (75 H. influenzae, 10 M. catarrhalis, 105 S. pneumoniae, and 100 S. pyogenes) were collected. Results and Conclusions: All H. influenzae isolates were susceptible to amoxicillin/clavulanic acid, ofloxacin, clarithromycin, cephalosporins, and macrolides. Overall, 26.7% of H. influenzae isolates were completely resistant to ampicillin. Among the M. catarrhalis isolates, 30% were resistant to ampicillin. All the isolates of H. influenzae and M. catarrhalis that were resistant to ampicillin were beta-lactamase producing strains. Among the S. pneumoniae isolates, 33.3% isolates exhibited intermediate susceptibility to penicillin G, and one isolate was completely resistant. All five isolates that were resistant to erythromycin expressed the M phenotype. S. pyogenes exhibited high susceptibility to all other antibiotics, except tetracycline. Our study suggests that except for M. catarrhalis, all other bacterial isolates are susceptible to cephalosporins, macrolides, and fluroquinolones.
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Luke, Nicole R., Thomas A. Russo, Neal Luther, and Anthony A. Campagnari. "Use of an Isogenic Mutant Constructed inMoraxella catarrhalis To Identify a Protective Epitope of Outer Membrane Protein B1 Defined by Monoclonal Antibody 11C6." Infection and Immunity 67, no. 2 (February 1, 1999): 681–87. http://dx.doi.org/10.1128/iai.67.2.681-687.1999.
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ABSTRACT Moraxella catarrhalis-induced otitis media continues to be a significant cause of infection in young children, prompting increased efforts at identifying effective vaccine antigens. We have previously demonstrated that M. catarrhalis expresses specific outer membrane proteins (OMPs) in response to iron limitation and that this organism can utilize transferrin and lactoferrin for in vitro growth. One of these proteins, which binds human transferrin, is OMP B1. As the human host presents a naturally iron-limited environment, proteins, like OMP B1, which are expressed in response to this nutritional stress are potential vaccine antigens. In this study, we have developed monoclonal antibody (MAb) 11C6, which reacts to a surface-exposed epitope of OMP B1 expressed by M. catarrhalis 7169. This antibody was used to cloneompB1, and sequence analysis suggested that OMP B1 is theM. catarrhalis homologue to the transferrin binding protein B described for pathogenic Neisseriaceae, Haemophilus influenzae, Actinobacillus pleuropneumoniae, andM. catarrhalis. Expression of recombinant OMP B1 on the surface of Escherichia coli confers transferrin binding activity, confirming that this protein is likely involved in iron acquisition. In addition, ompB1 was used to construct an isogenic mutant in M. catarrhalis 7169. This mutant, termed 7169b12, was used as the control in bactericidal assays designed to determine if OMP B1 elicits protective antibodies. In the presence of MAb 11C6 and human complement, wild-type 7169 demonstrated a 99% decline in viability, whereas the ompB1 isogenic mutant was resistant to this bactericidal activity. Further analysis with MAb 11C6 revealed the presence of this OMP B1 epitope on 31% of the clinical isolates tested. These data suggest that OMP B1 is a potential vaccine antigen against M. catarrhalis infections.
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Yano, Hisakazu, Mitsuko Suetake, Akio Kuga, Kazuhiko Irinoda, Ryoichi Okamoto, Toshimitsu Kobayashi, and Matsuhisa Inoue. "Pulsed-Field Gel Electrophoresis Analysis of Nasopharyngeal Flora in Children Attending a Day Care Center." Journal of Clinical Microbiology 38, no. 2 (2000): 625–29. http://dx.doi.org/10.1128/jcm.38.2.625-629.2000.
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To investigate how bacterial pathogens spread from child to child in a day care center, we monitored six children, two boys and four girls, born between August 1995 and November 1997, attending a day care center and analyzed nasopharyngeal samples from them using pulsed-field gel electrophoresis (PFGE). We obtained nasopharyngeal cultures from all of the affected children and almost all of the unaffected children between September 1998 and March 1999 after some children presented simultaneously with purulent rhinorrhea. Moreover, when a child was found to have acute otitis media, nasopharyngeal secretions from the child were independently cultured during treatment. During this period, 28 isolates of Moraxella catarrhalis, 13 ofStreptococcus pneumoniae, and 4 of Haemophilus influenzae were recovered. PFGE gave 8 patterns for M. catarrhalis, 10 for S. pneumoniae, and 1 for H. influenzae. PFGE patterns demonstrated spread of M. catarrhalis between children. However, each occurrence of clusters of infection with M. catarrhalis lasted 2 to 6 weeks, with a change in PFGE pattern between occurrences of clusters. The M. catarrhalis strain infecting each child also changed. Similarly, the S. pneumoniae strain in each child also changed. In contrast, infection with H. influenzaepersisted for about 3 months in an affected child.
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Шмыленко, Влада, Vlada Shmylenko, Альбина Бондаренко, Albina Bondarenko, Ольга Троценко, Olga Trotsenko, Вячеслав Туркутюков, and Vyacheslav Turkutyukov. "FREQUENCY OF DETECTION OF MORAXELLA CATARRHALIS IN CHILDREN WITH A RECURRENT COURSE OF RESPIRATORY DISEASES IN KHABAROVSK CITY DURING 2016-2017." Bulletin physiology and pathology of respiration 1, no. 68 (June 7, 2018): 52–56. http://dx.doi.org/10.12737/article_5b18b82fc43524.59761242.
