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PubMed2006

Human serum and mucosal antibody responses to outer membrane protein G1b of Moraxella catarrhalis in chronic obstructive pulmonary disease.

Moraxella catarrhalis is an important human pathogen that causes otitis media, sinusitis, and lower respiratory tract infections in adults with chronic obstructive pulmonary disease. Outer membrane protein G1b is a approximately 29-kDa protein that has a high degree of homology among strains, contains surface-exposed epitopes, and is a potential vaccine candidate. The ompG1b gene was cloned, expressed in Escherichia coli, and purified. To assess the expression of outer membrane protein G1b during human infection, paired serum and sputum supernatants from patients with chronic obstructive pulmonary disease followed prospectively were studied by enzyme-linked immunosorbent assays with recombinant outer membrane protein G1b to detect antibodies made specifically during carriage of M. catarrhalis. Overall, 39% of patients developed either a serum IgG (28.6%) or a sputum supernatant IgA (19.2%) response to outer membrane protein G1b following 100 episodes of acquisition and clearance of M. catarrhalis. A sputum supernatant IgA response was more likely following exacerbations compared with asymptomatic colonizations, whereas a serum IgG response occurred at similar rates. Serum IgG antibodies following natural infection were directed toward surface-exposed epitopes of outer membrane protein G1b. Overall, these studies show that outer membrane protein G1b is expressed during infection of the human respiratory tract and that human antibodies bind to outer membrane protein G1b epitopes on the bacterial surface. These observations indicate that outer membrane protein G1b should be evaluated further as a vaccine antigen.

Antibodies, Bacterial↗
PubMed2006

Moraxella catarrhalis stimulates the release of proinflammatory cytokines and prostaglandin E from human respiratory epithelial cells and monocyte-derived macrophages.

The outer membrane proteins of Moraxella catarrhalis, a bacterial pathogen which causes disease in both children and adults, play an important role in its phenotypic properties. However, their proinflammatory potential with regard to respiratory epithelium and macrophages is unclear. To this end, we examined the cytokine- and mediator-inducing capacity of a heat-killed wild-type M. catarrhalis strain and a nonautoagglutinating mutant as well as their outer membrane proteins and secretory/excretory products using the A549 respiratory epithelial cell line. The outer membrane proteins and secretory/excretory products from both isolates as well as the heat-killed bacteria all induced interleukin (IL)-6, IL-8 and prostaglandin E2, but not IL-1beta, from the A549 cell line in a dose- and time-dependent manner. Heat-killed bacteria and secretory/excretory products stimulated the release of IL-1beta, IL-6, IL-8 and prostaglandin E2 from human monocyte-derived macrophages. Both heat-killed isolates also stimulated nuclear translocation and transactivation of nuclear factor-kappaB. The heat-killed wild-type autoagglutinating isolate induced significantly greater amounts of IL-6 and IL-8 from A549 cells than the nonautoagglutinating mutant compared with the monocyte-derived macrophages but no significant differences in the amounts induced by the two strains were observed. These differences were also evident when the respiratory cell line was stimulated with outer membrane proteins as well as in the degree of nuclear factor-kappaB transactivation. There was little difference in the stimulatory activity of the secretory/excretory products. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis analyses revealed some differences in the outer membrane proteins and secretory excretory products between the two isolates. Combined, these data show that M. catarrhalis secretory excretory products and outer membrane proteins are associated with the induction of inflammatory responses in both respiratory epithelium and macrophages.

Bacterial Outer Membrane Proteins↗
PubMed1994

A haemolytic cell-free preparation of Moraxella bovis confers protection against infectious bovine keratoconjunctivitis.

Protection conferred by a cell-free preparation from a haemolytic Moraxella bovis isolate, UQV 148NF, was compared to an equivalent fraction from a non-haemolytic M. bovis isolate, Gordon 26L3, and to a recombinant DNA-derived pili vaccine. Three groups of ten calves were vaccinated twice with one of the three preparations and, together with ten non-vaccinated calves, challenged with virulent M. bovis isolate Dal 2d. Compared to the control group, significant protection was observed in the group receiving the pili vaccine and the group receiving the preparation from haemolytic isolate, UQV 148NF.

Animals↗
PubMed1996

Attachment of Moraxella catarrhalis to pharyngeal epithelial cells is mediated by a glycosphingolipid receptor.

