Branhamella catarrhalis: an organism gaining respect as a pathogen.

Catlin, B. Wesley

doi:10.1128/cmr.3.4.293-320.1990

Cited by 46 publications

(61 citation statements)

References 216 publications

(524 reference statements)

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“…Moraxella catarrhalis is the third most common isolate following Streptococcus pneumoniae and nontypeable Haemophilus influenzae as the causative agent of otitis media in infants and young children [1–3]. In developed countries, more than 80% of children under the age of 3 years will be diagnosed at least once with otitis media, and M. catarrhalis is responsible for 15–25% of all of these cases [4,5].…”

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confidence: 99%

Identification of two late acyltransferase genes responsible for lipid A biosynthesis in Moraxella catarrhalis

et al. 2008

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Lipid A is a biological component of the lipooligosaccharide (LOS) of a human pathogen, Moraxella catarrhalis. No other acyltransferases except UDP-GlcNAc acyltransferase responsible for lipid A biosynthesis in M. catarrhalis have been elucidated. By informatics, two late acyltransferase genes lpxX and lpxL responsible for lipid A biosynthesis were identified, and knockout mutants of each gene in M. catarrhalis strain O35E was constructed and named as O35ElpxX and O35ElpxL. Structural analysis of lipid A from the parental strain and derived mutants showed that O35ElpxX lacked two decanoic acids (C10:0) while O35ElpxL lacked one dodecanoic (lauric) acid (C12:0), suggesting that lpxX gene encoded decanoyl transferase and lpxL gene encoded dodecanoyl transferase. Phenotypic analysis revealed that both mutants were similar to the parental strain in their toxicity in vitro. However, the O35ElpxX was sensitive to bactericidal activity of normal human serum and hydrophobic reagents. It had a reduced growth rate in broth and an accelerated bacterial clearance at 3 h (p <0.01) or 6 h (p <0.05) after an aerosol challenge in a murine model of bacterial pulmonary clearance. Meanwhile, the O35ElpxL presented alike patterns as the parental strain except it was slightly sensitive to the hydrophobic reagents. These results indicate that these two genes, particularly lpxX, encoding late acyltransferases responsible for incorporation of the acyloxyacyl linked secondary acyl chains into the lipid A are important for biological activities of M. catarrhalis.

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Identification of two late acyltransferase genes responsible for lipid A biosynthesis in Moraxella catarrhalis

et al. 2008

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“…Moraxella catarrhalis is an uncapsulated gram‐negative diplococcus that causes respiratory tract infections in both children and adults 1–4. The species is a major causative agent of otitis media in children, responsible for up to 25% of the reported cases.…”

Section: Introductionmentioning

confidence: 99%

The IgD C_H1 region contains the binding site for the human respiratory pathogen Moraxella catarrhalis IgD‐binding protein MID

et al. 2006

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The Moraxella catarrhalis IgD‐binding protein (MID) has a unique specificity for human IgD, and the sequence with maximal IgD binding is located within the amino acids MID962–1200. In the present paper, we examined the MID binding site on IgD using a series of recombinant Ig. Full‐length IgD, IgD F(ab’)2, and an IgD F(ab’) C290R mutant lacking the inter‐heavy‐chain cysteine 290 were manufactured. Furthermore, a series of IgD/IgG chimeras were constructed. ELISA, dot blot and flow cytometry were used to study the binding of purified Ig to native MID, recombinant MID962–1200 or to Moraxella with or without MID. MID962–1200 bound both the IgD F(ab’)2 and F(ab’) C290R, indicating that the binding occurred independently of antibody structure. When amino acids 157–224 of the IgD CH1 region were substituted with IgG sequences, binding by M. catarrhalis or recombinant MID962–1200 was abolished. Subsequent smaller substitutions of IgD CH1 157–224 with IgG sequences led us to conclude that IgD CH1 amino acids 198–206 were crucial for the interaction between MID and IgD.

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“…Moraxella catarrhalis is frequently encountered as a commensal coloniser of the human upper respiratory tract [1,2]. It has emerged as a true pathogen that may cause upper respiratory tract infections [1]. Moreover, M. catarrhalis is the third most common cause of acute otitis media in children [3,4].…”

Section: Introductionmentioning

confidence: 99%

Complement-resistantMoraxella catarrhalisforms a genetically distinct lineage within the species

Verduin

Kools-Sijmons

Plas

et al. 2000

FEMS Microbiology Letters

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Moraxella catarrhalis is a bacterial species that has been implicated in 15-20% of all cases of otitis media in the USA and the complement-resistant variant of M. catarrhalis has been considered particularly pathogenic. A collection of geographically diverse, complement-sensitive (n=28) and -resistant strains (n=47) of M. catarrhalis was assembled in order to analyse the bacterial population structure. All strains were identified as M. catarrhalis by conventional microbiological and biochemical methods. Amplification of the small subunit (ssu) ribosomal RNA gene followed by restriction fragment length polymorphism (RFLP) analysis did not reveal consistent differences between serum-susceptible and -resistant M. catarrhalis isolates. Interestingly, upon automated ribotyping using the Qualicon RiboPrinter(R) microbial characterisation system, the complement-sensitive and -resistant strains segregated into two groups. This suggested the existence of two clearly distinguishable lineages within the species M. catarrhalis. This observation was corroborated by pulsed field gel electrophoresis (PFGE) of DNA macro-restriction fragments, a non-ribosomal PCR RFLP procedure and random amplification of polymorphic DNA (RAPD) analysis. All procedures grouped the two variants similarly. Redefinition of the taxonomic status of complement-resistant M. catarrhalis or even the definition of a new species may be opportune.

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Branhamella catarrhalis: an organism gaining respect as a pathogen.

Cited by 46 publications

References 216 publications

Identification of two late acyltransferase genes responsible for lipid A biosynthesis in Moraxella catarrhalis

Identification of two late acyltransferase genes responsible for lipid A biosynthesis in Moraxella catarrhalis

The IgD C_H1 region contains the binding site for the human respiratory pathogen Moraxella catarrhalis IgD‐binding protein MID

Complement-resistantMoraxella catarrhalisforms a genetically distinct lineage within the species

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Branhamella catarrhalis: an organism gaining respect as a pathogen.

Cited by 46 publications

References 216 publications

Identification of two late acyltransferase genes responsible for lipid A biosynthesis in Moraxella catarrhalis

Identification of two late acyltransferase genes responsible for lipid A biosynthesis in Moraxella catarrhalis

The IgD CH1 region contains the binding site for the human respiratory pathogen Moraxella catarrhalis IgD‐binding protein MID

Complement-resistantMoraxella catarrhalisforms a genetically distinct lineage within the species

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The IgD C_H1 region contains the binding site for the human respiratory pathogen Moraxella catarrhalis IgD‐binding protein MID