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The aim of the study was to evaluate the Moraxella catarrhalis nasopharyngeal carriage prevalence in children of different age groups with a recurrent course of respiratory diseases and perform a comparative analysis of bacterial carriage levels as well as peculiarities of within-year distribution of nasopharyngeal carriage in 2016-2017 years. Bacteriological assessment was performed for 1769 children aged 0 to 14 years old including 1082 children examined in 2016 and 687 children examined in 2017. During the two years of observation the average level of M. catarrhalis carriage for the entire study group was equal to 11.5±0.76%. Nasopharyngeal carriage was detected in children of all age groups with the lowest index in children of 7-14 years (4.1±1.03%) and highest levels of bacterial carriage in children of 2-6 years old (13.8±0.98%). Similarities in distribution of M. catarrhalis nasopharyngeal carriage levels in susceptible age groups were detected during 2016 and 2017 years. The analysis of M. catarrhalis carriage levels dynamics revealed within-year undulation of the index – low levels were detected in February and July and high levels in October and November. The research revealed statistically significant and profound concordance of within-year distribution of M. catarrhalis carriage levels in children during 2016 and 2017 years.
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Murphy, Timothy F., Aimee L. Brauer, Christoph Aebi, and Sanjay Sethi. "Antigenic Specificity of the Mucosal Antibody Response to Moraxella catarrhalis in Chronic Obstructive Pulmonary Disease." Infection and Immunity 73, no. 12 (December 2005): 8161–66. http://dx.doi.org/10.1128/iai.73.12.8161-8166.2005.
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ABSTRACT Moraxella catarrhalis is an important human mucosal pathogen causing otitis media in children and lower respiratory tract infection in adults with chronic obstructive pulmonary disease (COPD). Little is known about the mucosal antibody response to M. catarrhalis in adults with COPD. In this study, 10 pairs of well-characterized sputum supernatant samples from adults with COPD who had acquired and subsequently cleared M. catarrhalis from their respiratory tracts were studied in detail in an effort to begin to elucidate potentially protective immune responses. Flow cytometry analysis was used to study the distribution of immunoglobulin isotypes in paired preacquisition and postclearance sputum samples. The results showed that immunoglobulin A (IgA) is the predominant M. catarrhalis-specific immunoglobulin isotype and that the sputum IgA contains a secretory component, indicating that it is locally produced at the mucosal site. Most patients made new sputum IgA responses to the adhesins UspA1 and Hag, along with the surface protein UspA2. A smaller proportion of patients made new sputum IgA responses to the iron-regulated proteins TbpB and CopB and to lipooligosaccharide. These results have important implications in understanding the mucosal immune response to M. catarrhalis in the setting of COPD and in elucidating the elements of a protective immune response.
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Hu, Wei-Gang, Jing Chen, James F. Battey, and Xin-Xing Gu. "Enhancement of Clearance of Bacteria from Murine Lungs by Immunization with Detoxified Lipooligosaccharide fromMoraxella catarrhalis Conjugated to Proteins." Infection and Immunity 68, no. 9 (September 1, 2000): 4980–85. http://dx.doi.org/10.1128/iai.68.9.4980-4985.2000.
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ABSTRACT Moraxella catarrhalis strain 25238 detoxified lipooligosaccharide (dLOS)-protein conjugates induced a significant rise of bactericidal anti-LOS antibodies in animals. This study reports the effect of active or passive immunization with the conjugates or their antiserum on pulmonary clearance of M. catarrhalis in an aerosol challenge mouse model. Mice were injected subcutaneously with dLOS-tetanus toxoid (dLOS-TT), dLOS–high-molecular-weight proteins (dLOS-HMP) from nontypeable Haemophilus influenzae(NTHi), or nonconjugated materials in Ribi adjuvant and then challenged with M. catarrhalis strain 25238 or O35E or NTHi strain 12. Immunization with dLOS-TT or dLOS-HMP generated a significant rise of serum anti-LOS immunoglobulin G and 68% and 35 to 41% reductions of bacteria in lungs compared with the control (P < 0.01) following challenge with homologous strain 25238 and heterologous strain O35E, respectively. Serum anti-LOS antibody levels correlated with its bactericidal titers against M. catarrhalis and bacterial CFU in lungs. Additionally, immunization with dLOS-HMP generated a 54% reduction of NTHi strain 12 compared with the control (P < 0.01). Passive immunization with a rabbit antiserum against dLOS-TT conferred a significant reduction of strain 25238 CFU in lungs in a dose- and time-dependent pattern compared with preimmune serum-treated mice. Kinetic examination of lung tissue sections demonstrated that antiserum-treated mice initiated and offset inflammatory responses more rapidly than preimmune serum-treated mice. These data indicate that LOS antibodies (whether active or passive) play a major role in the enhancement of pulmonary clearance of different test strains of M. catarrhalis in mice. In addition, dLOS-HMP is a potential candidate for a bivalent vaccine against M. catarrhalis and NTHi infections.
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Luke, Nicole R., Richard J. Karalus, and Anthony A. Campagnari. "Inactivation of the Moraxella catarrhalis Superoxide Dismutase SodA Induces Constitutive Expression of Iron-Repressible Outer Membrane Proteins." Infection and Immunity 70, no. 4 (April 2002): 1889–95. http://dx.doi.org/10.1128/iai.70.4.1889-1895.2002.
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ABSTRACT Many pathogens produce one or more superoxide dismutases (SODs), enzymes involved in the detoxification of endogenous and exogenous reactive oxygen species that are encountered during the infection process. One detectable cytoplasmic SOD was identified in the human mucosal pathogen Moraxella catarrhalis, and the gene responsible for the SOD activity, sodA, was isolated from a recent pediatric clinical isolate (strain 7169). Sequence analysis of the cloned M. catarrhalis 7169 DNA fragment revealed an open reading frame of 618 bp encoding a polypeptide of 205 amino acids with 48 to 67% identity to known bacterial manganese-cofactored SODs. An isogenic M. catarrhalis sodA mutant was constructed in strain 7169 by allelic exchange. In contrast to the wild-type 7169, the 7169::sodK20 mutant was severely attenuated for aerobic growth, even in rich medium containing supplemental amino acids, and exhibited extreme sensitivity to the redox-active agent methyl viologen. The ability of recombinant SodA to rescue the aerobic growth defects of E. coli QC774, a sodA sodB-deficient mutant, demonstrated the functional expression of SOD activity by cloned M. catarrhalis sodA. Indirect SOD detection assays were used to visualize both native and recombinant SodA activity in bacterial lysates. This study demonstrates that M. catarrhalis SodA plays a critical role in the detoxification of endogenous, metabolically produced oxygen radicals. In addition, the outer membrane protein (OMP) profile of 7169::sodK20 was consistent with iron starvation in spite of growth under iron-replete conditions. This novel observation indicates that M. catarrhalis strains lacking SodA constitutively express immunogenic OMPs previously described as iron repressible, and this potentially attenuated mutant strain may be an attractive vaccine candidate.