Moraxella catarrhalis is one of the major pathogens of respiratory infections and has the ability to attach to the pharyngeal cells iva fimbriae. We characterized the epithelial cell receptor to which fimbriate M. catarrhalis binds. Neuraminidase pretreatment of pharyngeal epithelial cells resulted in a significant decrease of M. catarrhalis attachment, suggesting interaction with the sialic acid component. The attachment was not decreased in M. catarrhalis pretreated with 2 and 1 mg/ml of fucose, N-acetyl-neuraminic acid, N-acetyl-glucosamine, N-acetyl-galactosamine, acetyl-salicylic acid and colominic acid. However, M. catarrhalis treated with gangliosides M1, M2, D1a, D1b and T1a at a concentration of 2.5 micrograms/ml had significantly decreased the attachment compared to the control. In contrast treatment with gangliosides M3 and asialoganglioside M1 did not decrease the attachment of M. catarrhalis and thereby provided evidence for specificity of the inhibition. Concentration dependent effects of ganglioside M2 on the attachment were also observed. Other fimbriate isolates of M. catarrhalis showed decrease in attachment after treatment with ganglioside M2. However there was no effect on attachment when a nonfimbriate isolate was treated with ganglioside M2. This study indicates that the receptor of fimbriate M. catarrhalis on pharyngeal epithelial cells resides in the sequences of ganglioside M2.

Bacterial Adhesion↗
PubMed1996

Tetrameric repeat units associated with virulence factor phase variation in Haemophilus also occur in Neisseria spp. and Moraxella catarrhalis.

The tetrameric repeat units 5'-CAAT-3' and 5'-GCAA-3' are associated with phase variable expression of lipopolysaccharide biosynthetic genes in Haemophilus influenzae. Four other tetrameric repeat units have also been reported from H. influenzae strain Rd, 5'-CAAC-3', 5'-GACA-3', 5'-AGCT-3', and 5'-TTTA-3', which are also associated with putative virulence factors. Using oligonucleotide probes corresponding to five tandem copies of each of these tetramers, we have screened three strains of Neisseria meningitidis and one each of Neisseria gonorrhoeae, Neisseria lactamica, Haemophilus parainfluenzae, Bordetella pertussis, Bordetella parapertussis, Bordetella bronchiceptica and Moraxella catarrhalis for the presence of these motifs. We have demonstrated the presence of multiple copies of the 5'-GCAA-3' motif in all the Neisseria strains tested, and also the repeated motif 5'-CAAC-3' in M. catarrhalis. We have further demonstrated by Southern blot analysis that the 5'-CAAC-3' repeats detected in M. catarrhalis are probably associated with the same genes as in H. influenzae, but that the 5'-GCAA-3' motifs in N. meningitidis are not. The use of characterised tetrameric DNA sequences as hybridisation probes may prove useful in the identification of novel phase variable virulence determinants in organisms other than H. influenzae.

Base Sequence↗
PubMed2000

Complement-resistant Moraxella catarrhalis forms a genetically distinct lineage within the species.

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.

Bacterial Typing Techniques↗
PubMed2006

Unveiling electrotransformation of Moraxella catarrhalis as a process of natural transformation.

The human respiratory tract pathogen Moraxella catarrhalis is a naturally competent microorganism. However, electrotransformation has long been used to introduce foreign DNA into this organism. This study demonstrated that electrotransformants obtained with linear or circular nonreplicating plasmid DNA originated exclusively from natural transformation processes taking place during the recovery phase after the application of current. Only replicating plasmid DNA could be introduced into M. catarrhalis by electrotransformation, in a type IV pilus-independent manner. Electrotransformation with homologous genomic DNA indicated that restriction of double-stranded DNA was independent of type III restriction-methylation systems. Nontransformability of M. catarrhalis by electrotransformation was observed using double- as well as single-stranded DNA. In addition, the study showed that natural competence is a very constant feature of M. catarrhalis.

DNA↗
PubMed2005

Weekly point prevalence of Streptococcus pneumoniae, Hemophilus influenzae and Moraxella catarrhalis in the upper airways of normal young children: effect of respiratory illness and season.

The aim was to determine the effect of respiratory illness and season on carriage rates in the upper airways of Streptococcus pneumoniae, Hemophilus influenzae and Moraxella catarrhalis in normal children. Sixteen healthy children, 1-10 years old, amenable to weekly sampling were followed longitudinally for at least three seasons of the year. Respiratory symptoms were recorded daily; weekly nasal aspirate/wash samples were cultured on selective agars. Urea concentration in samples was used to define dilution of secretion. 68% of 950 samples were culture positive; 44% of positives had two or all three species. Each species was detected in about one third of samples. Bacteria were detected in 76% of samples during illness vs. 65% during wellness (p=0.004). Seasonal carriage rates varied from 56% in summer and fall to 85% in winter. There was a strong inverse correlation between dilution of secretion and bacterial detection rate in illness and wellness aspirate samples during the four seasons (r=-0.82, p=0.01). Detection of bacteria varied with the amount of secretion in the sample. This variation accounts for the apparent differences in bacterial carriage during illness vs. wellness and during different seasons.