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Faden, Howard, Jung J. Hong, and Nickesh Pahade. "Immune Response to Moraxella Catarrhalis in Children with Otitis Media: Opsonophagocytosis with Antigen-Coated Latex Beads." Annals of Otology, Rhinology & Laryngology 103, no. 7 (July 1994): 522–24. http://dx.doi.org/10.1177/000348949410300704.
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Opsonic antibody activity against Moraxella catarrhalis was determined in sera from children with otitis media. The antibody was determined with a new assay utilizing outer membrane antigen-coated latex beads. Antigen-coated beads opsonized in heat-inactivated pooled human serum phagocytosed 47.5 ± 36.1 beads per 100 neutrophils compared to 15.6 ± 10.2 beads per 100 neutrophils opsonized in hypogammaglobulinemic serum (p < .025). Antigen-coated beads opsonized in homologous sera from 11 children with M catarrhalis otitis media demonstrated increased opsonic activity in convalescent sera (34.6 ± 27.1) compared to acute sera (15.5 ± 6.7;p< .05). These data suggest that infection with M catarrhalis is associated with the development of opsonic antibody.
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Liu, Dai-Fang, John C. McMichael, and Steven M. Baker. "Moraxella catarrhalis Outer Membrane Protein CD Elicits Antibodies That Inhibit CD Binding to Human Mucin and Enhance Pulmonary Clearance of M. catarrhalis in a Mouse Model." Infection and Immunity 75, no. 6 (April 2, 2007): 2818–25. http://dx.doi.org/10.1128/iai.00074-07.
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ABSTRACT The outer membrane protein CD of Moraxella catarrhalis is considered to be a potential vaccine antigen against Moraxella infection. We purified the native CD from isolate O35E, administered it to mice, and detected considerable titers of anti-CD antibodies. Anti-CD sera were cross-reactive towards six different M. catarrhalis isolates and promoted bacterial clearance of O35E in a pulmonary challenge model. To circumvent the difficulty of generating large quantities of CD from M. catarrhalis for vaccine use, the CD gene from O35E was cloned into Escherichia coli, and the recombinant CD, expressed without a signal sequence or fusion tags, represented ∼70% of the total E. coli proteins. The recombinant CD formed inclusion bodies that were solubilized with 6 M urea and then purified by ion-exchange chromatography, a procedure that produced soluble CD of high purity and yield. Mice immunized with the purified recombinant CD had significant titers of anti-CD antibodies that were cross-reactive towards 24 different M. catarrhalis isolates. Upon challenge, these mice showed enhanced bacterial clearance of both O35E and a heterologous M. catarrhalis isolate, TTA24. In an in vitro assay, antisera to either the native or the recombinant CD inhibited the binding activity of CD to human tracheobronchial mucin in a serum concentration-dependent manner, and the extent of inhibition appeared to correlate with the corresponding anti-CD antibody titer and whole-cell enzyme-linked immunosorbent assay titer. Our results demonstrate that the recombinant CD is a promising vaccine candidate for preventing Moraxella infection.
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Murphy, Timothy F., Aimee L. Brauer, Norine Yuskiw, Erin R. McNamara, and Charmaine Kirkham. "Conservation of Outer Membrane Protein E among Strains of Moraxella catarrhalis." Infection and Immunity 69, no. 6 (June 1, 2001): 3576–80. http://dx.doi.org/10.1128/iai.69.6.3576-3580.2001.
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ABSTRACT Outer membrane protein E (OMP E) is a 50-kDa protein ofMoraxella catarrhalis which has several features that suggest that the protein may be an effective vaccine antigen. To assess the conservation of OMP E among strains of M. catarrhalis,22 isolates were studied with eight monoclonal antibodies which recognize epitopes on different regions of the protein. Eighteen of 22 strains were reactive with all eight antibodies. The sequences ofompE from 16 strains of M. catarrhalis were determined, including the 4 strains which were nonreactive with selected monoclonal antibodies. Analysis of sequences indicate a high degree of conservation among strains, with sequence differences clustered in limited regions of the gene. To assess the stability ofompE during colonization of the human respiratory tract, the sequences of ompE of isolates collected from patients colonized with the same strain for 3 to 9 months were determined. The sequences remained unchanged. These results indicate that OMP E is highly conserved among strains of M. catarrhalis, and preliminary studies indicate that the gene which encodes OMP E remains stable during colonization of the human respiratory tract.
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Wang, Wei, Larry Reitzer, David A. Rasko, Melanie M. Pearson, Robert J. Blick, Cassie Laurence, and Eric J. Hansen. "Metabolic Analysis of Moraxella catarrhalis and the Effect of Selected In Vitro Growth Conditions on Global Gene Expression." Infection and Immunity 75, no. 10 (July 9, 2007): 4959–71. http://dx.doi.org/10.1128/iai.00073-07.
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ABSTRACT The nucleotide sequence from the genome of Moraxella catarrhalis ATCC 43617 was annotated and used both to assess the metabolic capabilities and limitations of this bacterium and to design probes for a DNA microarray. An absence of gene products for utilization of exogenous carbohydrates was noteworthy and could be correlated with published phenotypic data. Gene products necessary for aerobic energy generation were present, as were a few gene products generally ascribed to anaerobic systems. Enzymes for synthesis of all amino acids except proline and arginine were present. M. catarrhalis DNA microarrays containing 70-mer oligonucleotide probes were designed from the genome-derived nucleotide sequence data. Analysis of total RNA extracted from M. catarrhalis ATCC 43617 cells grown under iron-replete and iron-restricted conditions was used to establish the utility of these DNA microarrays. These DNA microarrays were then used to analyze total RNA from M. catarrhalis cells grown in a continuous-flow biofilm system and in the planktonic state. The genes whose expression was most dramatically increased by growth in the biofilm state included those encoding a nitrate reductase, a nitrite reductase, and a nitric oxide reductase. Real-time reverse transcriptase PCR analysis was used to validate these DNA microarray results. These results indicate that growth of M. catarrhalis in a biofilm results in increased expression of gene products which can function not only in energy generation but also in resisting certain elements of the innate immune response.
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Lafontaine, Eric R., David Wall, Serena L. Vanlerberg, Haig Donabedian, and Darren D. Sledjeski. "Moraxella catarrhalis Coaggregates with Streptococcus pyogenes and Modulates Interactions of S. pyogenes with Human Epithelial Cells." Infection and Immunity 72, no. 11 (November 2004): 6689–93. http://dx.doi.org/10.1128/iai.72.11.6689-6693.2004.
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ABSTRACT The pathogens Streptococcus pyogenes and Moraxella catarrhalis colonize overlapping regions of the human nasopharynx. We have found that M. catarrhalis can dramatically increase S. pyogenes adherence to human epithelial cells and that species-specific coaggregation of these bacteria correlates with this enhanced adherence.
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Easton, Donna M., Elke Maier, Roland Benz, A. Ruth Foxwell, Allan W. Cripps, and Jennelle M. Kyd. "Moraxella catarrhalis M35 Is a General Porin That Is Important for Growth under Nutrient-Limiting Conditions and in the Nasopharynges of Mice." Journal of Bacteriology 190, no. 24 (October 17, 2008): 7994–8002. http://dx.doi.org/10.1128/jb.01039-08.
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ABSTRACT Moraxella catarrhalis is a gram-negative respiratory pathogen that is an important causative agent for otitis media and exacerbations of chronic obstructive pulmonary disease. We have previously predicted the outer membrane protein M35 to be a general porin, and in the current study, we have investigated the function of M35 and its importance for survival of M. catarrhalis in vivo. Lipid bilayer experiments reveal that refolded M35 functions as a channel that is typical of gram-negative bacterial porins. M35 forms wide and water-filled channels with a single-channel conductance of about 1.25 nS in 1 M KCl solution and has only a small selectivity for cations over anions. When the in vitro growth characteristics of two M35 deletion mutant strains of M. catarrhalis were compared to the wild-type parent isolates, the growth of the mutant strains was inhibited only under nutrient-poor conditions. This growth defect could be eliminated by additional glutamic acid, but not additional aspartic acid, glycine, sucrose, or glucose. The mutant strains compensated for the lack of M35 by enhancing their uptake of glutamic acid, and this enhanced rate of glutamic acid uptake was attributed to the compensatory upregulation of a protein of approximately 40 kDa. M35 was also found to be essential for nasal colonization of mice, demonstrating that its presence is essential for survival of M. catarrhalis in vivo. These results suggest that M35 is a general porin that is necessary for the uptake of important energy sources by M. catarrhalis and that it is likely that M35 is an essential functional protein for in vivo colonization.
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Hu, Wei-Gang, Jing Chen, John C. McMichael, and Xin-Xing Gu. "Functional Characteristics of a Protective Monoclonal Antibody against Serotype A and C Lipooligosaccharides from Moraxella catarrhalis." Infection and Immunity 69, no. 3 (March 1, 2001): 1358–63. http://dx.doi.org/10.1128/iai.69.3.1358-1363.2001.
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ABSTRACT A monoclonal antibody (MAb), designated MAb 8E7 (immunoglobulin G3), specific for Moraxella catarrhalislipooligosaccharide (LOS) was evaluated for its functional activity in vitro and in a mouse model of colonization. Enzyme-linked immunosorbent assay (ELISA) demonstrated that the MAb 8E7 could be prepared to a high titer against LOS of the homologous strain 035E, and that it had bactericidal activity. MAb 8E7 reacted with M. catarrhalisserotype A and C LOSs but not serotype B LOS, as measured by ELISA and Western blotting. On the basis of published structures of LOSs, this suggests that the epitope recognized by MAb 8E7 is directed to a common sequence of either α-GlcNAc-(1→2)-β-Glc-(1→ at the branch substituting position 4 of the trisubstituted Glc residue or a terminal tetrasaccharide α-Gal-(1→4)-β-Gal-(1→4)-α-Glc-(1→2)-β-Glc-(1→ at the branch substituting position 6 of the trisubstituted Glc residue. In a whole-cell ELISA, MAb 8E7 reacted with 70% of the 30 wild-type strains and clinical isolates tested. Immuno-electron microscopy demonstrated that MAb 8E7 reacted with a cell surface-exposed epitope of LOS on strain O35E. MAb 8E7 inhibited the adherence of strain O35E to Chang conjunctival epithelial cells by 90%. Passive immunization with MAb 8E7 could significantly enhance the clearance of strain O35E from mouse lungs in an aerosol challenge mouse model. This enhanced bacterial clearance was inhibited when MAb 8E7 was absorbed by M. catarrhalis serotype A LOS, indicating that the M. catarrhalis LOS-directed antibody may play a major role in the enhancement of M. catarrhalis clearance from lungs. These data suggest that MAb 8E7, which recognizes surface-exposed LOS of M. catarrhalis, is a protective antibody against M. catarrhalis.
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Myers, Lisa E., Yan-ping Yang, Run-pan Du, Qijun Wang, Robin E. Harkness, Anthony B. Schryvers, Michel H. Klein, and Sheena M. Loosmore. "The Transferrin Binding Protein B of Moraxella catarrhalis Elicits Bactericidal Antibodies and Is a Potential Vaccine Antigen." Infection and Immunity 66, no. 9 (September 1, 1998): 4183–92. http://dx.doi.org/10.1128/iai.66.9.4183-4192.1998.