Carrier State↗
PubMed1992

Role of Moraxella (Branhamella) catarrhalis as a respiratory pathogen in children.

During a 12-month surveillance period in 1981-1982, Moraxella catarrhalis was detected in cultures from nasopharyngeal aspirates from 76 (17%) of 449 children hospitalized with middle or lower respiratory tract infection. Seroconversion to M. catarrhalis was positive in 4 (5%) of the 76 patients with M. catarrhalis present in nasopharyngeal aspirates and in 4 (1%) of 373 patients with a negative finding. Although children with respiratory tract infections were often colonized by the organism, this was rarely the infective agent of the middle or lower airways. Four of 8 patients with seroconversion to M. catarrhalis exhibited a concomitant RSV infection. The carriage of this species was more closely associated with parainfluenza virus infections. Serological responses to M. catarrhalis were not associated with acute otitis media, and were also rare in children with pneumonia. It is concluded that bronchopulmonary infections caused by M. catarrhalis are rare in children, and that M. catarrhalis aetiology need not be considered in the selection of antibiotics in cases of community-acquired pneumonia or other infections of the middle or lower respiratory tract affecting primarily healthy children.

Adolescent↗
PubMed1996

Shunt nephritis associated with Moraxella bovis.

Moraxella bovis was repeatedly isolated from cerebrospinal fluid in a girl with two episodes of shunt nephritis. Clinical remission of nephritis was achieved only after shunt replacement. A list of about 20 infectious agents reported to date in patients with shunt nephritis is given. M. bovis is yet another agent previously not reported in patients with shunt nephritis.

Cerebrospinal Fluid Shunts↗
PubMed1978

Density gradient centrifugation in urografin of Moraxella and Kingella cells and appendages.

Purification of fimbriae (pili) by density gradient banding in Urografin medium was attempted. Moraxella nonliquefaciens and Kingella kingae fimbriae were of higher density than their cells of origin, but fimbrial fractions obtained by homogenization and differential centrifugation still banded together with presumed outer membrane fragments and some whole cells in Urografin gradients. The cellular density of genetic variants with different fimbriation/competence levels was also studied. For one strain of M. nonliquefaciens and two strains of K. kingae, cells harvested from agar plates tended to show several bands on isopycnic density gradient centrifugation, with slightly higher general density of fimbriated variants than non-fimbriated. A single density band could be observed with cells from log phase broth cultures of selected strains which showed no distinct difference between fimbriation or competence variants of each strain. Cells of M. nonliquefaciens and M. bovis showed comparable buoyant densities, whereas those of K. kingae had a higher density.

Bacteriological Techniques↗
PubMed1978

Antigenic characterisitcs of Moraxella nonliquefaciens fimbriae in double immunodiffusion.

Rabbit antisera against purified fimbriae (pili) from Moraxella nonliquefaciens detected three fimbrial antigenic components, one or two of which appeared to be present in other fimbriated strains of M. nonliquefaciens and the closely related M. bovis. Maximal precipitation with the antisera required some denaturation of the antigen. Ultrasonication, repeated freeze-thawing, heating, and agents like KBr, NaSCN and urea were effective in liberating the antigen in diffusible forms. The morphology of the fimbriae was altered by heat treatment in 1 M KBr.

Antigens, Bacterial↗
PubMedDate not supplied

The beta-lactamases of Moraxella (Branhamella) catarrhalis isolated from Danish children.

Two distinct beta-lactamases have been isolated from Moraxella catarrhalis: the stronger acting BRO-1 enzyme and the weaker acting BRO-2. Several reports have noted an effect of penicillin and ampicillin on infections caused by M. catarrhalis in spite of the presence of beta-lactamase production. The purpose of this work was to charaterize the beta-lactamases of M. catarrhalis isolated from Danish children regarding type and susceptibility, and to relate these findings to the eradication of beta-lactamases-producing strains by use of antibiotic treatment with penicillin or ampicillin. MICs for penicillin V, ampicillin, cefuroxime and amoxicillin/clavulanic acid (2:1) were determined in 70 strains of M. catarrhalis: 46 strains from children with lower respiratory tract infection (LRTI) and 24 strains from respiratory healthy children, beta-lactamase production was found in 59 strains. The BRO-1 enzyme was identified by isoelectric focusing in 55 strains (93.2%) and BRO-2 in 3 strains (5.1%); in 1 strain no isoelectric bands were produced. All strains were susceptible to cefuroxime and amoxicillin/clavulanic acid, and non-beta-lactamase-producing strains were susceptible to penicillin and ampicillin. For the beta-lactamase-producing strains, MIC50 of penicillin was 8.0 micrograms/ml, while MIC50 of ampicillin was 1.0 microgram/ml and MIC90 of ampicillin was 2.0 micrograms/ml. M. catarrhalis was more often eradicated from the children who received antibiotic treatment with penicillin or ampicillin than from those who did not receive any treatment, indicating an in vivo effect of penicillin and ampicillin in spite of the beta-lactamase production.