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ABSTRACT The transferrin binding protein genes (tbpA andtbpB) from two strains of Moraxella catarrhalis have been cloned and sequenced. The genomic organization of the M. catarrhalistransferrin binding protein genes is unique among known bacteria in that tbpA precedes tbpB and there is a third gene located between them. The deduced sequences of the M. catarrhalis TbpA proteins from two strains were 98% identical, while those of the TbpB proteins from the same strains were 63% identical and 70% similar. The third gene, tentatively called orf3, encodes a protein of approximately 58 kDa that is 98% identical between the two strains. The tbpB genes from four additional strains ofM. catarrhalis were cloned and sequenced, and two potential families of TbpB proteins were identified based on sequence similarities. Recombinant TbpA (rTbpA), rTbpB, and rORF3 proteins were expressed in Escherichia coli and purified. rTbpB was shown to retain its ability to bind human transferrin after transfer to a membrane, but neither rTbpA nor rORF3 did. Monospecific anti-rTbpA and anti-rTbpB antibodies were generated and used for immunoblot analysis, which demonstrated that epitopes of M. catarrhalis TbpA and TbpB were antigenically conserved and that there was constitutive expression of the tbp genes. In the absence of an appropriate animal model, anti-rTbpA and anti-rTbpB antibodies were tested for their bactericidal activities. The anti-rTbpA antiserum was not bactericidal, but anti-rTbpB antisera were found to kill heterologous strains within the same family. Thus, if bactericidal ability is clinically relevant, a vaccine comprising multiple rTbpB antigens may protect against M. catarrhalis disease.
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Gao, Ya, Jumin Lee, Göran Widmalm, and Wonpil Im. "Preferred conformations of lipooligosaccharides and oligosaccharides of Moraxella catarrhalis." Glycobiology 30, no. 2 (October 16, 2019): 86–94. http://dx.doi.org/10.1093/glycob/cwz086.
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Abstract Moraxella catarrhalis (M. catarrhalis) is a pathogenic gram-negative bacterium that causes otitis media and sinusitis in children. Three major serotypes A, B and C are identified to account for approximately 95% of the clinical isolates. Understanding the conformational properties of different serotypes of M. catarrhalis provides insights into antigenic determinants. In this work, all-atom molecular dynamics simulations were conducted for M. catarrhalis lipooligosaccharide (LOS) bilayer systems and oligosaccharides (OS) in water solution to investigate the conformational similarities and differences of three serotypes. For up to 10 neutral monosaccharides in the core part, the conformational ensembles described by the pair-wise root mean square deviation distributions are similar among the three serotypes of either the LOS or OS. At the central β-($1\to4$)-linkage, anti-$\psi$ conformation in conjunction with the gauche-gauche (g−) conformation of the central trisubstituted glucosyl residue is observed as the dominant conformation to sustain the structural characteristics of M. catarrhalis three types, which is further supported by calculated transglycosidic ${}^3{J}_{C,H}\Big({\psi}_H\Big)$ of serotype A in comparison to experimental data. Interestingly, the conformational variability of three serotypes is more restricted for the OS in water solution than that in the LOS bilayer systems. The LOS–LOS interactions in the bilayer systems are responsible for the increased conformational diversity despite of tight packing. Solvent-accessible surface area analysis suggests that a trisaccharide attached to the β-($1\to 6$)-linked sugar in all three serotypes of LOS could be the common epitope and have the possibility to interact with antibodies.
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Schwingel, Johanna M., Katie J. Edwards, Andrew D. Cox, Hussein Masoud, James C. Richards, Frank St. Michael, Carmen D. Tekwe, Sanjay Sethi, Timothy F. Murphy, and Anthony A. Campagnari. "Use of Moraxella catarrhalis Lipooligosaccharide Mutants To Identify Specific Oligosaccharide Epitopes Recognized by Human Serum Antibodies." Infection and Immunity 77, no. 10 (August 3, 2009): 4548–58. http://dx.doi.org/10.1128/iai.00294-09.
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ABSTRACT Moraxella catarrhalis is a causative agent of otitis media in children and lower respiratory tract infections in adults suffering from chronic obstructive pulmonary disease (COPD). This strict human pathogen continues to be a significant cause of disease in this broad spectrum of patients because there is no available vaccine. Although numerous putative vaccine antigens have been described, little is known about the human immune response to M. catarrhalis infection in vivo. Human serum antibodies are directed at a number of surface proteins, and lipooligosaccharides (LOS) and detoxified LOS may be an effective immunogen in mice. In this study, we used a specific LOS-based enzyme-linked immunosorbent assay (ELISA), containing the three major M. catarrhalis serotypes together with a complete series of truncated LOS mutants, to detect the development of new antibodies to specific regions of the oligosaccharide molecule. We compared serum samples from COPD patients who had recently cleared an M. catarrhalis infection to serum samples collected prior to their infection. Variability in the antibody response to LOS was observed, as some patients developed serotype-specific antibodies, others developed antibodies to the LOS of each serotype, others developed broadly cross-reactive antibodies, and some did not develop new antibodies. These newly developed human antibodies are directed at both side chains and core structures in the LOS molecule. This LOS-based ELISA can be used to dissect the human antibody response to both internal and external carbohydrate epitopes, thus providing a better understanding of the humoral immune response to M. catarrhalis LOS epitopes developed during natural infection.
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Pearson, Melanie M., Cassie A. Laurence, Sarah E. Guinn, and Eric J. Hansen. "Biofilm Formation by Moraxella catarrhalis In Vitro: Roles of the UspA1 Adhesin and the Hag Hemagglutinin." Infection and Immunity 74, no. 3 (March 2006): 1588–96. http://dx.doi.org/10.1128/iai.74.3.1588-1596.2006.