Ampicillin↗
PubMed1997

Human immunoglobulin isotype and IgG subclass response to different antigens of Moraxella catarrhalis.

Enzyme immunoassays were tested for the determination of antibodies of different isotypes and IgG subclasses to Moraxella catarrhalis in human sera. An assay based on an outer membrane protein preparation (OMP) as antigen was compared to assays using whole bacterial cells and a purified lipopolysaccharide preparation. There was a good correlation between the results obtained with the OMP preparation and the whole-cell antigen. In paired sera, optimal sensitivity was obtained by using the OMP preparation as coating antigen and testing for a rise in IgG3 antibodies. However, patients with high levels of antibodies in acute serum had no or only an insignificant antibody response during infection.

Adult↗
PubMed1994

Plasmid-mediated degradation of hydroxylated, methoxylated, and carboxylated benzene derivatives in Moraxella sp.

Chemical industries produce wastewater that contains large amount of aromatic substances including chlorinated compounds. Moraxella sp. isolated from a petroleum refinery unit efficiently used a variety of benzene derivatives bearing hydroxyl, methoxyl, carboxyl, and chloro- groups as the sole carbon source. The isolate harbored two plasmids of high mobility that are responsible for the utilization of these substrates.

Benzene Derivatives↗
PubMed1987

Infectious bovine keratoconjunctivitis: seasonal variation in cultural, biochemical and immunoreactive properties of Moraxella bovis isolated from the eyes of cattle.

The eyes of 20 young cattle were examined over an 18 month period in which 12 members of the group contracted infectious bovine keratoconjunctivitis (IBK). On each of 23 occasions cultural, biochemical and immunoreactive properties of up to 6 isolates of Moraxella bovis derived from each eye were determined. Relationships between the clinical response of eyes, phenotypic properties of M. bovis and annual variations in the level of solar ultraviolet radiation of 280 to 320 nm wavelength were examined. M. bovis was isolated from all IBK-affected and some unaffected eyes less than one month after the maximum annual level of the mean weekly UV radiation (2,840 mWh.m-2 X nm-1) was recorded. A high proportion of M. bovis from IBK lesions were simultaneously active in haemolysis, agar corrosion, gelatin liquefaction and litmus milk peptonisation. Some of these characteristics showed marked dissociation despite consistent reactivity in the fluorescent antibody test, which had a sensitivity and specificity of 95%. Fall in the mean weekly level of UV radiation below 1,438 mWh X m-2 X nm-1 in autumn was accompanied by healing of ulcers, persistent scar formation and a decline in the number of M. bovis isolated from affected eyes. A slower decline in the number of M. bovis isolated from apparently healthy eyes occurred in the winter and occasional fresh IBK lesions occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Infectivity and virulence of Australian strains of Moraxella bovis for the murine and bovine eye in relation to pilus serogroup sub-unit size and degree of piliation.

The degree of piliation of 29 haemolytic and 4 non-haemolytic Australian strains of Moraxella bovis representing 7 different pilus antigen groups was determined. The infectivity and virulence for the eye was measured in steroid-treated mice and in cattle. Non-piliated strains failed to infect the murine eye. Most moderately or heavily piliated strains reproducibly produced the highest infectivity and virulence scores in mice when compared with lightly or very lightly piliated strains (p less than 0.05). Non-haemolytic, piliated strains were infective and in one instance virulent for mice. Almost similar levels of infectivity and virulence were observed for 7 representative haemolytic strains tested in both cattle and mice. The relative molecular weight of pilin sub-units was compared using sodium dodecyl-sulphate polyacrylamide gel electrophoresis. Three classes of pili, alpha, beta and gamma of ascending sub-unit size were identified among the 7 pilus antigen serogroups. Pilin sub-unit size bore no relationship to the degree of piliation but most strains that were highly virulent in mice and cattle expressed alpha and gamma sub-units. Some strains appeared capable of switching from alpha to beta or form beta to gamma sub-unit production.

Animals↗