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ABSTRACT Mutant analysis was used to identify Moraxella catarrhalis gene products necessary for biofilm development in a crystal violet-based assay involving 24-well tissue culture plates. The wild-type M. catarrhalis strains that formed the most extensive biofilms in this system proved to be refractory to transposon mutagenesis, so an M. catarrhalis strain was constructed that was both able to form biofilms in vitro and amenable to transposon mutagenesis. Chromosomal DNA from the biofilm-positive strain O46E was used to transform the biofilm-negative strain O35E; transformants able to form biofilms were identified and subjected to transposon-mediated mutagenesis. Biofilm-negative mutants of these transformants were shown to have a transposon insertion in the uspA1 gene. Nucleotide sequence analysis revealed that the biofilm-positive transformant T14 contained a hybrid O46E-O35E uspA1 gene, with the N-terminal 155 amino acids being derived from the O46E UspA1 protein. Transformant T14 was also shown to be unable to express the Hag protein, which normally extends from the surface of the M. catarrhalis cell. Introduction of a wild-type O35E hag gene into T14 eliminated its ability to form a biofilm. When the hybrid O46E-O35E uspA1 gene from T14 was used to replace the uspA1 gene of O35E, this transformant strain did not form a biofilm. However, inactivation of the hag gene did allow biofilm formation by strain O35E expressing the hybrid O46E-O35E uspA1 gene product. The Hag protein was shown to have an inhibitory or negative effect on biofilm formation by these M. catarrhalis strains in the crystal violet-based assay.
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Riesbeck, Kristian, Thuan Tong Tan, and Arne Forsgren. "MID and UspA1/A2 of the human respiratory pathogen Moraxella catarrhalis, and interactions with the human host as basis for vaccine development." Acta Biochimica Polonica 53, no. 3 (September 9, 2006): 445–56. http://dx.doi.org/10.18388/abp.2006_3315.
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Moraxella catarrhalis IgD-binding protein MID is a 200 kDa autotransporter protein that exists as a oligomer and is governed at the transcriptional level. The majority of M. catarrhalis clinical isolates expresses MID. Two functional domains have been attributed to MID; MID764-913 functions as an adhesin and promotes the bacteria to attach to epithelial cells, whereas the IgD-binding domain is located within MID962-1200. In parallel, MID is stimulatory for B lymphocytes through the IgD B cell receptor. M. catarrhalis ubiquitous surface proteins A1 and A2 (UspA1/A2) are multifunctional outer membrane proteins that can bind complement and extracellular matrix proteins such as vitronectin and fibronectin. An interaction between the complement fluid phase regulator of the classical pathway, C4b binding protein (C4BP), and UspA1/A2 has also been observed. Moreover, UspA1/A2 has a unique feature to interfere with the innate immune system of complement by binding C3. Taken together, a growing body of knowledge on M. catarrhalis outer membrane proteins MID and UspA1/A2 and their precise interactions with the human host make them promising vaccine candidates in a future multicomponent vaccine.
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Bullard, Brian, Serena L. Lipski, and Eric R. Lafontaine. "Hag Directly Mediates the Adherence of Moraxella catarrhalis to Human Middle Ear Cells." Infection and Immunity 73, no. 8 (August 2005): 5127–36. http://dx.doi.org/10.1128/iai.73.8.5127-5136.2005.
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ABSTRACT Moraxella catarrhalis is a human pathogen that causes otitis media in young children and lung infections in patients with chronic obstructive pulmonary disease. In this study, the role of the surface protein Hag in the adherence of multiple M. catarrhalis strains was examined. The hag genes of four clinical isolates were disrupted with a spectinomycin resistance cassette, and the binding of isogenic mutants to primary cultures of human middle ear epithelial cells (HMEE), as well as A549 pneumocytes, was measured. These experiments revealed that the attachment of most mutants to both cell types was 10-fold less than that of their wild-type progenitors. To determine whether Hag directly mediates adherence to human cells, the hag genes from three M. catarrhalis isolates were cloned and expressed in a nonadherent Escherichia coli cloning strain. At least 17-fold more E. coli bacteria expressing Hag attached to HMEE cells than an adherence-negative control. Surprisingly, Hag expression did not increase the binding of recombinant E. coli to A549 monolayers. Our data demonstrate that the involvement of Hag in M. catarrhalis adherence to A549 and HMEE cells is conserved among isolates and that Hag directly mediates binding to HMEE cells.
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Citron, Diane M., Yumi A. Warren, Kerin L. Tyrrell, and Ellie J. C. Goldstein. "Activity of Ceftaroline against Aerobic Gram-Positive and Gram-Negative Pathogens: Effect of Test Method Variability." ISRN Microbiology 2011 (November 17, 2011): 1–5. http://dx.doi.org/10.5402/2011/787290.
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Ceftaroline is a new cephalosporin with bactericidal activity against methicillin-resistant S. aureus (MRSA) as well as gram-negative pathogens. Variations of in vitro test conditions were found to affect ceftaroline activity, with 5% NaCl inhibiting growth and/or reducing the minimum inhibitory concentrations (MICs) for E. coli, K. pneumoniae, M. catarrhalis, H. influenzae, and streptococci, while an inoculum of 106 CFU/mL raised MICs of some E. coli, K. pneumoniae, and M. catarrhalis strains.
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Brueggemann, Angela B., Gary V. Doern, Holly K. Huynh, Elizabeth M. Wingert, and Paul R. Rhomberg. "In Vitro Activity of ABT-773, a New Ketolide, against Recent Clinical Isolates of Streptococcus pneumoniae, Haemophilus influenzae, andMoraxella catarrhalis." Antimicrobial Agents and Chemotherapy 44, no. 2 (February 1, 2000): 447–49. http://dx.doi.org/10.1128/aac.44.2.447-449.2000.
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ABSTRACT The in vitro activity of ABT-773 was evaluated againstStreptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis isolates. ABT-773 was the most active antimicrobial tested against S. pneumoniae. ABT-773 and azithromycin were equivalent in activity against H. influenzae and M. catarrhalis and more active than either clarithromycin or erythromycin.
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Brook, Itzhak, and Alan E. Gober. "Increased recovery of Moraxella catarrhalis and Haemophilus influenzae in association with group A β-haemolytic streptococci in healthy children and those with pharyngo-tonsillitis." Journal of Medical Microbiology 55, no. 8 (August 1, 2006): 989–92. http://dx.doi.org/10.1099/jmm.0.46325-0.
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The inflamed tonsils harbour numerous types of bacteria, alone or in combination with group A β-haemolytic streptococci (GABHS). The cohabitation of the tonsils by GABHS and certain other bacterial species may contribute to the inflammatory process and the failure of penicillin therapy. This study evaluated the recovery of Moraxella catarrhalis, Haemophilus influenzae, Staphylococcus aureus and Streptococcus pneumoniae in association with GABHS in healthy children and those with acute pharyngo-tonsillitis (APT). Pharyngo-tonsillar cultures were obtained from 548 children with APT and 866 healthy children. GABHS was recovered from 112 (20.4 %) children with APT. Of the 114 H. influenzae isolates, 32 were recovered in association with GABHS (29 % of all patients who had GABHS) and 82 were isolated without GABHS (19 %) (P=0.0267). Of the 69 M. catarrhalis isolates, 25 were recovered in association with GABHS (22 % of all patients who had GABHS) and 44 were isolated without GABHS (10 %) (P=0.0012). In contrast, there was no association between the isolation of GABHS and the recovery of Staph. aureus or Strep. pneumoniae. GABHS was recovered from 104 (12 %) healthy children. Of the 69 M. catarrhalis isolates, 24 were recovered in association with GABHS (23 % of all patients who had GABHS) and 80 were isolated without GABHS (10 %) (P=0.006). There was no association between the isolation of GABHS and the recovery of H. influenzae, Staph. aureus or Strep. pneumoniae. This study demonstrates an association between the recovery of GABHS and H. influenzae and M. catarrhalis from pharyngo-tonsillar cultures of patients with APT and M. catarrhalis from pharyngo-tonsillar cultures of healthy children.
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Attia, Ahmed S., Sanjay Ram, Peter A. Rice, and Eric J. Hansen. "Binding of Vitronectin by the Moraxella catarrhalis UspA2 Protein Interferes with Late Stages of the Complement Cascade." Infection and Immunity 74, no. 3 (March 2006): 1597–611. http://dx.doi.org/10.1128/iai.74.3.1597-1611.2006.
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ABSTRACT Many Moraxella catarrhalis strains are resistant to the bactericidal activity of normal human serum (NHS). The UspA2 protein of the serum-resistant strain O35E has previously been shown to be directly involved in conferring serum resistance on this strain. Testing of 11 additional serum-resistant M. catarrhalis wild-type isolates and their uspA1 and uspA2 mutants showed that the uspA1 mutants of all 11 strains were consistently serum resistant and that the uspA2 mutants of these same 11 strains were always serum sensitive. Analysis of complement deposition on four different serum-resistant M. catarrhalis strains and their serum-sensitive uspA2 mutants showed that, for three of these four strain sets, the wild-type and mutant strains bound similar amounts of early complement components. In contrast, there was a significant reduction in the amount of the polymerized C9 on the wild-type strains relative to that on the uspA2 mutants. These same three wild-type strains bound more vitronectin than did their uspA2 mutants. UspA2 proteins from these three strains, when expressed in Haemophilus influenzae, bound vitronectin and conferred serum resistance on this organism. Furthermore, vitronectin-depleted NHS exhibited bactericidal activity against these same three serum-resistant wild-type strains; addition of purified vitronectin to this serum restored serum resistance. In contrast, binding of the complement regulator C4b-binding protein by the M. catarrhalis strains used in this study was found to be highly variable and did not appear to correlate with the serum-resistant phenotype. These results indicate that binding of vitronectin by UspA2 is involved in the serum resistance of M. catarrhalis; this represents the first example of vitronectin-mediated serum resistance on a microbe.
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Tan, Thuan Tong, Jens Jørgen Christensen, Morten Hanefeld Dziegiel, Arne Forsgren, and Kristian Riesbeck. "Comparison of the Serological Responses to Moraxella catarrhalis Immunoglobulin D-Binding Outer Membrane Protein and the Ubiquitous Surface Proteins A1 and A2." Infection and Immunity 74, no. 11 (September 11, 2006): 6377–86. http://dx.doi.org/10.1128/iai.00702-06.
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ABSTRACT Moraxella catarrhalis immunoglobulin D-binding protein (MID) is a complex antigen with unique immunoglobulin D (IgD)-binding, adhesion, and hemagglutination properties. Previous studies have shown that antibodies raised against MID764-913 in rabbits inhibited M. catarrhalis adhesion to human alveolar epithelial cells, and immunization with MID764-913 resulted in an increased pulmonary clearance in a murine model. Strong immune responses against MID have also consistently been shown in humans. Here, the MID-specified IgG responses were compared to those of ubiquitous surface proteins A1 and A2 (UspA1/A2) using a series of recombinant fragments that spanned all three proteins. Sera were obtained from young children, aged 6 months to 1 year (n = 8) and 2 to 3 years (n = 15), and healthy adults (n = 16). Acute- and convalescent-phase sera from chronic obstructive pulmonary disease (COPD) patients with M. catarrhalis infective exacerbations (n = 23) were also analyzed. Young children, who are at risk of M. catarrhalis infection, had low levels of anti-MID and anti-UspA1/A2 antibodies. Healthy adults and the majority of COPD patients (16/23) had high levels of antibodies directed against, among others, the adhesive domain of MID and the fibronectin- and C3-binding domains of UspA1/A2. Among eight COPD patients in whom a rise in antibody levels could be detected, these functional domains were also the main regions targeted by the antibodies. In addition, human IgG directed against MID was bactericidal and anti-MID antibodies were additive to antibodies targeting UspA1/A2. Hence, the functional domains in these three antigens may have significant potential in a future vaccine against M. catarrhalis.
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Soltan, Mohamed A., Nada Elbassiouny, Helmy Gamal, Eslam B. Elkaeed, Refaat A. Eid, Muhammad Alaa Eldeen, and Ahmed A. Al-Karmalawy. "In Silico Prediction of a Multitope Vaccine against Moraxella catarrhalis: Reverse Vaccinology and Immunoinformatics." Vaccines 9, no. 6 (June 18, 2021): 669. http://dx.doi.org/10.3390/vaccines9060669.
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Moraxella catarrhalis (M. catarrhalis) is a Gram-negative bacterium that can cause serious respiratory tract infections and middle ear infections in children and adults. M. catarrhalis has demonstrated an increasing rate of antibiotic resistance in the last few years, thus development of an effective vaccine is a major health priority. We report here a novel designed multitope vaccine based on the mapped epitopes of the vaccine candidates filtered out of the whole proteome of M. catarrhalis. After analysis of 1615 proteins using a reverse vaccinology approach, only two proteins (outer membrane protein assembly factor BamA and LPS assembly protein LptD) were nominated as potential vaccine candidates. These proteins were found to be essential, outer membrane, virulent and non-human homologs with appropriate molecular weight and high antigenicity score. For each protein, cytotoxic T lymphocyte (CTL), helper T lymphocyte (HTL) and B cell lymphocyte (BCL) epitopes were predicted and confirmed to be highly antigenic and cover conserved regions of the proteins. The mapped epitopes constituted the base of the designed multitope vaccine where suitable linkers were added to conjugate them. Additionally, beta defensin adjuvant and pan-HLA DR-binding epitope (PADRE) peptide were also incorporated into the construct to improve the stimulated immune response. The constructed multitope vaccine was analyzed for its physicochemical, structural and immunological characteristics and it was found to be antigenic, soluble, stable, non-allergenic and have a high affinity to its target receptor. Although the in silico analysis of the current study revealed that the designed multitope vaccine has the ability to trigger a specific immune response against M. catarrhalis, additional translational research is required to confirm the effectiveness of the designed vaccine.
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Abdolrasouli, A., A. Amin, M. Baharsefat, A. Roushan, and Y. Hemmati. "Moraxella catarrhalis associated with acute urethritis imitating gonorrhoea acquired by oral–genital contact." International Journal of STD & AIDS 18, no. 8 (August 1, 2007): 579–80. http://dx.doi.org/10.1258/095646207781439775.
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A case of heterosexual transmission of Moraxella catarrhalis by fellatio, which resulted in acute purulent urethritis mimicking gonorrhoea in the male partner, is described. In male patients with urethritis due to M. catarrhalis, orogenital contact with a sexual partner carrying the organism in his/her oropharynx is the probable route of transmission.
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Otsuka, Taketo, Charmaine Kirkham, Antoinette Johnson, Megan M. Jones, and Timothy F. Murphy. "Substrate Binding Protein SBP2 of a Putative ABC Transporter as a Novel Vaccine Antigen of Moraxella catarrhalis." Infection and Immunity 82, no. 8 (June 9, 2014): 3503–12. http://dx.doi.org/10.1128/iai.01832-14.
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ABSTRACTMoraxella catarrhalisis a common respiratory tract pathogen that causes otitis media in children and infections in adults with chronic obstructive pulmonary disease. Since the introduction of the pneumococcal conjugate vaccines with/without protein D of nontypeableHaemophilus influenzae,M. catarrhalishas become a high-priority pathogen in otitis media. For the development of antibacterial vaccines and therapies, substrate binding proteins of ATP-binding cassette transporters are important targets. In this study, we identified and characterized a substrate binding protein, SBP2, ofM. catarrhalis. Among 30 clinical isolates tested, thesbp2gene sequence was highly conserved. In 2 different analyses (whole-cell enzyme-linked immunosorbent assay and flow cytometry), polyclonal antibodies raised to recombinant SBP2 demonstrated that SBP2 expresses epitopes on the bacterial surface of the wild type but not thesbp2mutant. Mice immunized with recombinant SBP2 showed significantly enhanced clearance ofM. catarrhalisfrom the lung compared to that in the control group at both 25-μg and 50-μg doses (P< 0.001). We conclude that SBP2 is a novel, attractive candidate as a vaccine antigen againstM. catarrhalis.
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NAVNE, J. E., M. L. BØRRESEN, H. C. SLOTVED, M. ANDERSSON, M. MELBYE, K. LADEFOGED, and A. KOCH. "Nasopharyngeal bacterial carriage in young children in Greenland: a population at high risk of respiratory infections." Epidemiology and Infection 144, no. 15 (July 13, 2016): 3226–36. http://dx.doi.org/10.1017/s0950268816001461.
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SUMMARYThe incidence of childhood respiratory infections in Greenland is among the highest globally. We performed a population-based study of 352 Greenlandic children aged 0–6 years aiming to describe rates and risk factors for carriage of four key bacteria associated with respiratory infections, their antimicrobial susceptibility and inter-bacterial associations. Nasopharyngeal swabs were tested for Streptococcus pneumoniae grouped by serotypes included (VT) or not included (NVT) in the 13-valent pneumococcal conjugate vaccine, non-typable Haemophilus influenzae (NTHi), Staphylococcus aureus and Moraxella catarrhalis. S. pneumoniae was detected from age 2 weeks with a peak carriage rate of 60% in 2-year-olds. Young age and having siblings attending a daycare institution were associated with pneumococcal carriage. Overall co-colonization with ⩾2 of the studied bacteria was 52%. NTHi showed a positive association with NVT pneumococci and M. catarrhalis, respectively, M. catarrhalis was positively associated with S. pneumoniae, particular VT pneumococci, whereas S. aureus were negatively associated with NTHi and M. catarrhalis. Nasopharyngeal bacterial carriage was present unusually early in life and with frequent co-colonization. Domestic crowding increased odds of carriage. Due to important bacterial associations we suggest future surveillance of pneumococcal conjugate vaccine's impact on carriage in Greenland to also include other pathogens.